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Journal articles on the topic 'Heavy metal chemistry'
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1
Wang, Lei, and Qi Chen. "Study on the Stabilization of Heavy Metal by Cement with Quantum Chemistry." Advanced Materials Research 955-959 (June 2014): 2935–39. http://dx.doi.org/10.4028/www.scientific.net/amr.955-959.2935.
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The quantum chemistry is a kind of efficient theoretical research methodology; it has become an important foundation and core technology to the computational materials science. The researches of melting mechanism, doping mechanism, mechanism of hydration activity can be used in the related areas of stabilization of heavy metal by cement. Density functional theory is reviewed in the study of the affective mechanism of cement hydration activity and the intensity of hydration by heavy metal, the mechanism of fixating heavy metals by mineral and the mechanism of lowering melting temperature. It is considered that quantum chemistry can be used to make a simulation at the micro level to explore the mechanism of cement-enclosed heavy metals and has a perfect theoretical guiding significance for further research.
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Percival, H. J., T. W. Speir, and A. Parshotam. "Soil solution chemistry of contrasting soils amended with heavy metals." Soil Research 37, no. 5 (1999): 993. http://dx.doi.org/10.1071/sr98055.
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The soil solution chemistry of heavy metal amended soils is of great importance in assessing the bioavailability of heavy metals and their toxicity to the soil biota. Three contrasting soils were amended with Cd(II), Cu(II), Ni(II), Pb(II), Zn(II), and Cr(III) nitrate salts at rates of 10–100 mmol/kg. This concentration range was chosen to encompass a wide range of effects on sensitive soil biochemical properties as part of a larger project. Soil solutions were extracted and analysed for pH, and for concentrations of heavy metals, and major cations and anions. Heavy metal speciation was calculated with the GEOCHEM-PC model. Heavy metal concentrations in the soil solutions increased both in absolute terms and as a percentage of added heavy metal as amendment rates increased. This observation is due to decreasing specific adsorption (caused by decreasing pH induced by the amendments), and to increasing saturation of cation exchange sites. For all 3 soils, the percentage increase commonly follows the order Cr(III) < Pb < Cu < Ni < Cd < Zn. The percentage of each metal held in the soil solution increased from soil to soil as cation exchange capacity, and therefore sorptivity, decreased. Both the concentration and activity of free heavy metal ions were substantially lower than the corresponding total metal concentration. This was ascribed to ion-pairing of metal ions with anions, particularly nitrate introduced in the amending solutions, as well as to increases in ionic strength as a result of amendment. Metal-anion species were mainly inorganic but where Cu and Pb were relatively low in concentration because of strong adsorption by the soils, organic complexation was likely to be significant. Speciation trends were similar for the 3 soils but different in magnitude.
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Maranescu, Bianca, Lavinia Lupa, and Aurelia Visa. "Heavy metal removal from waste waters by phosphonate metal organic frameworks." Pure and Applied Chemistry 90, no. 1 (January 26, 2018): 35–47. http://dx.doi.org/10.1515/pac-2017-0307.
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AbstractThe increase attention in the area of phosphonate metal organic framework is exemplified with a variety of applications and a rich chemistry of these compounds. Water pollution caused by heavy metal ions is a major concern due to their toxicity to many life forms. In order to decrease the heavy metals impact upon the environment various technologies of water treatment such as: chemical sedimentation, ion exchange, redox process are studied. The tendency is to find a versatile and economical method of heavy metals removal from waste waters. Phosphonate metal organic frameworks were obtained by the reaction of Ni(CH3COO)2·4H2O, phosphonic acid (phosphonoacetic (CP), vinyl phosphonic acid (VP) and N,N-bis(phosphonomethyl)glycine (Gly)) in hydrothermal conditions. Coordination polymers synthesized were characterized by FTIR, XRD, scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). The adsorption processes represent a very good alternative for heavy metals removal due to low costs and ease of operation. In the present paper the adsorption performance of the mentioned materials in the removal process of heavy metals from aqueous solutions, was studied using the batch method. The adsorption conditions were investigated by varying the initial pH, contact time and adsorbate initial concentration for chromium metal ions removal from aqueous solutions. It was found that the adsorption efficiency of the studied materials in the removal process of Cr(VI) ions from aqueous solutions is in the following order: Ni-CP<Ni-Gly≤Ni-VP.
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Sita, Lawrence R. "Heavy-Metal Organic Chemistry: Building with Tin." Accounts of Chemical Research 27, no. 7 (July 1994): 191–97. http://dx.doi.org/10.1021/ar00043a002.
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Rumhayati, Barlah, and Catur Retnaningdyah. "Integrative Assessment of Pb and Cd Pollution in Porong Estuaries Using Sediment Chemistry, Bioavailability, and Bioconcentration Factor." Indonesian Journal of Chemistry 18, no. 3 (August 30, 2018): 464. http://dx.doi.org/10.22146/ijc.26603.
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The aims of the research were to perform an integrative assessment of high metal pollution in Porong Estuary by determining (i) the distribution of heavy metals fraction in sediment, (ii) the potential risk of sediment to the metal bioavailability, and (iii) the bioaccumulation factor of heavy metals in benthic. Fractionation of heavy metals in the sediments was carried out by the European Community Bureau of Reference (BCR) sequential extraction method. The potential risk of sediment was determined from RAC (risk assessment code) value. Bioconcentration factor was determined based on the ratio of the concentration of heavy metals in benthic to the concentration of bioavailable metals from sediments. Heavy metal concentrations were measured using AAS. The results showed that non-resistant Pb and Cd was higher than resistant fractions. As a non-resistant fraction, Pb was found mostly as fraction 2, i.e., metal fraction adsorbed on the surface of the iron oxy/hydroxide sediment (34.5 ± 4.9%). Cd was more prevalent as fraction 3, i.e., an organic bound fraction (29.0 ± 1.8%). Furthermore, Porong Estuary sediments had medium risk for contributing the bioavailable Cd in the water bodies based on the RAC (15.6 ± 1.8%). Based on the bioconcentration factor, accumulation of Cd and Pb was low (48.00 ± 7.62% for BCF-Cd and 32.29 ± 6.90% for BCF-Pb). Based on the results above, it could be concluded that the Porong Estuary water bodies have not been polluted by Pb and Cd released from the aquatic sediment.
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Yona, Defri, Mochamad Arif Zainul Fuad, and Nurin Hidayati. "Spatial Distribution of Heavy Metals in the Surface Sediments of the Southern Coast of Pacitan, Indonesia." Indonesian Journal of Chemistry 18, no. 1 (February 28, 2018): 137. http://dx.doi.org/10.22146/ijc.22400.
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This study was conducted to analyze the spatial distribution of heavy metals from four different coastal areas in southern Pacitan, Indonesia: Pantai Watu Karung (WK), Pantai Teleng Ria (TL), Pantai Pancer (TP) dan Pantai Soge (SG). Data collected in this study included: temperature, salinity, DO, pH, sediment, organic matter and heavy metals in the sediments (Pb, Hg and Cd). The results showed different distribution patterns of heavy metals. Heavy metal concentrations, especially Pb and Hg, were found to be higher in Pantai Soge, while the concentration of Cd was higher in Pantai Pancer. An ANOVA test showed the distributions of Pb and Cd were significantly different (p < 0.01) between sampling sites. Variability of the physicochemical parameters influenced the variabilities of heavy metal concentrations among sampling sites. Overall, heavy metal concentrations in the study areas are rather low; however, attention is still needed due to heavy activities in the coastal areas of southern Pacitan that can contribute to heavy metal pollution.
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Percival, H. J. "Soil and soil solution chemistry of a New Zealand pasture soil amended with heavy metal-containing sewage sludge." Soil Research 41, no. 1 (2003): 1. http://dx.doi.org/10.1071/sr01061.
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The disposal of wastewater treatment sewage sludge onto agricultural land in New Zealand has led to the development of guidelines for the upper limit concentrations for total heavy metals in the underlying soil. However, those soil biological and biochemical processes now known to be most sensitive to environmental change are being used internationally to set new soil limits. The soil solution chemistry of a pasture soil amended with heavy metals has been used to assess the bioavailability of several important heavy metals. Field trial plots were treated with both spiked (Cu, Ni, or Zn) and unspiked sewage sludge to raise total soil metal concentrations, both above and below the current New Zealand guideline values. Soils were sampled pre-amendment in 1997 and post-amendment in 1998, 1999, and 2000. Soil solutions were extracted by centrifugation and analysed for pH, for concentrations of heavy metals, major cations and anions, and dissolved organic carbon. Heavy metal speciation was calculated with the GEOCHEM-PC model.Soil solution concentrations of Cu, Ni, and Zn increased with increasing levels of metal in the spiked sludge, reflecting increases in total soil metal concentrations. Cu concentrations changed little with time, but those of Ni and Zn tended to decrease. Cu was much more adsorbed by the soil than was Ni or Zn. The free metal ions, Cu2+, Ni2+, and Zn2+ (representing the most 'bioavailable' fraction), were the dominant metal species in the soil solutions. Variations in free metal ion percentages with metal-spiking level depended on the balance between organic and sulfate complexation for Cu, but on sulfate complexation alone for Ni and Zn. Cu and Ni free metal-ion activities in soil solution were relatively low even at the highest metal loadings in the soil, but may be high enough to cause toxicity problems. Zn activities were very much higher, and at the regulatory limit for zinc likely to affect sensitive biological and biochemical properties of the soil.
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Le Roch, Adrien, and Alexandre Gagnon. "Heavy metal orchestration." Nature Chemistry 12, no. 3 (February 27, 2020): 223–24. http://dx.doi.org/10.1038/s41557-020-0434-3.
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Kordialik-Bogacka, Edyta. "Surface properties of yeast cells during heavy metal biosorption." Open Chemistry 9, no. 2 (April 1, 2011): 348–51. http://dx.doi.org/10.2478/s11532-011-0008-8.
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AbstractProperties of metal solution, environmental conditions and the type of biomaterials (microorganism genus, species or even strain) influence the mechanism of metal biosorption and consequently metal adsorption capacity, affinity and specificity. Cell surface properties determine the metal-microorganism interactions to a large extent. In this work the relationship between yeast surface properties and yeast’s ability to bind cadmium, lead and copper was studied. Surface charge and hydrophobicity before and after biosorption were determined using dye retention and solvent partition assays, respectively. There were differences in the surface charge and relative hydrophobicity among different yeast strains. A higher metal adsorption capacity for more negatively charged yeast cells was observed. Biosorption of heavy metals resulted in modifications to the surface charge and hydrophobicity of yeast cells. However, there were not statistically significant changes in the yeast surface charge and hydrophobicity after binding of heavy metals depending on the nature of the metal, initial metal concentration and solution pH.
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Rusanescu, Marin, Carmen Otilia Rusanescu, Gheorghe Voicu, and Mihaela Begea. "Applications of Bentonite to Soil Decontamination." Revista de Chimie 69, no. 7 (August 15, 2018): 1695–98. http://dx.doi.org/10.37358/rc.18.7.6397.
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A calcium bentonite from Orasu Nou deposit (Satu Mare Romania) was used as raw material. We have conducted laboratory experiments to determine the influence of bentonite on the degree of heavy metal retention. It has been observed that the rate of retention increases as the heavy metal concentration decreases. Experimental studies have been carried out on metal retention ( Zn) in bentonite. In this paper, we realized laboratory experiments for determining the influence of metal (Zn) on the growth and development of two types of plants (Pelargonium domesticum and Kalanchoe) and the effect of bentonite on the absorption of pollutants. These flowers were planted in unpolluted soil, in heavy metal polluted soil and in heavy metal polluted soil to which bentonite was added to observe the positive effect of bentonite. It has been noticed that the flowers planted in unpolluted soil and polluted with heavy metals to which bentonite has been added, the flowers have flourished, the leaves are still green and the plants whose soils have been polluted with heavy metals began to dry after 6 days, three weeks have yellowish leaves and flowers have dried. Experiments have demonstrated the essential role of bentonite for the removal of heavy metals polluted soil.
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Stefan, Mircea, Adriana Bors, Daniela Simina Stefan, Ionut Alexandru Savu Radu, and Cicerone Marinescu. "Sorption of Heavy Metal on Natural Clay." Revista de Chimie 68, no. 12 (January 15, 2018): 2804–7. http://dx.doi.org/10.37358/rc.17.12.5982.
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Sorption of heavy metals on Na-montmorillonite was studied as a function of solution pH and different concentrations of background electrolyte and also a function of added metal ion at constant pH. Equilibrium isotherms have been measured and analyzed using a Langmuir isotherm model. The metal ions were predominantly adsorbed on the permanent charge sites in a easily replaceable state. There was also evident a substantial involvement of the hydroxyl groups on the edges of Na-montmorillonite in specific adsorption of the cations especially at higher pH.
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Müller, Jens, Roland K. O. Sigel, and Bernhard Lippert. "Heavy metal mutagenicity: insights from bioinorganic model chemistry." Journal of Inorganic Biochemistry 79, no. 1-4 (April 2000): 261–65. http://dx.doi.org/10.1016/s0162-0134(99)00179-8.
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Noegrohati, Sri. "BIOACCUMULATION DYNAMICS OF HEAVY METALS IN Oreochromis nilotycus: PREDICTED THROUGH A BIOACCUMULATION MODEL CONSTRUCTED BASED ON BIOTIC LIGAND MODEL (BLM)." Indonesian Journal of Chemistry 6, no. 1 (June 13, 2010): 61–69. http://dx.doi.org/10.22146/ijc.21775.
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In estuarine ecosystem, sediments are not only functioning as heavy metal scavenger, but also as one of potential sources for heavy metals to the ecosystem. Due the capability of aquatic organisms to accumulate heavy metals, there is possibility of heavy metals to exert their toxic effect towards the organisms and other organisms positioned in higher trophic level, such as fish, and further to human beings. To understand the different processes of heavy metal bioaccumulation in a dynamic manner, a bioaccumulation model is required. Since bioaccumulation starts with the uptake of chemical across a biological membrane, the bioaccumulation model was constructed based on Biotic Ligand Model (BLM). The input for the model was determined from laboratory scale simulated estuarine ecosystem of sediment-brackish water (seawater:Aquaâ 1:1) for determining the heavy metal fractions in sediments; simulated Oreochromis nilotycus - brackish water (fish-water) ecosystem for determining the rate constants; simulated fish-water-sediment ecosystem for evaluating the closeness between model-predicted and measured concentration, routes and distribution within specific internal organs. From these bioaccumulation studies, it was confirmed that the internalization of metals into the cells of gills and internal epithelias follows similar mechanisms, and governed mostly by the waterborne or hydrophilic heavy metals. The level of hydrophilic heavy metals are determined by desorption equilibrium coefficients, 1/KD, and influenced by salinity. Physiologically, the essential Cu and Zn body burden in O. nilotycus are tightly homeostasis regulated, shown as decreasing uptake efficiency factor, EW, at higher exposure concentrations, while non essential Cd and Hg were less or not regulated. From the distribution within specific internal organs, it was revealed that carcass was more relevant in describing the bioaccumulation condition than liver. It is clear that every heavy metal has its own bioaccumulation dynamics, depend to the metal studied and environmental conditions, however the obtained parameters are applicable to bioaccumulation of Cd and Hg in natural estuarine ecosystem of Segara Anakan, Central Java. Keywords: heavy metal, estuarine, bioaccumulation, model, dynamics
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Wuana, Raymond A., and Felix E. Okieimen. "Heavy Metals in Contaminated Soils: A Review of Sources, Chemistry, Risks and Best Available Strategies for Remediation." ISRN Ecology 2011 (October 24, 2011): 1–20. http://dx.doi.org/10.5402/2011/402647.
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Scattered literature is harnessed to critically review the possible sources, chemistry, potential biohazards and best available remedial strategies for a number of heavy metals (lead, chromium, arsenic, zinc, cadmium, copper, mercury and nickel) commonly found in contaminated soils. The principles, advantages and disadvantages of immobilization, soil washing and phytoremediation techniques which are frequently listed among the best demonstrated available technologies for cleaning up heavy metal contaminated sites are presented. Remediation of heavy metal contaminated soils is necessary to reduce the associated risks, make the land resource available for agricultural production, enhance food security and scale down land tenure problems arising from changes in the land use pattern.
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Lace, Annija, and John Cleary. "A Review of Microfluidic Detection Strategies for Heavy Metals in Water." Chemosensors 9, no. 4 (March 24, 2021): 60. http://dx.doi.org/10.3390/chemosensors9040060.
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Heavy metal pollution of water has become a global issue and is especially problematic in some developing countries. Heavy metals are toxic to living organisms, even at very low concentrations. Therefore, effective and reliable heavy metal detection in environmental water is very important. Current laboratory-based methods used for analysis of heavy metals in water require sophisticated instrumentation and highly trained technicians, making them unsuitable for routine heavy metal monitoring in the environment. Consequently, there is a growing demand for autonomous detection systems that could perform in situ or point-of-use measurements. Microfluidic detection systems, which are defined by their small size, have many characteristics that make them suitable for environmental analysis. Some of these advantages include portability, high sample throughput, reduced reagent consumption and waste generation, and reduced production cost. This review focusses on developments in the application of microfluidic detection systems to heavy metal detection in water. Microfluidic detection strategies based on optical techniques, electrochemical techniques, and quartz crystal microbalance are discussed.
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Volaric, Ana, Zorica Svircev, Dragana Tamindzija, and Dragan Radnovic. "Microbial bioremediation of heavy metals." Chemical Industry 75, no. 2 (2021): 103–15. http://dx.doi.org/10.2298/hemind200915010v.
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Heavy metal pollution is one of the most serious environmental problems, due to metal ions persistence, bioavailability, and toxicity. There are many conventional physical and chemical techniques traditionally used for environmental clean-up. Due to several drawbacks regarding these methods, the use of living organisms, or bioremediation, is becoming more prevalent. Biotechnological application of microorganisms is already successfully implemented and is in constant development, with many microbial strains successfully removing heavy metals. This paper provides an overview of the main heavy metal characteristics and describes the interactions with microorganisms. Key heavy metal resistance mechanisms in microorganisms are described, as well as the main principles and types of heavy metal bioremediation methods, with details on successful pilot scale bioreactor studies. Special attention should be given to indigenous bacteria isolated from the polluted environments since such species are already adapted to contamination and possess resistance mechanisms. Utilization of bacterial biofilms or consortia could be advantageous due to higher resistance and a combination of several metabolic pathways, and thus, the possibility to remove several heavy metals simultaneously. Novel technologies covered in this review, such as nanotechnology, genetic engineering, and metagenomics, are being introduced to the field of bioremediation in order to improve the process. To conclude, bioremediation is a potentially powerful solution for cleaning the environment.
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Hu, Ri Cha, and Li Bo Sun. "Migration Patterns of Heavy Metals in Soil in Wastewater Irrigation Area in the Suburb of Eastern Inner Mongolia." Advanced Materials Research 343-344 (September 2011): 340–43. http://dx.doi.org/10.4028/www.scientific.net/amr.343-344.340.
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Based on the soil test of heavy metals in wastewater irrigation area in eastern Inner Mongolia, this paper analyses the content of heavy metals Cr, Cu, Cd, Pb in different layers of soil samples and reveals the internal relations between heavy metal concentration gradient in the vertical direction and soil properties, thus providing a scientific basis to guide sewage irrigation, solve the problem of water shortage in wastewater irrigation area and carry out environmental impact assessment. Soil is an important subsystem in natural environmental systems, through which many pollutants, especially heavy metals, produced by human activities, enter the food chain and ultimately do harm to human health. Currently, heavy metal ion contamination to the soil caused by wastewater irrigation has become one of the focuses in the study of soil chemistry and agricultural environment pollution. For this reason, it is particularly important to study the migration mechanism of heavy metals in soil and to provide a reliable theoretical basis for the prevention and management of soil contaminants.
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Neuhausen, Jörg. "Radionuclide Chemistry in Nuclear Facilities Based on Heavy Liquid Metal Coolants: Past, Present and Future." CHIMIA International Journal for Chemistry 74, no. 12 (December 23, 2020): 976–83. http://dx.doi.org/10.2533/chimia.2020.976.
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Heavy liquid metals such as lead and lead bismuth eutectic (LBE) are considered as spallation target material for next-generation neutron sources and as coolant of fast spectrum nuclear reactors that are developed to facilitate more efficient use of nuclear fuel as well as transmutation of long-lived nuclear waste. During the operation of such facilities, the heavy liquid metal will be activated by nuclear reactions. Additionally, fission product radionuclides may be introduced into the liquid metal from leaking fuel pins or by fission of the target nuclei in spallation. The chemical behaviour of these radioactive contaminants in the liquid metal – especially their immediate volatilization or volatilization of formed secondary compounds – may affect the safety of such facilities. The present article summarizes the activities of PSI's Laboratory of Radiochemistry towards a better understanding of the chemistry of potentially hazardous radionuclides in LBE and discusses aspects that need to be addressed in future to support the licensing of heavy liquid metal-based nuclear facilities.
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Mosbah, Rachid, and Mohamed Sahmoune. "Biosorption of heavy metals by Streptomyces species — an overview." Open Chemistry 11, no. 9 (September 1, 2013): 1412–22. http://dx.doi.org/10.2478/s11532-013-0268-6.
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AbstractAbstract Heavy metals, derived from industrial wastewater discharge, present a serious threat to human health and to natural water. Biosorption is regarded as a cost-effective biotechnology for the treatment of high volume and low concentration wastewaters containing heavy metal(s) in the order of 1 to 100 mg L−1. Among the biomaterials for heavy metal removal which have been researched during the past decades is the Streptomyces species, a by-product of an industrial antibiotic fermentation process. This paper describes the hazards posed by heavy metals effluents on the environment and use of various Streptomyces species to remove heavy metals from aqueous solution. Characterization of Streptomyces species, factors affecting biosorption, biosorption isotherms and biosorption kinetics is discussed. Graphical abstract
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Dabaibeh, Reem Naser. "Spatial Distribution of Heavy Metals in Al-Zarqa, Jordan." Indonesian Journal of Chemistry 21, no. 2 (March 18, 2021): 478. http://dx.doi.org/10.22146/ijc.58304.
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Al-Zarqa is experiencing challenges in industry conversion and extensive urbanization. The environmental quality of soil in the Al-Zarqa region was analyzed by Spatial analysis for the identification of sources and estimation of the concentration of heavy metals, which helped in the assessment of soil quality and heavy metal pollution. The reason for the elevation of heavy metal pollution is increased urbanization, industrialization, traffic, oil refinery emissions, and mixed anthropogenic sources in that region. The main objective of this research was to assess the ecological impact of heavy metals pollutants in the Al-Zarqa region. The concentrations of (Cd, Cr, Cu, Mn, Ni, Pb, Zn, and Fe) were estimated and compared with the existing literature. The distribution pattern of each metal was identified by spatial distribution analysis. Results revealed that metals concentration (Cd, Cr, and Ni) is higher, and the concentration of Pb, Zn, and Cu is less than the maximum allowed limits. Factor analysis identified the potential sources of heavy metals in the investigated area, and spatial distribution showed the geographical distribution of heavy metals over the study area. Consequently, it is better than showing only the individual point concentration without identifying their potential sources and their geographical variations.
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Radu, Violeta Monica, Petra Ionescu, Elena Diacu, and Alexandru Anton Ivanov. "Removal of Heavy Metals from Aquatic Environments Using Water Hyacinth and Water Lettuce." Revista de Chimie 68, no. 12 (January 15, 2018): 2765–67. http://dx.doi.org/10.37358/rc.17.12.5973.
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The quality of the aquatic environment was strongly influenced by the development of urbanization, industrialization and population growth, and therefore water pollution, mainly due to the presence of heavy metal, becoming a widespread concern. The objective of this work was to evaluate the possibility to remove heavy metals Cd, Zn, Cr and Ni from wastewater using two aquatic plants, water hyacinth (Eichornia crassipes) and water lettuce (Pistia stratiottes). These plants possess excellent abilities to metabolize and bioaccumulate heavy metals from various polluted aquatic environments. For a period of 30 days, the content of heavy metals from wastewater and aquatic plants samples was monitored weakly and the efficacy of these plants to remove heavy metals was quantified. Heavy metals were determined by atomic absorption spectrophotometry with graphite furnace (GFAAS). The obtained results have shown the efficacy of Eichornia crassipes and Pistia stratiottes to remove metals from the studied wastewater. The bioaccumulation rate of heavy metals in plants was effective until day 24 of the period of 30 days of the experiment, as the plants become inefficient beyond this period. The uptake of heavy metals in the studied aquatic plants depends on the concentration of each heavy metal present in the used wastewater and the exposure time.
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Hubo, R., G. Garrigues, F. Schröter, and J. Flahaut. "Heavy plates for bridge construction." Revue de Métallurgie 98, no. 6 (June 2001): 613–21. http://dx.doi.org/10.1051/metal:2001110.
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Dumbaugh, William H., and Josef C. Lapp. "Heavy-Metal Oxide Glasses." Journal of the American Ceramic Society 75, no. 9 (September 1992): 2315–26. http://dx.doi.org/10.1111/j.1151-2916.1992.tb05581.x.
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Duffus, John H. ""Heavy metals" a meaningless term? (IUPAC Technical Report)." Pure and Applied Chemistry 74, no. 5 (January 1, 2002): 793–807. http://dx.doi.org/10.1351/pac200274050793.
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Over the past two decades, the term "heavy metals" has been widely used. It is often used as a group name for metals and semimetals (metalloids) that have been associated with contamination and potential toxicity or ecotoxicity. At the same time, legal regulations often specify a list of "heavy metals" to which they apply. Such lists differ from one set of regulations to another and the term is sometimes used without even specifying which "heavy metals" are covered. However, there is no authoritative definition to be found in the relevant literature. There is a tendency, unsupported by the facts, to assume that all so-called "heavy metals" and their compounds have highly toxic or ecotoxic properties. This has no basis in chemical or toxicological data. Thus, the term "heavy metals" is both meaningless and misleading. Even the term "metal" is commonly misused in both toxicological literature and in legislation to mean the pure metal and all the chemical species in which it may exist. This usage implies that the pure metal and all its compounds have the same physicochemical, biological, and toxicological properties, which is untrue. In order to avoid the use of the term "heavy metal", a new classification based on the periodic table is needed. Such a classification should reflect our understanding of the chemical basis of toxicity and allow toxic effects to be predicted.
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Selvaraj, Suresh, S. Ravichandran, S. R. Boselin Prabhu, G. K. Prashanth, and H. M. Sathyananda. "Novel Foam Adsorbents in Dyes and Heavy Metals Removal: A Review." Asian Journal of Chemistry 33, no. 3 (2021): 499–508. http://dx.doi.org/10.14233/ajchem.2021.22987.
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The present review comprises various novel foam adsorbents with unique adsorption performance in process of removal of dyes and heavy metals. Water pollution because of toxic dyes and heavy metals and its ill-effect on the ecosystem is of great concern to researchers, as it affects the living creatures on the planet. Novel foam adsorbents from carbon foam, chitosan foam, metal foam and polymer foam were developed as efficient materials with good chelating ability to adsorb dyes and heavy metal ions. Novel carbon foam adsorbents were reported to have superior adsorption capacity in removal of dyes and heavy metals. This review aims to look at various novel foam adsorbents used in adsorption studies and their potential in dyes and heavy metals removal. This work provides a worthy challenge and the future possibility for designing novel foam materials for various applications.
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Andrejic, Gordana, Tamara Rakic, Jasmina Sinzar-Sekulic, Nevena Mihailovic, Jasmina Grubin, Branka Stevanovic, and Gordana Tomovic. "Assessment of heavy metal pollution of topsoils and plants in the City of Belgrade." Journal of the Serbian Chemical Society 81, no. 4 (2016): 447–58. http://dx.doi.org/10.2298/jsc150829096a.
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In order to assess heavy metal pollution in the city of Belgrade (Serbia) concentrations of V, Cr, Mn, Co, Ni, Cu, Zn, Cd and Pb were measured on 18 topsoil samples collected in the proximity to central urban boulevards and in urban parks. In addition, concentrations of specified elements were determined in leaves of three evergreen plant species Buxus sempervirens L., Mahonia aquifolium (Pursh) Nutt. and Prunus laurocerasus L. so as to estimate their sensitivity to heavy metal pollution. Even though various types of soils from different quarts of Belgrade were sampled, their heavy metal contents were very similar, with somewhat higher concentrations of almost all elements detected in the proximity to high traffic roads. Generally, concentrations of heavy metals in leaves of investigated plant species paralleled the heavy metal concentrations found in their respective soils and were higher in plants sampled from boulevards then from urban parks. Since investigated plant show no visible injuries induced by detected heavy metal pollution these species are suitable for the successful urban landscaping.
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DeLaHunt, John. "Light metal, heavy hand." Journal of Chemical Health and Safety 15, no. 4 (July 2008): 51. http://dx.doi.org/10.1016/j.jchas.2008.05.007.
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SITA, L. R. "ChemInform Abstract: Heavy-Metal Organic Chemistry: Building with Tin." ChemInform 25, no. 49 (August 18, 2010): no. http://dx.doi.org/10.1002/chin.199449297.
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Sun, Xia, Bao-Shi Li, Xuan-Li Liu, and Cheng-Xuan Li. "Spatial Variations and Potential Risks of Heavy Metals in Seawater, Sediments, and Living Organisms in Jiuzhen Bay, China." Journal of Chemistry 2020 (February 3, 2020): 1–13. http://dx.doi.org/10.1155/2020/7971294.
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Coastal waters are polluted by heavy metals to varying degrees, posing potential risks to marine ecology and human health. In May 2006, the pollution levels, sources, and ecological risks of heavy metals (Cu, Pb, Zn, Cd, Hg, and As) in seawater, surface sediments, and living organisms were studied in Jiuzhen Bay in Fujian, China. This study identified Hg (0.26–0.72 µg/L) and As (20.3–31.5 µg/L) pollution in the seawater of Jiuzhen Bay. In sediments, heavy Pb pollution (946 µg/g dw) was only detected at one station at a level posing very serious potential risk, while Hg pollution (0.052–0.087 µg/g dw) was observed at three stations at a level posing serious potential risk. No heavy metal pollution was detected in sediments at other stations. The concentrations of five heavy metals (Cu, Zn, As, Cd, and Pb) exceeded the corresponding National Quality Standards for oysters, indicating heavy pollution, based on an ecological risk assessment. In clams, two heavy metals (Pb and As) exceeded the standards, indicating light pollution, based on an ecological risk assessment. No heavy metal pollution was found in fish or shrimps. The heavy metals in the seawater and sediments of Jiuzhen Bay are mainly derived from the river discharges of Luxi and Wujiang Rivers although sewage discharge along the coast of Jiuzhen Bay is another source of heavy metal pollution at some stations. Given the pollution of Pb, Hg, and As in seawater and sediments at some stations within the bay, the potential risks of Pb, Hg, and As in living organisms to both the marine ecology and human health deserve increased attention.
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Uçurum, Metin, Akın Özdemir, Çağatay Teke, Hüseyin Serencam, and Mümtaz İpek. "Optimization of Adsorption Parameters for Ultra-Fine Calcite Using a Box-Behnken Experimental Design." Open Chemistry 16, no. 1 (October 22, 2018): 992–1000. http://dx.doi.org/10.1515/chem-2018-0114.
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AbstractRemoval of heavy metals from wastewater is a significant issue because it prevents environmental-based concerns and impacts a large number of diseases and disorders. Many low-cost natural materials have been offered recently as possible precursors to commercial synthetic adsorbents. Ultra-fine calcite, one of these natural materials, has been investigated as a potential commercial adsorbent. Response surface designs are effective experimental techniques to investigate the heavy metal adsorption capacity of ultra-fine calcite. In the present study, one such response surface design, Box-Behnken, is used in order to optimize adsorption factors, such as pH level, initial metal concentration, stirring rate and adsorption time, and to determine the heavy metal capacity of this adsorbent. Our results show that the proposed methodology is an effective approach to optimizing the adsorption process and to maximize the heavy metal capacity.
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Manea, Alexandrina, Nicoleta Vrinceanu, Carmen-Alina Eftene, and Daniela Raducu. "The Heavy Metal Status of Some Agricultural Soils." Revista de Chimie 71, no. 12 (January 7, 2021): 10–17. http://dx.doi.org/10.37358/rc.20.12.8382.
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In order to evaluate the loadings of some agricultural soils with heavy metals, field studies were made across the Iasi County. The heavy metals concentration range were as follows: 15.4 - 36 mg/kg (Cu), 49 - 115 mg/kg (Zn), 7.4 - 20.4 mg/kg (Pb), 0.13 - 0.43 mg/kg (Cd), 6.9 - 13.15 mg/kg (Co), 25 - 100 mg/kg (Ni) and 463 - 798 mg/kg (Mn), respectively. The median of the heavy metals decreased in the next order: Mn (589) ] Zn (67) ] Ni (46) ]Cu (22,1)]Pb (12.1)]Co (10.2)]Cd (0.32). The studied heavy metal median was higher than the same metal median from European soils. According to the Romanian legislation, the normal values are exceeding in 13% the samples for Zn, 73% for Cu, 93% for Ni, and in one case, the value of Ni exceeded the alert threshold (75 mg/kg). A direct relationship between Cu, Pb, Zn and Co was noticed, which may indicate a common source of these metals. The Pearson`s coefficients of these elements were: Pb-Cu (0.863), Cu-Zn (0.826), Pb-Zn (0.74), Cu-Co (0.730), Pb-Co (0.703). According to the values of Pearson correlation coefficient, the significant positive correlations were identified between Cu, Zn, Pb, Co and clay content, while the same metals are highly negative correlated with CaCO3 and fine sand contents. In case of Pb, Co, and Mn no influence of agricultural activities can be detected, wich suggestes that geogenic factors control the contents of these heavy metals. The Cu content exhibited a positive correlation with total Nitrogen, while the Cd content showed a positive significant relationship only with Km content. On the other hand, the Ni content exhibited correlation with both Pm and Km concentrations. The correlations of Cu-Nt, Cd-Km, Ni-Pm, and Ni-Km could be an index of the anthropogenic input of Cd, Cu, and Ni from the use of fertilizers.
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Gabrielyan, A. V., G. A. Shahnazaryan, and S. H. Minasyan. "Distribution and Identification of Sources of Heavy Metals in the Voghji River Basin Impacted by Mining Activities (Armenia)." Journal of Chemistry 2018 (2018): 1–9. http://dx.doi.org/10.1155/2018/7172426.
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The objective of this research is to assess the distribution of heavy metals in the waters and sediments of the Voghji River and its tributaries impacted by mining activity and to reveal the real source of each of the heavy metals in the environment for assessing the pollution level of heavy metals. Voghji River with two main tributaries (Geghi and Norashenik) drain two mining regions. To identify distribution and pollution sources of heavy metals, the water and sediment samples were collected from eight sampling sites. The results of statistical analysis based on data sets of the period 2014–2016 showed that, after the influence of drainage water and wastewater of mining regions, heavy metal contents in the Voghji River basin dramatically increased. The waters of the Voghji River were highly polluted by Mn, Co, Cu, Zn, Mo, Cd, and Pb. The relation of metals content was highly changed due to anthropogenic impact disturbing the geochemical balance of the Voghji River. The water quality based on only heavy metal contents in the source of the Voghji River belongs to “good” chemical status, and in the sources of Geghi and Norashenik Rivers it is “moderate.” The water quality of Voghji and Norashenik Rivers is sharply worsening after the influence of mining activity, becoming “bad” chemical status. The research revealed the pollution sources of each metal.
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Mungray, Alka, Shrirang Kulkarni, and Arvind Mungray. "Removal of heavy metals from wastewater using micellar enhanced ultrafiltration technique: a review." Open Chemistry 10, no. 1 (February 1, 2012): 27–46. http://dx.doi.org/10.2478/s11532-011-0134-3.
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AbstractApplication of Micellar enhanced ultrafiltration (MEUF) for the removal of different heavy metals has been reviewed. It is considered an economical alternative available to the conventional membrane separation process, because it reduces the requirement of higher pressure and high membrane costs. MEUF is a separation processes which uses surfactants and ultrafiltration membranes to remove multivalent ions from wastewater with high percent rejection using electrostatic attraction between metals and micelles.This review seeks to define the effect of the operating parameters, i.e., applied pressure, surfactant concentration, feed temperature, metal ion concentration, feed flow rate, operating time etc. on the removal of metal ions. Emphasis is given to the application of MEUF for the removal of single metal ions, multiple metal ions and different metals along with other organic materials. Also, this review focuses on studies related to micelle formation, attraction between metal ions and micelles, and recovery of surfactants for future research.
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Ma, Jingxi, Shuqing Wu, N. V. Ravi Shekhar, Supriya Biswas, and Anoop Kumar Sahu. "Determination of Physicochemical Parameters and Levels of Heavy Metals in Food Waste Water with Environmental Effects." Bioinorganic Chemistry and Applications 2020 (August 20, 2020): 1–9. http://dx.doi.org/10.1155/2020/8886093.
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Bioinorganic chemistry is found as a sizzling field in today’s era. It deals with chemistry amongst the heavy metals with natural resources, i.e., air, soil, water, plant byproducts (foods), and environmental essences. The aim of this research is to determine the concentration of heavy metals present in the food waste water sample and to study the environmental effects of metal ion concentration. To conduct the research work, the physicochemical parameters and levels of five heavy metals of food waste water samples were collected from five sampling points of renowned hotels, restaurants, canteens, and confectionaries of a state of India and assessed using the standard analytical procedure. Sampling was carried out from January 2017 up to December 2017. The physicochemical parameters were determined such as pH, temperature, turbidity, conductivity, total dissolved solids, total suspended solids, total alkalinity, biological oxygen demand, chemical oxygen demand, dissolved oxygen, total organic carbon, sulphate, nitrate, and phosphate. The heavy metal concentration was determined by using the UV-spectrophotometer, and the results were compared with the standards prescribed by the WHO, BIS, ICMR, and municipal authorities. The results obtained in the physicochemical analysis revealed that a few parameters were found beyond limits, and the metal ion concentration (iron and zinc) results were found above the permissible limits set by the CPCB (Central Pollution Control Board), ICMR, BIS, and World Health Organization (WHO), most especially, effluent from point P1. It was concluded that all the effluents required further treatment before releasing them into the water body or land to prevent pollution. The obtained results reveal that waste water used for irrigation and farming of nearby areas and water drained from restaurant kitchens were considerably polluted and not suitable for aquatic organisms, irrigation, and agricultural purposes.
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Hong, Ya-jun, Wei Liao, Zhen-fei Yan, Ying-chen Bai, Cheng-lian Feng, Zu-xin Xu, and Da-yong Xu. "Progress in the Research of the Toxicity Effect Mechanisms of Heavy Metals on Freshwater Organisms and Their Water Quality Criteria in China." Journal of Chemistry 2020 (May 18, 2020): 1–12. http://dx.doi.org/10.1155/2020/9010348.
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Water quality criteria are the scientific basis for formulating water quality standards and environmental management practices. Due to the development of urbanization and industrialization, the problem of heavy metal pollution has become a serious environmental problem. Heavy metals not only have major impacts on aquatic organisms, but also seriously threaten human health. However, the current environmental criteria refer to the maximum value limitations of environmental factors in environmental media where harmful or detrimental effects are not produced on specific protected objects. This study reviewed the sources, hazard levels, toxic effect mechanisms, and the current research status of China’s water quality criteria for heavy metal pollutants. In addition, the focus and direction of future research on the toxic effects of heavy metal on aquatic organisms and the necessary criteria changes were discussed. The present study would provide an important theoretical basis for the future research of water quality criteria and risk assessment of heavy metal pollutants.
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Pal, Sudip, Steve Wallis, and Scott Arthur. "Assessment of heavy metals emission from traffic on road surfaces." Open Chemistry 9, no. 2 (April 1, 2011): 314–19. http://dx.doi.org/10.2478/s11532-011-0005-y.
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AbstractThis study aims to analyse RDS heavy metal concentrations on road deposited sediment (RDS) using Riccarton Campus of Heriot-Watt University, Edinburgh, Scotland as a study site. RDS samples were collected at two transverse positions from different sites over a 4 month period in order to describe the influence of traffic on heavy metal emissions. The heavy metal concentrations of the RDS were determined by strong nitric acid digestion and atomic absorption spectrometry. The mean concentrations for Zn, Cu, Cd, Cr, Ni, Pb and Fe were found to be 213, 57, 1, 16, 15, 118, and 13497 mg kg-1 from samples near to the curb and 211, 79, 2, 15, 9, 35, and 14276 mg kg−1 from samples 1 m from the curb respectively. Furthermore for both positions the highest concentrations for all metals were associated with the finer fraction (<63 µm) and stronger correlations between the metals were found further from the curb than near the curb, indicating that metals accumulating on the road surface further from the curb may likely be from the same source (traffic), while the sources of metals near the curb are more diverse.
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Sheng, Danrui, Jun Wu, Xiaohu Wen, Min Wu, and Chuanqi Zhang. "Contamination and ecological health risks of heavy metals in groundwater of a typical agricultural area in NW China." Geochemistry: Exploration, Environment, Analysis 20, no. 4 (May 11, 2020): 440–50. http://dx.doi.org/10.1144/geochem2020-014.
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Heavy metal pollution in groundwater has become a widespread issue worldwide. However, information on heavy metal pollution in groundwater of inland river basins in NW China remains limited. This study evaluated pollution and ecological health risks of heavy metals in groundwater of the Zhangye Basin, which is a typical inland river basin in NW China. The concentrations of heavy metals in groundwater were relatively low. Heavy metals in groundwater of the northeastern edge and western regions of the study area showed a higher concentration than those of the remaining parts. Iron was the dominant heavy metal in groundwater with a maximum concentration of 1270 μg L−1. Results of heavy metal pollution index calculations showed that approximately 3.5% of groundwater samples are classified into moderate or high pollution levels. The ecological risks of heavy metals in groundwater were relatively low with several metal(loid)s including As, Ni and Cd serving as the dominant risk contributors. The ingestion pathway contributed to 97.2%/93.6% of non-cancer risks and 97.5%/97.5% of cancer risks for children/adults, respectively. Ingestion was the main health risk contributor. Total hazard quotients and cancer risks for children were 3.5 and 9.7 times higher than those for adults, suggesting that children are much more susceptible to potential harm caused by heavy metals in groundwater. Therefore, more effective control strategies should be taken in the study area as soon as possible.Supplementary material: Spatial distribution of health risks of heavy metals is available at https://doi.org/10.6084/m9.figshare.c.4967510
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Jing, Jingyun, and Congling Shi. "Reusable Magnetic Nanoparticle Immobilized Nitrogen-Containing Ligand for Classified and Easy Recovery of Heavy Metal Ions." Molecules 25, no. 14 (July 14, 2020): 3204. http://dx.doi.org/10.3390/molecules25143204.
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Functionalized Tris[2-(dimethylamino) ethyl] amine (Me6TREN) ligands tethered-Fe3O4@Me6TREN nanoparticles (NPs) with a size of 150 nm were prepared to achieve classified and easy recovery of heavy metal ions in wastewater. The preparation of such NPs related to sequential silane ligand exchange and a following cure and Schiff base reactions for Fe3O4 NPs. Fe3O4@Me6TREN NPs as an effective nano-adsorbent of heavy metals exhibited significant differences in maximum adsorption capacity for Cr(III) (61.4 mg/g), Cu(II) (245.0 mg/g), Pb(II) (5.3 mg/g), and Cd(II) (1136.2 mg/g), in favor of classified removal of heavy metals from wastewater. Furthermore, Fe3O4@Me6TREN NPs can be regenerated by desorbing metal ions from NP surfaces eluted with ethylenediaminetetraacetic acid disodium salt (EDTA-Na2) aqueous, which endows such NPs promising potency as new nano-vectors for the removal of heavy metals.
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Bu, Qingwei, Qingshan Li, Handan Zhang, Hongmei Cao, Wenwen Gong, Xin Zhang, Ke Ling, and Yibo Cao. "Concentrations, Spatial Distributions, and Sources of Heavy Metals in Surface Soils of the Coal Mining City Wuhai, China." Journal of Chemistry 2020 (July 22, 2020): 1–10. http://dx.doi.org/10.1155/2020/4705954.
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Various studies have shown that soils surrounding mining areas are seriously polluted by heavy metals. In this study, 58 topsoil samples were systematically collected throughout the coal mining city Wuhai, located within the Inner Mongolia Autonomous Region of China. The concentrations of As, Hg, Cr, Ni, Cu, Zn, Cd, and Pb in these samples were measured and statistically analyzed. The mean concentrations of all heavy metals were lower than their Grade I values defined by the Chinese Soil Quality Standard. However, the mean concentrations of individual heavy metals in many samples exceeded their background values. The spatial distribution of heavy metals was analyzed by the ordinary kriging interpolation method. The positive matrix factorization model was used to ascertain contamination sources of the eight heavy metals and to apportion the contribution of each source. The most severely polluted area was the Wuhushan mine site in the Wuda district of Wuhai. Our results showed that coal mining strongly affected heavy metal contamination of the local soils. Results of source apportionment indicated that contributions from industrial activities, atmospheric deposition, agricultural activities, and natural sources were 31.3%, 26.3%, 21.9%, and 20.5%, respectively. This clearly demonstrates that anthropogenic activities have markedly higher contribution rates than natural sources to heavy metal pollution in soils in this area.
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Alfadaly, Reham A., Ashraf Elsayed, Rabeay Y. A. Hassan, Ahmed Noureldeen, Hadeer Darwish, and Ahmed S. Gebreil. "Microbial Sensing and Removal of Heavy Metals: Bioelectrochemical Detection and Removal of Chromium(VI) and Cadmium(II)." Molecules 26, no. 9 (April 27, 2021): 2549. http://dx.doi.org/10.3390/molecules26092549.
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The presence of inorganic pollutants such as Cadmium(II) and Chromium(VI) could destroy our environment and ecosystem. To overcome this problem, much attention was directed to microbial technology, whereas some microorganisms could resist the toxic effects and decrease pollutants concentration while the microbial viability is sustained. Therefore, we built up a complementary strategy to study the biofilm formation of isolated strains under the stress of heavy metals. As target resistive organisms, Rhizobium-MAP7 and Rhodotorula ALT72 were identified. However, Pontoea agglumerans strains were exploited as the susceptible organism to the heavy metal exposure. Among the methods of sensing and analysis, bioelectrochemical measurements showed the most effective tools to study the susceptibility and resistivity to the heavy metals. The tested Rhizobium strain showed higher ability of removal of heavy metals and more resistive to metals ions since its cell viability was not strongly inhibited by the toxic metal ions over various concentrations. On the other hand, electrochemically active biofilm exhibited higher bioelectrochemical signals in presence of heavy metals ions. So by using the two strains, especially Rhizobium-MAP7, the detection and removal of heavy metals Cr(VI) and Cd(II) is highly supported and recommended.
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Hu, Cong, Zheng-miao Deng, Yong-hong Xie, Xin-sheng Chen, and Feng Li. "The Risk Assessment of Sediment Heavy Metal Pollution in the East Dongting Lake Wetland." Journal of Chemistry 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/835487.
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Total concentrations of cadmium (Cd), lead (Pb), chrome (Cr), and nickel (Ni) in surface sediment (0–10 cm) from the East Dongting Lake wetlands were determined and the spatial distribution of heavy metals was mapped. The results showed that the single risk indices (Eri) of heavy metals were ranked in the order of Cd > Pb > Ni > Cr. The content of Cd and Pb was gradually reduced from the east (Xiangjiang River) to the west, while the Cr and Ni content had a patchy distribution pattern in the East Dongting Lake wetlands. Cd and Pb contents were correlated with soil pH significantly, while Cr and Ni contents were correlated with soil organic carbon (SOC) and total nitrogen (TN). The origination of heavy metal (Cd, Cr, Ni, and Pb) could be divided into two groups: Cd and Pb from anthropogenic source and Cr and Ni from parent material weathering. Our results indicated that Cd posed a high risk to local ecosystem. The relatively lower pH and higher soil organic carbon (SOC) and total nitrogen (TN) in sediment may inhibit the fixation of heavy metals, which in turn increased the concentration of heavy metal in sediment.
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Ali, Hazrat, Ezzat Khan, and Ikram Ilahi. "Environmental Chemistry and Ecotoxicology of Hazardous Heavy Metals: Environmental Persistence, Toxicity, and Bioaccumulation." Journal of Chemistry 2019 (March 5, 2019): 1–14. http://dx.doi.org/10.1155/2019/6730305.
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Heavy metals are well-known environmental pollutants due to their toxicity, persistence in the environment, and bioaccumulative nature. Their natural sources include weathering of metal-bearing rocks and volcanic eruptions, while anthropogenic sources include mining and various industrial and agricultural activities. Mining and industrial processing for extraction of mineral resources and their subsequent applications for industrial, agricultural, and economic development has led to an increase in the mobilization of these elements in the environment and disturbance of their biogeochemical cycles. Contamination of aquatic and terrestrial ecosystems with toxic heavy metals is an environmental problem of public health concern. Being persistent pollutants, heavy metals accumulate in the environment and consequently contaminate the food chains. Accumulation of potentially toxic heavy metals in biota causes a potential health threat to their consumers including humans. This article comprehensively reviews the different aspects of heavy metals as hazardous materials with special focus on their environmental persistence, toxicity for living organisms, and bioaccumulative potential. The bioaccumulation of these elements and its implications for human health are discussed with a special coverage on fish, rice, and tobacco. The article will serve as a valuable educational resource for both undergraduate and graduate students and for researchers in environmental sciences. Environmentally relevant most hazardous heavy metals and metalloids include Cr, Ni, Cu, Zn, Cd, Pb, Hg, and As. The trophic transfer of these elements in aquatic and terrestrial food chains/webs has important implications for wildlife and human health. It is very important to assess and monitor the concentrations of potentially toxic heavy metals and metalloids in different environmental segments and in the resident biota. A comprehensive study of the environmental chemistry and ecotoxicology of hazardous heavy metals and metalloids shows that steps should be taken to minimize the impact of these elements on human health and the environment.
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Patwa, Jayant, and Swaran Jeet Singh Flora. "Heavy Metal-Induced Cerebral Small Vessel Disease: Insights into Molecular Mechanisms and Possible Reversal Strategies." International Journal of Molecular Sciences 21, no. 11 (May 29, 2020): 3862. http://dx.doi.org/10.3390/ijms21113862.
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Heavy metals are considered a continuous threat to humanity, as they cannot be eradicated. Prolonged exposure to heavy metals/metalloids in humans has been associated with several health risks, including neurodegeneration, vascular dysfunction, metabolic disorders, cancer, etc. Small blood vessels are highly vulnerable to heavy metals as they are directly exposed to the blood circulatory system, which has comparatively higher concentration of heavy metals than other organs. Cerebral small vessel disease (CSVD) is an umbrella term used to describe various pathological processes that affect the cerebral small blood vessels and is accepted as a primary contributor in associated disorders, such as dementia, cognitive disabilities, mood disorder, and ischemic, as well as a hemorrhagic stroke. In this review, we discuss the possible implication of heavy metals/metalloid exposure in CSVD and its associated disorders based on in-vitro, preclinical, and clinical evidences. We briefly discuss the CSVD, prevalence, epidemiology, and risk factors for development such as genetic, traditional, and environmental factors. Toxic effects of specific heavy metal/metalloid intoxication (As, Cd, Pb, Hg, and Cu) in the small vessel associated endothelium and vascular dysfunction too have been reviewed. An attempt has been made to highlight the possible molecular mechanism involved in the pathophysiology, such as oxidative stress, inflammatory pathway, matrix metalloproteinases (MMPs) expression, and amyloid angiopathy in the CSVD and related disorders. Finally, we discussed the role of cellular antioxidant defense enzymes to neutralize the toxic effect, and also highlighted the potential reversal strategies to combat heavy metal-induced vascular changes. In conclusion, heavy metals in small vessels are strongly associated with the development as well as the progression of CSVD. Chelation therapy may be an effective strategy to reduce the toxic metal load and the associated complications.
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Claridge, G. G. C., I. B. Campbell, H. K. J. Powell, Z. H. Amin, and M. R. Balks. "Heavy metal contamination in some soils of the McMurdo Sound region, Antarctica." Antarctic Science 7, no. 1 (March 1995): 9–14. http://dx.doi.org/10.1017/s0954102095000034.
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Soil samples from eight sites at Marble Point and Pram Point, McMurdo Sound region, contaminated by human activities were examined for heavy metal content, using sequential extraction methods. The redistribution of lead, zinc and copper arising from point sources of these metals was demonstrated. The levels found are not considered to represent serious pollution but do indicate that human activities can change the chemistry of the Antarctic environment in localized areas.
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Lin, Kunsen, Jia-Hong Kuo, Chiou-Liang Lin, Zhen-Shu Liu, and Jingyong Liu. "Sequential extraction for heavy metal distribution of bottom ash from fluidized bed co-combusted phosphorus-rich sludge under the agglomeration/defluidization process." Waste Management & Research 38, no. 2 (December 3, 2019): 122–33. http://dx.doi.org/10.1177/0734242x19886927.
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Agglomeration that occurs during municipal sewage sludge (MSS) fluidized bed co-combustion might affect heavy metal distribution and the transformation of bottom ash. A study on the mobility and speciation of heavy metals that accompanies agglomeration behavior and phosphorus addition should be examined during MSS co-combustion. Meanwhile, the aim of this study was to evaluate the total content and speciation of heavy metals during the MSS fluidized bed co-combustion by the chemical sequential extraction procedure (SEP). The risk assessment code (RAC) and individual contamination factor (ICF) are calculated to evaluate the mobility of heavy metals and their environmental risks in agglomerates. Moreover, identification of agglomerates is established by both characterization (scanning electron microscopy/energy-dispersive spectroscopy, X-ray photoelectron spectroscopy) and thermodynamic simulation (HSC chemistry software). The experimental results indicated that P and Na would form the lower melting-point compounds such as NaPO3 and Na2O in the bottom ash, which promoted agglomeration during MSS fluidized bed co-combustion. According to the simulation, Na and P have a stronger affinity than Si and Cr, and this reaction is not only influenced by particle agglomeration, but also by heavy metal distribution during modified MSS co-combustion. Nevertheless, the results of ICFs and RACs obtained from the SEP indicated that for heavy metals trapped in agglomerates, a weaker binding such as physical covering by eutectics might be considered as the dominant reaction compared with chemical binding to form a metal complex.
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Kobielska, Paulina A., Ashlee J. Howarth, Omar K. Farha, and Sanjit Nayak. "Metal–organic frameworks for heavy metal removal from water." Coordination Chemistry Reviews 358 (March 2018): 92–107. http://dx.doi.org/10.1016/j.ccr.2017.12.010.
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Purcarea, Cornelia, Malgorzata Dzugan, Monika Wesolowska, Adriana Monica Chis, Grzegorz Zagula, Alin Cristian Teusdea, and Czeslaw Puchalski. "A Comparative Study of Metal Content in Selected Polish and Romanian Honey Samples." Revista de Chimie 68, no. 6 (July 15, 2017): 1163–69. http://dx.doi.org/10.37358/rc.17.6.5634.
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The aim of the study was to compare the heavy metal contamination and study the mineral content of Polish and Romanian honeys. We used Polish varietal honeys (n=18) produced in the year 2013-2014 in ecologically clean Podkarpackie region, and Romanian honeys (n=36) from Bihor district produced in 2013. The heavy metals concentration as well as mineral composition of honey was assayed by ICP-OES method with prior microwave mineralization. The cadmium and lead level in tested Polish honeys ranged from 0.007 to 0.021mg/kg and 0.02 to 0.098 mg/kg, respectively. Cadmium was not detected in Romanian honeys, and the lead contamination was lower than in Polish honey (0.018-0.05 mg/kg). Mercury was not detected in any tested honey samples. The aluminum content in Polish honeydew honeys was 34.6-times higher than in Romanian honeys. Honey samples from Poland were richest in potassium (2.5-fold for honeydew, lime and acacia, excluding heather), but they included less calcium. Generally, dark honeys include the highest mineral concentration and are more contaminated by heavy metals. However, all tested samples met the legal requirements for heavy metals residues. The geographical origin and soil composition strongly influenced honey chemical composition and the crucial factor for heavy metal transfer seems to be soil pH.
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Protchenko, Andrey V., Deepak Dange, Andrew D. Schwarz, Christina Y. Tang, Nicholas Phillips, Philip Mountford, Cameron Jones, and Simon Aldridge. "Heavy metal boryl chemistry: complexes of cadmium, mercury and lead." Chem. Commun. 50, no. 29 (2014): 3841–44. http://dx.doi.org/10.1039/c4cc00697f.
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Heavy metal boryl complexes: the first boryl complexes of cadmium and mercury are reportedviatransmetallation from boryllithium; the syntheses of related tin and lead systems highlight the additional factors associated with extension to more redox-active post-transition elements.
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Nyika, Joan Mwihaki, Ednah Kwamboka Onyari, Megersa Olumana Dinka, and Shivani Bhardwaj Mishra. "Heavy Metal Pollution and Mobility in Soils within a Landfill Vicinity: A South African Case study." Oriental Journal Of Chemistry 35, no. 4 (August 19, 2019): 1286–96. http://dx.doi.org/10.13005/ojc/350406.
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Heavy metal contamination in soils results from anthropogenic and lithologic factors and is a potential hazard to land and water resources. Sources of such pollution include landfills, domestic sewage, agricultural fertilisers and industries. In this work, soils from Roundhill landfill vicinity in South Africa were sampled and analyzed to determine the concentrations of particular heavy metals, namely As, Co, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn. The main objectives of this work were to: quantify the concentration levels of heavy metals in the soil; determine the mobility of the heavy metals in the soil; and establish their origins and interrelationships. The soils were collected at various distances and depths from the landfill facility. The concentrations of heavy metals in the soil samples were analysed by ICP-MS and statistical analysis was carried out to establish their relationships and sources. From the analysis, some elements including Cr, Mn, Cu and Ni had measured concentrations beyond the threshold limits in most sampling sites irrespective of their distance and depth from the landfill vicinity. Conversely, some elements were observed to be immobile and had higher concentrations on the top soils closer to the landfill, such as As, Pb, Zn, Co and V. Iron (Fe) had high concentrations in all the sampling sites due to its natural occurrence in the parent rocks. In conclusion, the potential of soil quality deterioration due to heavy metal pollution in a landfill vicinity was observed. Furthermore, all heavy metals observed showed positive correlation to each other except for As and Co, indicating same origin.
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Wada, B., H. Sumi, I. Ueda, and K. Suzuki. "Automatic gauge control for heavy plate mill." Revue de Métallurgie 91, no. 3 (March 1994): 465–70. http://dx.doi.org/10.1051/metal/199491030465.
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