| In recent years,water pollution has become more and more serious,and pathogenic viruses with different kinds found in water have become one of the most potential threats to human existence.Traditional methods of virus removal include chemical method,physical method and combination method.But most of these methods have common disadvantages,such as complex process,high cost and easy to cause secondary pollution.As a new type of functional material,due to its unique electrostatic adsorption effect,charge materials have the advantages of simple operation,low cost,use safety and good adsorption performance in virus separation.This paper researched the adsorption and separation performance of positively charged microporous ceramic membrane to virus in water,and explored the separation mechanism through preparation of positively charged microporous ceramic membrane,characterization of composition and structure and assessment of the electric properties.Positively charged microporous ceramic membrane with nano-Y2O3 coating was prepared by dipping and sintering process with diatomite microporous ceramic membrane as support membrane,YCl3·6H2O and urea as raw material.The composition and structure of the membrane was characterized with FT-IR,XRD,EDS and SEM analysis.The results showed that,the charged membrane prepared with average pore size of 0.60 μm,specific surface area of 1.85 m2/g,water flux of 421 L/m2·h,and Yttrium content on membrane surface of 24.76 wt%.Y2O3 uniformly distributed on the membrane surface and the particle size was about 10 nm,and it was cubical crystal.The electrical properties of positively charged microporous membrane were characterized through zeta potential analysis and evaluation on adsorption performance of negatively charged dye titan yellow.The effects of coating liquid concentration of Y3+,membrane thickness,pH and other factors on the adsorption of Titan Yellow was investigated.The results showed that isoelectric point(IEP)of the charged membrane was pH 8.3,that was,when pH was less than 8.3,the Zeta potential was positive,and the maximum Zeta potential was 31.90 mV,indicated the membrane surface have positive charges.The removal rate of Titan Yellow increased with the increase of Y3+ concentration.When the concentration of Y3+ was 0.015 mol/L,in the pH range of 3.0 to 8.0,positively charged microporous ceramic membrane with thickness of 0.50 cm always had a removal rate larger than 90.00%.Charged membrane’s saturation adsorption capacity of Titan Yellow was 3.86 mg/cm3.The removal rate of charged membrane regenerated after adsorption saturation to Titan Yellow could be restored to 95.60%.The separation and removal performance of positively charged microporous ceramic membrane to virus was investigated through separation experiments of bacterial endotoxin and Escherichia coli bacteriophage MS2.Charged membrane had good separation effect to bacterial endotoxin and MS2 coliphages,and the removal rate were 99.60%and 99.99%respectively.PH of water had some influence on removal of MS2,but in the pH range of 5.0 to 8.0,positively charged microporous ceramic membrane had stable adsorption performance to MS2.Through electrical properties analysis and the removal experiments to virus,especially the control experiment of base membrane and charged membrane,it could be determined the separation mechanism of positively charged microporous ceramic membrane to virus was electrostatic interaction between positive and negative charges,rather than physical entrapment of membrane pore.Owing to positive charges,positively charged microporous ceramic membrane can adsorb and separate virus through interaction between positive and negative charges,besides screening interception of the common microporous ceramic membrane.This study will provide a new method for the separation,concentration and detection of virus,which has a broad application prospect. |
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