Study On Novel Alkynyl Carbon Composite Nanofiltration Membrane And Its Nanofiltration Performance

Nanofiltration technology has received wide attention in the fields of drinking water production,desalination and wastewater treatment because of its good water permeability,low operating pressure,and good retention of dye molecules.However,traditional nanofiltration membranes are limited by the"Trade-Off" effect and cannot maintain high selectivity while increasing water flux.Therefore,the development of new membrane materials and optimization of composite membranes has been a research hotspot for scientists.The alkynyl carbon material(ACM)is a new type of carbon-based nanomaterial,mainly composed of sp2 hybrid carbon and sp1 hybrid carbon.ACM is an ideal choice for highly permeable and selective membranes.Due to its high porosity and superhydrophilicity on the surface.In this study,a new type of ACM composite nanofiltration membrane was prepared for the first-time using ACM as a nano-additive,and its nanofiltration performance was studied.In this study,ACM was first modified with DA,and then ACM-V composite membranes were prepared on PAN substrates by a vacuum-assisted method.DA improves the stability of the composite membrane while modifying ACM.The effects of different ACMs and different polymer substrate composite membranes were discussed,and the optimal membrane-forming materials were determined:ACM-5 material and PAN substrate.FTIR,XPS,SEM,AFM and other methods were used to analyze and characterize the structural changes in the composite membrane preparation process,and combined with the effects of different DA and ACM content composite membrane properties,the optimal membrane formation conditions were determined.Under these conditions,the rejection rate of the prepared composite membrane for methyl blue is 95%,and the flux is 207 Lm-2h-1Mpa-1.The ACM-C composite membrane was prepared by coprecipitation DA with PEI.Not only is it crosslinked in the coating formed by the reaction between DA and PEI,but it is also stacked on the surface of the composite membrane to form a dense separation layer.Through the above characterization and CA analysis,the surface of the composite film was super hydrophilic and the contact angle was 0°.The rejection rate for methyl blue is 96%,and the flux rises to 360 Lm-2h-1Mpa-1.Compared with the composite membrane without ACM,the water flux of the composite membrane is doubled while maintaining the retention effect and broke the "Trade-Off" phenomenon.