紫外/次氯酸钠和紫外/过碳酸钠工艺降解水杨酸的影响因素及降解机理  

Ultraviolet/sodium hypochlorite and ultraviolet/sodium percarbonate processes for degradation of salicylic acid:Influencing factors and mechanism

作　　者：杨帆 马晓雁[2] 李青松[1,3] 杨庆云 黄华翰 梁馨蕊 陈国元 李国新 YANG Fan;MA Xiaoyan;LI Qingsong;YANG Qingyun;HUANG Huahan;LIANG Xinrui;CHEN Guoyuan;LI Guoxin(Water Resource and Environment Institute of Xiamen University of Technology,Xiamen 361024,China;College of Civil Engineering and Architecture,Zhejiang University of Technology,Hangzhou 310014,China;Key Laboratory of Water Resources Utilization and Protection,Xiamen City,Xiamen 361024,China)

机构地区：[1]厦门理工学院水资源环境研究所,厦门361024 [2]浙江工业大学土木工程学院,杭州310014 [3]厦门市水资源利用与保护重点实验室,厦门361024

出　　处：《环境工程学报》2023年第1期82-94,共13页Chinese Journal of Environmental Engineering

基　　金：国家自然科学基金资助面上项目(51878582,41801219);福建省科技计划引导性资助项目(2021Y0041);福建省自然科学基金项目(2020J01256);福建省高校新世纪优秀人才支持计划项目(JA14227)。

摘　　要：采用紫外/次氯酸钠(UV/NaClO)和紫外/过碳酸钠(UV/SPC)工艺降解水中水杨酸(SA),且利用协同因子(R)作为评价指标,分别考察了氧化剂投加量、pH、阴离子(NO_(3)^(-)、HCO_(3)-)和腐殖酸(HA)等因素对SA去除的影响,结合TOC对比了2种工艺对SA的去除效果,通过鉴定中间降解产物探讨了SA可能的降解路径。结果表明:UV/NaClO和UV/SPC工艺中SA的去除均符合拟一级反应动力学,R与拟一级反应动力学常数(kobs)变化趋势相似。当NaClO和SPC质量浓度分别为3 mg·L^(-1)和12 mg·L^(-1)时,2种工艺中kobs分别为0.1732 min^(-1)和0.2588 min^(-1),而R_(UV/NaClO)和R_(UV/SPC)分别为9.5和15.9。kobs和R随氧化剂投加量的增加而升高,因过量的SPC消耗产生的羟基自由基(·OH)会导致kobs降低。初始pH对SA去除有较大影响,酸性环境有利于UV/NaClO工艺去除SA,而UV/SPC工艺则在pH=7具有较好的SA去除效果。NO_(3)^(-)与HCO_(3)-对UV/NaClO工艺去除SA有轻微的促进作用,而显著抑制UV/SPC工艺对SA的去除。HA对2种工艺中SA的去除均有抑制作用。相比UV/NaClO,UV/SPC工艺对TOC去除更为显著。通过分析SA的密度泛函理论(DFT)并结合主要的降解产物推测SA的降解机理主要为自由基的取代和氧化。The UV/NaClO and UV/SPC processes were used to degrade salicylic acid(SA)in water.Based on the synergy factor(R)as the evaluation index,the effects of oxidant dosage,pH,anions(NO_(3)^(-),HCO_(3)-)and humic acid(HA)on SA removal were investigated.Combined with TOC,the SA removal during UV/NaClO process and UV/SPC process was compared,the degradation path of SA and the possible intermediate products were also discussed.The results showed that SA removal in UV/NaClO and UV/SPC processes fitted well with the pseudo-first-order reaction kinetics model,and R and pseudo-first-order reaction kinetical constant(kobs)presented the similar variation trend.When the concentrations of NaClO and SPC were 3 mg·L^(-1)and 12 mg·L^(-1),respectively,the kobsvalues of the two processes were 0.1732 min^(-1)and 0.2588 min^(-1),respectively,the R_(UV/NaClO)and R_(UV/SPC)were 9.5 and 15.9,respectively.kobsand R increased with the increase of oxidant dosage,but the excessive SPC would consume the generated hydroxyl radicals(·OH),resulting in the decrease of kobs.The initial pH had a distinctly influence on both processes,the UV/NaClO process was more effective in an acidic environment than in an alkaline one,and the UV/SPC process demonstrated an excellent removal performance in a neutral environment(pH=7).NO_(3)^(-)and HCO_(3)^(-)could slightly promote SA degradation by the UV/NaClO process,but significantly inhibit SA degradation by the UV/SPC process.HA inhibited SA removal by both processes.UV/SPC process was superior to UV/NaClO process in TOC removal.Based on the density functional theory(DFT)analysis of SA and the main intermediate products,the main mechanism of SA degradation was the substitution and oxidation of radicals.

关 键 词：高级氧化工艺 协同效应 影响因素 降解路径 模拟毒性 

分 类 号：X703[环境科学与工程—环境工程]