Study On The Influence Of Mineral On Biomass In Carbonization Process

The biomass has attracted researchers’considerable attentions all over the world due to its low cost,the wide raw material sources and reproducibility via photosynthesis and the preparation of carbon materials by biomass has become a hot topic in current research.The preparation carbon materials are widely used in the field of soil augmentation,environmental remediation,novel carbon-based anode materials of Li-ion batteries,ion exchange resins,adsorbing materials,and catalysts.During the research and application process,it was found that there are lots of coexistence systems of biomass and minerals in nature.The presence of minerals can have a subtle effect on the carbonization of biomass,thus affecting the performance of biomass carbon materials.However,there are few reports on the impact of mineral on the carbonization of biomass,and lack of in-depth understanding of influence of mineral on biomass.Therefore,this paper choose two common mineral（opal and kaolinite）and glucose,chitosan,cellulose and willow leaf as biomass forming carbonization system.By testing the structure,morphology and properties of carbonized product characteristics to explore the influence of the mineral raw material on the biomass in carbonization process.Firstly,the hydrothermal carbonization method was adopted to study the opal and hydroxypropyl methyl cellulose（HPMC）in this paper.The effect of opal on hydrothermal carbonization of HPMC was explored by changing the additional mass of opal and the hydrothermal time.It was found that the increase of opal could promote the form of hydrothermal product and make the hydrothermal production assemble densely better on the surface of opal.Meanwhile,the existence of opal made the structure of composite more steady.The reaction time has remarkable influence on reaction production.We found dehydration reaction of HPMC mainly occurred within 105-120 min,and afterwards,the hydrochar polycondensation and carbonization were gradually intensified.The presence of opal significantly accelerated the dehydration,dehydroxylation and small-molecule dissolution during the hydrothermal reactions.The addition of opal made the aromatic hydrochar appear earlier in the solid products,and accelerated the formation of hydrochar.The presence of opal was contributive to the formation of hydrothermal carbon nanospheres（20-100 nm）in the hydrochar.It is confirmed that amorphous siliceous minerals could significantly promote HTC of biomass and accelerate the formation of solid production and transformation of biomass.In order to explore the effect of amorphous silica mineral kaolinite on the hydrothermal carbonization of biomass,the hydrothermal carbonization system was formed with a variety of biomass.And then the influence of kaolinite on biomass conversion was discussed.The experiment results show that the structures of chitason and willow leaf basically remain unchanged,while the hydrothermal carbon spheres were formed in glucose and HPMC system under 230°C with 4 h.The presence of kaolinite made the carbon spheres bigger compared with not kaolinite in glucose system.Kaolinite can adhere to some organic matter,inhibit the accumulation of hydrothermal carbonization products to a certain extent,and reduce the particle size of biomass complex at macroscopic sense.Furthermore the hydrothermal liquid of biomass has certain fluorescence effect,while the willow leaf system has best fluorescence effect of hydrothermal liquid in the selected four kinds of biomass.Finally,the work of the influence of kaolinite of chitosan and willow leaf and the impacts of kaolinite of willow leaf under different atmosphere（air,buried carbon and Ar）were studied by pyrolysis carbonization.The results shows that the existence of the kaolinite made compounds form mesoporous,but structure of chitosan compounds collapsed and the pore volume decreased with the temperature increasing.In the atmosphere of Ar,the pore channel of the pyrolysis product of willow leaves obviously appeared,compared with the air and buried carbon atmosphere,indicating that it was beneficial for the carbonization of biomass to form porous materials in the atmosphere of argon.Under the condition of different pyrolysis carbonization temperature,the existence of the willow leaves promoted the partial kaolinite phase intoα-Al₂O₃ phase.In the process of carbonization of biomass,biomass also influences the transformation of mineralization.