Insights on the role of organic matters of some Egyptian clays in methyl orange adsorption: Isotherm and kinetic studies
Insights on the role of organic matters of some Egyptian clays in methyl orange adsorption: Isotherm and kinetic studies
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DOI：
10.1016/j.clay.2018.09.013
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发表时间：
2018-12
影响因子：
5.6
通讯作者：
A. M. Zayed;M. Wahed;E. Mohamed;M. Sillanpää
中科院分区：
文献类型：
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作者：
A. M. Zayed;M. Wahed;E. Mohamed;M. Sillanpää
首次研究了有机质（OM）在埃及粘土吸附水中橙子（MO）过程中的作用。为了详细说明这一作用，在500 °C/4 h下煅烧原始富含有机物质的粘土（OMRC）以通过氧化去除其相关的OM。然后在不同的实验参数下测试了OMRC及其煅烧衍生物（COMRC）对MO的去除效率。吸附剂对MO的吸附是一个pH和时间依赖的过程，60 min后达到平衡。两种吸附剂对MO的吸附动力学均符合准二级动力学模型，其决定系数R2> 0.999，但颗粒内扩散不是速率控制步骤。结果表明，OMRC和COMRC的吸附平衡数据分别符合Freundlich和Langmuir吸附模型。静电相互作用是主要的，但不是唯一的管理机制MO吸附所调查的吸附剂，参与氢键机制，与COMRC的一些偏好。OMRC对MO的吸附优于COMRC，这是由于有机物和粘土矿物中的含氧和含氮基团参与了吸附过程，而COMRC只吸收了粘土矿物中的含氧基团。
The role of organic matters (OM) of some Egyptian clay in Methyl Orange (MO) adsorption from aqueous solutions was tested for the first time. To elaborate this role, the raw Organic Matters-Rich Clays (OMRC) was calcinated at 500 °C/4 h to remove their associated OM by oxidation. Then the MO removal efficiency by both OMRC and its calcinated derivative (COMRC) was tested at different experimental parameters. The adsorption of MO by the studied adsorbents was pH- and time-dependent process and the equilibrium was attained after 60 min. The pseudo-second-order model with high determination coefficients (R2> 0.999) fitted well the adsorption kinetics, while the intra-particle diffusion was not the rate governing step in MO adsorption by both adsorbents. The MO adsorption characteristics revealed that equilibrium data of OMRC and COMRC fitted well to the Freundlich and Langmuir models, respectively. Electrostatic interaction was the primary but not the only governing mechanism for MO adsorption by the investigated adsorbents; participation from hydrogen bonding mechanism was involved, with some preference for COMRC. The superiority of OMRC over COMRC in MO adsorption can be attributed to the involvement of oxygen- and nitrogen-bearing groups of both OM and clay minerals in the adsorption process on the contrary of COMRC in which only oxygen-bearing groups of the clay minerals were incorporated.