Lian Zheng, Wei Chaohui, Gao Bin, Yang Xiaogang, Chan Yue, Wang Jing, Chen George Zheng, Koh Kai Seng, Shi Yong, Yan Yuying, Ren Yong, He Jun, Liu Fu
International Doctoral Innovation Centre, University of Nottingham Ningbo China Ningbo China.
Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham Ningbo China Ningbo China
RSC Adv. 2020 Mar 5;10(16):9210-9225. doi: 10.1039/c9ra10899h. eCollection 2020 Mar 2.
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/TiO) 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/TiO nanocomposites with TiO 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/TiO 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, 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/TiO 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/TiO 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.
高效处理纺织工业中偶氮染料污染的废水是一个重要但具有挑战性的问题。在此，通过吸附和光催化降解相结合的协同方法，成功合成了包含多壁碳纳米管/二氧化钛（MWCNTs/TiO₂）纳米复合材料的聚二甲基硅氧烷（PDMS）微粒，用于处理含罗丹明B（RhB）染料的废水。采用表面活性剂包裹溶胶 - 凝胶法合成MWCNTs/TiO₂纳米复合材料，使TiO₂纳米颗粒均匀分布在MWCNTs表面。使用基于针的微流控装置，以水包油（O/W）单乳液模板制备PDMS微粒。将MWCNTs/TiO₂纳米复合材料（重量比分别为1%和2%）与PDMS前驱体混合作为分散相，聚乙烯醇（PVA）水溶液用作连续相。在分散相和连续相的流速分别为30和200 μL min的条件下，形成了平均直径为692.7 μm（变异系数，CV = 0.74%）和678.3 μm（CV = 1.04%）的高度单分散微粒。所制备的杂化微粒用于处理RhB，包括5小时的暗平衡和3小时的紫外照射。研究了所应用的PDMS类型、质量负载量、处理持续时间、光降解动力学、污染物初始浓度和环境pH值等实验条件。含有2 wt% MWCNTs/TiO₂纳米复合材料的PDMS微粒去除效率可达85%。值得注意的是，微粒在循环再利用3次后仍可保持70%的效率。与传统的染料污染废水处理方法相比，PDMS-MWCNTs/TiO₂微粒具有卓越的性能，尤其是在可回收性和防止二次污染方面。这项工作为开发一种高效、低成本的微流控方法来处理复杂的水环境系统提供了一条可行且环保的途径。
