Preparation of hydrophilic nanofiltration membranes for removal of pharmaceuticals from water.

Maryam Omidvar,Ehsan Saljoughi,Ahmad Moarefian,Seyed Mahmoud Mousavi,Mohammad Soltanieh,Hoda Saffaran

doi:10.1186/s40201-015-0201-3

Abstract

Asymmetric polyethersulfone (PES) nanofiltration membranes were prepared via phase inversion technique. PES polymer, Brij 58 as surfactant additive, polyvinylpyrrolidone (PVP) as pore former and 1-methyl-2-pyrrolidone (NMP) as solvent were used in preparation of the casting solutions. Distillated water was used as the gelation media. The scanning electron microscopy (SEM) images and measurements of contact angle (CA) and zeta potential were used to characterize the prepared membranes. Also performance of the membranes was examined by determining the pure water flux (PWF) and pharmaceuticals rejection. The addition of Brij 58 to the casting solution resulted in formation of the membranes with higher thickness and more porous structure in the sublayer in comparison with the net PES membrane. The surface hydrophilicity of the membranes was remarkably enhanced via the presence of Brij 58 in the casting solution, so that, the contact angel diminished from 74.7° to 28.3° with adding 6 wt. % of Brij 58 to the casting solution. The addition of Brij 58 to the casting solution resulted in formation of the membranes with superior PWF and higher rejection of amoxicillin and ceftriaxone in comparison with the pure PES membrane.

Highlights

PES is a commercially available, thermally stable polymer, which is used in high-performance applications due to its toughness, good thermal resistance and chemical inertness [1]
Addition of Brij 58 resulted in the membranes with thinner skin-layer and more porous sublayer in comparison with the net PES membrane; while addition of 8 wt. % Brij 58 resulted in formation of a less porous structure with thicker skin-layer in comparison with the membrane prepared with 6 wt. % of Brij 58
Addition of a hydrophilic additive into the casting solution leads to the formation of complexes between additive and polymer resulting in a reduction of the interactions between polymer chains

Summary

Introduction

PES is a commercially available, thermally stable polymer, which is used in high-performance applications due to its toughness, good thermal resistance and chemical inertness [1]. PES is one of the most important polymeric materials and is widely used in separation fields [2, 3]. Though PES and PES-based membranes have been broadly applied in separation processes, they have disadvantages. The main disadvantage of the PES membranes is related to their relatively hydrophobic character [2]. Their hydrophobicity leads to a low membrane flux and poor anti-fouling properties, which have a great impact on PES membrane application and useful life [4, 5]. Membrane fouling is a common serious problem in water treatment and desalination plants employing nanofiltration (NF) and reverse osmosis (RO) membranes [6, 7].

Objectives

Methods

Results

Conclusion