Green production of silica nanoparticles from maize stalk

Abstract

Amorphous silica has been produced from some agricultural wastes but with drawbacks on agglomeration challenges. In the present study, potential of maize stalk (MS) wastes as a source of nano silica was studied through modified sol-gel techniques, which involved acid pretreatment, calcination, leaching, sol-gel modification, and post-filtration treatments. Nano silica particles obtained were characterized by XRD, SEM, EDS, TEM, PSA, Raman, and FT-IR for morphology, elemental composition, particle size, and surface chemistry. Results obtained revealed that pre-calcination acid treatment of the MS did not improve the silica yield but reduced the Van der Waal’s interaction of the silica particles resulting in silica particles with a smaller degree of agglomeration. Sodium silicate modified with ethylene glycol sol-gel treatment prior to titration reduced silica agglomeration. Silica nanoparticles obtained according to XRD, TEM, and PSA are below 30 nm.

Keywords:

• Maize stalk
• silica
• nanoparticle
• agglomeration
• morphology

Acknowledgments

Authors wish to show their appreciation to Materials Laboratory of Karunya University, Coimbatore, India and Institute of Nano Engineering Research (INER), Tshwane University of Technology, Pretoria, South Africa for allowing access to their laboratories for execution of this project.