Study On Preparation Of Polysulfide Composites And Their Adsorption Properties Of Hg(Ⅱ)

In recent year,the mercury industry has developed rapidly in our country,the discharge of a large amount of mercury-containing wastewater not only pollutes the water source and endangers the aquatic creatures,but also the mercury in the water migrates into the soil and the atmospHere through various channels,mercury is easily enriched in the organism and can enter the biospHere through the food chain,which ultimately endangers the human body and the ecological environment.Therefore,it is important to look for some efficient ways to solve the mercury pollution problem in wastewater.Today,adsorption method is widely used in heavy metal adsorption due to cheap materials,simple devices and no secondary pollution.Because of its high affinity to mercury,polysulftide is a good material for absorbing mercury ions.In this paper,anacardol polysulfide/diatomite composite materials(SAD)were compounded of petroleum waste-sulfur,agricultural waste-anacardol and diatomite via inverse vulcanization.At the same time,oleylamine polysulfide/mesoporous composite material(SOM)were compounded of sulfur,oleylamine and mesoporous SiO2 material modified by mercapto(MCM-41-SH)via inverse vulcanization.The structures and morphologies of SAD and SOM were characterized by Fourier transform infrared spectroscopy(FT-IR),scanning electron microscope(SEM),X-ray diffraction(XRD)and thermogravimetry analysis(TGA),the results showed that SAD and SOM were synthesized successfully.The effects of various factors on the adsorption properties of SAD and SOM were comprehensively investigated.The results showed that the adsorption capacity of SAD to Hg(Ⅱ)reached the optimum when the raw materials were 7 g sulfur,3 g cashew phenol and 2 g diatomite when the reaction temperature was 185℃.When m(oleylamine):m(MCM-41-SH)=4:2 and the reaction temperature was 185℃,the adsorption capacity of Hg(Ⅱ)by SOM reached the best.The adsorption performance of Hg(Ⅱ)was studied by changing the adsorbent pH value,reaction time and initial Hg(Ⅱ)concentration.The experimental results showed that when the pH value was 4,the temperature was 25℃,the initial Hg(II)concentration was 50 mg/L and the adsorption time was 2 h,the adsorption effect of SAD was the best,and the maximum adsorption capacity of Hg(II)was 60.15 mg/g.When the pH value was 4 and the adsorption time was 6 h,the initial Hg(II)concentration was 50 mg/L,SOM achieved the best adsorption effect and the adsorption capacity was 70.08 mg/g.The kinetic study shows that the adsorption process of SAD and SOM conformed to the quasi-second order rate equation.Thermodynamic studies showed that the adsorption of Hg(II)by SAD and SOM was a spontaneous exothermic process.The adsorption process of SAD and SOM conformed to Langrnuir model,indicating that the adsorption of both materials is monolayer adsorption based on the active site on the surface.The co-existing cations in the system had no significant effect on the adsorption of Hg(II)by SAD and SOM.The reproducibility of the two materials showed that SAD had good reproducibility.In addition,the adsorption material SOM was treated with industrial wastewater,and the adsorption capacity of SOM can reach 70%of the standard mercury ion solution,laying a certain foundation for future application and research.