Adsorption Properties Of Hexagonal Boron Nitride Nanomaterials For Gaseous Pollutants

Activated porous boron nitride materials have broad application prospects in pollution control because of many excellent properties,such as non-toxic,light,anti-oxidation,acid and alkali resistance,high specific surface area as well as large pore volume.At present,many studies focus on the adsorption properties of boron nitride materials in aqueous solution.Although the hydrophobicity of boron nitride materials will restrict its contact with pollutants in water,thus impairing the adsorption process,these materials still perform excellent adsorption characteristics.This will undoubtedly make the performance of boron nitride materials in the treatment of air pollutants more expected.In this paper,the activated porous boron nitride(p-BN)was synthesized by a two-step method at low temperature,meanwhile,the adsorption performance of porous BN materials for different gases was explored.The p-BN@Cu composite was obtained by a one-step method,and its adsorption capacity is studied.Besides,p-BN@HKUST-1 composite was prepared for the first time by combining p-BN with Metal-Organic Frame Structures(MOFS)HKUST-1.A study of the adsorption capacity of p-BN@HKUST-1 composites for volatile gaseous pollutants was carried out systematically.The main research contents are as follows:(1)The p-BN was prepared by a two-step method at low temperature.The adsorption performance of p-BN on gaseous pollutants in air was studied by static method and dynamic method,respectively.The structural characteristics of p-BN materials prepared at different temperatures were analyzed systematically,and their effects on adsorption propertise of organic and inorganic gases were also studied.Among them,the p-BN prepared at 900?has the best adsorption performance.(2)Carbon disulfide(CS₂)was selected as a simulated pollutant to study the adsorption performance of p-BN for inorganic pollutants in air.The adsorption characteristics and influencing factors of p-BN on carbon disulfide in mixed gases were both studied by static and dynamic methods at 25?.In the study of static method,the adsorption capacity of p-BN on CS₂ can reach 65.5 mg/g after 24 hours placed in CS₂ atmosphere,which is superior to commercial boron nitride sheets,boron nitride spheres and activated carbon materials.The adsorbed CS₂ can be completely removed by annealing at 600?to realize the recycling of p-BN materials.After six cycling,p-BN still retained 96%of its original adsorption capacity.The adsorption performance of p-BN on CS₂ was also studied by dynamic method.Yoon-Nelson model can well fit the dynamic breakthrough curves under different conditions.The adsorption capacity of p-BN on CS₂ in dynamic adsorption was calculated as 57.12mg/g.(3)In order to investigate the adsorption performance and influencing factors of p-BN on organic gases,toluene(C₇H₈)was used as an experimental gas.The adsorption capacity of p-BN for C₇H₈ is relatively high.Using static adsorption method and dynamic adsorption method,the adsorption capacity of p-BN on toluene are 314.6 mg/g and 300.76 mg/g,respectively.Similar to CS₂ gas,Yoon-Nelson model can well fit the dynamic breakthrough curves of toluene.The adsorption isotherm of p-BN on toluene conforms to Langmuir adsorption model,which means that the adsorption belongs to monolayer adsorption model.(4)P-BN@Cu composites were prepared by a one-step synthesis method,and their adsorption properties for gaseous inorganic pollutants were investigated.Copper is loaded on p-BN fibers in the form of nanoparticles.However,the adsorption of p-BN can not be improved by the combination of copper.(5)P-BN@HKUST-1 composites were successfully prepared by hydrothermal method.P-BN fibers were used as the base material while the MOFS HKUST-1 were distributed into the pores of p-BN.The stability of HKUST-1 have been improved due to the protective effect of p-BN.Meanwhile,the adsorption performance of p-BN@HKUST-1 much higher than untreated p-BN.In the study of static and dynamic adsorption methods,the adsorption capacitys of p-BN@HKUST-1 composite on CS₂ were 120.4 mg/g and 112.5 mg/g,respectively.