Optimization of RHA-based zeolite phase using hydrothermal method for adsorption application

Rice husk was used as a silicate source to produce RHA-based zeolites through hydrothermal method. The synthesis of zeolite undergone different types and concentrations of alkaline solutions which were 3M and 5M of sodium hydroxide (NaOH) and 5M of potassium hydroxide (KOH), respectively. The rice husk ash and resulted zeolites were then being characterized by X-ray fluorescence (XRF), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analyses. Analyses of XRF, SEM and BET results shown that RHA has high content of silica (83.90%) with irregular particles due to large surface area of 48.7 m2g-1. For FTIR analysis, RHA at band 1040.52 cm-1 assigned to asymmetric Si-O-Si bond stretching in SiO4 tetrahedron. The band at 794.71 cm-1 was corresponded to the stretching vibrations quartz of Si-O-Si. Subsequently, the zeolites were applied as an adsorbent in sugarcane bagasse wastewater and tested for total suspended solid (TSS) and chemical oxygen demand (COD). The adsorption capacity of TSS, COD and colour by the previous synthesized zeolites was then observed experimentally through the effects of contact time. Results indicated that adsorption capacity for COD is 13% to 22% and ranged from 50% to 57% for TSS.