Aparna Pandey; Pratibha Singh; Divya Gupta; Abreeq Fatima; Sheo Mohan Prasad
Abstract
Soil pollution cannot be directly assessed or visually perceived generally and has become a hidden danger. It is mainly contributed by contamination from chemicals, heavy metals, pesticides, polycyclic aromatic hydrocarbons, and persistent organic pollutants. Soil pollutants are antagonistic to ...
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Soil pollution cannot be directly assessed or visually perceived generally and has become a hidden danger. It is mainly contributed by contamination from chemicals, heavy metals, pesticides, polycyclic aromatic hydrocarbons, and persistent organic pollutants. Soil pollutants are antagonistic to diversified life forms on earth ranging from soil microbes, plants, and mankind to water inhabitants and aerial lives, food security, agricultural productivity thereby exerting detrimental effects and so need immediate attention. The remediation of contaminated soil is necessary for sustainable development and continual existence of life forms on the planet. Ecological remediation depends chiefly on utilizing different innovations like adsorption, assimilation, compound responses, photo-catalysis, and filtration for the expulsion of contaminants from natural media like soil. This review elucidates various soil pollutants from natural to manmade sources and its affect on the environmental components. It further aims to look at recent advances in various remediation technologies for removing contaminants from soil. Besides the traditional methods of remediation, techniques involving biological methods, biotechnological approach and nanotechnology have been focused. Some possible opportunities and challenges of varying soil remediation strategies are discussed. It would suggest new perspectives and future challenges in soil remediation.
David G. Rickerby
Abstract
An overview is presented of potential improvements in performance that can be achieved by using three different types of nanomaterials in water treatment applications: (i) zerovalent iron for reducing concentrations of chlorinated hydrocarbons and heavy metals in groundwater; (ii) titanium dioxide for ...
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An overview is presented of potential improvements in performance that can be achieved by using three different types of nanomaterials in water treatment applications: (i) zerovalent iron for reducing concentrations of chlorinated hydrocarbons and heavy metals in groundwater; (ii) titanium dioxide for photocatalytic drinking water purification, enabling reduced consumption of chemicals for disinfection; (iii) carbon nanotube membrane filters that transport water molecules at elevated fluxes, while rejecting other molecules and ions. The distinctive characteristics of the nanomaterials, such as high specific surface area, enhanced reactivity and adsorption capacity, have already led to significant increases in efficiency. Future developments are expected based on surface modification of zerovalent iron to improve its reactivity and transport characteristics, advanced chemical synthesis methods to increase the area of photoreactive facets and doping to inhibit electron-hole recombination or to allow visible light photocatalysis in titanium dioxide, and functionalization of carbon nanotubes to increase ion rejection rates. Implementation of these innovative methods for removal of contaminants from water will be contingent on reduction of the present high cost of the nanomaterials and assessment of the possible risks associated with their, as yet only partly understood, toxic and ecotoxic properties.
M. Vinuth; H. S. Bhojya Naik; M. M. Mahadev Swamy; B.M. Vinoda; R. Viswanath; H. Gururaj
Abstract
Herein we reported the malachite green dye removal by Fe(III)−Mt through adsorption process under ambient conditions. The amount of MG dye removal by Fe(III)–Montmorillonite(Fe(III)–Mt) was estimated from its optical density at lmax = 617 nm using UV-Vis spectrophotometer. The MG dye ...
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Herein we reported the malachite green dye removal by Fe(III)−Mt through adsorption process under ambient conditions. The amount of MG dye removal by Fe(III)–Montmorillonite(Fe(III)–Mt) was estimated from its optical density at lmax = 617 nm using UV-Vis spectrophotometer. The MG dye removal was found to be rapid at basic pH and increased further with temperature up to 50°C. At pH 7 & 8, a complete reduction (100%) was observed within 5 min and 7 min, whereas at pH 4 & 5, it took 10 min &15 min respectively. The time taken for complete reduction at 0°C, RT (30°C) and 50°C were 10, 7 and 5 min respectively. The removal followed by adsorption of dye molecules on the spent clay mineral was evident from FESEM/EDX analysis. More importantly, Fe(III)–Mt could be separated and retrieved easily after the reaction by centrifugation from the degraded MG dye solution. The experimental results of MG dye removal from Fe(III)–Mt follows the pseudo first order kinetics. We believe that Fe(III)–Mt could be the efficient and suitable material to augment the real filed applications. This study provides a new avenue to gain in-depth insight to the applications of Fe(III)–Mt as an effective clay mineral for remediation of dye effluents. Overall Fe(III)–Mt bears the capability for environmental remediation in relation to the dye pollution.
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