Preparation And Applied Research Of Ultrafiltration Membrane To Purify Mercury In Water

Polyvinylidene fluoride has good thermal and chemical stability, and is easy to dissolve incommon organic solvents. Porous polyvinylidene fluoride membrane can be prepared by themethod of phase inversion. Polyvinylidene fluoride membrane is very suitable to be used forwastewater treatment and application in the field of biomedical and biological separation.What’s more, polyvinylidene fluoride membrane can be chemically modified, so that it can bewith some special function. This paper uses the method of blending modification, which makesthe colorant with adsorption capacity of Hg²⁺blend to polyvinylidene fluoride ultrafiltrationmembrane. So that we can prepared polyvinylidene fluoride ultrafiltration membrane withadsorption capacity of Hg²⁺, which can be applied in some specific areas, and determine thebest membrane process.In this paper, we firstly study the preparation of traditional polyvinylidene fluorideultrafiltration membrane, and then determine the best molding process. The optimumparameter include15g of polyvinylidene fluoride,9.78mL of the additive PEG400,77.38mL ofsolvent DMAc,0.94mL of Twain80,30℃of coagulation bath temperature, stir2hours at80℃, and10seconds of pre-evaporation time. The polyvinylidene fluoride （PVDF）ultrafiltration membrane has294L/m²Â·h of pure water flux,90.6%of ovalbumin rejection rate,and82.25°of contact angle.In the preparation of2-mercapto benzothiazole modified ultrafiltration membrane, theoptimum parameter include0.4g of2-mercapto benzothiazole,4hours of blending time, and80℃of blending temperature. The2-mercapto benzothiazole modified ultrafiltrationmembrane has186L/m²Â·h of pure water flux,77.33%of ovalbumin rejection rate, and80.15°of contact angle, which illustrates some improvement of hydrophilic of modifiedultrafiltration membrane, and the descent of retention rate. With pH controlled at7, andtemperature at25℃, adsorption equilibrium can be made after4hours, and the maximumadsorption capacity is0.283mg/cm². After desorption twice, the desorption rate can still reach93.3%, and the water flux can maintain up to72.0%than the first time. So, we can know that theadsorption performance of Hg²⁺of ultrafiltration membrane is good.In the preparation of2-mercapto benzimidazole modified ultrafiltration membrane, the optimum parameter include0.4g of2-mercapto benzimidazole,4hours of blending time, and70℃of blending temperature. The2-mercapto benzimidazole modified ultrafiltrationmembrane has318L/m²Â·h of pure water flux,79.46%of ovalbumin rejection rate, and80.15°of contact angle, which illustrates some improvement of hydrophilic of modifiedultrafiltration membrane, and the descent of retention rate. With pH controlled at7, andtemperature at25℃, adsorption equilibrium can be made after6hours, and the maximumadsorption capacity is0.358mg/cm². After desorption twice, the desorption rate can still reach95.3%, and the water flux can maintain up to73.6%than the first time. So, we can know that theadsorption performance of Hg²⁺of ultrafiltration membrane is good.In the preparation of dibenzothiazyl disulfide modified ultrafiltration membrane, theoptimum parameter include0.4g of dibenzothiazyl disulfide,6hours of blending time, and70℃of blending temperature. The dibenzothiazyl disulfide modified ultrafiltration membranehas312L/m²Â·h of pure water flux,83.46%of ovalbumin rejection rate, and86.5°of contactangle, which illustrate some improvement of hydrophilic of modified ultrafiltration membrane,and the descent of retention rate. With pH controlled at7, and temperature at25℃, adsorptionequilibrium can be made after6hours, and the maximum adsorption capacity is0.331mg/cm².After desorption twice, the desorption rate can still reach90.9%, and the water flux canmaintain up to86.5%than the first time. So, we can know that adsorption performance of Hg²⁺of ultrafiltration membrane is good.In this paper, during the Preparation of polyvinylidene fluoride ultrafiltration membranewe use some colorant which can absorb Hg²⁺in water. We successfully preparedpolyvinylidene fluoride ultrafiltration membranes with adsorption capacity of Hg²⁺, anddetermine the optimal film formation process, and provide a reference for industrialapplications ultrafiltration membrane.