Modified ZSM-5 Molecular Sieve And Its Performance In Removing Hg~0

As a kind of toxic and heavy metal,Hg~0 in flue gas has caused great harm to biological and environment,and made a wide attention of scholar both at home and abroad.The efficient mercury removal adsorbent is an effective way to solve this problem.This paper selected the ZSM-5 molecular sieve as carrier,K2FeO4,and KMnO4 as the active material,and maked two kinds of modified molecular sieve with solid phase grinding method by means of software simulation combined and experiments.Then the best adsorption properties of the modified molecular sieve was confirm for subsequent experiments.The influence of adsorbent dosage,adsorption temperature,inlet concentration of Hg~0 were analyzed,and made dynamic analysis in this article.Finally,the modified and unmodified molecular sieve were characterized by BET,XRD,FTIR,SEM,XPS,and its adsorption mechanism for Hg~0 was analyzed.The main research conclusions are as follows:(1)The optimum mass mixed ratio of active substance in modified Fe-ZSM-5,Mn-ZSM-5 molecular sieve is 1~0:1.5 and 1~0:2.6.The best calcination temperature is 25~0?and 4~0~0?.(2)The increment of adsorption reaction temperature and inlet concentration of Hg~0 was against modified molecular sieve adsorption for Hg~0,while the increment of adsorbent dosage can improve the modified molecular sieve adsorption efficiency of Hg~0.(3)This paper fitted the adsorption curve of two modified molecular sieve under the different temperature,which based on the pseudo-first order kinetic model,pseudo-second order kinetic model,intraparticle diffusion model and Elovich model.The results showed that the adsorption process of two kinds of modified molecular sieve for mercury is controlled by external diffusion,intraparticle diffusion,surface adsorption,and surface chemical adsorption is the main step of speed control.The adsorption process obeys the Langmuir and Temkin adsorption isotherm equation.(4)Characterization results show that: Iron and manganese oxides is main existence form of active substances in the modified Fe-ZSM-5,Mn-ZSM-5 molecular sieve;the modified molecular sieve can convert Hg~0 into Hg2+;the adsorption process obeys Mars-Maessen mechanism.