Experimental studies on the effects of coagulation and adsorption as a pretreatment process on the microfiltration of oily wastewater. Issue 4 (30th November 2022)

• Record Type: Journal Article
• Authors: Shafiei, Niloufar Lashkari; Zokaee Ashtiani, Farzin; Fouladitajar, Amir
• Is Part Of: Water reuse. Volume 12:Issue 4(2022)
• Page Start: 420
• Page End: 437
• Publication Date: 2022-11-30
• Subjects: adsorption -- coagulation -- membrane separation -- oily wastewater -- pretreatment; Water reuse; Water -- Purification; Periodicals; 628.16
• DOI: 10.2166/wrd.2022.052
• Languages: English
• ISSNs: 2709-6092

Abstract

Abstract: To improve the performance of the membrane process in the treatment of oily wastewater, the combined effects of pretreatment, membrane modification, and optimization of operating parameters on the microfiltration membrane system were investigated. First, coagulation and adsorption were used as pretreatment steps. Polyaluminium chloride and ferric chloride were employed as coagulants, and granular activated carbon was used as an adsorbent. In the optimal coagulation condition (1 g/L polyaluminium chloride, pH 7.5), chemical oxygen demand (COD) was reduced by 96%, while in the optimal adsorption condition, in which large amounts of activated carbon were utilized, 48% of COD was eliminated. A membrane of polyethersulfone containing SiO2 -g-polymethacrylic acid (PMAA) nanoparticles was then prepared by the non-solvent-induced phase separation method. To reduce fouling and increase the flux of the membrane, the SiO2 nanoparticles were first activated with amine groups and then PMAA was grafted onto the surface of the particles. Subsequently, the operating parameters were studied to optimize the performance of the polyethersulfone (PES)/SiO2 -g-PMAA membrane using the response surface methodology (RSM) method. The results indicated that the flux of the modified membrane for pretreated wastewater was 72.2% higher than that of the PES membrane and non-pretreated wastewater at an optimum pressure of 2 bar and a flow rate of 3.5 L/min. HIGHLIGHTS: A combination of conventional wastewater treatment and membrane-based process was studied. A polyethersulfone membrane modified with SiO2 -g-PMAA nanoparticles was prepared. The effects of coagulation and adsorption as the pretreatment were investigated. The response surface methodology model was used to determine the best-operating conditions (cross flow velocity (CFV), transmembrane pressure (TMP), and feed concentration). The combined process showed high MF performance and chemical oxygen demand removal. Graphical Abstract