A sustainable filtering material for efficient removal of volatile organic compounds from their aqueous mixtures

Xianqi Zhu,Feng Jiang,Zhirong Chen,Yong Lv,Xiangju Xi,Yijiao Xue,Lei Dai

doi:10.1007/s10570-021-03938-z

Xianqi Zhu, Feng Jiang + Show 5 more

Open Access

https://doi.org/10.1007/s10570-021-03938-z

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Abstract

Volatile organic compounds (VOCs) are hazardous to the environment and human health. Thus, tremendous effort has gone into developing effective/efficient techniques for separation of VOCs from their aqueous mixtures. In this work, a simple and versatile strategy was proposed to fabricate a new material for hydrophobic VOC separations, in which a self-assembling hydrogel consisting of TEMPO-oxidized cellulose nanofibers (TOCNs) and cationic guar gum (CGG) was used. Specifically, TOCNs and CGG were deposited onto a filter paper via a layer-by-layer procedure, resulting in a TOCN/CGG hydrogel-coated filtering material, in which no crosslinking agent was used. The hydrogel is spontaneously formed by electrostatic interactions and hydrogen bonding. The as-prepared filtering material exhibits oil-repellence and underwater oleophobicity resulting from the formation of hydration layer on hydrogel, thus demonstrating good VOC separation performance. One-layer of TOCN/CGG hydrogel coating (dried mass of 0.032 g·m− 2) was proved to realize the VOC separation (separation efficiency of around 99 % and water flux of as high as 905.14 L·m− 2·h− 1). Further increase of the hydrogel layers has negligible influence on the separation efficiency although it decreases the water flux. This filtering material also exhibits good stability during recycling. Consequently, this TOCN/CGG self-assembling hydrogel-coated filtering material has great potential in VOCs-contaminated wastewater treatment.

Highlights

Organic solvents and its products are widely used in industrial activity, which results in large amounts of organic solvents-contaminated wastewater that seriously threatens the global environment and even causes human health issues (Rutkiewicz et al 2010, Kang et al 2019, Perego et al 2013, Levchuk et al 2014)
A simple and versatile strategy was proposed to fabricate a new material for hydrophobic volatile organic compounds (VOCs) separation, in which a self-assembling hydrogel consisting of TEMPO-oxidized cellulose nanofibers (TOCN) and cationic guar gum (CGG) was used
We previously reported self-assembling hydrogels made of guar gum and nanocellulose (Dai et al 2019a, b)

Summary

Introduction

Organic solvents and its products are widely used in industrial activity, which results in large amounts of organic solvents-contaminated wastewater that seriously threatens the global environment and even causes human health issues (Rutkiewicz et al 2010, Kang et al 2019, Perego et al 2013, Levchuk et al 2014). The separation efficiency of many existing techniques is still low, and some complex instruments limit the practical application of these techniques (Zhu et al 2015, 2016, Tummons et al 2016) In this context, novel materials with wettability stand out as a promising alternative, owing to their good performance in separating oil/water two-phase mixtures. We proposed to use TEMPO-oxidized cellulose nanofibers (TOCN) and cationic guar gum (CGG) to coat filter papers through a layer-by-layer procedure. Hydrogel-coated filtering material can be obtained since TOCN and CGG autonomously generate a hydrogel due to the electrostatic interactions and hydrogen bonding between them, without the need of any extraneous crosslinkers. The performance of TOCN/CGG selfassembling hydrogel-coated filtering material in removing VOCs from their aqueous mixtures was thoroughly studied

Materials

Characterizations

Results And Discussion

Conclusions