Remediation of 2,4-dichlorophenol-contaminated groundwater using nano-sized CaO2 in a two-dimensiona

• 作 者: Tianyi Li Chengwu Zhang Jingyi Zhang Song Yan Chuanyu Qin
• 机 构: Key Laboratory of Groundwater Resources and Environment (Ministry of Education),Jilin University,Cha
• 出 处: 环境科学与工程前沿
• 发表日期: 2021年5期
• 关键词: Calcium peroxide 2 4-DCP Reaction zone Fenton reaction

This study evaluates the applicability of nano-sized calcium peroxide (CaO2) as a source of H2O2 to remediate 2,4-dichlorophenol (2,4-DCP) contaminated groundwater via the advanced oxidation process (AOP).First,the effect and mechanism of 2,4-DCP degradation by CaO2 at different Fe concentrations were studied (Fenton reaction).We found that at high Fe concentrations,2,4-DCP almost completely degrades via primarily the oxidation of·OH within 5 h.At low Fe concentrations,the degradation rate of 2,4-DCP decreased rapidly.The main mechanism was the combined action of· OH and O2·-.Without Fe,the 2,4-DCP degradation reached 13.6％ in 213 h,primarily via the heterogeneous reaction on the surface of CaO2.Besides,2,4-DCP degradation was significantly affected by solution pH.When the solution pH was＞ 10,the degradation was almost completely inhibited.Thus,we adopted a two-dimensional water tank experiment to study the remediation efficiency CaO2 on the water sample.We noticed that the degradation took place mainly in regions of pH ＜ 10 (i.e.,CaO2 distribution area),both upstream and downstream of the tank.After 28 days of treatment,the average 2,4-DCP degradation level was ≈36.5％.Given the inadequacy of the results,we recommend that groundwater remediation using nano CaO2:(1) a buffer solution should be added to retard the rapid increase in pH,and (2) the nano CaO2 should be injected copiously in batches to reduce CaO2 deposition.