Cu^(2+)共存对磺胺嘧啶在土壤中吸附的影响

Effect of Cu^(2+) coexistence on adsorption of sulfadiazine in soil

选取土壤环境中检出率高的铜和磺胺类抗生素为目标污染物,采用批次平衡试验法研究了在Cu^(2+)共存时,磺胺嘧啶(SDZ)在pH值、离子浓度、有机质含量、颗粒粒径等因子影响下的吸附特征,并对吸附前后的土样进行傅里叶红外光谱(FT-IR)表征.结果表明,在不同pH值环境中,Cu^(2+)显著提高了SDZ的吸附量;Cu^(2+)和Ca^(2+)均能与SDZ通过络合反应和离子桥作用促进SDZ的土壤吸附;有机质对SDZ的土壤吸附的影响与共存Cu^(2+)浓度密切相关;Cu^(2+)对黏粒吸附SDZ的影响较小;FT-IR分析表明,土壤对SDZ-Cu的吸附以物理吸附为主,并伴随氢键作用、表面络合、π-π共轭等作用.Cu^(2+)可显著增加SDZ在土壤中持留能力,降低其环境迁移的风险.

Copper(Cu) and Sulfadiazine(SDZ)were selected as target pollutants as their high detection rate in soil environment.The batch sorption methods were used to investigate effects of pH,ion concentration,organic matter content and particle size on SDZ adsorption to soil with Cu^(2+) co-existing.The adsorption mechanism of SDZ in soil was characterized by FT-IR analysis.Co-existence of Cu^(2+) significantly increased the adsorption amount of SDZ on soil even with different pH conditions.Both Cu^(2+) and Ca^(2+) could promote SDZ adsorption to soil particles by complexation and ion-bridge.The effect of organic matter on adsorption of SDZ on soil was greatly related to concentrations of the co-existing Cu^(2+).The adsorption of SDZ to soil clay was little influenced by the co-existing Cu^(2+).FT-IR analysis showed that the physical adsorption was the main mechanism of SDZ adsorption to soil,which was also accompanied by hydrogen bonding interactions,complexation andπ-πconjugation.Cu^(2+) can significantly increase the retention capacity of SDZ in soil and reduce its risk of environmental migration.