Carbothermally Derived Silicon Carbide Nanoparticles from Rice-Husk Silica: Structural, Optical and UV-LightDriven Photocatalytic Decolorization of Methylene Blue
Experimental study demonstrates enhanced methylene blue decolorization using rice-husk-derived silicon carbide nanoparticles, highlighting viable agricultural waste valorization.
Key Points
To synthesize silicon carbide nanoparticles from agricultural rice-husk silica and evaluate their structural, optical, and UV-light-driven photocatalytic properties.
Synthesized 3C-SiC nanoparticles via carbothermal reduction of rice-husk-derived silica with activated carbon at 1500°C for 5 h under argon flow with a polyvinyl alcohol binder.
Characterized sample properties using X-ray diffraction line-profile analysis, FTIR spectroscopy, diffuse-reflectance spectroscopy, and scanning electron microscopy.
Assessed photocatalytic degradation of 10 mg L^-1 methylene blue using 30 mg catalyst per 50 mL under a 300 W UV lamp for 60 min against a catalyst-free control.
Achieved 52% methylene blue removal within 60 min compared with 14% removal for the catalyst-free photolysis control, with an apparent pseudo-first-order rate constant of 0.0117 ± 0.0006 min^-1 (R^2 = 0.987).
Produced predominantly single-phase cubic 3C-SiC with a mean crystallite size of 19.5 ± 3.8 nm, a microstrain of 1.1 × 10^-3, and an optical band gap of 2.17 eV.
Identified residual surface silica/oxide, grain agglomeration (clusters spanning 40 to 398 nm), and potential charge recombination as primary constraints on photocatalytic efficiency.