Abstract: In order to improve the removal efficiency of Cu2+ from serpentine leaching tailings (ALS) and realize the efficient removal of Cu2+ from wastewater,the study modified serpentine leaching tailings by alkali leaching,and explored the influence of modified serpentine leaching tailings (AALS) on Cu2+ removal performance in wastewater. The results showed that the optimum modification effect was obtained when the mass ratio of serpentine leaching tailings to sodium hydroxide was 1 ∶0. 12, the modification temperature was 30. 0℃ and the modification time was 90. 0 min. The mechanism of alkali modified serpentine leaching tailings was studied by means of BET,SEM,XRD and FTIR. The results showed that the specific surface area of serpentine leaching tailings was increased from 22. 62 m2 / g to 67. 19 m2 / g by alkali modification,and the structure of serpentine leaching tailings was eroded by alkali,which resulted in the exposure of more Si—O—Si and Si—O functional groups and enhanced the adsorption sites of Cu2+ on the particle surface. The optimum adsorption conditions of AALS for Cu2+ in solution are as follows:the amount of AALS is 0. 15 g,the adsorption time is 15. 0 min,the pH value of the solution is 5. 39,the adsorption capacity and the removal rate of Cu2+ in 50. 0 mL of 125. 0 mg / L Cu2+ solution are 40. 68 mg / g and 95. 27%,respectively. The adsorption kinetics fitting results show that the adsorption of Cu2+ on AALS is more suitable to be simulated by a quasi-secondorder kinetic model,which shows that Cu2+ is mainly chemisorbed on AALS surface. The desorption test shows that hydrochloric acid can not only regenerate the AALS,but also has a high adsorption rate for copper ions in the solution after repeated analytical regeneration. This study provides reference and guidance for the preparation of serpentine tailings modified materials and the adsorption treatment of heavy metal Cu2+ in solution.

Key words: serpentine leaching residue,alkali leaching modification,copper ions,adsorption kinetics