缓释硫化剂对硫化物颗粒沉降性能的影响及作用机理  

Effects and mechanisms of sustained-release sulfuration reagent on the settling performance of sulfide particles

作　　者：朱锋 张新妙[3] 孔令昊 胡星云[1] 彭先佳[1,2] ZHU Feng;ZHANG Xinmiao;KONG Linghao;HU Xingyun;PENG Xianjia(Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China;University of Chinese Academy of Sciences,Beijing 100049,China;Environmental Protection Research Institute,Sinopec(Beijing)Research Institute of Chemical Industry Co.,Ltd.,Beijing,100013,China)

机构地区：[1]中国科学院生态环境研究中心,北京100085 [2]中国科学院大学,北京100049 [3]中石化(北京)化工研究院环境保护研究所,北京100013

出　　处：《环境工程学报》2025年第1期62-71,共10页Chinese Journal of Environmental Engineering

基　　金：国家自然科学基金面上资助项目(22076208)。

摘　　要：硫化沉淀法常被用于去除强酸性废水中的重金属/砷,但是,传统硫化剂中H_(2)S的快速释放导致生成的重金属/砷硫化物颗粒粒径细小且沉降性能差。因此,本研究合成了一种以CaS为硫化氢供体和有机硅聚合物(OSCS)为包覆材料的缓释硫化剂(CaS-OSCS)。CaS-OSCS能够在强酸性条件下稳定且持续地释放H_(2)S。CaS-OSCS作为供体,能够显著增大生成的硫化物颗粒粒径和改善颗粒沉降性能。CaS-OSCS生成的CdS颗粒粒径增大至22.40μm,分别为CaS和Na_(2)S作为供体生成的CdS颗粒粒径的1.6和7.2倍;生成的CdS颗粒沉降速率为2.69 mm·min^(−1),分别为CaS和Na_(2)S作为供体生成的CdS颗粒沉降速率的1.2和11倍。XRD和SEM-EDS表征证明生成的硫化物颗粒在CaS表面聚集生长。密度泛函理论(DFT)计算表明,CaS对S2-和Cd^(2+)都具有极强的吸附能力(ΔG<-30 kJ·mol^(−1)),使CdS的成核模式从均相成核转变为异相成核,促使生成的硫化物颗粒在CaS表面聚集生长。Derjaguin-Landau-Verwey-Overbeek(DLVO)理论计算证明OSCS与CdS之间存在明显排斥作用(ΔE=7.53 mJ·m^(−2)),OSCS无法为CdS颗粒的异相成核提供成核位点。本研究对提高金属硫化物在强酸性废水中的沉降性能具有重要意义。Sulfide precipitation is an effective method for the removal of heavy metal and arsenic from strongly acidic wastewater,but a large number of fine metal sulfide particles with poor settling performance form because of the rapid release of H_(2)S from traditional sulfuration reagents.Hence,a sustained-release sulfuration reagent(CaS-OSCS)with CaS as the H_(2)S dondor and organosilicon polymers(OSCS)as the clad material was developed,which could release H_(2)S steadily and continuously under strongly acidic conditions.CaS-OSCS as the donor significantly increased the particle size of sulfide particles and improve the settling performance.The CdS particles generated by CaS-OSCS increased to 22.40μm,which was 1.6 and 7.2 times of that generated by CaS and Na_(2)S,respectively.The settling velocity of CdS particles was 2.69 mm·min^(−1),which was 1.2 and 11 times of that of CdS particles generated by CaS and Na_(2)S,respectively.The XRD and SEM-EDS analyses showed that the sulfide particles accumulated and grew on the CaS surface.Density functional theory(DFT)calculations showed that the CaS exhibit strong adsorption capacity for S2-and Cd^(2+)(ΔG<-30 kJ·mol^(−1)),which could induce a transition in the nucleation mode of CdS from homogeneous nucleation to heterogeneous nucleation and promote the formation of sulfide particles on the surface of CaS.Derjaguin-Landau-Verwey-Overbeek(DLVO)theory calculations proved that a significant repulsive interaction between OSCS and CdS(ΔE=7.53 mJ·m^(−2)),indicating that OSCS cannot provide nucleation sites for the heterogeneous nucleation of CdS particles.This study is of great significance for improving the settling performance of metal sulfides in strongly acidic wastewater.

关 键 词：缓释硫化剂 硫化物颗粒 粒径 沉降性能 

分 类 号：X756[环境科学与工程—环境工程]