Beyond traditional bio-oil potential: Converting to high-energy solid fuel, Pb²⁺ sensing carbon nanodots, and efficient photocatalysts for environmental applications

Background

Pyrolysis oil, typically derived from biomass, is primarily used as a liquid fuel or chemical feedstock. This study investigates an innovative method to expand the potential of rice straw-derived pyrolysis oil by converting it into high-energy bio-coal and bio-oil-derived carbon nanodots (BCDs).

Methods

Rice straw was subjected to slow pyrolysis to generate bio-oil, which was distilled to produce solid fuel, bio-coal. This bio-coal was then used as a precursor for the synthesis of fluorescence carbon nanodots through a hydrothermal process. The photocatalytic performance of BCDs was assessed by the degradation of methylene blue (MB) dye, and their capability to detect Pb²⁺ ions was examined through fluorescence quenching assays.

Significant Findings

The bio-coal exhibited remarkable fuel properties, including a high carbon content (70.19 %), low oxygen content (20.52 %), and high calorific value (28.51 MJ/kg), making it a promising alternative to fossil fuels. The BCDs, with an average size of 3.32 nm and a quantum yield of 17 %, demonstrated excellent sensitivity for Pb²⁺ detection (detection limit 5.6 μM) and photocatalytic degradation of MB dye (93.76 % in 180 min). The work aims to address both energy production challenges and environmental pollution, particularly focusing on the detection of Pb²⁺ ions and dye degradation in water.