Synthesis of potassium zeolite from rice husk ash as a silicon source

Abstract

Rice is of great economic, social and cultural importance for many countries. However, rice industry generates rice husk ash (RHA), a low-density silicon-rich waste. The current work studied a way to minimize the impacts of this waste by synthesizing potassium zeolites from RHA. It was not found in the literature studies that have synthesized template-free potassic zeolites from this waste material. Commercial KOH and public supply water were used to approach industrial conditions. Time and temperature of the hydrothermal treatment were evaluated. The synthesized materials were mesoporous and it was identified the formation of potassium zeolites (Chabazite-K and Merlinoite). This zeolite was synthesized using low cost bio-precursors and this material can be potentially used as a potassium fertilizer. Based on this future application, the optimum condition for synthesis was using a 5 mol L −1 KOH solution, 2 mL g −1 solution:RHA ratio, 8 h of reaction time, and 125 °C of temperature reaction.