摘要
To investigate the potential use of ( ) residue for Cd adsorption, poly alcohol Na alginate (PVA) was applied to immobilize it. The parameters including contact time, pH, adsorbent dosages, and coexisting metal ions were studied. The suitable pH for immobilized was 4–7 wider than that for raw (pH 6–7). In the presence of Pb concentration varying from 0 to 30 mg·L , the Cd adsorption ratios declined by 6.71% and 47.45% for immobilized and raw , respectively. While, with the coexisting ion Cu concentration varied from 0 to 30 mg·L , the Cd adsorption ratios declined by 12.97% and 50.56% for immobilized and raw , respectively. The Cd adsorption isotherms in single–metal and dual-metal solutions were analyzed by using Langmuir, Freundlich, and Dubinin–Radushkevich models. The Cd adsorption capacities ( ) in single-metal solution were 6.448 mg·L and 2.832 mg·L for immobilized and raw , respectively. The of immobilized were 1.850 mg Cd·g in Cd + Pb solution and 3.961 mg Cd·g in Cd + Cu solution, respectively. The Cd adsorption processes subjected to both adsorbents follow pseudo-second-order model. Mechanism study showed the functional group of was –OH, –NH, –CO, and PVA played an important role in metal adsorbing. Mining wastewater treatment test showed that PVA–SA-immobilized was effective in mixed pollutant treatment even for wastewater containing metal ions in very low concentration.