Research On The Removal Mechanism Of Pollutants By Biochar Prepared By Industrial Solid Waste Catalysis And Synthesized Zeolite

For the characteristics of inferior resources such as wood chips and industrial solid waste,it is upgraded by catalytic pyrolysis and alkali fusion synthesis.This paper innovatively proposes a new technology route for the coordinated use of biomass and industrial solid waste.Due to the heterogeneity of biochar itself and the nature of contaminant species,there are differences in the adsorption process,effect and mechanism of biochar on pollutants.The physicochemical properties of biochar and synthetic zeolite were characterized by specific surface(BET),infrared spectroscopy(FTIR),scanning electron microscopy(SEM/EDX)and X-ray diffraction(XRD)to explore the removal mechanism of methylene blue,heavy metals,phosphate and nitrogen oxides,and the mechanism of pollutant adsorption by active components in industrial solid waste was revealed.Two kinds of industrial solid waste(fly ash,coal gangue) were used to catalyze the pyrolysis of biomass(wood chips).At 500°C,the prepared biochar has a well-developed pore structure and is rich in functional groups such as hydroxyl group,amino group,carboxyl group and phenolic hydroxyl group.Due to the limitation of adsorption capacity,it is necessary to improve the quality of biochar by subsequent modification.Firstly,the modification of biochar by using alkaline solution NaOH can increase the specific surface area,and the alkaline solution can activate the active sites in fly ash and coal gangue,which helps to increase the adsorption capacity.The adsorption characteristics of Cu²⁺ in solution by NaOH modified biochar,as follows:pH has a great influence on the removal of Cu²⁺ by NaOH modified biochar.When the initial solution pH is 7,the removal rate of modified fly ash-based biochar reaches the maximum,and the removal rate can reach 86.76%.Secondly,according to the results of adsorption of methylene blue by biochar,if it is used as adsorbent for phosphorus removal,the adsorption capacity of biochar needs to be further improved.Some studies have shown that iron ions can be adsorbed on the surface of fly ash and coal gangue,which increases the positive electricity of the particles and has a good adsorbability to anions in water.Fe³⁺ can form Fe(OH)₃ flocculant in the treatment of wastewater by iron ion modified fly ash,which plays the role of flocculation and precipitation.Based on the above reasons,biochar was modified by iron salt.Moreover,Biochar produced by industrial solid waste catalysis is rich in mineral components,mainly metal oxides.Studies have shown that mineral components such as K,Ca,Na,Mg and Fe have a certain catalytic effects in the reduction of NO by carbon.The effects of biochar species,temperature and oxygen content on the reduction of NO by biochar were investigated.Another application of industrial solid waste is to use it as a raw material to synthesize zeolite.Y zeolite was successfully synthesized from fly ash by alkali fusion.The results show that the Y-type zeolite synthesized by fly ash has a certain adsorption effect on methylene blue,but the purification effect needs further improvement.Y-type zeolite has a higher reduction rate of NO than fly ash.