Production and Evaluation of Activated Hybrid Biochar Briquettes From Date Palm and Pistachio Wastes: Thermochemical, Physical, and Mechanical Behavior

As global fossil fuel reserves decline and concerns about climate change intensify, interest in briquettes as a sustainable biofuel source is increasing. This study investigated the effects of CO 2 activation temperature on the physicochemical, mechanical, thermal, and combustion properties of hybrid biochar briquettes produced from date palm and pistachio biochars at a 60:40 ratio using 15% and 20% starch binder. The results showed that the non‐activated hybrid biochar briquettes with 20% starch binder (HB20) exhibited the highest density (1.06 g/cm 3 ), whereas the briquettes produced at 400°C had a substantially lower density (0.60 g/cm 3 ). Increasing the starch binder content and activation temperature affected the mechanical and combustion properties of the briquettes, including impact resistance, shatter resistance, compressive strength, and burning rate. The briquettes containing 15% starch exhibited the lowest compressive strength at the lower carbonization and activation temperature of 400°C, whereas increasing the treatment temperature to 600°C resulted in higher compressive strength. Activation reduced the burning time of the hybrid biochar briquettes and increased their burning rate; AHB15 at 600°C showed the shortest burning time (300 s) and highest burning rate (1.05 g/min). Thermogravimetric analysis showed that the activated hybrid biochar briquettes containing 15% starch exhibited the lowest total mass loss (16.30%). Furthermore, FESEM images revealed more pronounced pore structures in the activated briquettes than in the non‐activated hybrid biochar briquettes.