Fe2+催化过碳酸钠降解水体中的磺胺二甲嘧啶

研究了过碳酸钠(SPC)在Fe~(2+)催化作用下对磺胺二甲嘧啶(SMT)的降解作用,探究了Fe~(2+)和SPC的初始浓度及溶液初始p H对Fe~(2+)/SPC体系降解磺胺二甲嘧啶的影响,分析了体系中起主要作用的活性物种,并采用HPLC-MS/MS技术鉴定其降解的主要产物并提出可能的降解途径.结果表明,适当提高Fe~(2+)与SPC初始浓度可以提高磺胺二甲嘧啶的降解率,但超过一定范围后反而会抑制其降解,实验中Fe~(2+)/SPC/SMT的最佳物质的量比为15∶10∶1,此时磺胺二甲嘧啶的降解率可以达到84%;溶液初始p H的提高会抑制磺胺二甲嘧啶的降解,但抑制幅度不大,即使在偏碱性条件下仍能达到75%的降解率;Fe~(2+)/SPC体系中主要活性物种是HO·;磺胺二甲嘧啶可能的降解途径有3种,主要包括苯环相连N原子的羟基化、磺酰胺键S—N]的断裂及分子间重排脱SO2.

Degradation of sulfamethazine with Fe2+-catalyzed sodium percarbonate system

The performance of Fe²⁺-catalyzed sodium percarbonate (SPC) stimulating the oxidation of Sulfamethazine (SMT) was investigated. The effects of initial concentration of Fe²⁺ and SPC and the initial solution pH were evaluated. The main active species in Fe²⁺/SPC system were also discussed by adding scavenger. The main products were identified by using LC-MS technique. Possible degradation pathway was proposed. Results show that the degradation rate was enhanced with the increase of the concentration of Fe²⁺ and SPC. the best ratio of Fe²⁺/SPC/SMT was 15:10:1 where the degradation rate reached 84% in the present study. over optimum concentrations, increasing Fe²⁺ and SPC inhibited the SMT degradation.The increase of initial pH had a little inhibiting effect on the SMT degradation rate, but the degradation rate was still normal/higher than expected even in the alkaline condition(the degradation rate reached 75% under pH 8.0).HO·was the main active species in the Fe²⁺/SPC system, and hydroxylation,S-N] bond cleavage and SO₂ extrusion were found to be the three possible degradation pathway.