Mechanistic insights of hexavalent chromium remediation by halloysite-supported copper nanoclusters

Amal Kanti Deb; Bhabananda Biswas; Ravi Naidu; Mohammad Mahmudur Rahman

doi:10.1016/j.jhazmat.2021.126812

Mechanistic insights of hexavalent chromium remediation by halloysite-supported copper nanoclusters

J Hazard Mater. 2022 Jan 5:421:126812. doi: 10.1016/j.jhazmat.2021.126812. Epub 2021 Aug 4.

Authors

Amal Kanti Deb¹, Bhabananda Biswas², Ravi Naidu³, Mohammad Mahmudur Rahman⁴

Affiliations

¹ Global Centre for Environmental Remediation (GCER), College of Engineering, Science and Environment, The University of Newcastle, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), The University of Newcastle, Callaghan, NSW 2308, Australia; Institute of Leather Engineering and Technology, University of Dhaka, Dhaka 1000, Bangladesh. Electronic address: amal.deb@uon.edu.au.
² Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), The University of Newcastle, Callaghan, NSW 2308, Australia; Future Industries Institute, University of South Australia, STEM UniSA, Mawson Lakes Campus, SA 5095, Australia.
³ Global Centre for Environmental Remediation (GCER), College of Engineering, Science and Environment, The University of Newcastle, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), The University of Newcastle, Callaghan, NSW 2308, Australia.
⁴ Global Centre for Environmental Remediation (GCER), College of Engineering, Science and Environment, The University of Newcastle, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), The University of Newcastle, Callaghan, NSW 2308, Australia. Electronic address: mahmud.rahman@newcastle.edu.au.

PMID: 34396956
DOI: 10.1016/j.jhazmat.2021.126812

Abstract

Chromium (Cr) pollution is a significant environmental concern with remediation challenge. Hexavalent chromium (Cr(VI)) is more toxic than trivalent chromium (Cr(III)) due to its mutagenicity and oncogenicity. In this investigation, a multi-functional material, copper nanoclusters (CuNCs)-halloysite nanotubes (HNT) composite (CuNCs@HNT), has been synthesised in an eco-friendly manner and utilised for Cr(VI) remediation. Advanced analytical tools confirmed the seeding of ultra-fine CuNCs onto HNT surfaces. The maximum adsorption capacity of CuNCs@HNT is 79.14 ± 6.99 mg/g at pH 5 ± 0.1 with an increment at lower pHs. This performance was comparable for real surface stream water as well as other reported materials. The pseudo-second-order kinetic-, intra-particle diffusion- and Freundlich isotherm models well fit the experimental data implying that the chemisorption, multiphase diffusion and multi-molecular layer distribution occurred during adsorption. The Fourier-transform infrared and the x-ray photoelectron spectra also ensured the transformation of Cr(VI) to Cr(III) indicating the material's suitability for concurrent adsorption and reduction of Cr(VI). While coexisting cations and anions did not overwhelm this adsorption, CuNCs@HNT was regenerated and reused five successive times in adsorption-desorption cycles without significant loss of adsorption capacity and material's integrity. Therefore, this multi-functional, biocompatible, low-cost and stable CuNCs@HNT composite may have practical application for similar toxic metals remediation.

Keywords: Adsorption; Chromium (VI); Copper-nanoclusters; CuNCs@HNT; Halloysite-nanotube; Regeneration-reuse.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adsorption
Chromium / analysis
Clay
Copper*
Hydrogen-Ion Concentration
Kinetics
Water Pollutants, Chemical* / analysis

Substances

Water Pollutants, Chemical
Chromium
chromium hexavalent ion
Copper
Clay