Design And Preparation Of Biochar Functional Materials And Applied In Environmental Catalysis

Biomass is a series of renewable resources with the largest reserves in nature with great application potential.As a method of utilizing biomass,biochar has the advantages of low cost,easy fabrication,and sustainable.Biochar was often used as a soil conditioner traditionally.In recent years,biochar has attracted increasing attention as a low-cost and sustainable alternative to conventional porous carbon materials.It’s worth to research that how to expand biochar,a green and renewable carbon material,in the field of environmental catalysis.In this paper,a series of doped biochar catalytic materials were designed and prepared for persulfate activated degradation of environmental pollutants or biomass platform compound conversion.Therefore,it provided some new ideas for expanding the application of biochar materials in the field of environmental and energy catalysis.The main research contents and results of this paper are as follows:1.Synthesis and application of cobalt/nitrogen co-doped biochar materials.In this work,the doped biochar materials were prepared with sawdust and CoCl2 as raw materials,through the hydrothermal-pyrolysis two-step method.The biochar materials were applied to degradation of environmental pollutants through activating the permonosulfate(PMS).The reactive oxygen species in the PMS activation process were detected through electron paramagnetic resonance(EPR)radicals capture experiments and radicals quenching experiments to explore the of oxidation of active material.The results show that the prepared doped biochar catalyst has good persulfate activation effect and environmental adaptability.The main reactive oxygen spec.ies in the oxidation process was detected as non-free radical singlet oxygen(1O2).It shows that the doped biochar materials can achieve a good catalytic performance in the activation of persulfate.2.Synthesis and application of iron/nitrogen co-doped biochar materials.The potential hazard caused by dissolution cobalt ion in cobalt-doped catalysts could lead serious secondary environmental pollution.In order to avoid this problem,we improved the synthesis method by using[BMIM]FeCl4 ionic liquid to achieve the doped of the iron/nitrogen elements.The catalyst was applied to the activation of PMS and the degradation of the environmental pollutant bisphenol A(BPA).The related reactive oxygen species in the oxidation process was detected as singlet oxygen through radicals quenching experiments.The degradation results showed that the prepared iron/nitrogen co-doped biochar catalyst could effectively adsorb pollutants and activate persulfate while avoiding the leaching of toxic metal ions.This work provides ideas for the design of iron-biochar composite materials for the application of persulfate activation.3.Preparation and application of foam biochar catalytic electrode.In order to broaden the application of biochar materials into the conversion of biomass platform compounds,we synthesize the foam biochar electrode by high temperature pyrolyzing the chitosan reinforced with phenolic resin as raw materials.The layered bimetallic hydroxide(LDH)catalysts were supported on the foam biochar electrodes through hydrothermal method and applied to the selective electrocatalytic oxidation of 5-hydroxymethylfurfural(5-HMF).The oxidation process of 5-HMF and the generation mechanism of by-products were detected by nuclear magnetic resonance(NMR)and mathematical modeling.The results show that the foam biochar catalytic electrode loaded with NiFe LDH has a great 5-HMF selective oxidation capacity.At the same time,5-HMF can spontaneously undergo some reversible oligomerization reactions,resulting in the decrease of conversion rate.In this study,the oxidation of 5-HMF was mainly achieved through the furan-2,5-dicarbaldehyde(DFF)pathway.This study proposes a new way to synthesize foam-based biochar materials,which broadens our understanding of the electrocatalytic oxidation process of 5-HMF and provides ideas for biochar materials in the field of biomass platform compound conversion.