Sustainable avenue for biochar production using bamboo dust through a novel thermo-electrochemical process

Abstract

Converting waste bamboo dust to biochar reduces greenhouse gas emissions (GHG) and air pollution from open burning, making it an environmentally friendly choice. This study examined the impact of molten salt electrolysis temperatures on the physicochemical parameters of biochar obtained from bamboo dust. Bamboo dust-based biochar is derived at 250 °C, 315 °C, and 380 °C for a reaction time of 3 h. The waste bamboo dust and bamboo biochar derived are evaluated by proximate, ultimate, FESEM, BET, FTIR, and XRD studies. Bamboo dust-derived biochar yields 20.80 % at 250 °C, 19.00 % at 315 °C, and 18.00 % at 380 °C with a constant voltage of 1.5V and current between −0.5 and 0.5 A. The fixed carbon content of bamboo dust-derived biochar ranged between 80.70 % and 86.18 %, which is significantly higher than that of bamboo dust. The carbon content of the biochar ranged from 81.68 % to 87.93 %, with the maximum carbon fraction reported at a molten salt electrolysis temperature of 380 °C. The low elemental ratios of C/H 0.54–0.72 and C/N 0.07–0.15 indicated that bamboo dust biochar is strongly carbonized. Bamboo dust-derived biochar exhibits a BET surface area between 37 and 187.10 m²/g, reaching its maximum at 380 °C. At that temperature, bamboo dust-derived biochar had a total pore volume ranging from 0.05 to 0.11 cc/g. The XRD analysis verified the existence of inorganic compounds like magnesium, manganese and sylvite, calcite, and calcium silicates in bamboo dust-derived biochar, which contribute to their heterogeneous composition and elevated ash content. This study explores the thermo-electrochemical process to produce high-performance activated biochar using alkali-based activation at lower temperatures and applied current. The technique improves porosity, surface area and carbon content, making it a more advanced and sustainable option compared to the traditional process.