三氯蔗糖在紫外/亚硫酸盐水处理过程中的还原产物及其可生化性研究  

Investigation into the reduction product of sucralose during ultraviolet/sulfite water treatment and its biodegradability

作　　者：龚杜美瑾 李雨馨 单超 Gong Dumeijin;Li Yuxin;Shan Chao(State Key Laboratory of Pollution Control and Resource Reuse,School of Environment,Nanjing University,Nanjing,210023,China)

机构地区：[1]污染控制与资源化研究国家重点实验室,南京大学环境学院,南京210023

出　　处：《南京大学学报（自然科学版）》2024年第4期674-682,共9页Journal of Nanjing University（Natural Science）

基　　金：国家重点研发计划课题(2021YFA1201701);国家自然科学基金(22222603)。

摘　　要：三氯蔗糖是典型的难生物利用有机物,其在化学还原水处理过程中的可还原性、还原产物种类及其可生化性均不明确.为阐明上述问题,探究了三氯蔗糖经过典型高级还原过程——紫外/亚硫酸盐(UV/SO_(3)^(2-))转化的还原产物种类及其可生化性.结果表明,三氯蔗糖经UV/SO_(3)^(2-)转化可几乎完全脱氯(>99.5%),同时总有机碳保持基本不变,脱氯速率随pH升高(5~9)和SO_(3)^(2-)浓度增加(0~5 mmol·L^(-1))而增大.通过高效液相色谱-高分辨质谱联用分析鉴定了其主要转化产物为4,1',6'-三脱氧蔗糖,结合动力学分析推断脱氯加氢为该反应的主要过程.测定了三氯蔗糖在UV/SO_(3)^(2-)转化过程中的五日生化需氧量(BOD5)和化学需氧量(COD)的变化,可生化性指标BOD5/COD值(B/C)从小于0.05大幅提升至0.4以上,BOD5显著提高至与同等测试条件下葡萄糖参比值相当(99.4%),表明其转化产物4,1',6'-三脱氧蔗糖是一种可生化性优良的微生物碳源.本研究为三氯蔗糖的潜在转化途径和环境归趋提供新认知,并为三氯蔗糖作为评估各类化学还原工艺效能的模式物质以及相应基准评价方法的建立提供参考.Sucralose is a typical recalcitrant organic compound.However,the reducibility of sucralose,the resultant reduction product of sucralose during chemical reduction water treatment processes and the biodegradability of the reduction product are still unknown.In order to address the above issues,the reduction product of sucralose during a typical advanced reduction process of ultraviolet/sulfite(UV/SO_(3)^(2-))and the biodegradability of the reduction product were investigated.The results showed that sucralose could be almost completely dechlorinated(>99.5%)by UV/SO_(3)^(2-) conversion while the total organic carbon(TOC)remained basically unchanged,and the rate of dechlorination improved with the increase of pH(5~9)and the increase of SO_(3)^(2-) concentration(0~5 mmol·L^(-1)).The dominant reduction product was identified as 4,1',6'⁃trideoxysucrose through the analysis of high⁃performance liquid chromatography coupled with high resolution mass spectrometry(HPLC⁃HRMS).The evolution kinetics of sucralose and 4,1',6'⁃trideoxysucrose revealed that the transformation of sucralose during the UV/SO_(3)^(2-) process was mainly a hydrodechlorination process.The evolution of the five⁃day biochemical oxygen demand(BOD5)and chemical oxygen demand(COD)during the conversion of sucralose in UV/SO_(3)^(2-) process were monitored,and the biodegradability index,BOD5 COD ratio(B/C),increased dramatically from<0.05 to>0.4,and BOD5 significantly increased to be comparable to the reference value of glucose under the identical testing conditions(99.4%),indicating that the dominant product 4,1',6'⁃trideoxysucrose is a well biodegradable microbial carbon source.This study provides new insights into the potential transformation pathways and environmental fate of sucralose,and paves the way for establishing standard methods employing sucralose as a model compound to evaluate the performances of various chemical reduction processes.

关 键 词：氯代有机物 化学还原 三氯蔗糖 可生化性 产物鉴定 

分 类 号：X52[环境科学与工程—环境工程]