Lin Dachao, Zhang Han, Wang Zhihong, Xu Daliang, Li Guibai, Ulbricht Mathias, Liang Heng
State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, Harbin 150090, PR China; School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, PR China; Lehrstuhl für Technische Chemie II, Universität Duisburg-Essen, Essen 45117, Germany.
State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, Harbin 150090, PR China.
Sci Total Environ. 2023 Dec 20;905:167364. doi: 10.1016/j.scitotenv.2023.167364. Epub 2023 Sep 26.
Even though pre-oxidation is usually considered as a promising method to alleviate membrane fouling, information on performance and inner mechanisms of pre-oxidation-influenced membrane fouling during nanofiltration of brackish water is still limited. This study is the first work in which oxidant reduction byproducts and interaction between different pollutants were particularly considered to address these problems. Herein, nanofiltration experiments with different pre-oxidized synthesis brackish water containing inorganic salts and organic pollutants were conducted. Membrane flux results showed that both NaClO and KFeO aggravated membrane fouling, but 0.45 mg/mg TOC KMnO mitigated it when simulation results of NICA-Donnan model showed that the complexation between calcium ions and humic acid (HA) was weakened. However, membrane fouling was enhanced by higher dosage of KMnO. Fourier transform infrared spectrometer using attenuated total reflection (ATR-FTIR) and X-ray diffraction (XRD) spectrum showed that the aggravated membrane fouling was mainly caused by the generation of amorphous manganese oxide, which was oxidant reduction byproduct and had strong capacity for adsorption of HA. Particle size distribution and zeta potential variation indicated that the accumulation of HA could enhance the crystallization process and then the electrostatic attraction between membrane and bulk crystallization was induced. According to SEM images and fitting results of Hermia's models, the already-formed bulk crystallization by 1.90 mg/mg TOC KMnO could deposit on membranes more easily, followed by the formation of a denser fouling layer. Overall, the present study provided new insights into the design of reliable pre-oxidation strategies for alleviating membrane fouling during nanofiltration of brackish water.
尽管预氧化通常被认为是减轻膜污染的一种有前景的方法，但关于微咸水纳滤过程中预氧化影响膜污染的性能和内在机制的信息仍然有限。本研究首次特别考虑了氧化剂还原副产物以及不同污染物之间的相互作用来解决这些问题。在此，进行了用含有无机盐和有机污染物的不同预氧化合成微咸水的纳滤实验。膜通量结果表明，NaClO和KFeO都会加剧膜污染，但当NICA-Donnan模型的模拟结果表明钙离子与腐殖酸（HA）之间的络合作用减弱时，0.45 mg/mg TOC的KMnO可减轻膜污染。然而，较高剂量的KMnO会加剧膜污染。采用衰减全反射的傅里叶变换红外光谱仪（ATR-FTIR）和X射线衍射（XRD）光谱表明，膜污染加剧主要是由无定形锰氧化物的生成引起的，它是氧化剂还原副产物，对HA有很强的吸附能力。粒径分布和zeta电位变化表明，HA的积累可以增强结晶过程，进而诱导膜与大量结晶之间的静电吸引。根据扫描电子显微镜图像和赫米亚模型拟合结果，1.90 mg/mg TOC的KMnO形成的大量结晶更容易沉积在膜上，随后形成更致密的污染层。总体而言，本研究为设计可靠的预氧化策略以减轻微咸水纳滤过程中的膜污染提供了新的见解。
