| Heavy metal elements in solid waste incineration flue gas will be enriched in fly ash particles by migration and conversion or directly in gaseous form,causing environmental pollution to harm organisms and human health.In this study,the modified boron nitride material was prepared by organic precursor method.The modified boron nitride material was solidified in the self-designed adsorption reaction experimental platform combined with specific surface area(BET),microwave digestion instrument and kinetic calculation.The adsorption rate and adsorption characteristics of modified boron nitride materials for heavy metals in solid waste incineration flue gas were determined.The experimental results show that the optimum conditions for the preparation of modified boron nitride by the precursor method are calcination at 1350℃ for 4 hours.Under this condition,the specific surface area and pore volume of the modified boron nitride material reach 765.67 m2/g and 0.59 cm3/g.When the adsorption reaction temperature is 400℃,the total adsorption of heavy metals in high temperature flue gas by modified boron nitride reaches 57.17 mg/g,which is 3.9 times that of activated carbon adsorbent(14.74 mg/g).The modified boron nitride has strong adsorption selectivity for heavy metal zinc(Zn),and the adsorption amount can reach 27.83 mg/g,which is 2～19 times of the adsorption amount of the remaining heavy metals under the same conditions.At the same time,the modified boron nitride material has better adsorption capacity for heavy metals in high temperature flue gas than activated carbon.The adsorption capacity of activated carbon adsorbent for Zn(8.33 mg/g)is only 29.93%of the amount of modified boron nitride to Zn adsorbed(27.83 mg/g)at 400℃.The adsorption kinetics equations show that the adsorption characteristics of modified boron nitride materials for heavy metals in incineration flue gas are well matched with the Bangham channel diffusion model. |
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