Mnisi Robert Londi, Ndibewu Peter Papoh
Department of Chemistry, Tshwane University of Technology, Private bag X680, Pretoria, 0001, South Africa.
Environ Monit Assess. 2017 Nov 4;189(12):606. doi: 10.1007/s10661-017-6329-0.
The bark of Moringa oleifera, a cheap and readily available natural biopolymeric resource material, found to significantly reduce coliform load and turbidity in contaminated water is investigated in this paper. Its surface and adsorptive properties are investigated to explore its adsorptive potential in removing V(V) from aqueous solutions. Surface properties were investigated using FTIR, HRSEM/EDS, IC, and BET-N adsorption techniques. Adsorptive properties were investigated by optimizing adsorption parameters such as pH, temperature, initial metal concentration, and adsorbent dosage, using V(V) as an adsorbate. The adsorption-desorption isotherms are typical of type II with a H3 hysteresis loop and is characteristic of a largely macroporous material. Bottle ink pores are observed, which can provide good accessibility of the active sites, even though the internal BET surface area is typically low (1.79 g/m). Solution pH significantly influences the adsorptive potential of the material. The low surface area negatively impacts on the adsorption capacity, but is compensated for by the exchangeable anions (Cl, F, PO, NO, and SO) and cations (Ca, K, Mg, and Al) at the surface and the accessibility of the active sites. Adsorption isotherm modeling show that the surface is largely heterogeneous with complex multiple sites and adsorption is not limited to monolayer.
本文研究了辣木的树皮，它是一种廉价且易于获取的天然生物聚合资源材料，已发现其能显著降低受污染水中的大肠菌群数量和浊度。对其表面和吸附特性进行了研究，以探索其从水溶液中去除V（V）的吸附潜力。使用傅里叶变换红外光谱（FTIR）、高分辨率扫描电子显微镜/能谱仪（HRSEM/EDS）、离子色谱（IC）和BET - N吸附技术研究了表面性质。以V（V）为吸附质，通过优化吸附参数，如pH值、温度、初始金属浓度和吸附剂用量，研究了吸附特性。吸附 - 解吸等温线属于典型的II型，具有H3滞后环，是大孔材料的特征。观察到瓶状墨水瓶孔，即使内部BET表面积通常较低（1.79 g/m），这些孔也能提供活性位点的良好可及性。溶液pH值显著影响该材料的吸附潜力。低表面积对吸附容量有负面影响，但表面的可交换阴离子（Cl、F、PO、NO和SO）和阳离子（Ca、K、Mg和Al）以及活性位点的可及性弥补了这一不足。吸附等温线模型表明，表面在很大程度上是不均匀的，具有复杂的多个位点，吸附不限于单层。
