Synthesis of Floral-Shaped Nanosilica from Coal Fly Ash and Its Application for the Remediation of Heavy Metals from Fly Ash Aqueous Solutions

Virendra Kumar Yadav (), Abdelfattah Amari (), Shivraj Gangadhar Wanale (), Haitham Osman and M. H. Fulekar
Additional contact information
Virendra Kumar Yadav: Department of Biosciences, School of Liberal Arts & Sciences, Mody University of Science and Technology, Sikar 332311, India
Abdelfattah Amari: Department of Chemical Engineering, College of Engineering, King Khalid University, Abha 61411, Saudi Arabia
Shivraj Gangadhar Wanale: School of Chemical Sciences, Swami Ramanand Teerth Marathwada University, Nanded 431603, India
Haitham Osman: Department of Chemical Engineering, College of Engineering, King Khalid University, Abha 61411, Saudi Arabia
M. H. Fulekar: School of Chemical Sciences, Swami Ramanand Teerth Marathwada University, Nanded 431603, India

Sustainability, 2023, vol. 15, issue 3, 1-18

Abstract: Every year a large amount of coal fly ash (CFA) is generated and dumped in fly ash ponds. Fly ash has numerous toxic heavy metals, which leads to water pollution due to the percolation of these heavy metals. Heavy metal toxicity has become a major issue for the whole globe. Moreover, CFA has several value-added minerals, such as silica, alumina, and ferrous in large amounts. Therefore, the synthesis of silica nanoparticles from CFA and their application for the removal of toxic heavy metals from fly ash aqueous solution will prove to be an economical and efficient approach. Here, in the present research work, investigators synthesized nanosilica from CFA by alkali dissolution and sol-gel methods and applied them for heavy metal removal. Firstly, CFA was treated with high molar NaOH, along with stirring and heating. Further, the sodium silicate leachate from CFA was treated with dilute HCl till the formation of a white gel at neutral pH. Purification of the nanosilica was achieved by treating with 1M HCl along with stirring followed by calcination at 400 °C for 4 h. The synthesized nanosilica was characterized by UV-Vis, Fourier transform infrared (FTIR), particle size analyzer (PSA), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), electron diffraction spectroscopy (EDS), and high-resolution transmission electron microscope (HR-TEM). The sizes of the floral-shaped nanosilica particles were 20–70 nm, and the purity was 90–95%, as confirmed by microscopy and EDS, respectively. The XRD and FTIR revealed the amorphous nature of nanosilica. Finally, the potential of the nanosilica was assessed for the removal of heavy metals from 20% CFA aqueous solutions in batch experiments. The nanosilica showed about 40–90% removal of heavy metals (Al, Pb, Cd, Cu, Cr, Ni, Co, Zn, Mn) from the fly ash aqueous solution.

Keywords: fly ash; silica nanoparticles; amorphous; alkali-treatment; heavy metal (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2023
References: View complete reference list from CitEc
Citations:

Downloads: (external link)
https://www.mdpi.com/2071-1050/15/3/2612/pdf (application/pdf)
https://www.mdpi.com/2071-1050/15/3/2612/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jsusta:v:15:y:2023:i:3:p:2612-:d:1054164

Access Statistics for this article

Sustainability is currently edited by Ms. Alexandra Wu

More articles in Sustainability from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().