Study On The Modification Of Sepiolite And Its Regeneration By Catalytic Oxidation Process Using High Temperature Gas Flow

As a kind of important chemical operation method,adsorption has very extensive application in the chemical industry and environmental protection industry. The regeneration process is a key step in the recycle of adsorbent, it plays an important role in reducing the production cost. In this paper, the sepiolite is modified by bimetal which acted as an adsorbent-catalyst, and the modified sepiolite is regenerated by high temperature gas.The main research contents and conclusions in this work are summarized as follows:1.The effects of different modification ways (temperature, acid and high temperature gas flow) on the adsorption efficiency of sepiolite are studied. The study showed that the adsorption effect of sepiolite which modified by high temperature and high temperature oxygen flow is superior to unmodified sepiolite. The adsorbance per unit quality of sepiolite which modified by high temperature oxygen flow of auramine is 239.35mg/g and adsorption capacity per unit mass of sepiolite which modified by high temperature of auramine is 161.82mg/g under the best conditions:adsorption temperature is 25℃, the dosing quantity of adsorbent is 0.12g, the solution concentration of auramine is 250mg/L, solution volume is 150mL, adsorption time is 8h, oscillators rotate speed is 170r/min.2.There inspected the regenerability of high temperature oxygen flow modified sepiolite which loaded thermometal. Through experiment contrast show that the regeneration rate of Ce-Ni/sepiolite and La-Ni/sepiolite made from Ni(NO3)2, Ce(NO3)3,La(NO3)3,Ni(NO3)2 were exceed 100%, their regeneration rate are superior to others modified sepiolite which loaded single metal salts and thermometal such as Ni(NO3)2,Ce(NO3)3,Cu(NO3)2,La(NO3)3)Fe(NO3)3,Co(NO3)2.3.The orthogonal experiments show that the concentration of nitrate and molar ratio of Ce(NO3)3 to Ni(NO3)2 are the key factor of regeneration rate of Ce-Ni-high temperature oxygen flow modified sepiolite.4.The adsorption of high temperature oxygen flow modified sepiolite and Ce-Ni-high temperature oxygen flow modified sepiolite to auramine O are studied. The results show that the adsorption isotherms are fitted accurately by the Langmuir equation. The maximum adsorption amount of both modified sepiolite increase with the rise of temperature. The enthalpy change calculation of both modified sepiolite show that the enthalpy change of adsorption are far greater than zero, so the adsorption was endothermic process.5.The kinetics studies show that the adsorption process of high temperature oxygen flow modified sepiolite are fitted Lagergren rate equation in 298K～308K, and are fitted the internal diffusion model which put forward Grank in 308K～318K. In the meantime, The kinetics studies show that the adsorption process of Ce-Ni-high temperature oxygen flow modified sepiolite to auramine O are fitted both the Lagergren rate equation and internal diffusion model in 298K～318K.6.The dynamic adsorption of high temperature oxygen flow modified sepiolite shows that the larger height-diameter ratio with low velocity and concentration of auramine O solution, the better adsorption. But high adsorption layer will increase the solution flow resistance, lower flow rate will lead to the increase of adsorption time, and it will create an operational problem in practical application if the concentration of dye is too low. So the condition parameters of adsorption conditions in practice should be strike an average.7.According to analyze the Ce-Ni/sepiolite and La-Ni/sepiolite use by kinds of detectable characterization methods, the adsorption and regeneration process were studied. The study showed that both modified sepiolite are keep fibrous structure weel after regenerated and possess catalysis action to auramine.