X-ray fluorescence analysis of coconut wood sawdust and coconut coir dust biochar prepared under low-temperature pyrolysis

Indonesia is an agricultural country with agriculture-based industries such as the wood industry for furniture as one of its developing industries. Wood-based industries typically generate a large amount of waste in the form of sawdust. The wood industry that utilizes coconut trees as a raw material will produce waste like sawdust and coir. Using pyrolysis techniques can convert sawdust and coir waste into biochar. Biochar is commonly used as a soil amendment because it can improve soil fertility. This research aims to determine the elemental content of biochar derived from wood sawdust and coconut coir dust and whether the resulting biochar is elementally suitable for use as a soil amendment. Biochar is created by burning coconut wood sawdust and coconut coir dust in a furnace at 250°C and 350°C for 4 hours, then grinding and sifting to a size of 355 micrometres at the Limnology and Water Resources Research Center. Elemental property analysis using an X-Ray Fluorescence Spectrometer (XRF) at Lampung Advanced Characterization-BRIN. According to the XRF analysis, the five dominant elements in coconut coir dust biochar are potassium (K) 42.97-43.87%, chlorine (Cl) 39.41-41.49, calcium (Ca) 11.68-12.51%, iron (Fe) 2.29-3.07%, and phosphorus (P) 0.51-0.54%. Meanwhile, the five most abundant elements in coconut sawdust biochar are iron (Fe) 46.37-50.08%, silica (Si) 19.05-20.56%, calcium (Ca) (7.94-12.10), aluminum (Al) (8.93-10.31%), and potassium (K) (4.01-5.62%). The findings of the study show that raw materials have a significant impact on elemental content. Furthermore, the elemental composition of sawdust biochar is dominated by toxic elements that are unfavorable when applied to the soil. Utilizing biochar from coir dust is better than biochar from sawdust based on elemental content.