Characteristic of Hg removal using zeolite adsorption and Echinodorus palaefolius phytoremediation in subsurface flow constructed wetland (SSF-CW) model

Abstract

Mercury (Hg) exposure as a result of artisanal small-scale gold mining (ASGM) activities in Indonesia potentially harms the living being in the surrounding areas. This study examined the use of subsurface flow constructed wetland (SSF-CW) consisted of Echinodorus palaefolius and natural zeolite to remove mercury from contaminated water in a laboratory scale apparatus. Artificial waste containing 14.94 mg/L Hg was pumped into the SSF-CW. Performance of the SSF-CW was observed for 12 h in continuous process followed by a batch process with the same amount of time (total of 12 h) for three days. The accumulation of effluent from the 1st cycle was used as influent for the 2nd cycle. Sampling was conducted from the effluent and drawn every 4 h to analyze. The isotherm model of zeolite adsorption was determined and proposed as the equation to calculate the amount of mercury adsorbed in the system. Adsorption isotherm fit the Freundlich model of qe = 0.1131Ce1/1.7036. Throughout all cycles, Hg removal was taken place by combined mechanism of both adsorption and phytoremediation. The removal of 91.84 % was achieved at the end of the experiment showing a promising application of SSF-CW to overcome mercury contamination in water, especially in the ex-artisanal gold mining sites in Indonesia.