Shao Yimin, Wang Xi, Kang Yuan, Shu Yuehong, Sun Qiangqiang, Li Laisheng
School of Chemistry & Environment, South China Normal University, Guangzhou 510006, China.
School of Chemistry & Environment, South China Normal University, Guangzhou 510006, China.
J Colloid Interface Sci. 2014 Sep 1;429:25-33. doi: 10.1016/j.jcis.2014.05.004. Epub 2014 May 17.
In this study, the application of Mn loaded MCM-41 (Mn/MCM-41) was reported as a novel adsorbent for methyl blue (MB) from aqueous solution. The mesoporous structure of Mn/MCM-41 was confirmed by XRD technique. Surface area, pore size and wall thickness were calculated from BET equation and BJH method using nitrogen sorption technique. FT-IR studies showed that Mn were loaded on the hexagonal mesoporous structures of MCM-41. It is found that the MCM-41 structure retained after loading of Mn but its surface area and pore diameter decreased due to pore blockage. Adsorption of MB from aqueous solution was investigated by Mn/MCM-41 with changing Mn content, adsorbent dosage, initial MB concentration, contact time, pH and the temperature. Under the chosen condition (25°C, 0.02 g adsorbent dosage, 6.32 pH, 50 mg L(-1) MB, 1 wt.% Mn), a high MB adsorption capacity (45.38 mg g(-1)) was achieved by Mn/MCM-41 process at 120 min, 8.6 times higher than MCM-41. The electrostatic interaction was considered to be the main mechanism for the dye adsorption. The experimental data fitted well to Freundlich and Dubinin-Radushkevich isotherms. The adsorption of MB on Mn/MCM-41 followed pseudo-second-order kinetics. Thermodynamic parameters suggested that the adsorption process is endothermic and spontaneous.
在本研究中，报道了负载锰的MCM-41（Mn/MCM-41）作为从水溶液中吸附亚甲基蓝（MB）的新型吸附剂的应用。通过XRD技术确认了Mn/MCM-41的介孔结构。使用氮气吸附技术，根据BET方程和BJH方法计算了比表面积、孔径和壁厚。傅里叶变换红外光谱（FT-IR）研究表明，锰负载在MCM-41的六方介孔结构上。发现负载锰后MCM-41结构得以保留，但其比表面积和孔径因孔堵塞而减小。通过改变锰含量、吸附剂用量、初始MB浓度、接触时间、pH值和温度，研究了Mn/MCM-41对水溶液中MB的吸附。在选定条件（25°C、0.02 g吸附剂用量、pH 6.32、50 mg L(-1) MB、1 wt.% Mn）下，Mn/MCM-41在120分钟时实现了高MB吸附容量（45.38 mg g(-1)），比MCM-41高8.6倍。静电相互作用被认为是染料吸附的主要机制。实验数据很好地拟合了Freundlich和Dubinin-Radushkevich等温线。MB在Mn/MCM-41上的吸附遵循准二级动力学。热力学参数表明吸附过程是吸热的且自发的。
