Well-structured 3D channels within GO-based membranes enable ultrafast wastewater treatment

Graphene oxide(GO)-based membranes have been widely studied for realizing efficient wastewater treatment,due to their easily functionalizeable surfaces and tunable interlayer structures.However,the irregular structure of water channels within GO-based membrane has largely confined water permeance and prevented the simultaneously improvement of purification performance.Herein,we purposely construct the well-structured three-dimensional(3D)water channels featuring regular and negatively-charged properties in the GO/SiO_(2)composite membrane via in situ close-packing assembly of SiO_(2)nanoparticles onto GO nanosheets.Such regular 3D channels can improve the water permeance to a record-high value of 33,431.5±559.9 L·m^(−2)·h−1(LMH)bar−1,which is several-fold higher than those of current state-of-the-art GO-based membranes.We further demonstrate that benefiting from negative charges on both GO and SiO2,these negatively-charged 3D channels enable the charge selectivity well toward dye in wastewater where the rejection for positive-charged and negative-charged dye molecules is 99.6%vs.7.2%,respectively.The 3D channels can also accelerate oil/water(O/W)separation process,in which the O/W permeance and oil rejection can reach 19,589.2±1,189.7 LMH bar−1 and 98.2%,respectively.The present work unveils the positive role of well-structured 3D channels on synchronizing the remarkable improvement of both water permeance and purification performance for highly efficient wastewater treatment.