title: Mechanism of interaction of hydrocalumites (Ca/Al-LDH) with methyl orange and acidic scarlet GR.
abstract: The development of new materials for water purification is of universal importance. Among these types of materials are layered double hydroxides (LDHs). Non-ionic materials pose a significant problem as pollutants. The interaction of methyl orange (MO) and acidic scarlet GR (GR) adsorption on hydrocalumite (Ca/Al-LDH-Cl) was studied by X-ray diffraction (XRD), infrared spectroscopy (MIR), scanning electron microscope (SEM), and near-infrared spectroscopy (NIR). The XRD results revealed that the basal spacing of Ca/Al-LDH-MO was expanded to 2.45 nm, and the MO molecules were intercalated with a interpenetrating bilayer model in the gallery of LDH, with 49° tilting angle. Yet, Ca/Al-LDH-GR was kept the same d-value as Ca/Al-LDH-Cl. The NIR spectrum for Ca/Al-LDH-MO showed a prominent band around 5994 cm(-1), assigned to the combination result of the NH stretching vibrations, which was considered as a mark to assess MO(-) ion intercalation into Ca/Al-LDH-Cl interlayers. From SEM images, the particle morphology of Ca/Al-LDH-MO mainly changed to irregular platelets, with a "honey-comb" like structure. Yet, the Ca/Al-LDH-GR maintained regular hexagon platelets, which was similar to that of Ca/Al-LDH-Cl. All results indicated that MO(-) ion was intercalated into Ca/Al-LDH-Cl interlayers, and acidic scarlet GR was only adsorbed upon Ca/Al-LDH-Cl surfaces.
authors.affiliation: Key Laboratory of Advanced Civil Engineering Materials (Tongji University), Ministry of Education, Shanghai 200092, PR China.
authors.forename: Ping
authors.initials: P
authors.lastname: Zhang
authors.forename: Guangren
authors.initials: G
authors.lastname: Qian
authors.forename: Huisheng
authors.initials: H
authors.lastname: Shi
authors.forename: Xiuxiu
authors.initials: X
authors.lastname: Ruan
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.forename: Ray L
authors.initials: RL
authors.lastname: Frost