Preparation And Separation Performence Of ZSM-5 Zeolite Membranes

In recent years,the effective use of natural gas has become a hot spot to alleviate the oil crisis,methane anaerobic aromatization reaction can be natural gas into high value-added chemical products,is one of the most promising research direction.ZSM-5 zeolite molecular sieve is a molecular Size of the pores and cavity of the crystalline aluminosilicate.ZSM-5 zeolite molecular sieve-based catalyst has a unique molecular sieving ability,highly effective adjustable active sites,harsh environment,good stability in the performance of methane aromatization Out of good performance.However,in the process of reaction,the catalyst is prone to carbon deposition and lead to deactivation,methane conversion effect is also affected by the catalyst structure and morphology.Researchers have carried out various modifications and treatments on molecular sieves,synthesizing a large number of new molecular sieves.In this paper,nano-sized zeolite molecular sieves were synthesized by seed-inducing method,and the characteristic peaks of ZSM-5 were observed by XRD.The effects of alkali,water,seed number and crystallization time on the synthesis were investigated.The main conclusions are as follows:(1)Under the condition that the organic template agent was not added,the silicon source and aluminum source were mixed to form a gel-like substance,and after adding a certain amount of seed crystal,the zeolite molecular sieve crystal was prepared by seed-induced nucleation,XRD characterization can be seen very obvious ZSM-5 characteristic peaks.(2)The effect of the conditions on the hydrothermal synthesis was summarized by comparing the SEM images of the zeolite molecular sieves.The amount of water is too high or too low are not conducive to the formation of molecular sieve;water increases will usually make the molecular sieve more dispersed,the morphology is more obvious,but will not change the shape of the crystal;crystal seed volume increase can increase the nucleation speed,The effect of crystallization temperature on molecular sieves is not clearly reflected in this experiment,which may be due to the influence of external factors leading to the instability of the oven temperature,but also need to repeat the experiment.(3)ZSM-5 molecular sieves were prepared by different synthetic methods.The effect of template method was the best,and seed-inducing method was the best.(4)Select the morphology and size of the molecular sieve preparation catalyst,and applied to the methane anaerobic aromatization reaction,by gas chromatography.The conversion rate of methane was 14.6%,and the highest yield of benzene reached 7.6%.