表层沉积物对水中F^-吸附及解析过程的影响

Analytical Experiment and Mechanism Study of Surface Sediment on Fluorine Solution

地表水受污染后,与表层沉积物接触发生反应,污染物将释放出来,形成二次污染源。为了研究土壤对F?的解析作用,明确F?解析过程中发生的化学反应,本文采用动力学试验和吸附解吸试验,并结合伪二级动力学方程、等温吸附方程,模拟三泉水库底泥与库水之间的反应动力学过程和解析过程,得出当反应时间和初始浓度变化时,水中F?的反应速率,反应历程及其迁移转化规律。结果表明:1) 在表层沉积物上可能以化学反应控制的动力学过程为主,可以用伪二级动力学方程描述,拟合方程为t/qt = 0.7401t + 0.1266,相关系数R2 = 0.9985;2) 表层沉积物对F?的吸附解析等温线符合线性关系,拟合得出F?的饱和解析量为30.56 mg/g;3)土样与氟溶液接触后,溶液pH值随加入F?质量浓度增大而上升,说明随着F?解析的进行不断地有OH?被释放出来;从其他离子的变化可以看出,F?解析过程中发生的化学作用有沉淀–溶解,吸附–解析,离子交换作用。

After the surface water is polluted, it reacts with the surface sediments and releases the pollutants to form the secondary pollution source. In order to study the adsorption and desorption of F? in soils and determine the chemical reactions that happened during the F? analysis, kinetic tests and ad-sorption and desorption experiments were used in this study. Combined with pseudo-second-order kinetic equation and isothermal adsorption equation, the reaction kinetics and adsorption analysis between the mud and the reservoir water show that when the reaction time and the initial concen-tration are changed;the reaction rate, the reaction process and the migration and transformation rules of F? in water are obtained. The results show that: 1) The kinetic process controlled by chemi-cal reaction may be the dominant surface sediment, which can be described by pseudo second-order kinetic equation. The fitting equation is y = 0.7401x + 0.1266 and the correlation coefficient is R2 = 0.9985. 2) The isotherm of F? adsorption by surface sediment is in accordance with the linear relationship, and the saturated analytical volume of F? is 30.56 mg?g?1. 3) After the soil sample is in contact with the fluorine solution, the pH value of the solution increases with the increase of the F-mass concentration, indicating that OH? is continuously released in the F? analysis progresses;it can be seen from the change of other ions. The chemical reactions of F? occurring during the analysis process are precipitation-dissolution, adsorption-analysis, and ion exchange.