摘要
用得到x-射线衍射及电子显微镜和红外光谱确证的人工合成针铁矿与三水铝石进行磷吸附的研究。结果表明,针铁矿和三水铝石具有强烈吸附磷的能力,所得吸附数据可用吸附等温方程——Langmuir方程,Freu-ndlich方程和Temkin方程描述,Langmuir方程的适用性较好。从方程得到的吸附参数Xm值和a值,三水铝石要比针铁矿高一倍,其ΔG值也高于针铁矿。这两种人工合成矿物的吸附参数同天然的高岭石、蒙脱石明显不同。此外,在高pH时,这两种合成矿物吸附的磷量均少于低pH时的吸附量,而当有竞争离子腐殖质或氟离子存在时,它们仍然能够强烈地吸附磷。
The adsorption of phosphate was studied using synthetic goelhite and gibbsite. The results showed that both goethitc and gibbsite adsorb phosphate strongly, and gibbsite adsorb more phosphate than goethite. The adsorption data of phosphate were found to agree very well with three adsorption equations, i.e. Langmuir, Freundlich and Temkin equations, but the Langmuir equation provided the best fit to the data. Some adsorption parameters, adsorption maximum ( Xm ), free energy ( G° ) and regression constant ( a ) were calculated from the Langmuir equation and the Freundlich equation respectively. All the parameters of gibbsite were higher than those of goethite. The adsorption parameters of the two synthetic goethite and gibbsite, however, differed from those of the naturally produced kaolinite and montmorillonite. The values of Xm and a of the synthetic goethite and gibbsite were higher than the natural minerals, but the values cf △G℃ were lower. The amounts of phosphate adsorbed on goethite and gibbsite were influenced by the final pH of the equilibrium solution. The higher the pH was, the less the amounts of phosphate were adsorbed. The suppression effect of competitive anions such as humale and fluoride ions on the phosphate adsorption by goethite and gibbsise was also studied.
关键词
针铁矿
吸附等温线
三水铝石
goethite
gibbsite
adsorption isotherm
anion competitive adsorption
