摘要
地表水与地下水中硝酸盐浓度的快速增长,已经成为一个全球性的问题。利用紫外活化简单有机物产生还原性活性物质去除硝酸盐的研究方兴未艾。常见的紫外活化底物有甲酸与甲酸盐、草酸与草酸盐等,但是这些物质具有一定的毒性,为此选择未见报道的乙醇作为活化底物,考察了紫外活化乙醇还原硝酸盐的效率与乙醇投加量、硝酸盐浓度、pH、紫外光强度等因素的影响。研究结果表明:在n NO-3∶nC 2 H5 OH为5∶7、紫外光强度为175 W、反应90 min的条件下,硝态氮的还原率和总氮的去除率分别为100%和86.8%;增加紫外光强度可提高硝酸盐的还原率,但会降低总氮去除率;初始pH对硝态氮的还原率无明显影响,但pH值≤2会降低总氮去除率;水体中腐植酸浓度的增加会降低硝酸盐的还原率和总氮的去除率。该体系在通氮气的条件下,硝态氮还原过程符合一级反应动力学,反应速率常数在0.0314~0.1657 min-1,通过电子顺磁共振波谱仪证明该体系中还原性活性物质为二氧化碳自由基(CO_(2)^(·-))。
The rapid growth of nitrate concentration in surface water and groundwater has become a global problem.The research on nitrate removal by using simple organic matter activated by UV to produce reductive active substances is in the ascendant.Common UV-activated substrates include formic acid and formate,oxalic acid and oxalate,etc.But these substances have certain toxicity.Therefore,ethanol,which has not been reported before,is selected as the activated substrate to investigate the efficiency of ultraviolet activated ethanol to reduce nitrate and the influence of alcohol dosage,nitrate concentration,pH,UV intensity and other factors.The results showed that under the conditions of n NO-3∶nC 2 H5 OH=5∶7,UV intensity of 175 W and reaction for 90 minutes,the nitrate nitrogen reduction rate and total nitrogen removal rate were 100%and 86.8%respectively;the nitrate nitrogen reduction rate increased with the increase of UV light intensity,but the total nitrogen removal rate decreased;The initial pH value had no obvious effect on the reduction rate of nitrate nitrogen,but when pH value was≤2,the total nitrogen removal rate could reduce;The increase of humic acid concentration in water could reduce nitrate reduction rate and total nitrogen removal rate.With nitrogen in the system,the nitrate reduction process of the system conformed to the first-order reaction kinetics,and the reaction rate constants were between 0.0314~0.1657 min-1.And electron paramagnetic resonance spectrometer(EPR)proved that the active substance in the system was CO_(2)^(·-).
作者
赵凯杰
吴磊
姜娥梅
李宏辞
刘双斐
ZHAO Kaijie;WU Lei;JIANG Emei;LI Hongci;LIU Shuangfei(School of Energy and Environment,Southeast University,Nanjing 210098,China;Jiangsu Academy of Environmental Industry and Technology Corporation,Nanjing 210098,China)
出处
《净水技术》
CAS
2024年第3期99-109,共11页
Water Purification Technology
基金
江苏省科技厅-农村生活污水精准化治理及信息化监管技术研究与科技示范(BE2021619)。
