ECONOMIC AND ACCURATE CHROMIUM DETERMINATION VIA MODELING AND MONITORING THE REMOVAL OF ADSORBED HEXAVALENT CHROMIUM BY LEAST COST ORGANIC WASTES AND THE OPTIMIZATION OF FLAME ATOMIC ABSORPTION SPECTROPHOTOMETER (FAAS)

The efficiency of non-conventional, least cost organic wastes (OWs), for chromium adsorption, was investigated through batch experiment. Organic wastes (OWs) such as, pine bark (PB), garden peat (GP), fresh ash (FA), coconut shell (CS) and coconut fiber (CF), compared with the blank (control), were used as filter beds for chromium Cr(VI) adsorption. Langmuir and Freundlich isotherm models for Cr(VI) adsorption by OWs, were analyzed. Statistically, highly significant (P <= 0.01) differences in Cr(VI) adsorption by OWs were revealed. The efficiency of adsorbents was in the order of PB > GP > FA > CS > CF. Amongst all, the highest adsorption was by pine bark (98%) followed by garden peat (96%). For highest accuracy of Cr(VI) analysis, by flame atomic absorption spectrophotometer (FAAS), and a step towards energy and economy conservation, the flame composition of agitation gas (ethylene gas (C2H2)) of FAAS, was evaluated for optimization. Calculation of ethylene consumption serving as additional fuel, in Cr(VI) determination per treatment, revealed that at higher flow rates, C2H2 had no impact on Cr(VI) determination. Thus, to avoid and terminate the effect and wastage of C2H2, the flame composition of agitation gas was recommended to be optimized.