基于协同体系的磁性材料在稀土吸附中的应用研究

通过二氧化硅溶胶—凝胶法，将2-乙基己基膦酸单(2-乙基己基)酯（P507）与二(2，4，4’-三甲基戊基)膦酸（C272）的协同体系引入磁性固体吸附材料中，并将其用于吸附低浓度稀土离子。吸附剂的吸附试验结果表明，当溶液pH值为2时，吸附剂具有较优的协同效果，协同系数高达22，最大吸附量为0.07 mmol/g，但由于离子强度的增加会产生竞争吸附，使得稀土吸附量降低；吸附热力学分析表明，吸附为自发的吸热过程，且吸附量随着温度的升高而增大；动力学试验研究结果表明，吸附过程与二级动力学模型具有最高的拟合度，在吸附90 min后基本达到平衡。 

Research on application of magnetic materials based on synergistic systems in rare earth adsorption

In this paper, a synergistic system of 2-ethylhexylphosphonic acid mono(2-ethylhexyl) ester (P507) and a bis(2, 4, 4'-trimethylpentyl) phosphonic acid (C272) was introduced into magnetic solid adsorbents and used for adsorbing low-concentration rare earth ions. The adsorption test results of the adsorbent show that when the pH value of solution is 2, the adsorbent has the best synergistic effect, of which the synergy coefficient is as high as 22, and the maximum adsorption capacity is 0.07 mmol/g. However, the increase in ionic strength will produce competitive adsorption, and thus the adsorption capacity of rare earth elements is reduced. The adsorption thermodynamics analysis shows that adsorption is a spontaneous endothermic process, in which adsorption capacity increases with increasing temperature. The results of the kinetic test show that the adsorption process has the highest fit degree with the second-order kinetic model, basically reaching equilibrium after 90 min.