KARAKTERISASI BIOCHAR YANG DIHASILKAN DARI PIROLISIS LAMBAT LIMBAH KULIT KAKAO DAN LIMBAH SERESAH KAYU DENGAN MELAKUKAN UJI SEM

Cocoa pod husks and wood litter are biomass sources with the potential to be processed into biochar via slow pyrolysis. This study aimed to characterize and compare biochar derived from cocoa pod husks and wood litter based on yield, pH, surface morphology, pore opening diameter, and surface elemental composition. The materials were pyrolyzed in a modified drum under limited-oxygen conditions for 300 minutes. The resulting biochar was analyzed descriptively through pH measurement and scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM–EDX) testing. Pore opening diameters were measured from SEM images at 2,000× magnification. Measurements were performed on a single sample of each material by randomly selecting 10 pore openings. The results showed that the biochar yield was 50.00% for cocoa pod husks and 46.67% for wood litter. Both biochars were alkaline, with pH values of 10.45 ± 0.01 for cocoa pod husk biochar and 8.57 ± 0.02 for wood litter biochar. SEM images revealed that both biochars possessed porous surfaces, though the shapes and sizes of the openings differed. The average pore opening diameter was 0.696 ± 0.468 µm for cocoa pod husk biochar and 1.812 ± 0.320 µm for wood litter biochar. SEM–EDX analysis indicated that the wood litter biochar surface had higher relative proportions of carbon and oxygen 45.30 ± 1.17% and 53.84 ± 1.35%, respectively whereas the cocoa pod husk biochar surface exhibited a higher relative proportion of magnesium (8.02 ± 0.47%). These results indicate that cocoa pod husk biochar is distinguished by its alkalinity and surface magnesium content, while wood litter biochar is characterized by higher carbon and oxygen content and larger pore opening sizes. Further testing is required to determine the suitability of both biochars as soil amendments.

Keywords : Biochar, cocoa pod husks, slow pyrolysis, SEM–EDX, wood litter.