Size-dependent nanocrystal sorbent for copper removal from water

In this study, ZnS nanocrystals (NCs) was synthesized and investigated as a novel sorbent for the copper removal from waste water. According to the adsorption experiments, the copper removal efficiency is over 99.0% in one minute. The saturated adsorption capacity of ZnS NCs sorbent on copper is about 650   mg/g which is closed to the theoretic adsorption capacity. The influence of pH value, other metal ions and NCs sorbent size on copper removal efficiency were investigated, respectively. The ZnS NCs sorbent was characterized by TEM and XPS to reveal the reaction mechanism. It was found that the NCs layer thickness played an important role in copper removal by ZnS NCs sorbent. It is more difficult to remove the copper from water for the sorbents with thicker NCs layer. Heat treatment method promoted the copper removal performance of sorbent greatly. Additionally, the sorbent and the copper removed by sorbent could be reclaimed easily. Therefore, it is a promising method to remove the copper from water by ZnS NCs sorbent.