Investigation into the reduction product of sucralose during ultraviolet/sulfite water treatment and its biodegradability
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/SO32-)and the biodegradability of the reduction product were investigated.The results showed that sucralose could be almost completely dechlorinated(＞99.5％)by UV/SO32-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 SO3-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/SO32-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/SO32-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.
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维普
