Upcycling of waste jute biomass to advanced biocarbon materials: the effect of pyrolysis temperature on their physicochemical and electrical properties

Abstract

In this work, waste burlap (jute) biomass from the coffee industry was valorized to synthesize advanced biocarbon. Waste burlap biomass was carbonized at various temperatures (325, 350, 400, 500, 600, 700, 800, 900 and 1000 °C), followed by ball-milling. The pyrolysis yield, functionality, particle size, surface area, interlayer d-spacing, ash content, thermal stability, carbon/oxygen content, graphitic content and electrical conductivity of the biocarbon obtained after each carbonization were determined. With an increase in the carbonization temperature a decrease in yield occurred. The yield of biocarbon obtained at 325 °C was noted to be ∼71 wt%, which decreased with an increase in the carbonization temperature and remained ∼22 wt% from 800–1000 °C. It was observed that the functional groups of the carbonized biomass (biocarbon) due to the presence of cellulose, hemicellulose and lignin in biomass were retained up to ∼600 °C and diminished at higher pyrolysis temperatures. In addition, among 325–1000 °C carbonization temperatures, the highest thermally stable biocarbon and highest carbon content (85%) were obtained after pyrolyzing burlap biomass at 1000 °C. XRD analysis revealed the reduction in d-spacing as the carbonization temperature increases leading to close packing of layers. Importantly, burlap biocarbon (pyrolyzed at ∼1000 °C, compressed at 1.12 MPa) showed significant enhancement in electrical conductivity (∼3.5 times higher) than commercial graphite. The research has demonstrated that the synthesized sustainable biocarbon can be further upcycled. High temperature (∼1000 °C) pyrolyzed biocarbon has the potential to be used as biographite and can substitute fossil fuel-derived for certain semi-conductive materials.