REMOVAL OF CHROMIUM (VI) FROM AQUEOUS SOLUTION BY EXTRACTED ONION PROCESSING WASTE

The aim of the present study was to examine the performance of residue from extracted onion processing waste for the ability to remove Cr (VI) ions from aqueous solutions. The characterization of applied biosorbent was conducted by FT-IR analysis. Batch experiments were carried out and the effects of different adsorption process parameters were determined. Maximum removal efficiency of 98.29 ± 0.17 % was obtained at pH = 1.0, adsorbent dose 0.5 g·L-1, initial Cr (VI) concentration 50 mg·L-1, temperature 25.0 ± 0.5 oC, agitation speed 200 rpm and contact time of 30 min. The pseudo-second order model and Langmuir model provided the best fit to experimental kinetics and equilibrium isotherm data, respectively. Based on the values determined for the maximum adsorption capacity (qmax = 47.17 mg·g-1) the extracted onion processing waste could be applied as a low cost biosorbent for removal of Cr (VI) ions from polluted water.