UV/O_3工艺降解水杨酸试验

TEST OF DEGRADATION OF SALICYLIC ACID VIA UV /O 3 PROCESS

采用O3、UV和UV/O3三种工艺,降解常见PPCPs物质——水杨酸(Salicylic Acid,SA)的合成废水,比较了不同工艺降解水杨酸的处理效果,并考察了O3浓度、溶液初始pH值等因素对UV/O3工艺降解水杨酸降解效果的影响。试验结果表明:在O3、UV和UV/O3工艺中,水杨酸降解效率由高到低排列依次为:UV/O3>O3>UV,其中UV/O3工艺的降解效率最高;当O3投加量为7 mg/L,水杨酸初始浓度为40 mg/L,溶液初始pH值为4.0,反应15 min时效果最佳,水杨酸可降解97%。此外,在工艺研究的基础上,对于UV/O3工艺降解水杨酸的机理进行初步探索,验证了水杨酸主要羟基化产物为2,5-DHBA和2,3-DHBA,且其浓度呈现先升高后降低的趋势,同时UV/O3体系中捕捉到的·OH的浓度也呈先升高后降低的趋势。

Comparison of salicylic acid（SA）degradation using 03, UV and UV/O3 processes was investigated with synthetic wastewater, and the effect of 03 dosage, initial pH value and reaction time on the salicylic acid degradation was also studied. The test results showed that the trend of salicylic acid degradation efficiency via the three processes was followed by UV/O3 〉 03 〉 UV. UV/O3 process was the most efficient. Nearly complete degradation （97%） of salicylic acid was achieved in the UV/O3 process with 03 dosage 7 mg/L, initial salicylic acid concentration 40 mg/L, pH value adjusted to 4.0 and reaction time 15 min. Moreover, based on the result of process research, the mechanism of degradation of salicylic acid was investigated. It was verified that the hydroxylation products of salicylic acid were mainly 2,5-DHBA and 2,3-DHBA. And there was a trend that the concentration of both of two products increased firstly and decreased later. At once,· OH concentration captured in the UV/O3 system had the same trend.