Paper Title
Preliminary Study of Manganese Removal in Surface Water Sampled Near Gold Mine Using Biochars

Abstract
The characteristics of 5-types of biochars BC1, BC2, BC3, BC4 and BC5 derived from different types and parts of biomass as well as their capacities to remove Mn from the surface water sampling from the area near gold mine were compared in order to screen biochars applied for pollutants removal. Results showed that their specific surface areas were in the range of 170-485 m2.g-1. Only BC1 was classified as high wettability material having 59-degree of water contact angle (WCA), while the others were hydrophobicity with >90-degree of WCA. H/Corg of all biochars were below 0.22 presenting high fused aromatic composition of biochars. In this study, the water sample represented the Mn-rich sample (11 mg.L-1) was used to study Mn removal efficiency of the biochar samples. Effect of pH (pH4, pH of as-received waters and pH9) of water samples on the removal of Mn was studied. The highest removal efficiencies of Mn at pH9 (95%) was found upon using BC1, while at pH4 and pH7, BC1 be able to remove Mn of 84-85%. At high pH, all biochars tended to have a better removal efficiency attributed to MnO2 could be formed onto the surface of biochars. BC1 had the highest Mn removal efficiency due to its high wettability property and large pore diameter. Keywords - Biochars, Manganese, Adsorption, Groundwater contamination, Specific Surface Area.