斜发沸石对模拟核素Sr^(2+)的吸附/解吸动力学研究

Kinetics of Simulated Nuclide Sr^(2+) Adsorption and Desorption by Clinoptilotite

以Sr(NO3)2为核素源、新疆富蕴县所产斜发沸石为吸附剂,研究斜发沸石对Sr2+的动力吸附/解吸效果。探讨吸附时间、Sr2+初始浓度与吸附量的关系以及吸附机理。用pH=6的水溶液对饱和吸附了Sr2+的斜发沸石进行解吸。结果表明:斜发沸石对Sr2+的吸附在4 h能达到最大吸附率的99%,Freundlich吸附等温式能对吸附曲线进行很好的描述,单位质量沸石对Sr2+的最大吸附量为38.34 mg/g,以阳离子交换吸附为主。4.5 h后解吸率为1.78%,解吸速率远小于吸附速率,解吸量与解吸时间的自然对数呈现明显的线性关系,用Elovich方程对解吸曲线进行拟合,R=0.9994,拟合方程为:qt=0.03375+0.11916lnt。理论上将5%的Sr2+解吸出来约需5044 d。该斜发沸石固Sr2+能力很强,对于处理含Sr2+放射性废液具有重要的意义。

AWith Sr（ NO3 ）2 for nuclide source and clinoptilotite from Xinjiang Autonomous Region for adsorbent, kinet- ics of Sr^2＋ adsorption and desorption by clinoptilotite was studied. Adsorption mechanism and the relationships be- tween adsorption time, Sr^2＋ initial concentration and the adsorption quantity were discussesed, respectively. In solu- tion of HC1 pH =6, clinoptilotite with saturated Sr^2＋ begin to desorb. The results show that the Sr^2＋ adsorption by ctinoptilotite for 4 h can reach the maximum at adsorption rate of 99%. Adsorption curve is fitted with Freundlich i- sotherm well. The maximum adsorption capacity is 38.34 mg/g, and adsorption is cation exchange adsorption princi- pally. After 4. 5 h, desorption rate is 1.78%. Desorption speed is far less than that of adsorption. Desorption capac- ity and the natural logarithms of desorption time have obvious linear relation. Elovich equation was used for fitting de- sorption curve, R =0. 9994, and the regression equation is q, =0. 03375 ＋ 0. l19161nt. For desorption of 5% Sr^2＋ , theoretically time is 5044 days. Clinoptilotite has strong ability to adsorb Sr^2＋ and is of vital significance for treating Sr^2＋ contained radioactive waste liquid.