Attapulgite was activated by high temperature calcinations,and phosphate adsorption on activated attapulgite was arranged with batch experiments.The result showed that heat activation efficacy of attapulgite was remarkable at the temperature of 773 K.Under the studied concentration,adsorption equilibrium data significantly fitted to Langmuir,Freundlich,and Dubinin-Radushkevich isotherms (P ＜0.01),and the adsorption was preferential process.Phosphate adsorption capacity increased with increasing temperature,while the theoretical saturation adsorption capacity was 2 408 mg P/kg at the temperature of 328 K.Adsorption kinetics data were well followed with Lagergren pseudo-second-order,Elovich and Kannan intraparticle diffusion equations (P ＜ 0.05),and the adsorption was heterogeneous diffusion and basically physical reaction.The main rate controlling steps were determined both by film and pore diffusions.Thermodynamic parameters of phosphate adsorption were ΔG ＜ 0,ΔH ＞ 0 and ΔS ＞ 0,which indicated the adsorption behavior was spontaneous endothermic reaction.Conclusions provide a scientific basis for the application of attapulgite in increasing nutrient efficiency of phosphate and compound fertilizers.%将凹凸棒土高温煅烧活化,通过静态实验研究其对磷的吸附行为.结果表明,温度773 K时热活化效果显著.在研究的浓度范围内,吸附平衡数据显著符合Langmuir、Freundlich和Dubinin-Radushkevich模型(P＜0.01),优惠吸附过程,磷吸附量随试验温度的升高而增加,328 K时理论饱和吸附量为2 408 mg P/kg.吸附动力学数据显著符合Lagergren伪二级动力学、Elovich和Kannan颗粒内扩散模型(P＜0.05),非均相扩散、物理吸附过程,主要控速步骤为液膜扩散和颗粒内扩散联合控制.吸附热力学参数ΔG＜0、ΔH＞0、ΔS ＞0,热活化凹凸棒土对磷的吸附为自发吸热反应.研究结论为凹凸棒土在提高磷肥与复混肥料养分利用率中的应用提供了科学依据.
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