Study On Hybrid Membranes Incorporation Co?OH?₂ Nanoparticles By In Situ Microemulsion Polymerization And Improve Of Pervaporation Performance

In this paper,Co?OH?₂ nanoparticles were first synthesized in reverse microemulsion usingpolymerizable allyl polyoxyethylene ether?APEG?as surfactant and the mixed liquid of methyl methacrylate and styrene as oil phase.Then Co?OH?₂/Poly?MMA-St-APEG?organic-inorganic hybrid membranes were prepared by in-situ polymerization.The pervaporation performance of the hybrid membranes were tested for separation of benzene/cyclohexane mixtures.Thestability of?Co?NO₃?₂+H₂O?/?MMA-St?/APEG and?NaOH+H₂O?/?MMA-St?/APEG microemulsion were investigated by conductivity method combined with the visual observation method.The synthesis morphology and structure of Co?OH?₂ nanoparticles were studied by FTIR,UV-vis and TEM.The results show that:?1?The composition of the inverse microemulsion system,such as the concentration of Co?NO₃?₂and NaOH solution,solubilized water amount???,and APEG mass fraction are the key factors of the stability of the microemulsions;?2?The particle size of Co?OH?₂ nanoparticles are 4⁸nm when the Co?OH?₂/?MMA-St?/APEG microemulsion in the steady state.And increasing the surfactant mass fraction and the concentration of the salt solution can conducive to obtaining a larger number of larger diameter Co?OH?₂ nanoparticles.When?=2,m_APEG=20 wt%,C_Co?NO3?2=0.1⁰.2 mol·L^-1,the Co?OH?₂/?MMA-St?/APEG microemulsion can get the optimal preparation conditions.On the basis of the above research,the Co?OH?₂/Poly?MMA-St-APEG?organic-inorganic hybrid membranes were further prepared by inverse microemulsion polymerization.The hybridization were investigated by FTIR,SEM,TGA,Zeta potential and static water contact angle.And then,the pervaporation performance of the benzene/cyclohexane mixtures of the hybrid membrane was observed.The results show that:?1?With the increase of?and the concentration of Co?NO₃?₂ in the inverse microemulsion system,the time required for the polymer emulsion formed by inverse microemulsion polymerization to reach the appropriate viscosity required for membranes is prolonged.With the concentration of salt in the system,the increase of the time to reach the desired viscosity is also prolonged.The suitable polymerization time of the system is 2.5³.5 h;?2?The Co?OH?₂nanoparticles are spherical and uniformly dispersed on the surface of the hybrid membrane and the number of the Co?OH?₂ nanoparticles in the hybrid membrane is positively correlated with the change of C_Co?NO3?2,?,m_APEG.When??3 or m_APEG>25 wt%,nanoparticles will agglomerate on the surface of the membrane occurs;?3?The number of Co?OH?₂nanoparticles will increase the Zeta potential of the membrane surface when nanoparticles were uniformly dispersed,and also improve the hydrophilicity of the membrane surface;?4?Appropriate doping of Co?OH?₂ nanoparticles is beneficial to improve the thermal stability of Co?OH?₂/Poly?MMA-St-APEG?hybrid membrane.?5?The equilibrium swelling degree of Co?OH?₂/Poly?MMA-St-APEG?hybrid film for benzene is about 3 times that for cyclohexane at 30?,the preferential adsorption and swelling of benzene is a key factor to improve the pervaporation performance of benzene/cyclohexane mixtures of hybrid membranes;?6?The volume of water???,Co?NO₃?₂ and emulsifier mass fraction(m _APEG)have a significant effect on the separation of hybrid membranes.When C_Co?NO3?2=0.2 mol·L^-1,?=2,m_APEG=20 wt%in the inverse microemulsion system,the separation factor of the hybrid membrane can reach7.21,and the permeate flux of hybrid membrane is 792.86 g·m^-2·h^-1.