Sorption isotherms and kinetics of chromium uptake

Authors: B A Shah A V Shah R R Singh

Publish Date: 2008/12/10

Volume: 6, Issue: 1, Pages: 77-90

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Abstract

Chromium VI which exists in many industrial wastewater is considered highly toxic The aim of the present investigation was to study the reduction of chromium VI to chromium III and then removing it with the help of weathered basalt andesite products Reduction of the chromium VI to chromium III by hydrazinium sulfate was investigated The influence of hydronium ion concentration contact time hydrazinium sulphate dosage and temperature has been tested in batch runs The process was found to be acid temperature and concentration dependent The suitability of weathered basalt andesite products as a potential sorbent was assessed for the removal of chromium III following batch mode of operation The effect of various parameters such as hydronium ion concentration shaking time sorbent dose initial metal ion concentration and temperature on the removal of chromium III from aqueous solution was studied Thermodynamic parameters H° S° and G° for the sorption process were evaluated Analysis of sorption obtained results showed that the sorption pattern followed the Freundlich Langmuir and DubininKaganerRadushkevich isotherms The process follows pseudo second order rate and surface diffusion is identified as the predominating mechanism The sorption process was shown to be reversible by the recovery of sorbed chromium III upon extraction with 05 M nitric acid The sorbent before and after sorption was characterized by fourier transform infrared spectrometer Xray diffraction scanning electron microscope transmision electron microscope and thermogravimetric analyse methodes An increase in crystallanity after sorption of chromium was observed An industrial effluent was successfully treated with the same sorbent with convincing results

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