不同 pH 值紫色土对 NH4+的吸附动力学

摘要

Ammonium adsorption and desorption properties by purple soils with dif-ferent pH were studied. The results showed that the adsorption and desorption amounts of NH4+ by purple soils increased with the increase of NH4+ concentration, regardless of soil pH values; the largest adsorption and desorption amounts of NH4+by purple soil at pH 6.0 were 10.3 and 7.96 mg/g, respectively; the largest adsorp-tion and desorption amounts of NH4+ by purple soil at pH 7.2 were 12.8 and 4.62 mg/g, respectively; the largest adsorption and desorption amounts of NH4+ by purple soil at pH 8.0 were 13.5 and 2.23 mg/g, respectively. The isothermal adsorption ki-netics of NH4+ by purple soils fits the Freundlich equation best (R>0.95). This study shows that the adsorption of NH4+ by purple soils with different pH values is multi-molecular layer uneven surface adsorption.%研究了不同 pH值条件下紫色土对NH4+的吸附/解吸性能。结果表明：3种 pH值的紫色土对 NH4+的吸附量和解吸量均随着加入 NH4+浓度的增大而增大，其中 pH值为6.0的紫色土的最大吸附量是10.3 mg/g，最大解吸量是7.96 mg/g；pH值为7.2的紫色土的最大吸附量是12.8 mg/g，最大解吸量是4.62 mg/g；pH值为8.0的紫色土的最大吸附量是13.5 mg/g，最大解吸量是2.23 mg/g。 Freundlich方程能很好地描述紫色土对 NH4+的等温吸附动力学过程，其 R值均在0.95以上。该研究表明紫色土对 NH4+的吸附属于不均匀表面的多分子层吸附。