Arini Fousty Badri - Department of Chemistry, Faculty of Mathematics and Natural Sciences, Sriwijaya University, Jl. Palembang-Prabumulih, Km. ۳۲, Ogan Ilir, South Sumatra, Indonesia
Neza Rahayu Palapa - Department of Chemistry, Faculty of Mathematicsand Natural Sciences, Sriwijaya University, Jl. Palembang-Prabumulih, Km. ۳۲, Ogan Ilir, South Sumatra, Indonesia
Risfidian Mohadi - Department of Environmental Science, Graduate School, Sriwijaya University, Jl. Padang Selasa No. ۵۲۴ Ilir Barat ۱, Palembang-South Sumatra, Indonesia
Mardiyanto Mardiyanto - Department of Pharmacy, Faculty of Mathematics and Natural Sciences, Sriwijaya University, Jl. Jl. Palembang-Prabumulih, Km. ۳۲, Ogan Ilir ۳۰۶۶۲, South Sumatra, Indonesia
Aldes Lesbani - Department of Chemistry, Faculty of Mathematicsand Natural Sciences, Sriwijaya University, Jl. Palembang-Prabumulih, Km. ۳۲, Ogan Ilir, South Sumatra, Indonesia

A MgCr-based layered double hydroxide (LDH) was synthesized by a coprecipitation method, followed by an intercalation process using an oxalic anion. The materials were characterized using X-ray diffraction analysis, FT-IR spectroscopy, and pH pzc measurement. The materials were then applied as adsorbents for removal of methylene blue (MB) and rhodamine B (RhB) from aqueous solution. Pristine Mg/Cr LDH exhibited RhB adsorption capacity of ۳۲.۱۵۴ mg g⁻۱, whereas the use of intercalated Mg/Cr LDH caused an increase in the capacity (۱۳۹.۵۲۶ mg g⁻۱). Kinetic studies indicated that the dye adsorption using both LDHs followed a pseudo-second-order kinetic model; the K۲ values of pristine and modified Mg/Cr LDH for RhB and MB were ۶.۹۷۰, ۰.۰۰۱, ۰.۴۲۶, and ۲.۰۵۶ g mg⁻۱ min⁻۱, respectively. The thermodynamic study identified that the adsorption of both dyes onto the LDHs was a spontaneous process and can be classified as physical adsorption with adsorption energies of <۴۰ kJ/mol. Moreover, the desorption and regeneration experiments indicated the high economic feasibility and reusability of the LDHs. By using HCl as the optimal solvent, the LDHs could desorb as much as ۹۸% of the dye and could be used as adsorbents with high adsorption capacity over three cycles.A MgCr-based layered double hydroxide (LDH) was synthesized by a coprecipitation method, followed by an intercalation process using an oxalic anion. The materials were characterized using X-ray diffraction analysis, FT-IR spectroscopy, and pH pzc measurement. The materials were then applied as adsorbents for removal of methylene blue (MB) and rhodamine B (RhB) from aqueous solution. Pristine Mg/Cr LDH exhibited RhB adsorption capacity of ۳۲.۱۵۴ mg g⁻۱, whereas the use of intercalated Mg/Cr LDH caused an increase in the capacity (۱۳۹.۵۲۶ mg g⁻۱). Kinetic studies indicated that the dye adsorption using both LDHs followed a pseudo-second-order kinetic model; the K۲ values of pristine and modified Mg/Cr LDH for RhB and MB were ۶.۹۷۰, ۰.۰۰۱, ۰.۴۲۶, and ۲.۰۵۶ g mg⁻۱ min⁻۱, respectively. The thermodynamic study identified that the adsorption of both dyes onto the LDHs was a spontaneous process and can be classified as physical adsorption with adsorption energies of <۴۰ kJ/mol. Moreover, the desorption and regeneration experiments indicated the high economic feasibility and reusability of the LDHs. By using HCl as the optimal solvent, the LDHs could desorb as much as ۹۸% of the dye and could be used as adsorbents with high adsorption capacity over three cycles.

Layered double hydroxide, MgCr, rhodamine B, methylene blue, intercalation