茶园土壤对氟的吸附与解吸特性

研究了我国主要砖茶产区湖南省和湖北省茶园土壤对氟的吸附与解吸特性。茶园土壤氟的吸附可由Freundlich方程描述 ,Langmuir方程只在低浓度 (初始氟浓度 0 5 - 2 0mmol/L)时适用 ,且拟合程度不如Freundlich方程 ,Temkin方程不能描述茶园土壤对氟的吸附特征。氟的解吸率随加入氟浓度而变化 ,在高浓度下吸附的氟更易被解吸。解吸率与Freundlich吸附方程的k值成显著或极显著负相关 ,与Langmuir方程参数的相关系数因加入氟浓度而变化 ,低浓度时 ,氟的解吸率与结合

Adsorption and Desorption of Fluoride by Tea Soils

The adsorption and desorption of fluoride were measured on 36 acidic soil samples from the 0-15, 15-30, and 30-45 cm horizons from tea fields in major brick tea producing areas in Hunan and Hubei provinces. Adsorption of fluoride could be well described by Freundlich equation for all soils over the entire fluoride concentration range (0.5-10 mmol/L), while conformed to Langmuir equation over limited initial concentrations (0 5-2 0 mmol/L). Temkin equation was not applicable to fluoride adsorption by these soils. Dithionite-extractable and oxalate-extractable Al correlated highly with both the Freundlich k and Langmuir Xm values, indicating that amorphous, poorly ordered Al oxyhydroxides and hydroxyl Al were the most important adsorbent for F- in these acidic tea soils.