The raw cladode of Opuntia ficus indica (OFI) was evaluated as a sustainable biosorbent for the removal of heavy metals (Ni, Pb, Cu, and Cd) from aqueous solutions. The functional groups of OFI were ...identified by employing DRIFT-FTIR and CP-MAS-NMR techniques before and after contact with the ions in an aqueous media, showing a rearrangement of the biomass structure due to the complexation between the metal and the functional groups. The adsorption process was studied in both single- and multi-component systems under batch conditions at different pHs (4.0, 5.0, and 6.0), different metal concentrations, and different biomass amounts. The results show that the raw OFI had a removal capacity at room temperature of over 80% for all metals studied after only 30 min of contact time, indicating a rapid adsorption process. Biosorption kinetics were successfully fitted by the pseudo-second-order equation, while Freundlich correctly modelled the biosorption data at equilibrium. The results of this work highlight the potential use of the untreated cladode of OFI as an economical and environmentally friendly biosorbent for the removal of heavy metals from the contaminated aqueous solution.
In this paper, a novel amino-functionalized Fe.sub.3O.sub.4-MnO.sub.2-SiO.sub.2-NH.sub.2 adsorbent material was prepared by successive modifying Fe.sub.3O.sub.4 with KMnO.sub.4 and SiO.sub.2 to ...remove heavy metal ions in mixed solution of Pb(II), Cu(II), and Ni(II). The adsorption experiments showed that initial pH value had a significant effect on the adsorption capacity of the materials for heavy metals in solution. Moreover, the materials exhibited strong selective adsorption for Pb(II). Transmission electron microscopy (TEM) results showed that the innermost dark center was the Fe.sub.3O.sub.4 core with a thickness of about 200 nm, and the outermost light circle was a coated SiO.sub.2 shell with a thickness of about 30 nm, while MnO.sub.2 can be seen between the dark center and the light circle. Various factors affecting the uptake behavior such as contact time, temperature, pH, and initial concentration of Pb(II) were investigated. The kinetics were evaluated utilizing the Lagergren pseudo-first-order and pseudo-second-order models. The best interpretation for the equilibrium data was given by Freundlich isotherm. The recycling experiment showed that Fe.sub.3O.sub.4-MnO.sub.2-SiO.sub.2-NH.sub.2 kept its adsorption and desorption efficiencies constant over 5 cycles. Importantly, the Fe.sub.3O.sub.4-MnO.sub.2-SiO.sub.2-NH.sub.2 was able to selectively remove over 73% of Pb(II) not only in mixed solution of Pb(II), Cu(II), and Ni(II) but also remove 94.7% in only Pb(II) solution at pH 6 within 1 h.
Heavy metal toxicity has proven to be a major threat and there are several health risks associated with it. The toxic effects of these metals, even though they do not have any biological role, remain ...present in some or the other form harmful for the human body and its proper functioning. They sometimes act as a pseudo element of the body while at certain times they may even interfere with metabolic processes. Few metals, such as aluminium, can be removed through elimination activities, while some metals get accumulated in the body and food chain, exhibiting a chronic nature. Various public health measures have been undertaken to control, prevent and treat metal toxicity occurring at various levels, such as occupational exposure, accidents and environmental factors. Metal toxicity depends upon the absorbed dose, the route of exposure and duration of exposure, i.e. acute or chronic. This can lead to various disorders and can also result in excessive damage due to oxidative stress induced by free radical formation. This review gives details about some heavy metals and their toxicity mechanisms, along with their health effects
Traditional freshwater sources have been over-abstracted in the worldwide crisis of water scarcity. Effluents have extremely high amounts of Znsup.2+ and Pbsup.2+, according to an investigation of ...wastewater samples taken from several industrial zones. However, these heavy metals are among the most harmful to both humans and wildlife that are currently known. Streptomyces sp. is utilized in this study as a biosorbent to biosorb Znsup.2+ and Pbsup.2+ from single and binary aqueous solutions. Several factors, such as biomass concentration (0.25–4 g), metal solution concentration (5–50 mg Lsup.−1), solution pH (2–5), and contact time were standardized. Streptomyces sp. biomass was able to extract 93% Pbsup.2+ and 91% Znsup.2+ from a single and 95% Pbsup.2+ and 97% Znsup.2+ from a binary metal aqueous solution containing 25 mg Lsup.−1 and pH 4. The highest adsorption capacity in both single and binary sorption experiments was determined to be shared by Znsup.2+ and Pbsup.2+. The biosorbent’s metal adsorption increased from 0.48 to 4.56 mg gsup.−1 for Pbsup.2+ and from 0.21 mg gsup.−1 to 4.65 mg gsup.−1 for Znsup.2+ when the metals were present singly, and from 0.44 to 4.18 mg gsup.−1 for Pbsup.2+ and from 0.41 mg gsup.−1 to 5.67 mg gsup.−1 for Znsup.2+ when the metals were present in binary form. The amount of metal ions was raised from 5 to 50 mg Lsup.−1. Correlation coefficient (Rsup.2) values indicate that the adsorption pattern for Znsup.2+ and Pbsup.2+ followed Freundlich isotherm Rsup.2 > 0.9543 for single and 0.9582 for binary sorption system. In order to remove Znsup.2+ and Pbsup.2+ from an aqueous solution, Streptomyces sp. is a potential and different source of adsorbents.
Biosorption is a technique that uses materials of biological origin to accumulate contaminants and represents an alternative for the treatment of soils contaminated by heavy metals. In our study, we ...analyzed the bioavailability of Cd.sup.2+ and Pb.sup.2+ in an Alfisol after the application of sisal residues (Agave sisalana) and related the adsorption of these ions with the characteristics of the residues. In a greenhouse experiment, we exposed the Sorghum bicolor plants to different types (mucilage (MUC), fibrils (FIB), and fiber dust (FD)) and levels of residues of sisal (0.0, 0.5, 1.0, 2.0, and 3.0% w/w) for 60 days. The application of FIB and MUC residues in the soil was able to reduce by up to 40% the available levels of Cd.sup.2+ and Pb.sup.2+ in the soil solution, regardless of the applied dose. In addition to the lower levels and accumulations of Cd in the roots and shoots, the application of residues increased dry mass of the plants. On the other hand, plants grown in soil contaminated by Pb.sup.2+ and which received application of the residues did not show symptoms of phytotoxicity; this is justified by the lower content and accumulation of Pb.sup.2+ in the plants that had a translocation factor < 1. Cd.sup.2+ was strongly correlated with all lignocellulosic parameters, while Pb.sup.2+ showed a lower correlation. Our results suggest that the application of residues decreases the availability of Cd.sup.2+ and Pb.sup.2+ in the soil solution, alleviates phytotoxicity, and maximizes the development of Sorghum bicolor.
Pallas Athena serves as a symbolic reminder of the original meaning of the world “palladium” – a protective figure or item believed to provide safety against the attacking enemy. In our design, we ...used a palladium compound to target one of the most aggressive tumors while sparing normal cells and tissues. More information can be found in the Research Article by M. A. Kinzhalov and co‐workers (DOI: 10.1002/chem.202400101).
Soil Heavy Metals Sherameti, Irena
2010, 2009, 20091006, 2014-07-30, Volume:
19
eBook
Human activities have dramatically changed the composition and organisation of soils. Industrial and urban wastes, agricultural application and also mining activities resulted in an increased ...concentration of heavy metals in soils. How plants and soil microorganisms cope with this situation and the sophisticated techniques developed for survival in contaminated soils is discussed in this volume.The topics presented include: the general role of heavy metals in biological soil systems, the relation of inorganic and organic pollutions, heavy metal, salt tolerance and combined effects with salinity, effects on abuscular mycorrhizal and on saprophytic soil fungi, heavy metal resistance by streptomycetes, trace element determination of environmental samples, the use of microbiological communities as indicators, phytostabilization of lead polluted sites by native plants, effects of soil earthworms on removal of heavy metals and the remediation of heavy metal contaminated tropical land.
Copper and cadmium ions are among the top 120 hazardous chemicals listed by the Agency for Toxic Substances and Disease Registry (ATSDR) that can bind to organic and inorganic chemicals. Silica is ...one of the most abundant oxides that can limit the transport of these chemicals into water resources. Limited work has focused on assessing the applicability of nanosilica for the removal of multicomponent metal ions and studying their interaction on the surface of this adsorbent. Therefore, this study focuses on utilizing a nanosilica for the adsorption of Cdsup.2+ and Cusup.2+ from water. Experimental work on the single- and multi-component adsorption of these ions was conducted and supported with theoretical interpretations. The nanosilica was characterized by its surface area, morphology, crystallinity, and functional groups. The BET surface area was 307.64 msup.2/g with a total pore volume of 4.95×10sup.−3 cmsup.3/g. The SEM showed an irregular amorphous shape with slits and cavities. Several Si-O-Si and hydroxyl groups were noticed on the surface of the silica. The single isotherm experiment showed that Cdsup.2+ has a higher uptake (72.13 mg/g) than Cusup.2+ (29.28 mg/g). The multicomponent adsorption equilibrium shows an affinity for Cdsup.2+ on the surface. This affinity decreases with increasing Cusup.2+ equilibrium concentration due to the higher isosteric heat from the interaction between Cd and the surface. The experimental data were modeled using isotherms for the single adsorption, with the Freundlich and the non-modified competitive Langmuir models showing the best fit. The molecular dynamics simulations support the experimental data where Cdsup.2+ shows a multilayer surface coverage. This study provides insight into utilizing nanosilica for removing heavy metals from water.
Tolerance to heavy metals in plants is a model process used to study adaptations to extremely unfavorable environments. One species capable of colonizing areas with high contents of heavy metals is ...Armeria maritima (Mill.) Wild. A. maritima plants growing in metalliferous areas differ in their morphological features and tolerance levels to heavy metals compared to individuals of the same species growing in non-metalliferous areas. The A. maritima adaptations to heavy metals occur at the organismal, tissue, and cellular levels (e.g., the retention of metals in roots, enrichment of the oldest leaves with metals, accumulation of metals in trichomes, and excretion of metals by salt glands of leaf epidermis). This species also undergoes physiological and biochemical adaptations (e.g., the accumulation of metals in vacuoles of the root's tannic cells and secretion of such compounds as glutathione, organic acids, or HSP17). This work reviews the current knowledge on A. maritima adaptations to heavy metals occurring in zinc-lead waste heaps and the species' genetic variation from exposure to such habitats. A. maritima is an excellent example of microevolution processes in plants inhabiting anthropogenically changed areas.
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