Cellulose acetate membranes fabricated by a combined vapor-induced/wet phase separation method: morphology and performan

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ORIGINAL RESEARCH

Cellulose acetate membranes fabricated by a combined vapor‑induced/wet phase separation method: morphology and performance evaluation Marzieh Moghiseh1   · Mahdie Safarpour1,2   · Jalal Barzin1  Received: 4 February 2020 / Accepted: 19 July 2020 © Iran Polymer and Petrochemical Institute 2020

Abstract Cellulose acetate (CA) microfiltration membranes were fabricated by a combined vapor-induced and wet phase separation technique. A systematic morphology study was performed on the membranes prepared under different fabrication conditions and dope solution compositions. The results showed that symmetric CA membranes could be obtained by controlling relative humidity, temperature and exposure time during vapor-induced phase separation step. While the surface morphology and pore size of the membranes could be mainly tailored by adjusting the dope solution composition. The performance study of the membranes showed that for operation at low transmembrane pressures, only symmetric membranes fabricated by vapor-induced phase separation process have permeability which can be reached 100 L/m2h using polyvinylpyrrolidone with an average molecular weight of 30,000 (PVPK30) or polyethylene glycol with an average molecular weight of 400 (PEG400) as additives. Bacteria removal performance of the membranes showed that samples prepared at optimized solution compositions of CA/PVP and CA/PEG fabricated at constant vapor-induced phase separation (VIPS) condition of 5 min exposure time, 45 °C and 55% relative humidity can completely filtrate the E. coli bacteria. The prepared CA membranes showed no cytotoxicity in mouse L929 fibroblast cells, confirming their biocompatible nature for possible water treatment or biomedical applications. Keywords  Vapor-induced phase separation · Microfiltration · Cellulose acetate · Bacteria removal · Symmetric membrane

Introduction Cellulose-based membranes were first introduced for seawater desalination [1, 2], and after that, widely used for several membrane-based applications due to their high biocompatibility, high antifouling ability, great hydrophilicity, long lifetime, and low cost [3, 4]. Cellulose acetate (CA) is the most preferred derivative of cellulose for the fabrication of polymeric membranes because of its proper solubility in some common solvents. This versatile property of the CA makes it possible to fabricate CA membranes by either * Jalal Barzin [email protected] 1



Department of Biomaterials, Faculty of Science, Iran Polymer and Petrochemical Institute, P.O. Box: 14965‑115, Tehran, Iran



Department of Chemistry, Faculty of Basic Science, Azarbaijan Shahid Madani University, P.O. box: 83714‑161, Tabriz, Iran

2

known phase inversion or solvent evaporation techniques [5–7]. Nowadays, phase inversion is the most common method for preparation of a wide range of polymeric membranes. Typically, a homogeneous polymeric solution (dope) containing a polymer, a solvent, and probable additives is cast into the desired shape (flat sheet, hollow fiber, etc.) and then