Removal of chloride ion from drinking water using Ag NPs-Modified bentonite: Characterization and optimization of effective parameters by response surface methodology-central composite design

• Published in: Environmental research Vol. 223; p. 115484
• Main Authors: Moradi, Hamidreza, Sabbaghi, Samad, Mirbagheri, Naghmeh Sadat, Chen, Pu, Rasouli, Kamal, Kamyab, Hesam, Chelliapan, Shreeshivadasan
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 15.04.2023
• Subjects: Adsorption; Adsorption process; Ag NPs-modified bentonite; Bentonite - chemistry; Chloride ion; Chlorides; Drinking Water; Ecosystem; Hydrogen-Ion Concentration; Kinetics; Na-bentonite; Spectroscopy, Fourier Transform Infrared; Thermodynamics; Water Pollutants, Chemical - chemistry; Drinking water; Na-bentonite; Adsorption process; Ag NPs-modified bentonite; Chloride ion
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2023.115484

The presence of chloride ion as an environmental pollutant is having a devastating and irreversible effect on aquatic and terrestrial ecosystems. To ensure safe and clean drinking water, it is vital to remove this substance using non-toxic and eco-friendly methods. This study presents a novel and highly efficient Ag NPs-modified bentonite adsorbent for removing chloride ion, a common environmental pollutant, from drinking water using a facile approach. The surface chemical properties and morphology of the pristine Na-bentonite and Ag NPs-Modified bentonite were characterized by field emission scanning electron microscopy (FESEM) and X-ray spectroscopy (EDX), X-Ray diffraction (XRD), Fourier transform infrared (FTIR), and zeta potential (ζ). To achieve maximum chloride ion removal, the effects of experimental parameters, including adsorbent dosage (1–9 g/L), chloride ion concentration (100–900 mg/L), and reaction time (5–25 h), were examined using the Response Surface Methodology (RSM). The chloride ion removal of 90% was obtained at optimum conditions (adsorbent dosage: 7 g/L, chloride ion concentration: 500 mg/L, and reaction time: 20 h). The adsorption isotherm and kinetics results indicated that the Langmuir isotherm model and pseudo-second-order kinetics were found suitable to chloride ion removal. Additionally, the regeneration and reusability of the Ag NPs-modified bentonite were further studied. In the regeneration and reusability study, the Ag NPs-modified bentonite has shown consistently ≥90% and ≥87% chloride ion removal even up to 2 repeated cycles, separately. Thus, the findings in this study provided convincing evidence for using Ag-NPs modified bentonite as a high-efficiency and promising adsorbent to remove chloride ion from drinking water. •The chloride ion was removed from drinking water using Ag NPs-modified bentonite.•The morphology and characterization of the adsorbent were investigated.•The effect of different parameters was studied using design expert software.•A considerably high maximum adsorption capacity of 107.64 mg/g was acquired.•The Langmuir isotherm and pseudo-second-order kinetics fitted to experimental data.