Preparation And Adsorption Properties Of Nano Polymer/actived Carbon Composite Material

At present,the harm of VOCs is becoming quite serious,so the technology of adsorption and detection of VOCs has attracted wide attention.Adsorbents are usually used to capture and enrich VOCs,followed by desorption and detection.The first step of detection is the absorption of VOCs,its result will cause direct effect on the analysis to chromatography,so the choice of absorption is of great importance.The activated carbon,as a widely used absorption,is characterized by larger superficial area,developed pore structure and good ability of absorption.The activated carbon exert physical absorption on VOCs,and the organic compounds are adsorbed onto the surface of activated carbon by the weak vad der waals force,the adsorption capacity is limited,and the detection sensitivity is not high.The physical structure and surface chemical composition of activated carbon have an effect on the adsorption performance.The adsorption performance of activated carbon can be improved by adjusting the physical structure or changing the surface chemical environment of activated carbon.Activated carbon was prepared from desilication rice husk which was impregnated in phosphoric acid and activated at high temperature.The effects of impregnation ratio,activation time and activation temperature on the yield of activated carbon and the adsorption of carbon tetrachloride were studied.The pore size distribution and specific surface area of activated carbon were measured by nitrogen adsorption,The results show that the surface of activated carbon is mainly composed of mesoporous structure.Polymer was synthesized by emulsion polymerization method using styrene as monomer,SDBS as emulsifier,potassium persulfate as initiator,the optimum polymer conditions were determined.The polymer was adhered onto the surface of activated carbon by vinyltriethoxysilane to prepare an absorbing material for organic compounds in air.The structure and morphology of the materials were examined by FT-IR and SEM.The results showed that polystyrene spheres were uniformly distributed on the surface of activated carbon.This composite material will be applied to detect seven kinds of VOCs in the air.The adsorption capacity and adsorption rate of nano polymer/actived carbon composite for acetone,butyl acetate,p-xylene,chlorobenzene,cyclohexanone,p-dichlorobenzene and 1,2,3-trichlorobenzene were 165.06 mg/g,149.38 mg/g,214.68 mg/g,67.08 mg/g,195.43 mg/g,129.11 mg/g,184.25 mg/g and 62.18%,85.16%,92.15%,61.77%,84.66%,53.45%,86.54% respectively.The method detection limit of components were 1.12 mg/m3,0.87 mg/m3,0.96 mg/m3,0.44 mg/m3,0.35 mg/m3,0.83 mg/m3,0.76 mg/m3.