Ultrafast and Selective Nanofiltration Enabled by Graphene Oxide Membranes with Unzipped Carbon Nanotube Networks
Zhenyang Han, Xiao Xiao, Huaijiao Qu, Menglei Hu, Christian Au, Ardo Nashalian, Xiao Xiao, Yanxin Wang, Liu Yang, Fengchun Jia, Tianmei Wang, Zhi Ye, Peyman Servati, Linjun Huang, Zhijun Zhu, Jianguo Tang, Jun Chen
Abstract
Carbon nanomaterials have proven their wide applicability in molecular separation and water purification techniques. Here, an unzipped carbon nanotubes (CNT) embedded graphene oxide (GO) membrane (uCNTm) is reported. The multiwalled CNTs were longitudinally cut into multilayer graphene oxide nanoribbons by a modified Hummer method. To investigate the varying effects of different bandwidths of unzipped CNTs on their properties, four uCNTms were prepared by a vacuum-assisted filtration process. Unzipped-CNTs with different bandwidths were made by unzipping multiwalled CNTs with outer diameters of 0–10, 10–20, 20–30, and 30–50 nm and named uCNTm-1, uCNTm-2, uCNTm-3, and uCNTm-4, respectively. The uCNTms exhibited good stability in different pH solutions, and the water permeability of the composite membranes showed an increasing trend with the increase of the inserted uCNTm’s bandwidth up to 107 L·m–2·h–1·bar–1, which was more than 10 times greater than that of pure GO membranes. The composite membranes showed decent dye screening performance with the rejection rate of methylene blue and rhodamine B both greater than 99%.