Feasible water flow filter with facilely functionalized Fe₃O₄-non-oxidative graphene/CNT composites for arsenic removal

Practical applications of carbon-based nanomaterials are important issues for water treatment technologies, especially for heavy metal adsorption. For the applications, a facile method to functionalize the carbon-based nanomaterials and a strategy for their typical uses are required. Here, we report a highly feasible water flow filter filled with Fe₃O₄-functionalized non-oxidative graphene/CNT prepared via facile functionalization in a Couette-Taylor flow reactor for arsenic removal. Fe₃O₄ was uniformly functionalized on the CNTs and the non-oxidative graphene using the Couette-Taylor flow method, which allows fast production of a large number of filters. The hybrid composite of Fe₃O₄-functionalized non-oxidative graphene/CNT demonstrated an improvement in the arsenic removal efficiency when it served as a flow filter rather than when used in the batch method because its 3D structure enhanced both the water flow pathway and the contact area with Fe₃O₄. Adaption for household use for continuous purification of water is simple for this proposed filter.