研究了粉煤灰模拟硫酸浸出液中的镓在聚苯乙烯树脂(LX-92)上吸附分离的可能性,采用固定床吸附装置考察了树脂动态吸附?脱附镓的行为,利用Thomas, Yoon-Nelson和Adam-Bohart经验模型对动态吸附过程进行了分析和预测。结果表明,降低流速(F)、增加床层高度(Z)、减小镓(Ш)初始浓度(C0)有助于提高固定床吸附效率和平衡吸附容量;在C0为260 mg/L, Fad为5.0 mL/min、吸附温度为55℃的条件下,树脂的最大动态平衡吸附容量为56.65 mg/g;用3.0 mol/L H2SO4在1.0 mL/min流速的最佳洗脱条件下,洗脱率达到94.40%;树脂在硫酸体系中对低浓度镓离子的吸附?脱附具有良好的循环使用性,经过吸附?脱附镓离子可富集10倍以上;树脂吸附镓的动态行为满足Yoon-Nelson动态吸附模型,建立了动态吸附速率常数KYN和半穿透时间τ值常数与初始离子浓度、流速、床层高度的对应方程,为低浓度镓离子的吸附法提取工程化提供了理论基础。
The dynamic adsorption-desorption behavior of gallium in simulated sulfuric acid leach solution of fly ash on polystyrene resin (LX-92) was investigated by fixed bed device. The dynamic adsorption process was analyzed by Thomas, Yoon-Nelson, and Adam-Bohart empirical models. The results showed that decreasing the flow rate (Fad) and the initial concentration of gallium(III) (C0), increasing the bed height (Z) were conducive to improve the fixed bed adsorption efficiency and equilibrium adsorption capacity. According to experiments data, the optimum conditions for dynamic adsorption process was as follow: Fad=5.0 mL/min, C0=260 mg/L and T=55℃, and the maximum adsorption capacity was 56.65 mg/g. The elution rate of gallium could reach 94.40% at the conditions of 3.0 mol/L H2SO4 and 1.0 mL/min flow rate. After the process of adsorption and desorption, the concentration of gallium ions could be enriched more than 10 times. The dynamic adsorption behavior of gallium by the resin was well fitted by the Yoon-Nelson dynamic adsorption model. The corresponding equations of the dynamic adsorption rate constant KYN and the half-through time τ value constant with the initial Ga(III) ion concentration, flow rate, and bed height were established. The dynamic adsorption results would be used for engineering purpose of the of low-concentration gallium ions recovery.