湖北恩施几种典型土壤对氟的吸附与解吸特性

采用室内试验方法,研究了恩施六种土壤氟吸附的特性。结果表明:(1)不同土壤的吸附量差异很大,表现为黄粘泥水田土>红粘壤土>泥质岩黄壤土>红砂泥水田土>中性紫色土>黑色石灰土;同一土壤的吸附量随氟离子初始浓度的增大而增大。不同土壤的解吸量在低浓度时差异不明显,高浓度时表现为黄粘泥水田土、红粘壤土、泥质岩黄壤土、红砂泥水田土>中性紫色土>黑色石灰土;同一土壤的解吸量随氟离子初始浓度的增大而增大。(2)Langmuir公式可以很好地描述土壤氟吸附的特性,Freundlich公式能够较好地描述土壤对氟的吸附。(3)去除铁、铝氧化物后土壤氟吸附量明显降低;草酸能够促进土壤对氟的吸附;共存PO43-能够抑制土壤对氟的吸附。

Adsorption and Desorption Characters of Fluoride by Several Soils of Enshi

The adsorption and desorption characters of fluoride by six soils in Enshi were studied by laboratory trails. The results showed as follows:(1) The soils showed different abilities in fluorine adsorption. The order is yellow clay paddy soil> red clay loam> argillite yellow earth>red sandy paddy soil>neutral purple soil>black limstone soil. The adsorption amounts of a soil could increase with the increase of initial concentrations. The desorption amounts of different soils had little difference in low initial concentration.(2) Langmuir equation can well describe the adsorption characters of fluoride, and Freundlich equation can also describe the adsorption characters. (3) The adsorption amounts of soils could decrease obviously when Fe and Al oxides were removed. Oxalic acid could increase the adsorption of fluoride, but PO43- could restrain the adsorption of fluoride.