Fast-thermoresponsive carboxylated carbon nanotube/chitosan aerogels with switchable wettability for oil/water separation

Songlin Fan; Zhenzhou Li; Chao Fan; Jian Chen; Hongmiao Huang; Guangliang Chen; Shigen Liu; Hemao Zhou; Rangtao Liu; Zhenfei Feng; Yanjuan Zhang; Huayu Hu; Zuqiang Huang; Yuben Qin; Jing Liang

doi:10.1016/j.jhazmat.2022.128808

Fast-thermoresponsive carboxylated carbon nanotube/chitosan aerogels with switchable wettability for oil/water separation

J Hazard Mater. 2022 Jul 5:433:128808. doi: 10.1016/j.jhazmat.2022.128808. Epub 2022 Mar 28.

Authors

Songlin Fan¹, Zhenzhou Li², Chao Fan¹, Jian Chen¹, Hongmiao Huang³, Guangliang Chen¹, Shigen Liu¹, Hemao Zhou¹, Rangtao Liu¹, Zhenfei Feng², Yanjuan Zhang⁴, Huayu Hu¹, Zuqiang Huang⁵, Yuben Qin¹, Jing Liang¹

Affiliations

¹ School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China.
² School of Mechanical Engineering, Guangxi University, Nanning 530004, China.
³ School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China; School of Pharmacy, Guangxi University of Chinese Medicine, Nanning 530200, China.
⁴ School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China. Electronic address: zhangyj@gxu.edu.cn.
⁵ School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China. Electronic address: huangzq@gxu.edu.cn.

PMID: 35381514
DOI: 10.1016/j.jhazmat.2022.128808

Abstract

The use of aerogels to selectively recover oil from oily wastewater is effective but challenging. In this study, a new carboxylated carbon nanotube/chitosan aerogel (CCNT/CA) with switchable wettability was developed as a smart adsorbent for fast oil absorption and oil recovery. Vinyltrimethoxysilane and thermoresponsive poly(N-isopropylacrylamide) (PNIPAAm) was grafted onto the surface of the CCNT/CA skeleton, and the resulting smart aerogel (PNI-Si@CCNT/CA) exhibited temperature responsiveness. PNI-Si@CCNT/CA exhibited an excellent reversible conversion between hydrophilicity and hydrophobicity when the temperature was changed to below or above the lower critical solution temperature (LCST) of PNIPAAm (~32 °C). Most importantly, CCNT significantly increased the oil absorption capacity, improved the mechanical properties, accelerated phonon conduction, enhanced thermal conductivity (80.57 mW m^-1 K^-1), improved the temperature response rate, shortened the oil desorption time (15 min), and improved the oil/water separation efficiency of PNI-Si@CCNT/CA because a strong interface interaction occurred between CCNT and chitosan. Moreover, PNI-Si@CCNT/CA absorbed oil at 45 °C and released the absorbed oil at 25 °C. It maintained its good adsorption performance after 15 cycles, and this was ascribed to its excellent mechanical properties and stable structure.

Keywords: Carboxylated carbon nanotube chitosan aerogel; Oil/water separation; PNIPAAm; Thermal conductivity; Thermoresponsive.