Sun Hongfang, Zhu Daoxu, Shi Peng, Ji Wenxiang, Cao Xun, Cheng Shi, Lou Yufeng, Li Aimin
State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
Yancheng Academy of Environmental Protection Technology and Engineering, Nanjing University, Yancheng 224000, China.
Membranes (Basel). 2022 Feb 27;12(3):273. doi: 10.3390/membranes12030273.
The anion exchange (AIX) spent brine, generated during the NDMP-3 resin regeneration process, highly loaded with organic substances mainly humic substances (HSs) and salts (mainly NaCl) remains an environmental concern. In this study, pilot-scale electro dialysis (ED) and ultrafiltration (UF) hybrid technologies were first used to recover NaCl solution as a resin regeneration agent and HSs, which could be utilized as a vital ingredient of organic fertilizer, from the AIX spent brine. Recovered ≈ 15% w/w NaCl solution obtained by two-stage pilot-scale ED can be used to regenerate saturated NDMP-3 anion exchange resins; the regeneration−readsorption performance of NDMP-3 resins was equivalent to that of fresh ≈ 15% w/w NaCl solution. The two-stage dilute solution with low-salt content (0.49% w/w) was further concentrated by pilot-scale UF, so that the HS content in the retentate solution was >30 g/L, which meets the HS content required for water-soluble organic fertilizers. The HS liquid fertilizer could significantly stimulate the growth of green vegetables with no phytotoxicity, mainly due to special properties of HSs. These results demonstrate that ED + UF hybrid technologies can be a promising approach for the sustainable treatment and resource recovery of AIX spent brine.
在NDMP - 3树脂再生过程中产生的阴离子交换（AIX）废盐水，含有大量主要为腐殖质（HSs）的有机物质和盐类（主要是NaCl），仍然是一个环境问题。在本研究中，首次采用中试规模的电渗析（ED）和超滤（UF）混合技术，从AIX废盐水中回收NaCl溶液作为树脂再生剂，并回收HSs，HSs可作为有机肥料的重要成分。通过两阶段中试规模的电渗析获得的约15% w/w的NaCl回收溶液可用于再生饱和的NDMP - 3阴离子交换树脂；NDMP - 3树脂的再生 - 再吸附性能与新鲜的约15% w/w的NaCl溶液相当。低盐含量（0.49% w/w）的两阶段稀释溶液通过中试规模的超滤进一步浓缩，使截留液中的HS含量>30 g/L，满足水溶性有机肥料所需的HS含量。HS液体肥料可显著促进青菜生长且无植物毒性，这主要归因于HSs的特殊性质。这些结果表明，ED + UF混合技术可能是一种有前景的AIX废盐水可持续处理和资源回收方法。
