Synergetic treatment of dye contaminated wastewater using microparticles functionalized with carbon nanotubes/titanium dioxide nanocomposites

Zheng Lian; Chaohui Wei; Bin Gao; Xiaogang Yang; Yue Chan; Jing Wang; George Zheng Chen; Kai Seng Koh; Yong Shi; Yuying Yan; Yong Ren; Jun He; Fu Liu

doi:10.1039/c9ra10899h

Synergetic treatment of dye contaminated wastewater using microparticles functionalized with carbon nanotubes/titanium dioxide nanocomposites

RSC Adv. 2020 Mar 5;10(16):9210-9225. doi: 10.1039/c9ra10899h. eCollection 2020 Mar 2.

Authors

Zheng Lian^{1

2

3}, Chaohui Wei⁴, Bin Gao⁵, Xiaogang Yang², Yue Chan⁶, Jing Wang⁷, George Zheng Chen^{4

8}, Kai Seng Koh⁹, Yong Shi^{2

3}, Yuying Yan^{3

10}, Yong Ren^{2

3}, Jun He⁴, Fu Liu¹¹

Affiliations

¹ International Doctoral Innovation Centre, University of Nottingham Ningbo China Ningbo China.
² Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham Ningbo China Ningbo China yong.ren@nottingham.edu.cn.
³ Research Group for Fluids and Thermal Engineering, University of Nottingham Ningbo China Ningbo China.
⁴ Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China Ningbo China jun.he@nottingham.edu.cn.
⁵ ECO Environmental Investment Limited Hong Kong China.
⁶ Institute for Advanced Study, Shenzhen University Shenzhen China.
⁷ Department of Electrical and Electronic Engineering, University of Nottingham Ningbo China Ningbo China.
⁸ Department of Chemical and Environmental Engineering, University of Nottingham Nottingham UK.
⁹ School of Engineering and Physical Sciences, Heriot-Watt University Malaysia Putrajaya Malaysia.
¹⁰ Research Group for Fluids and Thermal Engineering, University of Nottingham Nottingham UK.
¹¹ Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences Ningbo China fu.liu@nimte.ac.cn.

Abstract

The highly efficient treatment of azo dye contaminated wastewater from the textile industry is an important but challenging problem. Herein, polydimethylsiloxane (PDMS) microparticles, incorporating multiple-walled carbon nanotubes/titanium dioxide (MWCNTs/TiO₂) nanocomposites, were successfully synthesized to treat wastewater containing Rhodamine B (RhB) dyes in a synergetic approach, by combining sorption and photocatalytic degradation. The surfactant wrapping sol-gel method was applied to synthesize MWCNTs/TiO₂ nanocomposites with TiO₂ nanoparticles evenly distributed on the surface of the MWCNTs. The PDMS microparticles were fabricated with an oil-in-water (O/W) single emulsion template, using needle-based microfluidic devices. MWCNTs/TiO₂ nanocomposites (at a weight ratio of 1%, and 2%, respectively) were mixed with the PDMS precursor as the dispersed phase, and an aqueous solution of polyvinyl alcohol (PVA) was used as the continuous phase. Highly monodispersed microparticles, with average diameters of 692.7 μm (Coefficient of Variation, CV = 0.74%) and 678.3 μm (CV = 1.04%), were formed at an applied flow rate of the dispersed and continuous phase of 30 and 200 μL min^-1, respectively. The fabricated hybrid microparticles were employed for the treatment of RhB, involving a dark equilibrium for 5 hours and UV irradiation for 3 hours. The experimental conditions of applied PDMS type, mass loading amount, treatment duration, photodegradation kinetics, initial concentration of pollutants and environmental pH values were investigated in this work. The PDMS microparticles with 2 wt% MWCNTs/TiO₂ nanocomposites can exhibit a removal efficiency of 85%. Remarkably, an efficiency of 70% can be retained after the microparticles have been recycled and reused for 3 cycles. The PDMS-MWCNTs/TiO₂ microparticles possess a superior performance over conventional treatment approaches for dye contaminated wastewater, especially in recyclability and the prevention of secondary pollution. This work provides a feasible and eco-friendly route for developing an efficient and low-cost microfluidic method for treating complicated water environmental systems.