Biogenic Nanosilica Synthesis Employing Agro-Waste Rice Straw and Its Application Study in Photocatalytic Degradation of Cationic Dye

Abstract

The current study aims towards a holistic utilization of agro-waste rice straw (RS) to synthesize nanosilica (SiNPs) employing the sol–gel method. The effect of ashing temperature was evaluated for the synthesis process. X-ray diffraction demonstrated a broad spectrum at 21.22° for SiNPs obtained using RSA-600, signifying its amorphous nature, whereas crystalline SiNPs were synthesized using RSA-900. The EDX and FTIR spectra confirmed the significant peaks of Si and O for amorphous SiNPs, confirming their purity over crystalline SiNPs. FE-SEM and TEM micrographs indicated the spheroid morphology of the SiNPs with an average size of 27.47 nm (amorphous SiNPs) and 52.79 nm (crystalline SiNPs). Amorphous SiNPs possessed a high surface area of 226.11 m2/g over crystalline SiNPs (84.45 m2/g). The results obtained attest that the amorphous SiNPs possessed better attributes than crystalline SiNPs, omitting the need to incorporate high temperature. Photocatalytic degradation of methylene blue using SiNPs reflected that 66.26% of the dye was degraded in the first 10 min. The degradation study showed first-order kinetics with a half-life of 6.79 min. The cost-effective and environmentally friendly process offers a sustainable route to meet the increasing demand for SiNPs in industrial sectors. The study proposes a sustainable solution to stubble burning, intending towards zero waste generation, bioeconomy, and achieving the Sustainable Development Goals (SDGs), namely SDG 13(Climate Action), SDG 3(Good health and well-being), SDG 7(use of crop residues in industrial sectors) and SDG 8 (employment generation).

TiO2-modified g-C3N4 nanocomposite for photocatalytic degradation of organic dyes in aqueous solution

“…No phase change was observed in the XRD pattern ( Figure 9 (c)) of TiO 2 /g-C 3 N 4 nanocomposite after 4 cycles demonstrating good stability of the nanocomposite. The FTIR spectrum of nanocomposite after four degradation cycles ( Figure 9 (d)) shows an additional functional group around 1646 cm −1 due to the C=N stretching vibration of adsorbed MB in the nanocomposite [ 51 , 52 ]. Therefore, a slight reduction in degradation effectiveness after four cycles can be associated with the loss of surface-active sites of the catalyst as a result of the pollutants' adsorption, which prevents proper light absorption.…”

Phase controlled green synthesis of wurtzite (P63mc) ZnO nanoparticles: interplay of green ligands with precursor anions, anisotropy and photocatalysis

“…Further, the characterisation study of the synthesised nanoparticles was performed following the protocol reported by Singh et al (2022). 24 The phase and crystal structure of the synthesized zinc nanomaterial were determined by X-ray diffraction (XRD) in the 2 θ scanning range of 20–80° using an XRD X'Pert Pro (PANalytical, Netherlands) diffractometer with a Cu-Kα X-ray source ( λ = 1.5406 Å). SEM-EDX (scanning electron microscopy with Oxford-EDX system IE 250 X Max 80, Netherlands) and TEM (JEOL JEM-1400) at an accelerating voltage of 100 kV and HR-TEM (Tecnai G2 20) were performed for morphology analysis.…”

Green chemistry routed sugar press mud for (2D) ZnO nanostructure fabrication, mineral fortification, and climate-resilient wheat crop productivity

“…DLS Zetasizer Ver. 7.11 (Malvern Instruments) was used for measuring the hydrodynamic diameter and zeta (ζ) potential 18 . The summary of synthesis conditions is given in Table S1.…”