Abstract: The increasing emphasis on sustainable technologies has encouraged the utilization of agricultural waste as a renewable source for the development of functional materials. Residues such as rice husk, wheat straw, sugarcane bagasse, and corn cob are rich in silica and can be converted into efficient adsorbents for wastewater remediation. This review discusses the extraction of silica from agricultural by-products using different approaches, including controlled combustion, acid–alkali treatment, and sol–gel synthesis, which significantly affect the structural, morphological, and surface properties of the final material. The obtained silica is generally amorphous and exhibits high porosity, large surface area, and abundant silanol groups, making it highly effective for the removal of heavy metals, dyes, and other hazardous pollutants from aqueous media. The adsorption process is influenced by several interactions, such as electrostatic attraction, hydrogen bonding, surface complexation, and ion exchange, depending on the nature of the adsorbent and solution conditions. Surface engineering strategies, including amine functionalization, metal oxide incorporation, and composite fabrication, have been explored to improve adsorption capacity and selectivity. Reported studies demonstrate that silica derived from agricultural residues can perform similarly to conventional commercial adsorbents while offering advantages related to low production cost, resource availability, and environmental sustainability. Although challenges associated with regeneration, consistency of raw materials, and industrial-scale implementation still need attention, biomass-derived silica represents a promising and environmentally responsible material for sustainable water treatment applications. Keywords: Adsorption; Agricultural waste; Biosilica; Heavy metal removal; Rice husk ash; Water purification. Title: Agricultural Waste- Derived Silica as a Sustainable Adsorbent for Water Purification: A Review Author: Sweety Monga International Journal of Novel Research in Physics Chemistry & Mathematics ISSN 2394-9651 Vol. 13, Issue 2, May 2026 - August 2026 Page No: 1-18 Novelty Journals Website: www.noveltyjournals.com Published Date: 08-May-2026 DOI: https://doi.org/10.5281/zenodo.20083696 Paper Download Link (Source) https://www.noveltyjournals.com/upload/paper/Agricultural%20Waste-%20Derived%20Silica-08052026-6.pdf
Sweety Monga (Fri,) studied this question.