Metal-organic Framework (MOF) as a porous material has a potency for an organic dye adsorbent due to its tunable pore size. It can be a good candidate for selective separation of organic dye waste because of its organic functionality, high thermal and stability. In this study, MOF based on cobalt (Co) and iron (Fe) cations with succinic acid ligand was utilized for Methylene Blue (MB) removal from aqueous solution. Co-MOF and Fe-MOF were synthesized using solvothermal method at 120 °C for 20 h and characterized by using infrared spectroscopy, X-Ray diffraction technique, thermogravimetric analyses, N2 adsorption-desorption isotherm, and scanning electron microscope. The adsorption of MB from aqueous solution by Co-MOF and Fe-MOF were carried out and their adsorption properties were investigated in various parameters such as pH solution, contact time, MOF loading. Moreover, their adsorption isotherm and reusable capacity were explored. As the results, the optimal adsorption was achieved at pH 9 for both MOFs, 5 mg of MOFs loading in 5 mL MB and 180 min for Co-MOF and 150 min for Fe-MOF. Both MOFs could be reused as a good adsorbent with the ratio of ethanol and H2O (70:30) as an eluent. This adsorption activity followed the Langmuir isotherm with the maximum adsorption capacity (Qm) of 3.9494 mg/g and 4.6685 mg/g for Co-MOF and Fe-MOF respectively.

Hierarchical ZSM-5 zeolite was synthesized using a double template method using TPAOH and PDDA as templates, while microporous ZSM-5 was also prepared using only TPAOH as a template. The syntheses then were followed by impregnation with Mn(II) c.a. 2 wt.% and calcination at 550 °C to obtain MnOx/ZSM-5 zeolite catalysts. Extensive characterization of the zeolite catalysts was performed using XRD, SEM, AAS, EDX, FTIR and BET measurement. The characterization showed that hierarchical or mainly mesoporous ZSM-5 was successfully synthesized, having added features compared to the microporous counterpart. The catalysts then were used in conversion reaction of delignified rice husk to levulinic acid, a platform chemical. As a comparison, a certain amount of MnCl2.4H2O was used as a homogeneous catalyst in a similar reaction. The product of the reaction was separated and analyzed with HPLC. It showed that 8 h was the optimum condition for the conversion, with hierarchical MnOx/hi_ZSM-5 catalyst gave the highest amount of levulinic acid (%Y of 15.83%), followed by microporous MnOx/mi_ZSM-5 (%Y of 10%). The % yield of levulinic acid using homogeneous Mn(II) catalyst (%Y of 8.86%) gave more charcoal as a product. Meanwhile, the stability of the zeolite catalysts after the reaction has also been investigated, mainly by analyzing the FTIR spectra and EDX data of the used catalysts after separated and calcined at 550 °C. From the analysis, some of the silica and alumina are leached from the framework, as well as the manganese oxide due to acidic condition at the beginning of the reaction. Nevertheless, it can be concluded that the conversion took place as the interaction between the cellulose and either MnOx in zeolites or Mn2+ ions in the solution, with the support of porous ZSM-5 framework. Hierarchical system somehow assists the ZSM-5 structure stays intact.

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