Application of Supramolecular Strategy to the Removal of Coordinated Metal From Wastewater

摘要

Two poly-dithiocarboxy-group ligand compound， disodium N,N'-bis-(dithiocarboxy)piperazine（BDP) and sodium 1,3,5-hexahydrotriazinedithiocarbamate(HTDC)was pre-pared. It was found that they could remove free and stable complexcopper(Ⅱ) and ni-ckel(Ⅱ) from both synthetic and actual industrial wastewaterwastewaters by the formation of supramolecular precipitants For example，at 1:1stoichiometric of BDP/Cu an-d BDP/Ni，the free Cu 2+and Ni 2+concentration could bereduced from initial 50.00mg/Lto 0.04 mg/L and 0.10 mg/L，respectively，and 10%excess BDP of stoichiometric dose-s were enough for CuEDTA and nickel citratewastewaters to reach the first-grade emi-ssion standard of integrated wastewaterdischarge standard. BDP could be applied in the range of pH≥4 for free and complexcopper wastewaters and pH≥7 for nickel wastewaters. And [CuBDP]nu001eprecipitatespossessed favorable settling performances and hardl-y leached at weak acidic andalkaline conditions. BDP CS precipitant is more effecti-ve than commercial smallmolecular precipitant DDTC in treating metal wastewaters.