Synthesis and Application of Activated Charcoal from Indonesian Sugar Palm Bunches (<i>Arenga longipes</i>) as a Potential Absorbent for Heavy Metals

Activated charcoals were synthesized from sugar palm bunches (SPB) of the native tree of Arenga longipes in Indonesia. The synthesized activated charcoal (AC) was characterized, and utilized as an absorbent for heavy metals (lead/Pb and copper/Cu) through thermal activation. The synthesis of AC was accomplished through furnace activation at temperatures of 500°C, 600°C, 700°C, and 800°C. Acid chlorides were blended with the SPB-AC samples at 5% impregnation level and subsequently subjected to washing for activation, resulting in the elimination of volatile substances and ash content, which facilitates the development of a porous structure in the activated charcoal. The proximate analysis results indicated a reduction in weight and moisture content with an increase in activation temperature. The C-O, C=C, O-H stretching chains were not visible in the SPB-AC, indicating that the chains were broken after activation. The treatments at 600°C and 700°C exhibited superior thermal stability relative to the others. Moreover, there was a notable reduction in the signal strength of low-crystallinity amorphous carbon, indicating that the high-temperature treatment substantially altered the structural characteristics of the crystal. The SPB-AC produced at 700°C exhibited a primarily microporous architecture, characterized by a maximal surface area, reduced total pore volume, and small particle size. In conclusion, elevating the activation temperature to 700°C leads to notable improvement in the adsorption of Pb (91.61%) and Cu (95.19%) metals.