Self-assembled Membrane With Characteristics Of Phase Equilibrium And Rate Separation And Electromechanical Energy Conversion In Membrane System

Chemical separation technology is divided into phase equilibrium separation and rate separation.At present,researches about ultrafiltration and microfiltration membrane technology mainly focus on the rate separation process of size sieving,but phase equilibrium separation process is less studied and the selective adsorption performance of the membrane needs to be improved.In addition,there is still a lot of fluid kinetic energy released into the environment and lost during the membrane separation process.In this paper,bimetallic Ce-Ui O-66-NH₂/diatomite（CUD）were prepared to form a functional layer of self-assembled membrane on the porous support layer for water purification.The kinetic energy of the excess fluid in the membrane system is converted into electrical energy by an electromechanical conversion device and then stored for further use.In this dissertation,bimetallic Ce-Ui O-66-NH₂/diatomite was first prepared by solvothermal synthesis,and the optimal preparation conditions were determined.Under the optimal conditions,the prepared particles were characterized and analyzed by FTIR,XRD,SEM,EDS and so on.By layer-by-layer self-assembly technology,a uniform diatomite support layer and CUD functional layer are sequentially formed on the porous support by means of flow field regulation,to form a CUD self-assembled membrane for water purification.This paper mainly studied the effect of membrane-forming pressure and fluid flow pattern on the uniformity of self-assembled membranes,then used the formed self-assembled membranes to treat oily wastewater under the optimal process conditions.The effect of the amount of CUD,p H,and treatment class on the permeate water quality and the reuse performance of CUD self-assembled membrane were investigated.In addition,this paper also explored the selective adsorption performance and mechanism of CUD self-assembled membrane.Finally,the reducing pipe and electromechanical conversion device were designed.Moreover,the influence of the reducing pipe,operating pressure,volume flow on electromechanical energy conversion were studied.The results show that CUD particles have good spherical structure with particle size of 20μm.Doping cerium element improves the hydrophilicity of functional particles,and the water contact angle decreases from 25°to 15°,and the membrane resistance of the CUD self-assembled membrane is 2.23×10⁹ m^-1.After treating the oily wastewater for 30 min with as-prepared membrane,the oil concentration of permeate water reduces from 78.1 mg·L^-1 to 6.8 mg·L^-1,and the turbidity is 0.10NTU,meeting the discharge and reuse standards.Moreover,the adsorption capacity of anionic polyacrylamide in oily water is 161.5 mg·g^-1;and the water yield of the membrane is 789.5 L·m^-2·h^-1.In addition,the CUD self-assembled membrane can be reused after being calcined.Using 20 L·h^-1 self-assembled membrane module for separation under 0.08 MPa,resistance loss of the fluid through the reducing pipe is0.75 m,and membrane permeate water through the electromechanical energy conversion device convert the power of 1.37 W,showing electromechanical energy conversion ratio of 7.52%.Under the same operating conditions,the resistance loss of the straight pipe is as high as 2.707 m,and the converted electric power is 1.07 W,conversion ratio is 5.94%.Therefore,low-resistance CUD self-assembled membranes with characteristics of phase equilibrium and rate separation have promising prospects for the deep purification of oily wastewater and electromechanical energy conversion.