Ma Feng-feng, Zhao Bao-wei, Diao Jing-ru, Zhong Jin-kui, Li An-bang
Huan Jing Ke Xue. 2015 May;36(5):1678-85.
The adsorption characteristics of ammonium from aqueous solution onto biochar derived from dairy manure were investigated as a function of parameters such as solution pH, particle size, adsorbent dosage, temperature and competitive cations. The results indicated that the effects of other cations on the adsorption of ammonium followed the order of preference Na > Ca2+ at identical mass concentrations. It was observed that pH played an important role in the ammonium adsorption and the optimal pH values ranged between 5 and 8. The kinetic data fitted the pseudo-second-order model (R2 = 0.967 3) but showed very poor fits for the pseudo-first-order model (R2 = 0.765 9) and the Elovich model (R2 = 0.724 9). The results from the Intra-particle model also showed that there were two separate stages in sorption process, which were external diffusion and the diffusion of inter-particle. Adsorption isotherms for dairy manure biochar were fitted the Freundlich model (R2 = 0.976 2) more effectively than other models. Thermodynamics parameters such as free energy (ΔGθ), enthalpy (ΔHθ), and entropy (ΔSθ) were also determined, which indicated that the adsorption was a spontaneous and endothermic process.
研究了牛粪生物炭对水溶液中铵的吸附特性，考察了溶液pH值、粒径、吸附剂用量、温度和竞争阳离子等参数的影响。结果表明，在相同质量浓度下，其他阳离子对铵吸附的影响顺序为Na > Ca2+。研究发现，pH值在铵吸附过程中起重要作用，最佳pH值范围为5至8。动力学数据符合准二级模型（R2 = 0.967 3），但与准一级模型（R2 = 0.765 9）和Elovich模型（R2 = 0.724 9）的拟合效果很差。颗粒内模型的结果还表明，吸附过程存在两个不同阶段，即外部扩散和颗粒间扩散。牛粪生物炭的吸附等温线对Freundlich模型（R2 = 0.976 2）的拟合效果比其他模型更好。还测定了自由能（ΔGθ）、焓（ΔHθ）和熵（ΔSθ）等热力学参数，结果表明吸附是一个自发的吸热过程。
