芒果核壳炭的制备及对水中Cr6+的吸附

以芒果核壳为原料通过H3PO4活化制备了新型的吸附剂H3PO4-C。考察了影响该吸附剂对水体中Cr（VI）的去除效果的因素，并研究了吸附动力学特征和吸附过程控制机理。结果表明，芒果壳生物质炭对Cr（VI）具有良好的吸附能力，在25℃下，较佳的吸附条件为：当投加量为3 g·L-1，Cr（VI）初始浓度为50 mg·L-1，溶液pH值为3时，吸附5 h，去除率为93.8%。准一级、准二级动力学模型用来拟合吸附过程，结果表明，准二级动力学符合该吸附过程，吸附速率常数为0.001 3 g·（mg·min）-1。用Langmuir和Freundlich模型描述吸附等温过程，结果说明，该吸附过程服从Langmuir吸附，饱和吸附量为28.571 mg·g-1，内扩散为该吸附过程的限速步骤，内扩散系数D=4.21×10-9 cm2·s-1。

Adsorption of Cr6+ from aqueous solutions by modified mango shell

Mango shell was modified with H3PO4 to prepare a novel adsorbent. The effects of certain parameters on the removal rate and kinetic characteristics, as well as the mechanism governing the adsorption process, were investigated. The results showed that the maximum Cr6+ removal rate was 93.8% under the following conditions:temperature of 25℃, Cr6+ initial concentration of 50 mg·L-1, adsorption time of 5 h, pH of 3, adsorbent dosage of 3 g·L-1. The adsorption process was fitted to kinetic models, including first-order and pseudo-second-order equations. The process followed pseudo-second-order kinetics with an adsorption rate constant of 0.001 3 g·(mg·min)-1. Langmuir and Freundlich models were used to describe the adsorption equilibrium data. The results indicated that the Langmuir model provided a more acceptable fit to the experimental data than the Freundlich equation. The maximum Cr6+ uptake was Qm=28.571 mg·g-1. The inner diffusion was the key step in this adsorption system, and the inner diffusion coefficient was D=4.21 × 10-9 cm2·s-1.