Facile co-sintering process to fabricate sustainable antifouling silver nanoparticles (AgNPs)-enhanced tight ceramic ultrafiltration membranes for protein separation

Dong Zou,Xianfu Chen,Enrico Drioli,Xuebin Ke,Minghui Qiu,Yiqun Fan

doi:10.1016/j.memsci.2019.117402

Dong Zou, Xianfu Chen + Show 4 more

Open Access

https://doi.org/10.1016/j.memsci.2019.117402

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Abstract

Protein separation in chemical industry applications using tight ceramic ultrafiltration (UF) membranes with multilayer asymmetric structures is hindered by challenges in their fabrication and fouling phenomenon. In this study, a facile co-sintering method for fabrication of silver nanoparticles (AgNPs)-enhanced tight ceramic ultrafiltration membranes was comprehensively investigated. The introduction of AgNPs into the membrane layer not only controlled the membrane surface charge properties, but also alleviated the sintering stress in the co-sintering process, ensuring a complete membrane layer owing to the higher ductility. The AgNPs obtained from silver nitrate were introduced before the formation of boehmite nucleation, providing a uniform distribution of AgNPs within boehmite owing to the electric double layer. The final UF membranes prepared by the co-sintering process exhibited a molecular weight cut-off of 9000 Da and permeance of 62 Lm−2h−1bar−1. Furthermore, the isoelectric point of the membrane surface could be controlled by the AgNPs (from 9.0 to 2.7), providing sustainable antifouling properties for protein purification owing to the electrostatic repulsion force. The AgNPs-enhanced ceramic membrane material also exhibits a higher stability without silver leakage due to the thermal treatment at 1000 °C. The proposed facile co-sintering process for fabrication of antifouling ceramic UF membranes with the assistance of AgNPs could decrease the sintering time and energy consumption, and thus is promising for industrial protein separation applications.

Highlights

Pure proteins attract increasing attention owing to their potential applications in food, nutrition, and medical care [1, 2]
The AgNPs reduced from the silver nitrate during the thermal treatment [47] could be absorbed around the crystal nucleus of boehmite with the aid of glycerol, forming a stable system owing to the electric double-layer (EDL) effect
AgNPs-doped ceramic UF membrane (ACUM) with better antifouling performances for a bovine serum albumin (BSA) solution were fabricated by a facile co-sintering process

Summary

Introduction

Pure proteins attract increasing attention owing to their potential applications in food, nutrition, and medical care [1, 2]. Proteins with high purities have been employed to fight against various diseases [3, 4]. Ceramic tight ultrafiltration (UF) membranes with pore sizes of 2–5 nm have a large potential to separate and purify protein suspensions owing to their excellent chemical and physical stabilities and long operational lifetimes. Ceramic membrane materials are often composed of ZrO2, Al2O3, TiO2, and their mixtures [5]. These materials do not exhibit satisfactory antifouling performances while treating protein solutions. In order to alleviate the membrane fouling, various approaches have been employed to modify the membrane surface charge [6], hydrophilicity–hydrophobicity performance [7], surface roughness [8, 9], inhomogeneous pore size distribution [10], etc

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