Enhancing the selectivity of hydrogen isotopic water in membrane distillation by using graphene oxide

• Published in: Journal of membrane science 2020-09, Vol.610, p.118237, Article 118237
• Main Authors: Wen, Ming, Chen, Min, Ren, Guang-Kun, Li, Pei-Long, Lv, Chao, Yao, Yong, Liu, Yin-Ke, Deng, Sun-Jie, Zheng, Zhe, Xu, Ci-Gang, Luo, De-Li
• Format: Article
• Language: English
• Subjects: Air-gap membrane distillation; Functionalization; Graphene oxide membrane; Hydrogen isotopic water; Separation
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2020.118237

Isotopes of hydrogen are playing an increasingly important role in applications such as controllable nuclear fusion and other nuclear processes, yet directly separating isotopic water from its mixture is still energy-intensive and largely limited by the moderate separation factor values. In this study, Graphene oxide (GO) and reduced graphene oxide (rGO) nanosheets, combining optimized hydrophobicity by grafting perfluoroalkylsilanes (PFAS), have been used for improving the selectivity of isotopic water in membrane distillation. By utilizing heavy/light water mixture as a model, permeation flux and isotopic selectivity of the membranes are systematically evaluated. The graphene oxide membranes, particularly for the rGO grafted by PFAS, exhibit enhanced selectivity with an increased isotopic separation factor, as compared with that of commercial membranes, which is probably due to the efficient synergy between unimpeded nanochannels and near-super hydrophobic surface. A maximum mean separation factor value of 1.067, combined with a permeation flux of 0.47 kg m−2 h−1 have been achieved for the grafted rGO -membrane reduced at 750 °C. Furthermore, our study demonstrates utilizing two-dimensional materials, like GO and rGO, can be an effective avenue for promoting the isotopic selectivity in membrane distillation, based on increasing hydrophobic water vapor channels with higher selectivity. •Separation of hydrogen isotopic water by graphene oxide membrane in membrane distillation was carried out for the first time.•An effective functionalization method of graphene oxide membrane was developed.•Near-super hydrophobic graphene oxide membrane surface was achieved.•Near-super hydrophobic membrane surface and synergistic effect account for the enhanced separation factor.