Design and optimization of a batch sequential contactor for the removal of chromium(VI) from industrial wastewater using sheep wool as a low-cost adsorbent

Cr(VI) removal from wastewater streams using sheep wool in sequential batch contactors (SBC) mode was investigated. The influence of the number of contactors on removal efficiency was also studied. SBC was carried out in tanks containing 100 and 1000 mL solutions. Four SBC runs ensured complete removal of Cr(VI) whereas three runs reduced its concentration from 100 to 0.06 mg/L. Experiments in both tanks gave similar results, thus permitting scalability to a pilot plant and eventual industrial scale utilization. Regeneration studies were carried out using KCl. The optimum parameters in terms of time, concentration and temperature were 25 min, 0.10 m and 50.0 degrees C. Simultaneous adsorption-desorption cycles showed that sheep wool can be regenerated several times with no discernible change in removal efficiency.