The Quality of Coconut Shell Charcoal is Activated by Variations in Concentration of NaOH Solution and Variations in Temperature to Decrease Chromium (VI) Ion Levels

Cr (VI) ion is a heavy metal that can be carcinogenic, so it needs to be reduced by using coconut shell charcoal. The aim of this research is to determine the water content, ash content and iodine content in activated coconut shell charcoal varying the concentration of the NaOH solution 0.5; 1.0; and 2.0 %w/v at the variations temperature of 500; 600; and 700°C and to determine the decrease in Cr (VI) ion levels with activated coconut shell charcoal varying the NaOH solution and temperature, and characterization with Scanning Elecctrone Microscope (SEM). The method for measuring water content, ash using the gravimetric method, measuring iodine content using the yodometric method and Cr content (VI) determined using the visible spectrophotometric method. The research results showed that the quality of coconut shell charcoal activated with variations in NaOH solution has charcoal quality according to SNI No. 06-3730-1995, and the best was activated with NaOH 2 %w/v, 700°C with water content 1.87±0.06%, ash content 5.71±0.02%, and Iodine absorption 1724.10±6.77mg/g. The higher the concentration of NaOH and temperature were the more open the pore morphology, so the ability to adsorb Cr(VI) ions is greater. The higher the carbonation temperature, the percentage reduction in Cr (VI) levels also increases. Conclusion The highest reduction in Cr (VI) levels of 66.66% was obtained by using coconut shell charcoal activated with a 2.0 % b/v NaOH solution with an activation temperature of 700 °C for a soaking time of 120 minutes.