Remediation of uranium(VI)-containing wastewater based on a novel graphene oxide/hydroxyapatite membrane

Membrane separation technology with unique advantages was widely used in wastewater treatment, especially U(VI)-containing wastewater. However, due to the low water flux and the unsatisfactory U(VI) interception rate of the membrane, the important breakthrough in the field of practical wastewater treatment could not be achieved. A novel graphene oxide/hydroxyapatite (GO/HAP, GHP) membrane was prepared by a simple in-situ deposition self-assembly method. The GO/HAP dispersion was firstly obtained by in-situ growth of HAP nanoparticles on GO sheets and then self-assembled to prepare GO/HAP membranes by vacuum filtration. The membranes were provided with high water flux due to the fact that the addition of HAP nanoparticles effectively increased the layer spacing of graphene sheets. The flux of GHP-2 membrane to U(VI)-containing wastewater was about 273.4 L‧m−2‧h−1‧bar−1 and U(VI) retention rate was 99.4%. GHP-2 membrane also had good recycling performance and could still reach high retention rate (82.5%) after five cycles. The high rejection rate of GHP-2 membrane for U(VI) was owing to the internal induced separation mechanism. To sum up, the prepared GHP membranes had the potential for water environment renovation.