In the case of activated carbon, the removal percentage was the highest at pH 10 might also be due to the fact that cadmium normally precipitates at high pH and therefore, the final removal percentage was a combination of adsorption as well as precipitation (Regmi et al., 2012). It was observed that the bio-char had similar metal removal percentage as that of commercial activated carbon. Only the working pH was different. The activated bio-char had a high alkaline pH and caused the pH of the initial solution to rise up to a certain amount,which leads to a greater removal of cadmium