Incorporation of zeolitic imidazolate framework-8 (ZIF-8) in the polyamide and polysulfone layers of forward osmosis membranes for enhancing aquaculture wastewater recovery and PPCPs removal

• Published in: Journal of water process engineering 2024-09, Vol.66, p.105980, Article 105980
• Main Authors: Lin, Yi-Li, Zheng, Nai-Yun, Chen, You-Jie, Chang, Chao-Chin
• Format: Article
• Language: English
• Subjects: Dual-layer modification; Emerging contaminant removal; Thin-film composite forward osmosis membrane (TF-CFOM); Wastewater recovery; Zeolitic imidazolate framework-8 (ZIF-8)
• ISSN: 2214-7144; 2214-7144
• DOI: 10.1016/j.jwpe.2024.105980

Wastewater recovery is essential to alleviate water resource shortages, and this can be achieved through a high-energy-efficient forward osmosis (FO) process combined with an emerging material, zeolitic imidazolate framework-8 (ZIF-8). Here, we create thin-film composite FO membranes (TF-CFOMs) by incorporating ZIF-8 into the active polyamide (PA) and/or support polysulfone (PSf) layers to address the challenges of low water flux and loss of draw solutes during operation. Experimental factors included the dosage of ZIF-8 nanoparticles in PA preparation solutions and the dosages of 2-methylimidazole (2-Hmim) and zinc nitrate hexahydrate (ZNH) in n-methyl-2-pyrrolidone (NMP) to fabricate the PSf casting solutions with in-situ formed ZIF-8 nanoparticles. Successful ZIF-8 incorporation on the TF-CFOM surface was confirmed, and the ZIF-8 TF-CFOMs exhibited increased surface hydrophilicity and separation performance. Only modifying the PA layer by adding 0.025 wt% ZIF-8 nanoparticles in trimesoyl chloride (TMC) resulted in the membrane (PA0.025T-PSf0) with water flux 2.3 times higher than the pristine TF-CFOM (4.9 LMH). The pristine and modified TF-CFOMs were further applied for aquaculture wastewater (AWW) recovery and removal of pharmaceuticals and personal care products (PPCPs). Results of water recovery demonstrated that the recovery rate reached 89.1% in 3.5 days when using the dual-layer modified TF-CFOM. Results of PPCP removal indicated that both pristine and modified TF-CFOMs can achieve high PPCP rejection efficiency (>90%), with the modified TF-CFOM (PA0.025T-PSf2.0) performing the best. Overall, the PA0.025T-PSf2.0 TF-CFOM achieved high and stable separation efficiency in long-duration AWW recovery, making it well-suited for practical field applications. [Display omitted] •A promising membrane was successfully developed as a dual-layer ZIF-8 TF-CFOM.•ZIF-8 TF-CFOMs significatly improved hydrophilicity and PPCP rejection.•Achieved water flux of 6–11 LMH with ZIF-8 TF-CFOMs.•89% water recovery in 3.5 days during aquaculture wastewater recovery.