Department of Chemical Sciences (Formerly known as Department of Applied Chemistry, University of Johannesburg, Doornfontein Campus), University of Johannesburg, Doornfontein Campus, P.O. Box 17011, Johannesburg 2028, South Africa.
DST/Mintek Nanotechnology Innovation Centre, University of Johannesburg, Doornfontein 2028, South Africa.
Molecules. 2019 May 9;24(9):1792. doi: 10.3390/molecules24091792.
A magnetic multi-walled carbon nanotube/zeolite nanocomposite was applied for the adsorption and removal of arsenic ions in simulated and real acid mine drainage samples. The adsorption mechanism was investigated using two-parameter (Langmuir, Freundlich, Temkin) and three-parameter (Redlich-Peterson, and Sips) isotherm models. This was done in order to determine the characteristic parameters of the adsorptive removal process. The results showed that the removal process was described by both mono- and multilayer adsorptions. Adsorption studies demonstrated that a multi-walled carbon nanotube/zeolite nanocomposite could efficiently remove arsenic in simulated samples within 35 min. Based on the Langmuir isotherm, the adsorption capacity for arsenic was found to be 28 mg g. The nanocomposite was easily separated from the sample solution using an external magnet and the regeneration was achieved by washing the adsorbent with 0.05 mol L hydrochloric acid solution. Moreover, the nanoadsorbent was reusable for at least 10 cycles of adsorption-desorption with no significant decrease in the adsorption capacity. The nanoadsorbent was also used for the arsenic removal from acid mine drainage. Overall, the adsorbent displayed excellent reusability and stability; thus, they are promising nanoadsorbents for the removal of arsenic from acid mine drainage.
一种磁性多壁碳纳米管/沸石纳米复合材料被应用于模拟和实际酸性矿山排水样品中砷离子的吸附和去除。通过使用双参数（朗缪尔、弗伦德利希、坦金）和三参数（Redlich-Peterson 和 Sips）等温模型研究了吸附机制，以确定吸附去除过程的特征参数。结果表明，去除过程同时由单分子层和多分子层吸附描述。吸附研究表明，多壁碳纳米管/沸石纳米复合材料可以在 35 分钟内有效地去除模拟样品中的砷。根据朗缪尔等温线，砷的吸附容量为 28 mg g。纳米复合材料可以很容易地用外部磁铁从样品溶液中分离出来，并通过用 0.05 mol L 盐酸溶液洗涤吸附剂来实现再生。此外，纳米吸附剂在至少 10 次吸附-解吸循环中具有可重复使用性，而吸附容量没有明显下降。纳米吸附剂还用于从酸性矿山排水中去除砷。总的来说，该吸附剂表现出良好的可重复使用性和稳定性；因此，它们是从酸性矿山排水中去除砷的有前途的纳米吸附剂。
