Evaluation of an adsorbent prepared by treating coconut husk with polysulphide for the removal of mercury from wastewater

279-285Polysulphide treated coconut husk can be used as an effective adsorbent for the removal of Hg(II) from aqueous systems. The parameters affecting Hg(II) adsorption such as Hg(II) concentration, agitation time, pH ,sorbent dose, ionic strength and temperature were studied to estimate optimum conditions. Maximum adsorption capacity was observed in the pH range 5.5-10.0. The adsorption isotherm was also affected by temperature since the adsorption capacity was increased by raising the temperature form 30 to 60°C. Lagergren equation and Langmuir and Freundlich isotherm models have been used to determine rate constants of adsorption and capacity of treated coconut husk. Different reagents were tested for extracting Hg(II) from the spent adsorbent. High extraction efficiency was obtained with 0.5M HCl solution. Hg(II) can be successfully removed from synthetic and industrial wastewaters. The results obtained point towards viable adsorbent which is both effective as well as economically attractive for Hg(II) removal from wastewater.