REMOVAL OF CHROMIUM FROM WASTE WATER

Abstract

Water is the most natural resource and it is essential for all forms of life. Without water man can't survive. Due to population explosion, urbanization and industrialization the water is getting polluted day by day unlike in the past, When natural resources are considered to be abundant, the present situation is completely different. Outdated technologies by the industries cause a lot of waste. 1'hesc wastes enter into the water and soil systems directly or indirectly through various processes. It is a responsibility of any individual and environmental scientist to address this problem to control and take this problem at grass root to find an economical solution. Present investigation have been taken up for the removal of bioremediation of Chromium from Tannery Waste water. Both Trivalent and Hexavalent Chromium have been discharged from various industries including Electroplating, Leather Tanning, Textiles,etc. Hexavalent chromium are more toxic than Trivalent and produces an enormous effect on mankind. Hexavalent chromium is very toxic to flora and fauna. Together with insulin it removes glucose from blood, and it also plays a vital role in fat metabolism. Chromium deficits may enhance diabetes symptoms. Chromium can also be found in RNA. Thus various Environmental Protection Agencies have laid down the limitation on Chromium discharges as 0.5mg!l. Several control/ treatment technologied are there in the literature with various magnitude of merits and demerits. Biological methods are growing importance now-a-days due to its cheap cost of operation, no generation of secondary pollutants, easy applicability and due to many more other advantages. The adsorption of chromium(VI) ions from aqueous solutions has been investigated on Pine needle (PN), Rice husk(RH1 and RH2), litchi peel (LP) and Orange peel (OP). Characterization of adsorbent was carried out using various techniques such as FTIR, TGA, SEM, XRD, etc. The equilibrium studies was carried out in batch process by varying parameters like pH, contact time, hiornass dosage and initial metal concentration on biosorption. The biosorptive capacities of the hiosorbents were dependent on the pH of the chromium solution. The adsorption data fitted well with the freundlich isotherm model. Recently, a new and simple kinetic model was derived from a basic concept of the redox reaction between Cr(VI) and biornaterials, and successfully described the removal behaviour of Cr(VI) under various Cr(VI) and biomaterial concentrations. It was found that percentage removal by simultaneous adsorption and bioaccumulation exceeded that of adsorption.