摘要
为有效分解近中性废水中典型难降解强络合物Ni-EDTA,构建配体-金属电子转移强化类芬顿技术(LFGR),基于Ni(Ⅱ)去除效能等系统分析其在近中性条件下对Ni-EDTA的破络特性,重点探究Fe(Ⅲ)与H2O2投加量、pH值、浊度、常见有机酸与常规无机盐对LFGR破络特性的影响。结合H2O2消耗观测、自由基淬灭实验、自由基信号检测与降解产物分析等科学识别LFGR体系中主要活性氧物种,并进一步剖析Ni-EDTA的破络过程与主导机制。定量比较分析LFGR与其他UV活化氧化技术去除多种重金属EDTA络合物(M-EDTA)的特性,并进一步阐明LFGR的运行成本优势。对于络合物浓度为1.0 mmol/L的近中性模拟废水,LFGR的优化反应条件为:Fe(Ⅲ)投加量为0.1 mmol/L,H2O2投加量为50 mmol/L,UV光照时间为20 min。该条件下,EDTA可完全转化,且经碱沉淀后Ni(Ⅱ)去除率可高达99.40%;LFGR对水中常见有机酸与常规无机盐呈现出良好的抗干扰性;H_(2)O_(2)主要通过与配体-金属电子转移产生的Fe(Ⅱ)发生类芬顿反应消耗;LFGR的主要作用过程是Fe(Ⅲ)置换Ni(Ⅱ)并激发配体-金属电子转移反应从而促进EDTA光解,UV进一步驱动Fe(Ⅲ)还原并加快Fe物种循环,进而强化类芬顿技术活性氧自由基(主要为·OH和·O_(2)^(-))的催化作用。LFGR可在近中性条件下实现多种M-EDTA的良好破络效果,水处理费用合计为4.21元/t,具有良好技术经济性。
A ligand-to-metal charge-transfer synergistic and Fenton-like gathered reaction(LFGR)was developed to effectively decompose Ni-EDTA,a typical strong complex in near-neutral wastewater.Based on the removal efficiency of Ni(Ⅱ)and other systems,the complex broken characteristics of Ni-EDTA under near-neutral conditions were analyzed.The effects of Fe(Ⅲ)and H2O2 dosage,pH,turbidity,common organic acids and conventional inorganic salts on the complex broken characteristics of LFGR were investigated.The main reactive oxygen species in the LFGR system were identified in combination with the observation of H2O2 consumption,free radical quenching experiment,free radical signal detection and degradation product analysis,and the complex broken process and dominant mechanism of Ni-EDTA were further analyzed.The removal properties of heavy metal EDTA complexes(M-EDTA)by LFGR and other UV activated oxidation technologies were quantitatively compared,and the operating cost advantages of LFGR were further clarified.For the near-neutral simulated wastewater with 1.0 mmol/L complex concentration,the optimal reaction conditions of LFGR are as follows:Fe(Ⅲ)salt dosage=0.1 mmol/L,H_(2)O_(2) dosage=50 mmol/L,and UV illumination time is 20 min.Under the above reaction conditions,the EDTA can be completely transformed and the Ni(Ⅱ)removal rate of Ni-EDTA can reach 99.40% after alkali precipitation;LFGR shows good anti-interference to common organic acids and conventional inorganic salts in water.H2O2 is consumed by Fenton-like reaction with Fe(Ⅱ)produced by ligand-to-metal charge-transfer.The main process of LFGR is that Fe(Ⅲ)replaces Ni(Ⅱ),stimulates the ligand-to-metal charge-transfer reaction and promotes the photolysis of EDTA,UV further drives Fe(Ⅲ)reduction and accelerates Fe species cycling,and further coordinates with Fenton-like reactive oxygen species(mainly·OH and·O_(2)^(-))to enhance the complex decomposition.LFGR can achieve a variety of M-EDTA good breaking effect under near-neutral conditions,the total cost of treatment of each ton of water is 4.21 Yuan,with good technical economy.
作者
荆世超
李杰
王赟
宋丽
刘福强
JING Shichao;LI Jie;WANG Yun;SONG Li;LIU Fuqiang(School of the Environment,Nanjing University,Nanjing 210023,P.R.China;Nanjing Huachuang Institute of Environmental Technology Co.,Ltd.,Nanjing 211106,P.R.China)
出处
《土木与环境工程学报（中英文）》
CSCD
北大核心
2024年第4期220-230,共11页
Journal of Civil and Environmental Engineering
基金
国家水体污染控制与治理科技重大专项(2014ZX07204-008)
南京扬子江生态文明创新中心“扬子江菁英计划”(2020)。
关键词
络合物
破络
配体-金属电子转移
类芬顿
近中性废水
complex
complex broken
ligand-to-metal charge-transfer
Fenton-like
near-neutral wastewater
