Repurposing Disposable Bamboo Chopsticks Waste as Biochar for Agronomical Application

Disposable bamboo chopsticks (DBCs) are rarely recycled, and there are not many options for recycling them. Some treatment processes use high technology and complex processes that are not convenient for production at the local level, resulting in practical difficulties in upcycling DBC waste. DBC is lignocellulosic biomass; therefore, DBC has the potential to be recycled and upcycled. The waste management of wood that transforms it into a sustainable material as a biochar with a pyrolysis process accords well with the circular economy model. This research effort aims to upcycle DBC to convert it into biochar with different pyrolysis temperature ranges set at 400 °C (DBC-400), 450 °C (DBC-450), and 500 °C (DBC-500), with a holding time of 60 min. The morphology and essential physicochemical properties of the biochar were analyzed. The research found that all biochar had physicochemical properties and structures appropriate to the agricultural and environmental purposes. Based on the molar ratio of the O/C and H/C, it was indicated that all DBC biochar could persist in the soil for 100 to 1000 years. The DBC-500 had the least hydrophilic surface of biochar, while the DBC-400 had a lower degree of carbonization and aromaticity of biochar. The research concluded that biochar produced at 450 °C had the best properties for supplementary soil and soil treatment, given the cation exchange capacity, specific surface area, average pore diameter, and nutrient content. For future research on the practical application of DBC biochar for agronomical purposes, the results of the properties of DBC biochar with appropriate pyrolysis temperature will lead to the development of a biochar furnace with appropriate technology that is suitable for the local area to be able to produce large amounts of biochar that is effectively DBC. In addition, determining the absorption and release rate of the macronutrients of biochar can predict the frequency of biochar applied in agricultural areas.