Effective adsorptive removal of Zn2+, Cu2+, and Cr3+ heavy metals from aqueous solutions using silica-based embedded with NiO and MgO nanoparticles

Saqr Abuhatab; Amjad El-Qanni; Hana Al-Qalaq; Maryam Hmoudah; Wessal Al-Zerei

doi:10.1016/j.jenvman.2020.110713

Effective adsorptive removal of Zn²⁺, Cu²⁺, and Cr³⁺ heavy metals from aqueous solutions using silica-based embedded with NiO and MgO nanoparticles

J Environ Manage. 2020 Aug 15:268:110713. doi: 10.1016/j.jenvman.2020.110713. Epub 2020 May 14.

Authors

Saqr Abuhatab¹, Amjad El-Qanni², Hana Al-Qalaq³, Maryam Hmoudah⁴, Wessal Al-Zerei³

Affiliations

¹ Chemical Engineering Department, An-Najah National University, P.O. Box 7, Nablus, West Bank, Palestine; Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, Alberta, Canada.
² Chemical Engineering Department, An-Najah National University, P.O. Box 7, Nablus, West Bank, Palestine. Electronic address: a.elqanni@najah.edu.
³ Chemical Engineering Department, An-Najah National University, P.O. Box 7, Nablus, West Bank, Palestine.
⁴ Chemical Engineering Department, An-Najah National University, P.O. Box 7, Nablus, West Bank, Palestine. Electronic address: maryam.h@najah.edu.

PMID: 32510447
DOI: 10.1016/j.jenvman.2020.110713

Abstract

In this study, the adsorptive removal of Zn²⁺, Cu²⁺, and Cr³⁺ metal ions from aqueous solutions onto NiO-MgO silica-based nanoparticles (SBNs) has been studied. The effect of several factors such as solution pH, initial concentration, contact time, and coexisting ions on the adsorbed amounts of single Zn²⁺, Cu²⁺, and Cr³⁺ ions have been investigated within an array of batch mode experiments. Interestingly, the adsorption of Cr³⁺ at high and low concentrations was very fast, and equilibrium was achieved within 2 min compared to Cu²⁺ and Zn²⁺ which needed 30 and 60 min to reach equilibrium, respectively. The adsorption equilibrium data fitted very well with the Sips adsorption isotherm model for Cu²⁺ and Zn²⁺, and the BET model for Cr³⁺ ions. The maximum uptake was maintained at 7.23, 13.76, 41.36 (ions per nm²) for Zn²⁺, Cu²⁺, and Cr³⁺, respectively. This equals to 37.69, 69.68, 209.51 (mg adsorbate per g adsorbent), respectively, showing the promising industrial application of those SBNs. Moreover, the adsorption uptake results increase with increasing the pH in the range of 7.0-11.0 for all investigated metal ions. The thermodynamic parameters such as the changes in Gibbs free energy (ΔG^o), enthalpy (ΔH^o), and entropy (ΔS^o) were determined. The adsorption of Zn²⁺, Cu²⁺, and Cr³⁺ was spontaneous, endothermic, and physical for Cu²⁺ and Cr³⁺, while exothermic and chemical for Zn²⁺. The regeneration and reusability studies have proven that the NiO-MgO SBNs can be employed for the adsorptive of these metals repeatedly without impacting the adsorption capacity indicating their sustainability.

Keywords: Heavy metals; MgO; Nanoparticles; NiO; Silica-embedded metal oxide; Wastewater.

MeSH terms

Adsorption
Hydrogen-Ion Concentration
Kinetics
Magnesium Oxide
Metals, Heavy*
Nanoparticles*
Silicon Dioxide
Solutions
Thermodynamics
Water Pollutants, Chemical*
Zinc

Substances

Metals, Heavy
Solutions
Water Pollutants, Chemical
Magnesium Oxide
Silicon Dioxide
Zinc