UV/H_(2)O_(2)和UV/PDS体系下黑碳标志物苯六酸降解动力学研究  

Investigation of the Degradation Kinetics of Mellitic Acid,a Marker for Black Carbon,under UV/H_(2)O_(2) and UV/PDS Systems

作　　者：刘晓静 刘春晖 燕姝雯[1] LIU Xiaojing;LIU Chunhui;YAN Shuwen(Department of Environmental Science and Engineering,Fudan University,Shanghai 200433,China;Ningbo Maritime Safety Administration of People s Republic of China,Ningbo Zhejiang 315100,China)

机构地区：[1]复旦大学环境科学与工程系,上海200433 [2]宁波海事局,宁波315100

出　　处：《复旦学报（自然科学版）》2024年第4期519-528,共10页Journal of Fudan University：Natural Science

基　　金：国家自然科学基金(21976035);上海市自然科学基金(20ZR1407300)。

摘　　要：苯六酸是焦炭、木炭和炭黑等多种碳物质彻底氧化的最终产物,在自然界中广泛存在,其环境归趋备受关注。本研究基于HO·及SO_(4)^(-)·高级氧化技术,考察了不同pH下UV/H_(2)O_(2)和UV/PDS体系中苯六酸的降解,发现相应的二级反应速率常数随pH变化而变化。拟合得到苯六酸7种形态在UV/H_(2)O_(2)中降解的二级反应速率常数范围为(3.2~85.1)×107 mol^(-1)·L·s^(-1),在UV/PDS中降解的二级反应速率常数范围为(1.1~30.5)×107 mol^(-1)·L·s^(-1)。同时给出了其在两种体系下降解的二级反应速率常数预测公式,建立动力学模型并模拟了两种体系下HO·及SO_(4)^(-)·的稳态浓度,结果发现:两种自由基的稳态浓度数量级范围在10^(-13)~10^(-11) mol·L^(-1)随pH增大,UV/H_(2)O_(2)体系中[HO·]ss先增大后减小,UV/PDS体系中[SO_(4)^(-)·]ss逐渐减小,且在该体系中[HO·]ss在酸性条件下的数值明显高于碱性条件。苯六酸是黑碳经过迁移转化后形成的重要产物之一,将苯六酸的降解与黑碳在环境中的归趋联系起来,可为全球碳循环的理解与探索提供有益补充。The ultimate product of complete oxidation of various carbonaceous materials such as coke,charcoal,and black carbon is mellitic acid,which has attracted significant attention due to its environmental fate and impact.This study focuses on the application of advanced oxidation technologies involving hydroxyl radicals and sulfate radicals.The degradation of mellitic acid under different pH conditions in UV/H_(2)O_(2) and UV/PDS systems was investigated,and the corresponding second-order reaction rate constants were changed with pH.The range of second-order rate constants for the degradation of the seven forms of Mellitic acid in the UV/H_(2)O_(2) system was fitted and determined to be(3.2—85.1)×107 mol^(-1)·L·s^(-1).Similarly,in the UV/PDS system,the range was determined to be(1.1—30.5)×107 mol^(-1)·L·s^(-1).The predictive formulas for the second-order reaction rate constants of Mellitic acid degradation in both systems were established.The models used to simulate the steady-state concentrations of HO·and SO_(4)^(-)·in the two systems showed that the steady-state concentrations of both radicals ranged from 10^(-13) to 10^(-11) mol·L^(-1).As the pH increases,[HO·]ss initially increased and then decreased in the UV/H_(2)O_(2) system,while[SO_(4)^(-)·]ss gradually decreased in the UV/PDS system.Additionally,the value of[HO·]ss in acidic conditions is significantly higher than alkaline conditions in the UV/PDS system.Mellitic acid emerges as a significant product following the migration and transformation of black carbon.Establishing a connection between the degradation of mellitic acid and the destiny of black carbon in the environment could offer valuable supplementary insights into the comprehensive investigation and examination of the global carbon cycle.

关 键 词：苯六酸 羟基自由基 硫酸根自由基 降解动力学 

分 类 号：X13[环境科学与工程—环境科学]