Identifying polyvinylidene fluoride ultrafiltration membrane fouling behavior of different effluent organic matter fractions using colloidal probes

• Published in: Water research (Oxford) 2014-05, Vol.55, p.313-322
• Main Authors: Miao, Rui, Wang, Lei, Lv, Yongtao, Wang, Xudong, Feng, Ling, Liu, Ziwen, Huang, Danxi, Yang, Yongzhe
• Format: Article
• Language: English
• Subjects: Applied sciences; Atomic force microscopy; Colloidal probes; Colloids; Effluent organic matter; Effluents; Exact sciences and technology; Fouling; General purification processes; Interaction forces; Membrane fouling; Membranes; Membranes, Artificial; Molecular weight; Organic Chemicals - isolation & purification; Pollution; Polyvinylidene fluorides; Polyvinyls - chemistry; Strategy; Ultrafiltration; Ultrafiltration - standards; Wastewaters; Wastewaters reuse. Miscellaneous; Water Purification - methods; Water treatment and pollution
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2014.02.039

The interaction forces between effluent organic matter (EfOM) fractions and membrane were measured by atomic force microscopy in conjunction with self-made membrane material colloidal probes. The inter-EfOM-fraction and intra-EfOM-fraction interactions were investigated using corresponding EfOM-fraction-coated colloidal probe. We combined this analysis with corresponding fouling experiments to identify the EfOM fractions responsible for polyvinylidene fluoride (PVDF) ultrafiltration membrane fouling. Results show that hydrophilic and hydrophobic fractions were the dominant fractions responsible for membrane fouling and flux decline in the initial and later filtration stages, respectively, which was mainly attributed to the stronger PVDF-hydrophilic fraction and intra-hydrophobic-fraction interaction forces. This phenomenon, in conjunction with the fact that each interaction force of PVDF–EfOM fraction was stronger than corresponding intra-EfOM-fraction force, suggests that the elimination of the PVDF-hydrophilic fraction interaction force is the best strategy for controlling EfOM fouling. Moreover, the inter-EfOM-fraction interaction force was mainly controlled by the corresponding intra-EfOM-fraction interaction forces. And, while the membrane–EfOM fraction and intra-EfOM-fraction interactions for each type of EfOM fraction are equivalent, the EfOM fractions with the molecular weight smaller than the molecular weight cutoff of the membranes used were mainly responsible for membrane fouling rather than the relatively high-molecular-weight fractions. [Display omitted] •Membrane material and EfOM-fraction-coated colloidal probes were successfully made.•Force measurements were carried out by AFM combined with colloidal probes.•The strongest PVDF-HPI force caused the severest fouling in initial filtration stage.•PVDF UF membrane fouling was mainly dominated by HPO in later filtration stage.