再生液添加NaHCO3对硝酸盐选择性去除工艺的影响  

EFFECT OF NAHCO3 ADDITION INTO NaCl REGENERANT ON NITRATE-SELECTIVE ION EXCHANGE REMOVAL PROCESS

作　　者：段守鹏 郑少奎[1] DUAN Shou-peng;ZHENG Shao-kui(MOE Key Laboratory of Water and Sediment Sciences&State Key Lab of Water Environment Simulation,School of Environment,Beijing Normal University,Beijing 100875,China)

机构地区：[1]北京师范大学环境学院水沙科学教育部重点实验室/水环境模拟国家重点实验室,北京100875

出　　处：《环境工程》2020年第11期72-77,共6页Environmental Engineering

基　　金：国家自然科学基金(21677016,51878050,91547207,U1806217);国家重点研发专项(2018YFC1406404)。

摘　　要：在NaCl再生液中添加pH缓冲剂NaHCO3,重点调查了添加NaHCO3对失效再生液电解效果和地下水硝酸盐选择性离子交换-再生-失效再生液电解工艺长期运行稳定性的影响。结果表明:在6 g/L NaCl再生液中添加10 g/L NaHCO3后,电解8 h硝酸盐的去除率达到96%,溶液pH值变化较小,硝酸盐去除效果优于不调节pH或加稀盐酸调节pH,Fe阴极无显著腐蚀现象;再生液NaCl浓度从6 g/L提高到36 g/L,电解反应的硝酸盐去除率降低;地下水选择性离子交换-再生-失效再生液电解工艺长期运行过程中(13个工作循环),在6 g/L NaCl再生液中添加NaHCO3对产水水质、树脂选择性、再生液洗脱能力和硝酸盐积累规律均无负面影响,产水水质稳定、优良。The nitrate removal performance from spent brine by electrolysis was investigated,with 10 g/L NaHCO3 added into 6 g/L NaCl regenerant as a pH buffer.Besides a stable pH level(8.3~9.1)during 8 h electrolysis of spent brine,there was a higher nitrate removal efficiency(i.e.,96%)achieved by the addition of NaHCO3 than those achieved by the addition of diluted HCl solution and even without pH adjustment.The addition of NaHCO3 also protected Fe cathodic plate from attacks of aggressive ions(e.g.,chloride)in regenerant.The increase in NaCl concentration in regenerant from 6 g/L to 36 g/L led to a remarkable decrease in nitrate removal by 20%.Subsequently,this study investigated the long-term operation performance(i.e.,13 cycles)of the nitrate-selective ion exchange-regeneration-spent brine electrolysis process for nitrate-ridden groundwater treatment,with the addition of 10 g/L NaHCO3 into 6 g/L NaCl regenerant.There were no side effect on product water quality,resin nitrate selectivity,regenerant elution capacity,and nitrate accumulation characteristics in regenerant observed after the addition of NaHCO3.Nitrate concentration in product water stably met the required water quality standards for drinking water throughout the experimental periods.

关 键 词：地下水 硝酸盐 选择性离子交换 再生液 电化学 

分 类 号：X523[环境科学与工程—环境工程]