磺胺二甲基嘧啶在过硫酸盐存在下的辐照降解研究

本研究对磺胺二甲基嘧啶(SMT)在不同条件下的辐照降解进行了研究.SMT(20 mg·L~(-1),约0.072 mmol·L~(-1))在外加过硫酸根浓度为0、1、2、4、10和20 mmol·L~(-1)条件下分别进行辐照,发现伽马辐照可有效去除水中的SMT,并可极大地促进溶液TOC的去除,过硫酸盐与伽马辐照联合作用表现出明显的协同效应.在本研究中,各条件下的辐照降解反应均符合准一级反应动力学.在外加过硫酸盐的条件下,溶液的矿化度可以得到极大的提高,当吸收剂量为1 k Gy时,其矿化度由3.5%提高到22.8%,当吸收剂量为5 k Gy时,矿化度由14.1%提高到70.1%.在辐解后的溶液中,利用IC检测到硫酸根离子(SO_4~(2-))、甲酸根离子(HCOO~-)和乙酸根离子(CH_3COO~-)3种离子的存在,一部分中间产物通过GC-MS检测得到,常见的含氮离子(NO_2~-、NO_3~-和NH_4~++)并未在溶液中检测到.同时,本研究还深入探讨了SMT辐照降解机理和降解途径.

Radiolysis of sulfadiazine from wastewater in the presence of persulfate

Radiolysis of sulfamethazine (SMT) was characterized under different conditions in this research. SMT solutions (20 mg·L^-1) were irradiated in the presence of 0, 1, 2, 4, 10 and 20 mmol·L^-1 S₂O₈^2-, respectively. The results show that gamma radiation was effective in both SMT degradation and TOC removal, and the synergistic effects of gamma radiation with persulfate (S₂O₈^2-) were obviously. The degradation reactions conformed to the pseudo-first-order reaction kinetics. With absorbed doses of 1 kGy to 5 kGy, TOC removal rates were dramatically elevated after S₂O₈^2- was added -3.5% to 22.8% and 14.1% to 70.1%, respectively. In the process, three ions (SO₄^2-, HCOO^- and CH₃COO^-) were detected to be released from the radiolytic solutions by ion chromatography (IC). Furthermore, complicated products were identified by GC-MS. The normal N-containing ions (NO₂^-, NO₃^- and NH₄⁺) were not detected in the process. The pathways and mechanisms for the radiolytic process in the aqueous solution were proposed.