Mild Conditions Synthesis And Adsorption Performance Of Porous Silicon-based Materials

In recent years,with the development of chemical fiber fabrics,the types and properties of dyes are also increasing,which brings great difficulty to the treatment of printing and dyeing wastewater.Commonly used treatments include adsorption,electrolysis,oxidation and biological methods.In this paper,a kind of porous silicon-based material is designed and synthesized.The whole system is nearly neutral.This material has a large specific surface area and a large number of aperture,which greatly improves the adsorption performance of the material to dyes.Specific results are as follows:Porous silicon-based materials(PSM)were prepared by sol-gel method under mild conditions,and the morphology and structure of the samples were characterized by TEM,SEM,nitrogen adsorption and XRD.The results showed that the material was flaky with a large number of holes.The BET specific surface area of the prepared material was 320.7 mg/g,and the pore size was 4.9 nm.The porous silicon-based material was successfully prepared in the experiment.In this paper,the adsorption performance of porous silicon-based materials(PSM-n,n=1?5)on three dyes,namely methylene blue(MB),neutral red(NR)and Congo red(CR),was discussed.The results showed that the adsorption process of PSM for methylene blue and Congo red dyes was consistent with Langmuir adsorption isotherm.When the initial concentration of the dye was 40 mg/L,the theoretical maximum adsorption capacity of PSM-4 adsorbed MB and CR was 97.2 mg/g and 18.5 mg/g.The adsorption process of PSM for neutral red dyes conforms to Fruendlich adsorption isotherm,and the analysis of kinetic model indicates that the adsorption behavior of PSM for three dyes conforms to the quasi-second-order kinetic model.In addition,the study of adsorption thermodynamics showed that the adsorption process of PSM for the three dyes was exothermic.The adsorption,desorption and regeneration of different dyes by this material were studied.The experimental results showed that PSM had good adsorption performance on various dyes,such as MB and NR.The adsorption effect of CR dye was general,but the desorption effect was good.After five times of regeneration,PSM still has good regeneration performance,especially NR dye,and the removal rate is finally kept at about 96%,which can realize multiple recycling,and is a good adsorption material.The results show that the porous silicon-based material prepared has good adsorption and regeneration properties for methylene blue(MB)and neutral red(NR)dyes,and is expected to be applied in the field of environmental restoration.