UV/Na_(2)CO_(5)降解水中咪唑类离子液体影响因素的研究  

A Study on the Influencing Factors of Imidazolium Ionic Liquids Photodegradation in the UV/Na_(2)CO_(5) Reaction System

作　　者：刘娇琴 曲瑞娟[2] 王遵尧[2] 晋日亚 乔怡娜 LIU Jiaoqin;QU Ruijuan;WANG Zunyao;JIN Riya;QIAO Yina(School of Environment and Safety Engineering,North University of China,Taiyuan 030051,China;School of the Environment,Nanjing University,State Key Laboratory of Pollution Control and Resources Reuse,Nanjing 210093,China)

机构地区：[1]中北大学环境与安全工程学院,山西太原030051 [2]南京大学环境学院,污染控制与资源化研究国家重点实验室,江苏南京210093

出　　处：《水处理技术》2023年第7期90-95,99,共7页Technology of Water Treatment

基　　金：山西省基础研究计划自由探索类青年科学研究项目(20210302124335);山西省省筹资金资助回国留学人员科研项目(2022-152);南京大学污染控制与资源化研究国家重点实验室开放基金项目(PCRRF21024)。

摘　　要：采用UV/Na_(2)CO_(5)技术去除水中24种咪唑类离子液体,探究了过碳酸钠(Na_(2)CO_(5))浓度、不同初始pH、无机离子种类、腐殖酸(HA)浓度和不同真实水体等对降解的影响,并通过自由基淬灭实验推断了反应体系中起作用的自由基。实验结果表明,24种咪唑类离子液体的光降解均符合假一级动力学,但光降解速率常数与其自身结构性质未呈现明显相关性。离子液体的光降解速率随着Na_(2)CO_(5)浓度的升高而增加,当Na_(2)CO_(5)与1-辛基-3甲基咪唑溴盐(IL-5)的摩尔浓度比为10:1时,IL-5在5 min之内几乎可以100%被降解。反应体系的pH对IL-5的降解有重要影响,当pH=8时,IL-5的降解速率常数最高,为0.0114 s^(-1)。Na^(+)、K^(+)、Ca^(2+)、Mg^(2+)和Cl^(-)对IL-5的光降解无影响,SO_(4)^(2-)有明显的促进作用,Cu^(2+)、Fe^(3+)和NH_(4)^(+)则呈现出明显的抑制作用,NO_(3)^(-)和HCO_(3)^(-)轻微抑制IL-5的光降解。与1 mg/L HA相比,10 mg/L HA显著抑制IL-5的光降解,这可能是由于HA产生活性氧物种的促进作用低于吸光竞争的抑制作用造成的。IL-5在真实水体中的反应速率排序为超纯水>自来水>二沉池出水>九乡河水>好氧池出水。自由基淬灭实验结果表明,UV/Na_(2)CO_(5)反应体系中主要的活性自由基是羟基自由基(·OH),并存在少量的单线态氧(1O2)和超氧自由基(·O_(2)^(-))。In this work,the UV/Na_(2)CO_(5) method was used to remove the 24 kinds of imidazolium ionic liquids(ILs)in water,and the effects of sodium percarbonate(Na_(2)CO_(5))concentration,different initial pH,substrate concentration,inorganic ion species,and humic acid(HA)concentration on photodegradation of ILs were investigated.The main free radicals in this reaction system were deduced by the free radical quenching experiment.The photodegradation of 24 kinds of ILs was well-fitted with pseudo-first-order kinetics,and the photodegradation constants of ILs had no obvious correlation with its own structural properties.The photodegradation efficiencies of ILs increased with the increase of Na_(2)CO_(5) concentration.IL-5 can be degraded almost 100%within 5 min when the molar ratio of Na_(2)CO_(5) to 1-octyl-3-methylimidazolium bromide(IL-5)was 10:1.The degradation constant of IL-5 was the highest when pH=8,which was 0.0114 s^(-1).Na^(+),K^(+),Ca^(2+),Mg^(2+),and Cl^(-)had no significant effects,SO42-showed an accelerating effect,Cu^(2+),Fe^(3+),and NH_(4)^(+)had an obvious inhibition effect,and NO_(3)^(-)and HCO_(3)^(-)showed slightly inhibited on the photodegradation of IL-5,respectively.The order of the removal efficiencies of IL-5 in real waters was ultrapure water>tap water>effluent from secondary sedimentation tank>Jiuxiang River water>effluent from aerobic tank.10 mg/L HA showed a significant inhibited effect on the photodegradation of IL-5 compared with 1 mg/L HA.The main active free radical was hydroxyl radicals(·OH),and there were a small amount of singlet oxygen(1O2)and superoxide radicals(·O_(2)^(-))in the UV/Na_(2)CO_(5) reaction system.

关 键 词：咪唑类离子液体 UV/Na_(2)CO_(5) 降解动力学 影响因素 

分 类 号：X703.1[环境科学与工程—环境工程]