Nanofiltration (NF) is being increasingly applied to produce high-quality drinking water; however, its cost-effective operation remains challenging due to the perennial membrane fouling. On account of the low tolerance of common NF membranes to chemical oxidants, this study proposed high-dose UV irradiation as a pretreatment strategy for organic fouling mitigation. Results showed that the permeate flux decline of the membrane with UV-treated feedwater (with a dose of 750 mJ cm−2) was less drastic than that with raw feedwater, but slightly faster as compared to that with UV/Cl2 pretreatment. The final normalized fluxes were 0.69, 0.79, and 0.82, respectively, after 10 h of operation with raw, UV- and UV/Cl2-treated feedwaters. With the characterization of feedwaters and membranes, the fouling was found to be initiated by the adsorption of hydrophilic biopolymers onto the membrane, followed by the deposition of hydrophobic humic substances. Reduction of the “glue” biopolymers was crucial to membrane fouling mitigation. The applicability of UV pretreatment in practice was testified with a pilot-scale UV-NF system where permeate flux of the NF module decreased by 37% after six-week continuous operation. Moreover, UV pretreatment could remove most of the identified pesticides in the feedwater with a removal efficiency over 80% for metolachlor and imidacloprid, but had no or even a negative effect on perfluorinated compounds. This work discloses the efficacy and mechanism of high-dose UV irradiation for NF membrane fouling control, which facilitates future research and application of NF technology.

中文翻译：

---

高剂量紫外线照射在饮用水生产中作为纳滤预处理的应用：有机污垢缓解和微污染物去除


纳滤 （NF） 越来越多地用于生产高质量的饮用水;然而，由于常年膜污染，其经济高效的运行仍然具有挑战性。鉴于普通 NF 膜对化学氧化剂的耐受性低，本研究提出了高剂量紫外线照射作为减轻有机污染的预处理策略。结果表明，使用 UV 处理的给水（剂量为 750 mJ cm-2）的膜的渗透通量下降幅度小于原始给水，但与 UV/Cl2 预处理相比略快。使用经 UV/Cl2 处理的原始给水运行 10 小时后，最终归一化通量分别为 0.69、0.79 和 0.82。通过对给水和膜的表征，发现结垢是由亲水性生物聚合物吸附到膜上引发的，然后是疏水性腐殖质物质的沉积。减少“胶水”生物聚合物对于缓解膜污染至关重要。紫外线预处理在实践中的适用性通过中试规模的 UV-NF 系统得到证明，其中 NF 模块的渗透通量在连续运行六周后降低了 37%。此外，紫外线预处理可以去除给水中大部分已鉴定的农药，对异丙甲草胺和吡虫啉的去除效率超过 80%，但对全氟化合物没有影响，甚至没有负面影响。这项工作揭示了高剂量紫外辐照控制 NF 膜污染的功效和机制，为未来 NF 技术的研究和应用提供了便利。