Hierarchical nanostructures as novel antifouling agents in nanofiltration process

The goal of the present work is the preparation of novel positively charged nanofiltration membranes with high cation removal and low fouling for dye solutions. In this situation, we made a good use of hierarchical Mg(OH)2 nanostructures and branched poly(ethyleneimine). These membranes were prepared by the procedure of interfacial cross-linking polymerization. As a result, high CaCl2 and NaCl rejections were obtained for these membranes with values of 97.4% and 61.2%, respectively. Also, the most efficient membrane presented Basic Red 29 rejection of >98% with the lowest fouling and second type of hierarchical nanostructures. The flux recovery ratio and total fouling ratio resulted from this membrane were 95% and 5.11%, respectively. The second type of hierarchical Mg(OH)2 nanostructures was created by arrangement of 70nm thickness nanoplates. [Display omitted] •Positive membranes were prepared by PEI and interfacial cross-linking polymerization.•By adding hierarchical nanostructures in NF membrane, salt rejection was improved.•Spherical and hierarchical Mg(OH)2 nanostructures showed the lowest fouling for dye.