Preparation Of Biomass Carbon Aerogel And Oil-Water Separation Properties

Petroleum,an important natural resource,has greatly promoted the rapid development of the social economy and improved quality of life.However,frequent leakage of industrial oily wastewater and crude oil have happened during the oil exploration,transportation and utilization processes,usually bringing destructive effects on ecological environment,especially the water environment.Therefore,the study of new technologies and methods for oil-water separation has made some important academic significances and practical values on eliminating the environmental influence by oil pollution.Compared with traditional mechanical extraction,such as mechanical extraction,in situ burning,microbial degradation,adsorption materials,such as biomass carbon aerogel prepared from biomass cellulose,are believed to be one of the most concerned technologies to separate oil from water.The materials used in this new technology are low cost,non-toxic,have good degreasing effect and no secondary pollution during use.Therefore,the paper focuses on the use of low-cost,wide-ranging biomass cellulose as the raw material to prepare different sorts of biomass carbon aerogels,followed by study their performance in oil-water separation.The main four parts of research were illustrated as follows:（1）Preparation of leaf-based carbon aerogel for selective oil-water separationFabrication of biomass carbon aerogel prepared simply by freeze-drying amd pyrolysis of cellulose aerogels composed of premna microphylla leaves.The biomass carbon aerogel shows a low density,excellent hydrophobicity,and the interconnected network structure could offer a passageway to store the absorbed oils and transport oil.Moreover,the as-prepared aerogel exhibited high adsorption capacity（34-68 g/g）for different oils and organic solvents,and distillation can be employed to obtain the adsorded pollutants.Therefore,leaf-based biomass carbon aerogel has great potential application in spilled oil recovery and environmental protection.（2）Preparation of biomass carbon aerogel reinforced with sisal for selective oil-water separationDifferent biomass carbon aerogels were prepared by freeze-drying and carbonization pyrolysis using tofu leaves and sisal leaves as raw materials and controlling the ratio of the two compents.The results show that the maximum water contact angle has been found to be 158°when the ratio of sisal cellulose to leaf cellulose is 2:1.In addition,the as-prepared aerogel exhibits high adsorption capacity（77.7-147.3 g/g）for different oils and organic solvents and the as-prepared aerogel still maintains a superior adsorption capacity after 10 cycles of oil absorption experiments.Also,the adsorbed oil can be recovered by the simple squeeze process.（3）Preparation of biomass carbon@SiO₂@MnO₂ aerogel with hierarchical architectures for selective oil-water separationA compressible,superhydrophobic and multifunctional hierarchical biomass carbon@SiO₂@MnO₂ aerogel（HBCSM aerogel）was prepared by in-situ growth,freeze-drying and carbonization pyrolysis with sisal cellulose as main raw material.With the introduction of the hierarchical structure,the surface roughness of as-prepared HBCSM aerogel is effectively improved.And the hydrophobic property of the aerogel could be effectively improved,which maintains a stable hydrophobicity at different pH conditions,and the water contact angle was maintained above 145°.In addition,the as-prepared aerogel could adsorb different oils and organic solvents and it also could separate effectively surfactant-stabilized water-in-toluene emulsions.（4）Preparation of hierarchical biomass carbon aerogel assembled with TiO₂nanorods for selective oil/water separationSisal cellulose was used as raw material to construct TiO₂ nanorods on the surface of biomass carbon aerogel under hydrothermal conditions,followed by surface hydrophobic modification under hydrogen atmosphere.Compared with some hydrophobic modifications by using silicone polymers,it is environmental-friendly to use titanium dioxide to be calcined in a hydrogen atmosphere without secondary pollution.The as-prepared aerogel exhibited the excellent wettability at different pH conditions,and the water contact angle was maintained above 154°.In addition,the as-prepared aerogel could adsorb different oils and organic solvents,it also could separate effectively surfactant-stabilized water-in-toluene emulsions.