Chromium Removal From Industrial Wastewater By Immobilization And Adsorption Techniques

Abstract

Chromium chemicals has long been recognized as passivation agents to prevent newlinecorrosion of metals particularly of iron and steel bearing metallic structures and newlinepipelines. Chrome plating industry meets the growing passivation requirement of newlinepipelines and structures. Chrome plating industry is a small-scale industry that is located newlinethroughout the country with an objective of supplying passivation solution in order to newlineinhibit the corrosion of the bare metal surface. The present industry is located in newlineParadeep industrial area in India. Chromium salts like sodium or potassium dichromate newlineare used the main raw chemicals used in this plating process. Concentrated solution of newlinesodium dichromate in the range of having 150 to 250 gram/litre of Cr (VI) is required for newlineplating the bare metallic surface. Plating bath solution comprises of an electrolyte newlinesodium dichromate and sulfuric acid. Then a thin layer of chromium especially its newlinehexavalent salt is coated electrolytically on the bare and clean metal surfaces. newlineWastewater from plating industry comes from cleaning, rinsing and washing operations newlineand comprises of highly polluting and toxic hexavalent chromium concentration varying newlinebetween 100 to 300 mg/l.. Therefore, it is legally prohibited to dispose the untreated newlinewastewater to land surface and inland surface water bodies. In this work, management of newlinechromium bearing effluent in various methods including the reuse of the wastewater in newlineconcrete manufacturing activity is explored. newlineTreatment may include the commercially viable methods like reduction and Chemical newlineprecipitation, adsorption, ion exchange, reverse osmosis and electrodialysis methods. newlineEach method has its own merits and limitations. The versatility, simplicity, cost newlineeffectiveness, technical feasibility and environmental compatibility are the important newlinefactors that must be considered while selecting a particular method. One such methods newlineadsorption process using abundantly available biomass is considered. Even though, the newlineremoval of chromium is satis