title: Application of Mn/MCM-41 as an adsorbent to remove methyl blue from aqueous solution.
abstract: 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.
authors.affiliation: School of Chemistry & Environment, South China Normal University, Guangzhou 510006, China.
authors.forename: Yimin
authors.initials: Y
authors.lastname: Shao
authors.affiliation: School of Chemistry & Environment, South China Normal University, Guangzhou 510006, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Wang
authors.affiliation: School of Chemistry & Environment, South China Normal University, Guangzhou 510006, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Kang
authors.affiliation: School of Chemistry & Environment, South China Normal University, Guangzhou 510006, China. Electronic address: hongershu@163.com.
authors.forename: Yuehong
authors.initials: Y
authors.lastname: Shu
authors.affiliation: School of Chemistry & Environment, South China Normal University, Guangzhou 510006, China.
authors.forename: Qiangqiang
authors.initials: Q
authors.lastname: Sun
authors.affiliation: School of Chemistry & Environment, South China Normal University, Guangzhou 510006, China. Electronic address: llsh@scnu.edu.cn.
authors.forename: Laisheng
authors.initials: L
authors.lastname: Li
keywords: Adsorption; Kinetics; Methyl blue; Mn/MCM-41; Thermodynamic