Synthesised and modified zeolite for effective management of beryllium contaminants in aqueous media under different conditions

Md Rashidul Islam; Peter Sanderson; Timothy E Payne; Ravi Naidu

doi:10.1016/j.scitotenv.2023.166384

Synthesised and modified zeolite for effective management of beryllium contaminants in aqueous media under different conditions

Sci Total Environ. 2023 Dec 15:904:166384. doi: 10.1016/j.scitotenv.2023.166384. Epub 2023 Aug 17.

Authors

Md Rashidul Islam¹, Peter Sanderson², Timothy E Payne³, Ravi Naidu⁴

Affiliations

¹ Global Centre for Environmental Remediation (GCER), College of Engineering, Science and Environment, The University of Newcastle, University Drive, Callaghan Campus, NSW 2308, Australia; crc for Contamination Assessment and Remediation of the Environment (crcCARE), The University of Newcastle, University Drive, Callaghan Campus, NSW 2308, Australia. Electronic address: md.rashidul.islam@newcastle.edu.au.
² Global Centre for Environmental Remediation (GCER), College of Engineering, Science and Environment, The University of Newcastle, University Drive, Callaghan Campus, NSW 2308, Australia; crc for Contamination Assessment and Remediation of the Environment (crcCARE), The University of Newcastle, University Drive, Callaghan Campus, NSW 2308, Australia.
³ Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia.
⁴ Global Centre for Environmental Remediation (GCER), College of Engineering, Science and Environment, The University of Newcastle, University Drive, Callaghan Campus, NSW 2308, Australia; crc for Contamination Assessment and Remediation of the Environment (crcCARE), The University of Newcastle, University Drive, Callaghan Campus, NSW 2308, Australia. Electronic address: ravi.naidu@newcastle.edu.au.

PMID: 37597559
DOI: 10.1016/j.scitotenv.2023.166384

Abstract

The effective management of beryllium (Be) in solution is not well established. In this study, zeolite was synthesised from coal fly ash (CFA) and further modified to enhance Be sorption. Results indicated zeolite NaP1 was effectively synthesised, and cross-linked chitosan was grafted in/on the zeolite structure during modification. The Brunauer, Emmett, and Teller (BET) surface area substantially increased from 1.05 m²/g in CFA to 94.0 m²/g in the synthesised zeolite (SZ). Furthermore, the modified zeolite (MZ) showed improved functionality as a reactive site for Be sorption. A comparative sorption study revealed inferior sorption (11.3 %) and higher desorption (56.1 %) of Be using CFA than the sorption using SZ (93.0 % sorption, 2.9 % desorption) and MZ (93.0 % sorption, 1.5 % desorption). Consequently, SZ and MZ exhibited higher sorption efficacy than commercial zeolite (57.4 %) and other commercial sorbents. At an experimental pH of 5.5 [relevant to the pH of Little Forest Legacy Waste Site (LFLS) soil, a representative site for potential Be contamination], MZ showed higher sorption than SZ. The higher sorption in MZ resulted from its elevated ligand complexation [with nitrogen (N), phosphorous (P), and oxygen (O)] and some ion exchange (with Na⁺, -NH₃⁺, and H⁺ ions) mechanisms. Moreover, increased sorption (up to 99 %) was observed using colloidal soil solution (CSS) collected from LFLS soil to simulate field conditions after extensive rainfall. Different environmental factors (e.g. pH, temperature, time, CSS, concentrations of sorbate, and sorbent) regulated Be sorption. The sorption mechanism was best described by the Langmuir model, and the pseudo-second-order kinetic model (R² = 0.999). Moreover, the sorption reaction was spontaneous (ΔG = -Ve), enthalpically, and entropically influenced. Desorption hysteresis (n_desorption/n_sorption < 1) suggested irreversible sorption, and the chemisorption mechanism of Be was confirmed by Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis.

Keywords: Beryllium; Modification; Remediation; Sorption-desorption; Synthesised zeolite.