生物成因次生铁矿物对酸性矿山废水中三价砷的吸附  

THERMODYNAMICS AND KINETICS OF ADSORPTION OF ARSENITE IN ACID MINING DRAINAGE BY BIOGENIC SECONDARY IRON MINERALS

作　　者：谢越[1] 周立祥[1] 

机构地区：[1]南京农业大学资源与环境科学学院,南京210095

出　　处：《土壤学报》2012年第3期481-490,共10页Acta Pedologica Sinica

基　　金：国家自然科学基金重点项目(40930738)资助

摘　　要：在常温常压条件下,利用嗜酸性氧化亚铁硫杆菌的促进作用,生物合成了酸性矿山废水中常见的三种次生铁矿物:施氏矿物(schwertmannite)、黄钾铁矾(jarosite)和针铁矿(goethite)。在15℃、25℃、35℃三个不同温度下,通过序批式吸附试验研究,在pH3.0的模拟酸性矿山废水条件下,3种生物成因次生铁矿物对As(Ⅲ)的吸附性能。结果表明:3种生物成因的次生矿物对As(Ⅲ)的吸附属于拟二级反应,可以用Lagergren拟二级速率方程进行拟合,相关系数均在0.97以上。吸附速率常数K分别为施氏矿物0.094 g mg-1min-1,针铁矿0.042 g mg-1min-1,黄钾铁矾0.02 g mg-1min-1。3种生物成因铁矿物对As(Ⅲ)的吸附等温线符合Langmuir方程和Freundlich方程,相关系数均在0.94以上。吸附反应的焓变ΔH分别为11.76、18.40和9.34 kJ mol-1,ΔG均小于0,吸附过程属于吸热的自发反应。Schwertmannite,jarosite and goethite are common secondary iron minerals found in acid mining drainage.They were formed biological under normal temperature and pressure with the aid of Acidithiobacillus ferrooxidans in this study.Batch adsorption experiments were conducted under three different temperatures（15℃,25℃ and 35℃） to explore arsenite adsorption behaviors of the three biogenic secondary iron minerals in simulated acid mining drainage（pH3.0）.It was found that arsenite adsorption of the three biogenic minerals were of the second order of reaction and could well be described by the Lagergren pseudo-second order rate equation,with correlation coefficient being0.97.Their adsorption rate constant was 0.094 g mg-1 min-1 for schertmannite,0.042 g mg-1 min-1 for goethite and 0.02 g mg-1 min-1 for jarosite,and their sorption isotherms fitted the Langmuir and Freundlich model with correlation coefficient being 0.94.Their adsorption enthalpy was 11.76,18.40 and 9.34 kJ mol-1,separately for the three different minerals and their ΔG＇s were all0.The adsorption of arsenite was a kind of endothermic spontaneous process.

关 键 词：吸附 热力学 动力学 施氏矿物 黄钾铁矾 针铁矿 

分 类 号：X592[环境科学与工程—环境工程]