In this study, by adding zirconium anhydride (ZrO2) particles to a solution ofN–methylmorphorphine–N–oxide (NMMO) and bamboo cellulose (BC), we used interfacial polymerization (IP) to obtain regenerated cellulose nanofiltration membranes (IP–ZrO2/BC–NFMs) that exhibited high water flow and rejection of salts and dyes. During interfacial polymerization, anhydrous piperazine (PIP) was used as the waterborne monomer, and 1,3,5–trimesoyl chloride (TMC) and n–hexane were used as the organic phase. The procedure was adjusted by analyzing the impacts of the concentrations of the water and organic phase monomers and the reaction duration on the performance of the developed IP–ZrO2/BC–NFMs. The chemical structures and morphologies of the as–obtained IP–ZrO2/BC–NFMs were examined using various characterization techniques. The performance of these membranes for removal of inorganic salts and dyes as well as their water flow were investigated. IP–ZrO2/BC–NFMs obtained at a pressure of 0.5 MPa, PIP concentration of 1.5 wt.%, TMC concentration of 0.15 wt.%, and polymerization period of 2 min displayed the highest water flux (55.12 LMH) and the best desalination effect (NaCl rejection rate = 19.15%). Over 90% of both Methyl Blue (MB) and Congo Red (CR) dyes were intercepted. We demonstrated that the addition of ZrO2to nanofiltration membranes significantly enhanced the water flow of the IP–ZrO2/BC–NFMs as well as the salt ion rejection rate.Keywords:regenerated cellulose;nanofiltration membrane;rejection rate;interfacial polymerization
Water pollution has long been a significant issue, and the purification of dye wastewater plays a crucial role in addressing this problem. Graphene oxide (GO) has found extensive applications in water treatment due to its unique two-dimensional (2D) structure and a surface rich in a large number of oxygen-containing functional groups. We introduced silica(SiO 2 ) and polyethyleneimine(PEI) into GO to prepare a membrane. The experimental findings revealed that the 3-SiO 2 /GO binary composite membrane achieved a high water permeability of 45.6 L m −2 h −1 bar −1 while maintaining retention, which is nearly four times higher than that of the GO membrane (9.85 L m −2 h −1 bar −1 ).The water permeability of the PEI 0.2 -SiO 2 /GO ternary composite membrane achieved 42.37 L m −2 h −1 bar −1 . The rejection rate for methyl orange dye reached 92.36 %, with similar rejection rates all above 95 % observed for other dyes.
Yunfeng Guo,Weihua Gong,Jiayu Liu,Xiangyu Tang,Dong Wang,Zefang Xiao,Yanjun Xie,Yonggui Wang
Traditional COF nanosheets (CONs) suffer from poor mechanical properties due to weak interactions, which limits their widespread application in water treatment. This study proposes a multidimensional assembly strategy by combining them with one-dimensional cellulose nanofibrils (1D-TCNFs) to fabricate a multidimensional composite nanofiltration membrane. In this structure, the flexible TCNFs not only enhance the stability of the composite membrane but also significantly improve the membrane’s flux and rejection efficiency through enhanced pore size exclusion effects and charge synergistic mechanisms. Specifically, two-dimensional covalent organic framework nanosheets (2D-CONs) were synthesized using a sodium chloride interface confinement technique, and the CONs were further modified with sulfonic acid groups (SCONs) via thiol-ene click chemistry, significantly improving the hydrophilicity and pore structure of the nanosheets. Separation tests demonstrated that the T 75% SCONs membrane achieved a rejection rate of over 99 % for RhB filtration, with a permeation flux increase of 209 % compared to the T 75% CONs membrane. For inorganic salt MgSO 4 , the permeation flux increased by 187 %, with a rejection rate of 40.3 %. Long-term stability tests also showed that the T 75% SCONs membrane maintained excellent performance over multiple filtration cycles. In conclusion, the multidimensional assembled nanofiltration membrane based on sodium chloride interface confinement synthesis and click modification provides a novel solution for developing efficient water treatment technologies.
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