Cocopeat, a by-product of coconut husk, was used as sorbent to remove mercury and other heavy metals (As, Ba, Cd, Pb) collected from the tailings collection tank of a ball mill facility that employs amalgamation process in extracting gold located at an actual small scale gold mining (SSGM) area in Camarines Norte province, Philippines. Batch sorption experimens were carried out using raw wastewater samples with reduced suspended solids collected after 60 min of settling and without modifying the pH to simulate the actual condition in the field. Batch tests of water samples with an initial of pH 7.3 and adsorbent dose of 1.0 g/L were tested for Lagergren first-order, pseudo-second-order, intra-particle diffusion and Freundlich models to evaluate kinetic parameters and adsorption isotherms. The removal efficiency obtained for the heavy metals after 240 min were 97.14%, 94.74%, 10.00%, 66.67%, and 27.01% for Hg, As, Ba, Cd and Pb, respectively. Pseudo-second order kinetics model represented well the adsorption process as demonstrated with its higher correlation coefficients among the models.
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