Preparation And Application Of Biochar From Paulownia Leaves

With the rapid development of economy and industrialization,the shortage of energy supply and the increasingly serious environmental pollution have become the important factors restricting the rapid development of China.And China’s abundant biomass resources,biomass carbon technology is under the condition of limited oxygen through pyrolysis,discard some of biomass resources into biochar can reuse resources,the emergence of biomass carbon to solve the water pollution in our city development,air pollution,soil heavy metal pollution repair and increase crop yield,save non-renewable energy use,protect the ecological environment and has made an important contribution.Among them,the dead branches and fallen leaves in daily life as "green waste",the traditional treatment methods include incineration treatment,direct landfill,etc.,will not only cause environmental pollution,but also a serious waste of biological resources.Therefore,it is imperative to make full use of these forest wastes and deciduous resources.Biomass charcoal porous,large specific surface area,surface functional groups such as variety of features,there are a lot of research to biomass charcoal used in agriculture as fertilizer for crops,utilizing biomass carbon in the adsorption of organic pollutants in water and harmful heavy metal ions,the results also achieved satisfactory effect.But different biomass raw materials produced by the biochar will have different properties,for the application of the field is not the same.Will vary between different biomass carbon,so for the use of biomass carbon cannot treat as the same,need to be done according to the preparation of biomass carbon analysis of the specific physical and chemical properties,and preparation of biomass charcoal explored feasibility according to the nature of the experiment,can detect the safety performance of biomass carbon and use,can finally be put into use in real life or batch use.In this experiment,Paulownia leaves were used as biomass raw materials to prepare Paulownia leaves biochar by pyrolysis at different temperatures,and then their physical and chemical properties were determined.The prepared Paulownia leaf biochar was used as adsorbent and additive to study its adsorption properties of Cd2+in aqueous solution and its effects on seed germination and seedling growth of Paulownia.The main findings are as follows:(1)in paulownia leaf,France wutong leaves and camphor leaves living material raw materials,in the different pyrolysis temperature(350 ℃,450℃ and 550℃),the preparation of the biomass carbon,by element analysis,SEM,scanning electron microscopy(SEM),specific surface area and pore size analysis method for the preparation of biomass carbon are measured,analyzed their physical and chemical properties,observe their characterization of structure.The results showed that both biomass raw materials and pyrolysis temperature had effects on the preparation of biochar.With the increase of pyrolysis temperature,the yields of Paulownia leaf biochar,Indus sycamphoris biochar and Camphor’s camphoris biochar decreased gradually.The carbon content is gradually increasing;The pore structure is gradually clear,and the specific surface area is gradually increased.The surface of camphor leaf biochar prepared at 550℃ was compared with that of paulosa leaf biochar and sycamore leaf biochar prepared at the same temperature,and Al and Fe were detected.The specific surface area of Paulownia leaf biochar is larger than that of the other two biochar,and the pore size structure is more obvious.(2)Paulownia leaf biochar prepared at three temperatures was used as adsorbent to adsorb Cd ions in aqueous solution.Factors influencing the adsorption performance of different Paulownia leaf biochar on Cd ions were studied,and the most appropriate adsorption conditions and Paulownia leaf biochar were selected.In the single variable experiment,when the concentration of Cd2+in aqueous solution was taken as the variable,the adsorption capacity of three kinds of Paulownia leaf biochar for Cd2+gradually increased with the increase of the concentration.Taking pH as the variable,with the increase of pH,the adsorption capacity of the three kinds of Paulownia-leaf biochar for Cd2+increased first and then decreased.When pH was 6,the adsorption capacity of biochar for Cd2+reached the best.When the adsorption time was taken as the variable,the adsorption properties of the three Paulownia leaf biochar for Cd2+increased first and then remained stable with the extension of time.At 90min,the adsorption capacity for Cd2+ gradually reached saturation.When the amount of biochar was taken as the variable,with the increase of the amount of biochar,the adsorption performance of the three kinds of Paulowlowia leaf biochar for Cd2+rose slowly and reached equilibrium.When the amount of biochar was 3g/L,the adsorption capacity was the best and the cost performance was the highest.Among the three kinds of biochar,the adsorption performance of the biochar prepared at 550℃ is higher than that of the biochar prepared at 350℃ and 450℃.(1)The extraction solution of biochar from Paulownia leaves was used as the base solution for the germination of Paulownia seeds.The germination rate and germination potential of Paulownia seeds,as well as the length of bud,stem and root of Paulownia seedlings,and the average fresh weight of seedlings were measured.In this way,the effects of biochar from Paulownia leaves dissolved in water on Paulownia seeds and seedlings were discussed.The results showed that the germination rate and germination potential of Paulownia seeds in the original biochar extract and the treatment diluted 10 times were far lower than those in the control group,while the germination rate and germination potential of Paulownia seeds in the treatment diluted 50 times were increased,and the extraction diluted 50 times at 550℃ had the best effect on the germination of Paulownia seeds.The six kinds of biochar extracts from Paulownia leaves can promote the growth of shoot length and stem length of Paulownia seedlings,and the most obvious promotion effect is shown under the treatment of the extract diluted 10 times at 550℃.However,the root length of Paulownia seedlings treated with biochar extracts from six kinds of Paulownia leaves showed a state of inhibiting growth,and the biochar original solution showed the strongest inhibiting effect,which was slightly relieved after dilution of 50 times.The average fresh weight of Paulownia seedlings was significantly reduced by biochar extract and the treatment diluted by 10 times,while the average fresh weight of Paulownia seedlings was increased under the treatment diluted by 50 times,and the average fresh weight of Paulownia seedlings increased by the most at 550℃.