Preparation Of Biochar By Hydrothermal Method And Its Activation Evaluation

Straw is a sort of usual agricultural biomass with abundant sources and large distribution,which is renewable and environmentally friendly.Biomass hydrothermal carbonization technology is used to develop and make use of straw biomass resources to alleviate energy crisis and environmental problems,which is the most manageable technological know-how for application.However,few researchers have studied the catalytic hydrothermal carbonization of straw biomass to produce functional carbon substances and the mechanism of catalyst action.In this paper,citric acid(CA),Na OH,Zn Cl2 and(NH4)2Fe(SO4)2 are selected as catalysts for the HTC of maize straw biomass,and the catalytic mechanism is printed via combining the hydrothermal carbonization of model compounds such as cellulose,lignin and glucose.The physical shape and chemical houses of maize straw hydrothermal carbon has been similarly expanded with the aid of activation to discover the training path of carbon materials with excessive adsorption properties.With the expand of response intensity,the carbon content of the stable phase merchandise increased from 49.04 wt.% to 58.46 wt.%,and the calorific price expanded from 19.43MJ/kg to 24.18MJ/kg.It was once observed that the catalyst can promote the hydrolysis response of biomass and reduce the yield of modified hydrothermal carbon in exclusive stages by using adding the catalyst to the HTC response beneath the top of the line hydrothermal conditions.The unique surface area of hydrothermal carbons was expanded from 12.14m2/g to 17.98m2/g by Zn Cl2.The hydrothermal carbons had improved N-H infrared absorption peaks by means of(NH4)2Fe(SO4)2.The hydrothermal carbon had stronger C=O and C=C infrared absorption peaks due to the motion of Zn Cl2,and the hydrothermal carbon had enhanced C-O infrared absorption peaks due to the action of Na OH.In the HTC process,cellulose and lignin factors in actual biomass were hydrolyzed into oligomers with the aid of CA.Glucose reacted with CA to extend the aromaticity and oxygen-containing practical groups of hydrothermal charcoal.Cellulose factors in actual biomass had been hydrolyzed to D-glucose with the aid of Zn Cl2,and the secondary carbonization response of glucose was promoted.Na OH inhibited the carbonization of cellulose aspects in actual biomass into pellets and promoted the hydrolysis of lignin components into phenolic compounds,converting biomass into bio-oil.(NH4)2Fe(SO4)2 was doped with the lignin component of real biomass and glucose hydrolyzed from cellulose aspect to increase the amine useful agencies in straw hydrothermal charcoal.The properties of straw hydrothermal charcoal had been similarly regulated by way of activation treatment.The activated hydrothermal carbon modified by Zn Cl2 had a most specific surface vicinity of 1532.9m2/g and a most adsorption capacity of136.7cm3/g for CO2.The most adsorption capacity for Cr(Ⅵ)was 88.9mg/g after activated by way of CA modified hydrothermal carbon.The most adsorption capacity of Zn Cl2 modified carbon on Cr(Ⅵ)was 23.51mg/L.The kinetic and thermodynamic fitting effects exhibit that the adsorption of Cr(Ⅵ)on hydrothermal carbons was on the whole a monomolecular chemisorption process.