Carbonization of rice husk for adsorption of phosphate compounds: Influence of temperature and NaOH activator

Abstract

Rice husk is mostly composed of cellulose, hemicellulose, and lignin that can be converted into carbon to be used as an adsorbent. Phosphate is one of the elements that cause eutrophication, resulting in algae blooming. The purpose of this research is to determine the best carbonization temperature and concentration of NaOH activator. The phosphate compounds studied are Sodium Tripolyphosphate (STPP) as artificial phosphate compounds and phosphate compounds in laundry wastewater. Carbonization of rice husk was done for 1 hour with temperature varied at 400, 425 and 450°C. The carbon activation of rice husk was done for 24 hours with variation of NaOH concentrations of 0.3, 0.5, and 0.7 M. The performance test of 100 mesh activated carbon was performed at a speed of 100 rpm and stirring time of 45 minutes. Activated carbon with the best characteristics was obtained from a carbonization temperature of 450°C and activated by 0.3 M NaOH. The characteristics obtained were 1.90%, 35.82%, 20.04%, 42.25%, 49.4 mg/g for water content, ash content, volatile matters, fixed carbon, methylene blue adsorption, respectively. The best dose was 16 g/L of active carbon with an adsorption efficiency of 75.15% on STPP and 93.7% on laundry wastewater.