Engineering and Technology Horizons | 2026
Authors: Chaiya A.; Morgkhad A.; Kemudorn A.; Siri C.; Panphattharachai P.
DOI: 10.55003/ETH.430108
Journal: Engineering and Technology Horizons
Year: 2026
Publisher: King Mongkut's Institute of Technology Ladkrabang
Document Type: Article
Open Access: All Open Access; Gold Open Access
Cited by: 0
This study examined the slow pyrolysis of avocado peel (AP) and cashew nutshell (CNS) to produce biochar for adsorption, solid fuel, and carbon sequestration. Experiments were conducted at 400–600°C with residence times of 30–120 min, with process optimization via Response Surface Methodology (RSM). A central finding was a “physicochemical decoupling” effect, whereby conditions maximizing yield and adsorption capacity differ fundamentally from those required for carbon stability and energy densification. RSM models predicted maximum yield for both feedstocks at 400°C and 30 min, while peak iodine adsorption was achieved at 600°C — at 30 min for AP (530.19 mg/g) and 120 min for CNS (552.95 mg/g). SEM and elemental analyses confirmed that higher temperatures promoted well-developed porous networks and elevated carbon content, with Higher Heating Value (HHV) reaching 26.82 MJ/kg for AP and 32.20 MJ/kg for CNS, comparable to commercial biomass fuel benchmarks. Notably, CNS biochar at 600°C and 120 min achieved an O/C ratio of 0.055, classifying it as IBI Class 1 with a predicted carbon sequestration half-life exceeding 1,000 years. These results establish a condition-selection framework: 400°C for adsorbent production and 600°C for solid fuel and long-term carbon sequestration. © 2026, King Mongkut's Institute of Technology Ladkrabang. All rights reserved.
Avocado peel; Biochar; Carbon sequestration; Cashew nutshell; Slow pyrolysis