Preparation Of EPDM Ultrafine Fiber Mat And Oil Contaminants Cleanup Mechanisms

Nowadays,Oil pollution is the third contaminant for water environment.Every year there are 500×10⁴-1000×10⁴ t oil contaminant into water.Oil sorption materials are widely used for they are economic convenient and effective.On the basis of the analysis of the characteristic and mechanism,type and preparation method,research and application development of oil sorptive resin,form the molecular design point,Ethylene-propylene-diene(EPDM) was chosen as the raw material.In the present work,we prepared EPDM ultrafine fiber mat by means of electrospinning and ultraviolet radiation.The membrane,with following characteristics:fast oil sorption rate,large oil-sorption capacity,good sorption selectivity of oil over water,convenient shipping and storage,lower density compared to water to float with or without oil sorbed,is used as a hydrophobic sorbent for oil-like liquids,especially for oil and some environmental hormones spilled on water.Compared with the granular and bulk oil sorbents based on EPDM,the membrane showed a fast swelling property.In this article,electrospinning technology,fiber forming theory,the relation between structure and property,oil sorption dynamic thermodynamics and regeneration were studied.The main works and conclusions of the present study are as follows:Mathematical model is a key point for development of electrospinning technology.First, Through analysis of the initial stage,unstable stage and the final stage of electrospinning,we find the scaling is valid and obtain different scaling laws for different stages in the procedure. Also we obtain various scaling laws such as the relationships between fiber diameter and solution concentration(d∝C^1.91,d∝η^0.81,η∝C^2.37 ),voltage(d∝V),flow rate (d∝Q^1/2 ).All these scalings are experimentally verified and have many potential applications in experiment.The effects of process parameters on the oil sorption ability of EPDM ultrafine fiber mats were studied by using orthogonal experimental design method.The optimum process parameters can be obtained as following:the electrospun solution concentration is 10 wt %(EPDM/THF),the electrospun voltage is 20 kV,electrospun flow rate is 1mL/h,UV irradiation time is 96 h.While the membrane's stable mechanical parameters are as following: hardness is 59,100%tension stress is 1.8MPa,300%tension stress is 6.5MPa,tension strength is 17.8 MPa,broken extension rate is 452%,eternal transformation is 47%,tearing strength is 33.1 kN/m,which show that the oil sorption membrane has a good mechanical property and also it has the maximum values of oil sorbency to chloroform,cychlohexane, toluene,kerosene,which is 36.62g/g,26.8g/g,23.13g/g,22.15g/g,separately。The oil swelling process of the oil sorption membrane was studied.Swelling kinetics fit better for first order dynamic equation.To different oil,the swelling kinetic value K has the following sequence:chloroform(0.069)＞cychlohexane(0.063)＞toluene(0.053)＞kerosene(0.044).Compared with the granular and bulk oil sorbents based on EPDM,the oil sorption membrane showed a fast swelling property and better oil sorption ability.The thermodynamic study showed that Langmuir isotherms were found to fit well the adsorption data EPDM oil sorption membrane,in which the relevant parameter R is＞0.98 in all cases,the exponent factor n＞1 in Freundlich isotherm equations means the adsorption is thus favourable.The values of enthalpy changeâ–³H are all negative,the absolute value isbetween 40 kJ/mol～50 kJ/mol suggesting a spontaneous sorption process.The absolute value of sorption free energy changesâ–³G decreases with increasing temperature indicates that high temperature is not favourable to sorption.Furthermore,the EPDM oil sorption membranes were applied to the treatment of environmental hormeon(styrene) in water.The results indicated that the sorption efficiency of static and dynamic sorption is 99.47%and 98.99%,respetively.The oil sorption membrane can regenerate by using alcholo to exchange oil inside.However after five times recycle the self weight loss of EPDM oil sorption membrane is 40.16%.It is necessary to find more effective and economic recycle methods.Liu yanping(Environmental Science)Supervised by Prof.zhou meihua...