Preparation Of Biomass-Based Activated Carbon And Silica-Based Organic-Inorganic Composite Adsorption Materials

Adsorption is a widely used technology for the treatment of volatile organic compounds?VOCs?,with the advantages of quick effectiveness,small investment and highly adaptability,and the adsorbed VOCs can be recycled through desorption,so it has more significance for energy-saving and emission-reduction.The development of new-type and efficient adsorbent is the core of this technology.In this paper,sucrose was selected as a typical representative of biomass to synthesize activated carbon by hydrothermal carbonization and further heat treatment,and additives?H₃PO₄,ZnCl₂,SnCl₂,CaCl₂?was added in the two processes to explore the impact of additives on the textural properties of activated carbon products.The samples were characterized by BET,SEM,FTIR,XRD,water contact angle,results showed that when CaCl₂ was added in the hydrothermal process,the specific surface area of activated carbon was significantly increased,up to 1180 m²/g compared with that of the blank sample?i.e.,724 m²/g?,added H₃PO₄ in the process of heat treatment,the specific surface area was the largest,as high as 1529 m²/g,it can be seen that additive is very effective for the pore construction of activated carbon.Moreover,the micro-morphology of activated carbon microspheres was more homogeneous when additives were added in the heat treatment process,while the activated carbon microspheres were more hydrophobic when additives were added in the hydrothermal process.For the problem of poor hydrophobicity when silica gel was used as VOCs adsorbent,this study was conducted based on our previous study,to simplify and improve the hydrophobic modification scheme of silica gel.Divinyl benzene?DVB?monomer was introduced into the surface and pores of silica gel,and then polymerized to form PDVB polymer resin under solvothermal condition,finally the organic-inorganic composite adsorption materials were got.The samples were characterized by TG,BET,FTIR,water contact angle,results showed that different solvents?ethyl acetate and tetrahydrofuran?had little effect on the properties of the product;compared to pure silica gel,the surface area of PDVB/SiO₂-T-0.5 and PDVB/SiO₂-E-0.5 samples were greater,and average pore size were smaller;toluene adsorption properties of the composite materials also improved obviously,adsorption capacity was about 4 times of the original silica gel,the materials also had excellent hydrophobicity,the adsorption capacity was not significantly reduced even when relative humidity was 80%,so it can be a kind of VOCs adsorption material with wide application prospect in industry.