Synthesis Of Poly(tert-amine) Monophosphonic Acid Chelating Resin And Its Adsorption Properties For Rare Earth

In order to solve the problems of poor selectivity,low saturation capacity,difficult extraction and waste acid generation of traditional ion exchange resins used for enrichment and separation of rare earth,five amino phosphonic acid resins were prepared by amine methylation reaction,and characterized by infrared spectroscopy and scanning electron microscopy.The effects of resin on p H,reaction time,resin quality and eluent concentration during rare earth adsorption were studied.According to the adsorption kinetics,thermodynamics and the change of special functional groups on the surface of the resin,the adsorption performance of the resin was explored.The results showed that:At p H 2.5,the adsorption capacity of PAMR for La³⁺reached 133.32mg/g(0.96mmol/g),and adsorption equilibrium time exceeds 12h.When the concentration of hydrochloric acid was 2mol/L,The desorption rate was the highest,Langmuir isotherm model and quasi-second-order kinetic model were used to explain the kinetics and thermodynamics of the adsorption process,rare earth ions can be chemisorbed on resin with monomolecular layer,and the rate control is greatly affected by liquid film diffusion.The thermodynamic parameters show that the adsorption process of La³⁺is an endothermic reaction that can occur spontaneously.poly(amino single phosphonic acid)resin of piperazine basic(PAMR(?)),in the p H value of 5.5,resin quality under the condition of 6.5 g,adsorption rate is 89.73%,reached the highest in 5h after resin adsorption time on the adsorption quantity of La³⁺balance,saturated adsorption capacity up to 1016 mg/g,and adsorption process in line with the quasi secondary dynamics model and the Langmuir isotherm model,showed that the adsorption of resin conformed to the adsorption mechanism of monolayer;The resin has a good reusability for La³⁺,and still has a large adsorption capacity after three reuses.Analysis of thermodynamic data illustrated the process was a spontaneous endothermic reaction.Ethylenediamine base poly(amino phosphonic acid chelating resin)(PAMR(?))on the reaction conditions of p H 5.64,7g resin,the amount of adsorption rate up to 90%,The kinetics and thermodynamics of the adsorption process can be explain by pseudo-second order kinetic equation and Langmuir isotherm model,concluded that was a chemisorption through monomolecular layer.Thermodynamics parameters show that Ce³⁺adsorption process for the endothermic reaction of spontaneous for the endothermic reaction of spontaneous;When the concentration of HCl was 5.0 mol/L,the elution effect was the best.Poly(amino phosphonic acid)resin of diethylene triamine(PAMR(?))of neodymium ions adsorption process of optimal p H 5,adsorption equilibrium time is 6h,equilibrium adsorption quantity is 1306 mg/g,Adsorption of neodymium by PAMR(?)was accorded with pseudo-second order kinetic equation and Langmuir isotherm model,and for monolayer adsorption.It can be seen that the process was a spontaneous endothermic reaction by concluding thermodynamic parameter.IR analysis showed that PAMR(?)due to adsorption process of Nd³⁺phosphonic acid hydroxy groups of P=O and Nd³⁺the coordination between the role.Finally,a phosphonate oligomer extractant(PEMP)and extraction resin PEMP/AC were prepared.According to infrared characterization,PEMP and PEMP/AC are extracted from rare earth ions through the coordination of lone pair electrons on oxygen element in P=O.The extraction process of PEMP and PEMP/AC is exothermic reaction,which is more favorable to the extraction of rare earth at low temperature.PEMP/AC for Ce(?)best saturated adsorption capacity of 126.3 mg/g,liquid film diffusion for adsorption master steps;Low temperature and low acidity of rare earth liquid are more favorable to extraction.