| The direct discharge of acidic wastewater will destroy the natural ecology and endanger human health and safety,so it should be a reasonable treatment.Amphoteric snake cage resin has the advantages of larger adsorption capacity and regeneration of deionized water,which extraordinarily reduces the processing cost,and has great applications in many experiments or industrial separation processes.In this paper,the goal is to recover inorganic acids in acid wastewater,and an amphoteric snake cage resin containing-NR2H+ and-SO3-groups were synthesized by the interpenetration method,and the sulfonic acid group partition coefficient,total exchange capacity,and infrared spectroscopy were used to investigate Its synthesis effect,also studied the amphoteric snake cage resin adsorption of inorganic acid and deionized water desorption performance.The results are as follows:(1)According to 312 resin as the matrix resin,a gel-type amphoteric snake-cage resin was prepared.The distribution coefficient by a sulfonic acid group,characterized by IR spectrum and the total exchange capacity was confirmed the formation of internal salt bonds.The optimal synthesis conditions of the amphoteric snake cage resin were investigated as follows:the reaction temperature is 80℃ for the first 4 hours,and 70℃ for the last 4 hours;the ratio of the number of moles of tertiary amino groups to sodium vinyl sulfonate is n(NR2H+):n(SO3-)= 1:1.5;the ratio of sodium ethylene sulfonate to the number of moles of initiator is:n(SO3-):n(K2S2O8)=1:0.005,the static adsorption capacity of resin for H2SO4 is 0.00321 mol/g.The results of the static adsorption thermodynamics study show that the adsorption process conforms to the Langmuir and D-R isotherm adsorption models,it is mainly chemical adsorption and is a spontaneous exothermic process.The study of static adsorption kinetics found that the adsorption process conforms to the pseudo-first-order kinetic model,which is cooperated by both liquid film diffusion and intraparticle diffusion.The dynamic adsorption-desorption results show that the initial concentration of H2SO4 is 0.2 mol/L,the injection flow rate of H2SO4 is 2 mL/min,and the height of the adsorption column is 15 cm are the best-operating conditions under laboratory conditions,and the maximum is at room temperature.The maximum dynamic adsorption capacity at room temperature is 0.00183 mol/g.The resin has good deionized water regeneration capacity,and after repeated adsorption-desorption cycles,it still has good adsorption capacity for H2SO4.The fitting result of the breakthrough curve shows that the resin conforms to the Thomas model and Yoon-Nelson model,and the parameters obtained by the two models have a certain reference value.(2)In D301,MP-62,and three kinds of D314 macroporous resin as the matrix resin,synthetic macroporous amphoteric snake-cage resins.Through the determination of sulfonic acid group partition coefficient,infrared spectroscopy,and total exchange capacity,it is found that only part of the sodium ethylene sulfonate is polymerized inside the resin.The optimal synthesis conditions of the resin are roughly similar to the gel-type snake-cage resin.The results of static thermodynamic research show that the adsorption process conforms to the Freundlich,Temkin,and DR isotherm adsorption models.The adsorption process is dominated by ion-exchange reactions,and the maximum static adsorption capacity at room temperature is 0.0021 mol/g.The study of adsorption kinetics shows that the adsorption process conforms to the pseudo-second-order kinetic model,and intra-particle diffusion is also not the only rate control step of adsorption.The dynamic adsorption-desorption results show that the optimal operating conditions for dynamic adsorption are roughly the same as those of gel-type snake-cage resins,while macroporous amphoteric snake-cage resins have a better adsorption rate and mechanical strength due to the low formation rate of internal salt bonds,But the regeneration capacity of deionized water is poor. |
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