Synthesis And Application In Catalytic Oxidation Of Sulfite By MOF-derivative

Magnesium desulfurization is a common flue gas treatment process for small and medium-sized industrial boilers in China.The catalytic oxidation of magnesium sulphate to magnesium sulfate is a crucial step in magnesium desulfurization.The research on magnesium desulfurization catalyst is a hot issue.Among the catalytic materials developed in recent years,MOF-derived porous nanomaterials have narrow pore volume,specific topological structure and material properties and morphological variability,and have great application potential in magnesium desulfurization catalysis and other industrial catalytic fields.In this paper,MOF-derivative nanomaterials were prepared by a series of methods of impregnation and high-temperature carbonization using cobalt chloride hexahydrate as the central ion and 4,4'-bipyridine as the organic ligand,which was used as a catalyst for catalytic oxidation of magnesium sulfite..In this experiment,the coordination of ligands and metal ions was firstly studied,and the synthesis was carried out according to the different ratios of central ions and organic ligands.The optimal ratio was selected and the optimal preparation conditions of Co-MOF materials were screened out by experiments.Finally,the Co based nanomaterials were further prepared from Co-MOF materials for kinetic experiments.Under the condition of simulated working conditions,the macroscopic reaction kinetics of catalytic oxidation of magnesium sulfite was studied.The relevant parameters were obtained:the catalyst concentration and the partial pressure of oxygen were 0.360 and 0.337 respectively,and the pH was about 9.0.The rate is the largest,and the apparent activation energy of the catalytic reaction is calculated by Arrhenius'law to be 10.20134 KJ/mol.However,the desulfurization slurry contains not only magnesium sulfite but also heavy metal Hg²⁺,which causes secondary pollution.In order to study the adsorption performance of MOF-derivatives as adsorbents,we carried out MOF-derivative removal of Hg²⁺experiments by adsorption of Hg²⁺.Experimental studies have shown that MOF-derivatives are adsorbents that efficiently remove Hg²⁺.In this paper,the physicochemical properties of MOF-derivative catalysts were characterized.The specific surface area,pore volume and pore size distribution characteristics of the catalyst were obtained by BET.The apparent morphology and structural characteristics of the catalyst were investigated by SEM scanning electron microscopy.The internal structure of the catalyst was analyzed by TEM.The catalyst was obtained by XPS spectrum.The existence of cobalt,carbon and nitrogen was discussed.The morphological structure of the constituent elements of the catalyst was discussed.The bonding mode of MOF-derivatives was judged by IR spectroscopy.In this experiment,the recycling and recyclability of MOF-derivative catalysts were studied.The experimental data showed that the oxidation rate of magnesium sulfite decreased gradually with the increase of the number of recovery,from 0.092 mmol·L^-1 to0.052 mmol·L^-1,the oxidation rate of the recovered catalyst is different,and the oxidation rate of the recovered catalyst is low,but the cobalt ion of the structure in the MOF-derivative still has a catalytic effect,and its structure is relatively stable,so MOF-derivative catalyst can still be reused.