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以17年不同施肥处理土壤胡敏酸为材料,研究了不同性质胡敏酸与钙饱和蒙脱石的吸附特征。结果表明,钙饱和蒙脱石对土不同施肥处理胡敏酸的吸附曲线可用单表面Langmuir方程、双表面Langmuir方程以及Freundlich方程来描述。由单表面Langmuir方程计算的有机肥处理(厩肥、秸秆)胡敏酸的吸附量和吸附强度大于无肥、化肥处理。温度升高各处理胡敏酸吸附量增加,但吸附强度下降。双表面Langmuir揭示,蒙脱石对胡敏酸的吸附呈现高低两种能位的吸附。高能点位的吸附以化学吸附为主,是吸热反应,低能点位的吸附以物理吸附为主,是放热反应。有机肥处理和无肥、化肥处理相比,高能点位吸附相对减弱,低能点位吸附相对增强。
In this paper, different concentrations of humic acid and calcium-saturated montmorillonite were used to study the adsorption characteristics of humic acid in soils under different fertilization treatments for 17 years. The results showed that the adsorption curves of humic acid with different concentrations of calcium-saturated montmorillonite on soil could be described by single-surface Langmuir equation, double-surface Langmuir equation and Freundlich equation. The adsorption amount and adsorption strength of organic acids (manure, straw) humic acid calculated by single-surface Langmuir equation were higher than that of no-fertilizer and chemical fertilizer treatment. The humic acid adsorption increased with increasing temperature, but the adsorption strength decreased. The double-surface Langmuir revealed that adsorption of humic acid by montmorillonite exhibits adsorption at both high and low levels. The adsorption of high-energy point is dominated by chemisorption, which is an endothermic reaction. The adsorption of low-energy point is mainly physical adsorption and is exothermic reaction. Compared with no fertilizer and fertilizer treatment, the organic fertilizer treatment showed a relatively weaker adsorption at the high energy point and a relatively enhanced adsorption at the low energy point.