Environmental Remediation and Characterization of Bio-Synthesized Silicon Nanoparticles from Bamboo Stem

Abstract

ntal Remediation and Characterization of Bio-Synthesized Silicon Nanoparticles from Bamboo Stem

Ukeme N. Essien*, Nsikak Bassey Essien, Idongesit Akpan James

Received: 12 December 2025/Accepted: 12 March 2026/Published: 20 March 2026

Abstract This study investigated the green synthesis and characterization of silicon oxide nanoparticles (SiONPs) derived from discarded bamboo stem using an eco-friendly and cost-effective approach. The bamboo biomass was treated with 2 M hydrochloric acid and 50% sodium hydroxide, followed by calcination at 800 °C for 3 h to produce silica-rich nanoparticles. The synthesized SiONPs were characterized using X-ray Diffraction (XRD), Scanning Electron Microscopy coupled with Energy Dispersive X-ray spectroscopy (SEM–EDX), X-ray Fluorescence (XRF), Fourier Transform Infrared Spectroscopy (FTIR), and UV–Visible spectroscopy. XRD analysis revealed dominant diffraction peaks at 2θ ≈ 28.14° and 28.39° with d-spacing values of 3.171 Å and 3.144 Å, respectively, corresponding to the (101) crystalline plane of silicon/silica. The highest relative intensity recorded was 100%, confirming the predominance of crystalline silicon oxide phases. SEM analysis showed agglomerated, porous, flaky, and nanosheet-like morphologies with interconnected pore structures favorable for adsorption processes. EDX results confirmed the predominance of silicon and oxygen within the synthesized material. XRF analysis revealed that SiO₂ was the major oxide component with a concentration of 52.54 wt%, followed by Al₂O₃ (30.44 wt%) and Fe₂O₃ (3.59 wt%), indicating the formation of silica-rich aluminosilicate nanostructures. Minor oxides including TiO₂ (1.19 wt%), CaO (1.54 wt%), and K₂O (0.27 wt%) were also detected, while the low loss on ignition value of 0.50 wt% indicated effective calcination and minimal residual organic matter. FTIR spectra exhibited characteristic Si–O–Si stretching vibrations within the range of 1050–1100 cm⁻¹ and broad O–H absorption around 3400 cm⁻¹ corresponding to surface silanol groups. UV–Visible spectroscopy showed a maximum absorption wavelength (λmax) around 275 nm with an estimated optical band gap energy of 4.51 eV, confirming the semiconductor-like optical behavior of the nanoparticles. The combined characterization results confirmed the successful synthesis of structurally stable, silica-rich, semi-crystalline silicon oxide nanoparticles with high surface functionality and favorable optical properties. The porous morphology, high silica content, and abundant silanol groups indicate that the synthesized bamboo-derived SiONPs possess strong potential for adsorption, photocatalysis, wastewater treatment, heavy metal remediation, and other environmental applications.