Solid Phase Grinding Synthesis Of High-silica ZSM-5 Zeolites And Its Adsorption Properties Of VOCs

The emission of volatile organic compounds(VOCs)will lead to more serious atmospheric pollution phenomena such as atmospheric photochemical reactions,PM2.5 and secondary organic aerosols.Therefore,comprehensive and effective control of VOCs exhaust gas is required.Adsorption technology is one of the most widely used technologies in organic waste gas treatment,and the core of adsorption technology is adsorption materials,so the development of efficient adsorption materials is extremely important.The molecular sieve is widely used as an adsorbent due to its advantages of regular and orderly pore structure,artificial control,good chemical stability,high temperature resistance,good regeneration performance and so on.Traditional molecular sieves are often synthesized by adding organic template agents at high temperature for hydrothermal synthesis,which has the problems of high cost,low yield and high pressure in the kettle,as well as environmental pollution problems such as waste water discharge.In order to overcome the shortcomings of the traditional synthesis method,this paper uses solid-phase grinding method instead of hydrothermal method,and uses the seeding agent to replace the organic template agent to realize the green synthesis of zeolite molecular sieve.1.Guarantee production safety,and also greatly reduce environmental pollution.In this study,the reaction time,reaction temperature,seed crystal addition amount and ethanol addition amount were used as experimental variables to conduct a single factor experiment to synthesize highsilicon ZSM-5.Then X-ray powder diffraction(XRD)method was used to characterize the crystallization of the high-silicon ZSM-5 molecular sieve synthesized under different conditions,and to understand the changing trend of the molecular sieve synthesis degree as the reaction conditions changed.When the reaction time is 2d,the reaction temperature is 180 ?,and the amount of ethanol added is 4.5g,the crystallinity of the molecular sieve obtained is the highest.And rise.Using Design Expert 8.0.6 software and Box-Behnken design,select the reaction time,reaction temperature and ethanol addition amount that have a significant influence on the crystallinity in the single-factor experiment and have the optimal solution within the value range,and the crystallinity as For the response value,establish a response surface model based on the actual experimental data,make an intuitive response surface graph based on the function model,and calculate the optimal solution within a certain range,and the optimal solution reaction conditions:the reaction time is 2.27 d,the reaction temperature is 180.64 ° C,and the amount of ethanol added is 4.58 g.At this time,the crystallinity is expected to be 91.2936%..The penetration adsorption capacity of the molecular sieve synthesized under different conditions was tested,and it was found that its change trend was consistent with the change of crystallinity.Comparing the seeds synthesized by the traditional synthesis method with the samples synthesized by the green method,the penetration adsorption capacity of the seed crystal is 43.15mg/g,and the penetration adsorption capacity of the synthetic molecular sieve is 30.25mg/g.Calculate the production costs of the two synthesis methods.The cost of the traditional synthesis method is 44832 yuan/ton,the green molecular sieve is 22398 yuan/ton,and no toxic amine wastes are generated during the synthesis process.No solvent is involved.The pressure in the kettle is low and the safety is high.Therefore,this method is feasible.