Green nanosilica and highly efficient removal of methylene blue

Abstract

A new precipitation method has been developed for improving the production of nanosilica that is faster and more environmentally friendly. The study investigates the effects of different acid types and concentrations, as well as aging times, to determine the optimal conditions for preparing nanosilica from sugarcane bagasse ash (SCBA). Nanosilica synthesised with citric acid exhibits a higher specific surface area (554.01 m2 g−1) and yield (88.54%) compared to those synthesised with sulfuric, oxalic, and acetic acids. X-ray diffraction (XRD) patterns and transmission electron microscope (TEM) images show that the synthesised nanosilica has an amorphous silica phase with a particle diameter of approximately 5.6 nm. The applicability of the synthesised nanosilica as an adsorbent for methylene blue (MB) is studied. Various conditions such as adsorbent dosage, contact time, and initial concentration of MB are evaluated. The results reveal that the synthesised nanosilica has a high adsorption capacity (232.29 mg g−1) and removal efficiency (R%) of 90% for MB. The experimental results align with the Freundlich model and can be used for effective dye removal. The development of a simple and environmentally friendly method for synthesising nanosilica with superior adsorption properties is an important contribution to the field of waste management and provides a useful tool for tackling environmental pollution caused by organic dyes.