Venegas-García, Deysi J.Steiger, BerndWilson, Lee2023-07-072023-07-072023Venegas-García, D., Steiger, B.G.K., Wilson, L.D. (2023). A pyridinium-modified chitosan-based adsorbent for arsenic removal via a coagulation-like methodology. RSC Sustainability. https://doi.org/10.1039/D3SU00130Jhttps://hdl.handle.net/10388/14792This article is licensed under a Creative Commons Attribution Non-Commercial 3.0 Unported Licence. © 2023 The Author(s).The goal of this study was to synthesize a chitosan-derived adsorbent that can be used in a coagulation– flocculation (CF) process for facile integration into existing water treatment processes. Therefore, an insoluble pyridinium-modified chitosan (Chi-Py) was prepared. Structural characterization was achieved with spectroscopy (FT-IR, 13C solids NMR, and X-ray photoelectron) methods and thermogravimetric analysis. Approximately 7% di-nitrobenzene and ca. 30% pyridinium moieties were incorporated into the chitosan framework via an adapted, moderate-temperature, Zincke reaction. The arsenic removal efficiency was evaluated by a coagulation-inspired methodology at pH 7.5, where the results were compared against CF systems such as pristine chitosan, FeCl3 and chitosan–FeCl3. The kinetic and van't Hoff thermodynamic parameters for arsenic removal were calculated. Arsenic adsorption was shown to be a spontaneous and exothermic process (ΔG = −4.7 kJ mol−1; ΔH = −75.6 kJ mol−1) with a 76% arsenic removal efficiency at 23 °C and 96% at 5 °C with a maximum effective adsorbent dosage of Chi- Py of 300 mg L−1. The adsorption process for Chi-Py followed pseudo-first order kinetics, where the pyridinium-modified chitosan adsorbent can be successfully employed similar to coagulant-like systems in conventional water treatment processes. In contrast to conventional adsorbents (1–2 g L−1), a dosage of only 300 mg L−1 was required for Chi-Py that offers greater sustainability and recycling of materials. This is contrasted with single-use conventional coagulants such as FeCl3 or binary FeCl3–chitosan CF systems.enAttribution-NonCommercial 2.5 Canadaarsenic removalchitosan-derived adsorbent synthesiscoagulation-flocculationwater treatment processadsorptionArticle10.1039/D3SU00130J