Toxic metals have been excessively released into the environment due to rapid industrialization and have created a major global concern. Cadmium, zinc, copper, nickel, lead, mercury and chromium are often detected in industrial wastewaters. Various methods are available in literature although some of them facing difficulties to be applied. The present study, bagasse from sugarcane industry was used to remove chromium(VI) ions from wastewater. This study presents the adsorption behavior of hexavalent chromium from wastewater using low cost adsorbent modified sugarcane bagasse with citric acid (SCB). The effect of the initial concentration of chromium(VI), biosorbent dosage, temperature, contact time, and pH were studied. It was found that maximum % removal of chromium(VI) is obtained 92.19 % at pH 1.2 and contact time 40 min. The removal is decreased with increase in concentration and also pH. The maximum biosorption capacities qe of chromium(VI) ions by SCB was 13.5 mg g-1. This work proved that treated bagasse can be used as an efficient adsorbent material for removal of heavy metals from wastewater such as chromium(VI).

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Spectrophotometric studies have been made to investigate the reaction of Nickel and Lead with 2-carboxy-2'-hydroxy-5'-sulfoformazyl-benzene (zincon) in 50%(v/v) ethanol-water at 25 degrees C and an ionic strength of 0.1 M NaClO4. A complete picture of the complexation equilibria in the pH range (4.2-12.0) for nickel and (1.9-11.5) for lead are presented. Simple, rapid, selective and sensitive methods for the spectro-photometric determination of nickel and lead has been developed based on the color reaction of their complexes with zincon. The methods allow the determination of 4.69 microg mL(-1) of nickel at pH = 6.3 (lambdamax = 665 nm) and 10.3 microg ml(-1) of lead at pH = 5.6 (lambdamax = 610 nm). The apparent molar absorptivities were epsilon = 1.3 x 10(4) L mol(-1) cm(-1) for nickel and epsilon = 0.6 x 10(4) L mol(-1) cm(-1) for lead. The interference of a large number of foreign ions and complexing agents has been studied. Thiosulphate, as masking agent allows the simultaneous determination of nickel and lead in the presence of high concentrations of copper. Ascorbic acid, sodium cyanide and or sodium fluoride provide the elimination of many other interferences. The methods have been applied successfully to the simultaneous determination of nickel and lead in an aluminium and non-ferrous alloy.

Hexavalent chromium is a priority toxic and carcinogenic chemical when present in excess. It is very much required to remove it from effluents before allowing it to enter any water system or on to land. In the present study, the removal of Cr(VI) by adsorptionfrom wastewater using low cost adsorbent modified sugarcane bagasse by tartaric acid (SCB) was studied. The effect of the initial concentration of Cr(VI), bio sorbent dosage, temperature, contact time, and pH were studied. It was noted that the removal decreased with the increase in the initial concentration of Cr(VI) ions and also pH. The adsorption of Cr(VI) from water was favorable at low pH values. The kinetic of the Cr(VI) adsorption on SCB was found to follow pseudo -second order mechanism. The adsorption data can be satisfactorily explained by Freundlich isotherm. This work proved that treated bagasse can be used as an efficient adsorbent material for removal of Cr(VI) from wastewater.

The adsorption behavior of mordant yellow 12 (4-amino phenyl azo salicylic sodium salt) (MY12) from aqueous solutions using low cost adsorbent citric acid or tartaric acid treated Sugarcane bagasse (SCB) was carried out. The experimental results have been investigated according to Langmuir and Freundlich isotherms. The effect of initial concentration of the dye, biosorbent dosage, temperature, contact time and pH were involved in the experiments. It was reported that the maximum removal percentage of MY12 was 95.2 % at pH 2.8 and contact time 40 minutes. The removal percentage decreases, as the concentration of the dye increases. Similar trend was found with the pH factor. The maximum biosorption capacities qe of MY12 by SCB was 8.2 mg g-1. It was concluded that; bagasse can be used as an efficient adsorbent material for the removal of organic dyes from aqueous solutions.