Adsorption performance of palm oil EFB activated carbon prepared by ultrasonic-KOH activation

The increasing release of synthetic dyes like methylene blue (MB) from textile industries into water sources has raised serious environmental concerns, as these dyes are toxic, difficult to degrade, and harmful to aquatic life. Existing wastewater treatment systems often struggle to completely remove such pollutants. To tackle this problem, this study focused on developing an eco-friendly and effective adsorbent from palm oil empty fruit bunches (EFB), an abundant agricultural waste in Malaysia. The EFB was transformed into activated carbon (AC) through a combination of potassium hydroxide (KOH) activation and ultrasonic treatment to improve its surface area and pore structure. The material was characterized using Fourier transform infrared (FTIR), iodine number, moisture and ash content, bulk density, and pHpzc measurements. Batch adsorption experiments were then carried out to examine the effects of initial dye concentration, adsorbent dosage, and contact time on the removal efficiency of MB. The highest removal efficiency recorded was 95.70%, achieved at 200 mg/L MB concentration, 0.5 g of adsorbent, and 150 minutes contact time. The activated carbon produced showed excellent adsorption capacity with a high iodine value of 1125.34 mg/g and low ash content of 3.22%. These findings suggest that EFB-UAC is a promising, low-cost, and sustainable material for treating dye-contaminated wastewater and contributes towards better waste management practices in the palm oil industry.