Natural zeolites are easily found and abundant in Indonesia. The natural zeolites are low-cost minerals; however, their ammonium sorption is poor. A hydrothermal method was applied to improve the ammonium sorption. Hydrothermal treatment times were varied 8, 24, and 32 h. The parent and hydrothermal treated samples were characterized by using X-ray diffraction (XRD), Field Emission Scanning Electron Microscopes (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), and nitrogen physisorption. Ammonium adsorption was performed using a batch reactor to evaluate the adsorption performance of the prepared zeolite samples. The 8 h hydrothermal (HT 8 h) treated zeolites showed the highest ammonium removal percentage among others. The XRD analysis of HT 8 h shows a higher crystallinity of mordenite and the Brunauer–Emmett–Teller (BET) model shows a surface area of 105 m2/g, much larger as compared to the parent with a surface area of 19 m2/g. Various kinetic and isotherms models were also studied on the parent and HT 8 h samples. The intraparticle equation showed the most accurate model for the kinetic data and the Freundlich equation showed the most accurate model for the isotherm of the experimental data. In terms of ammonium removal efficiency, hydrothermally treated Bayah mordenite compares favorably with treated mordenite from other locations despite that clinoptilolite provides higher removal capacities than mordenite.

The increase in biodiesel production results in an excessive amount of crude glycerol by-product. Therefore, production of solketal –an effective additive of gasoline fuel-from glycerol and acetone via catalytic acetalization could improve the added value of glycerol. This study investigates enhancement of natural mordenite catalytic properties through the hydrothermal recrystallization method for glycerol acetalization. The hydrothermal temperature was varied at 150, 170 and 190 oC to form ZT 150, ZT 170 and ZT 190, respectively. The samples were characterized using the x-ray diffraction and the scanning electron microscope-Energy dispersive X-Ray. They were later used as catalysts for glycerol acetalization with acetone. The best obtained catalyst was further studied to explore the effect of acetone on glycerol ration. The glycerol conversion was deter-mined using the ASTM D7637-10 titration method. Solketal product was identified by using the Fourier transform infrared spectroscopy. The results show that the recrystallization temperature affects the intensity of the mordenite phase and quartz impurity phase in the modified zeolites. A high recrystallization temperature led to a higher phase of mordenite, peaking at 170oC, beyond which the quartz impurity phase increased. Glycerol acetalization conversions over zeolite parent, ZT 150, ZT 170 and ZT190 with acetone to glycerol ratio of 3 were 16.1%, 30.4%, 33.9% and 32.5%, respectively. When the ratio of acetone to glycerol was increased to 12, the glycerol conversion over ZT 170 catalyst reached 59%, a good starting point for further modifications. Overall finding demonstrated a straight-forward fabrication of catalyst from natural resource to enhance glycerol as the biodiesel production by-product into a higher value end-product of solketal.