CONCURRENT PRODUCTION OF BIOCHAR AND LIQUID SMOKE FROM COCOA POD HUSK FOR SUSTAINABLE AGRO-WASTE VALORIZATION
Authors: Muhammad Zulhajj Khan, G.K., Hanis Haziqah, I., Sannasi, P.*, Siti Nuurul Huda, M.A., and Ch’ng, H.Y.
Journal Issue: Malaysian Cocoa Journal, Volume 17 2025
Keywords: Biochar, carbonization, climate change, condensation, liquid smoke
Published On: 5/11/2025
Abstract
Cocoa pod husk (CPH), a major by-product of cocoa production, remains largely underutilized, posing environmental and economic challenges for smallholder farmers. This study investigates the concurrent conversion of CPH into biochar and liquid smoke through slow pyrolysis and condensation, offering a dual solution for waste management and value addition. The sustainable valorization of CPH was assessed by analyzing the process temperature profile, yield, and product characteristics. Five experimental trials were conducted using a custom-designed carbonization drum, with CPH sourced from Machang and Bagan Datuk Malaysian Cocoa Board stations. The process temperature ranged from 44.33°C to 358.47°C across three drum zones (bottom, middle, top) over 180 minutes. The recommended temperature range for complete carbonization is 350-450 oC. The trials successfully co-produced biochar and liquid smoke, with average yields of 43.71 ± 2.77% (biochar), 46.36 ± 8.89% (raw liquid smoke), and 7.78% (purified liquid smoke). Biochar exhibited an alkaline pH (10.1-10.3), low moisture content (4.64-7.42%), low ash content (5.5-5.8%), moderate volatile matter (19.7-33.08%), and high fixed carbon (54-69.28%), making it suitable for soil amendment or activated carbon precursor. The results indicated that larger particle sizes (> 1 mm) produced biochar with higher fixed carbon (69.28%) with lower volatile matter (20.55 ± 2.07%),and moisture content (4.64 ± 0.27%). While, smaller particles (≤ 125 μm) retain higher moisture (7.42 ± 0.15%) and volatile matter (33.08 ± 1.07%), but had reduced fixed carbon (54%). Purified liquid smoke (pH 8.9-9.63) obtained through fractional distillation (70-110°C), demonstrated potential as a soil enhancer, germination stimulant, biopesticide, and biochar activation agent, with notable antioxidant properties. Temperature variations significantly influenced product yield and characteristics. These findings highlight CPH as a viable feedstock for biochar and liquid smoke production, supporting sustainable agriculture, climate mitigation, and biomass-derived product development. Further research on economic feasibility is needed to facilitate implementation at cocoa farms.