Nanoparticle fouling and its combination with organic fouling during forward osmosis process for silver nanoparticles removal from simulated wastewater.

Yanxiao Zhao,Yueping Ren,Xiufen Li,Zhiwei Wang,Xinhua Wang

doi:10.1038/srep25859

Abstract

The increasing and wide application of silver nanoparticles (Ag NPs) has resulted in their appearance in wastewater. In consideration of their potential toxicity and environmental impacts, it is necessary to find effective technology for their removal from wastewater. Here, forward osmosis (FO) membrane was applied for Ag NPs removal from wastewater, and single and combined fouling of nanoparticles and organic macromolecules were further investigated during the FO process. The findings demonstrated that FO membrane can effectively remove Ag NPs from wastewater due to its high rejection performance. Fouling tests indicated that water flux declined appreciably even at the beginning of the single Ag NPs fouling test, and more remarkable flux decline and larger amounts of deposited Ag NPs were observed with an increase of Ag NPs concentration. However, the addition of bovine serum albumin (BSA) could effectively alleviate the FO membrane fouling induced by Ag NPs. The interaction between Ag NPs and BSA was responsible for this phenomenon. BSA can easily form a nanoparticle-protein corona surrounded nanoparticles, which prevented nanoparticles from aggregation due to the steric stabilization mechanism. Furthermore, the interaction between BSA and Ag NPs occurred not only in wastewater but also on FO membrane surface.

Highlights

Experimental conditions were as follows: thin film composite (TFC) FO membranes at the mode of active layer facing feed solution (AL-FS), 5.0 M NaNO3 as draw solution, temperatures controlled at 25 ± 1 °C and cross-flow rate of 12.9 cm/s
Considering their properties, the Ag NPs fouling belongs to colloidal/particulate fouling of FO membrane according to the classification of FO membrane fouling
This study aims to evaluate the feasibility of Ag NPs removal from wastewater by FO membrane, and to investigate the fouling behaviors of single Ag NPs and their combination with bovine serum albumin (BSA) fouling in the FO process

Summary

Introduction

Experimental conditions were as follows: thin film composite (TFC) FO membranes at the mode of AL-FS, 5.0 M NaNO3 as draw solution, temperatures controlled at 25 ± 1 °C and cross-flow rate of 12.9 cm/s. According to the specific type of foulants, FO membrane fouling can be generally categorized into biological fouling, inorganic scaling, organic fouling, and colloidal/particulate fouling[23,24,25,26]. Considering their properties, the Ag NPs fouling belongs to colloidal/particulate fouling of FO membrane according to the classification of FO membrane fouling. This study aims to evaluate the feasibility of Ag NPs removal from wastewater by FO membrane, and to investigate the fouling behaviors of single Ag NPs and their combination with BSA fouling in the FO process. To the best knowledge of the authors, this is the first study for analyzing the fouling behaviors of Ag NPs in the FO process

Objectives

Methods

Results