Chloroacetyl‐Mediated Modification of Chitosan by Tannic Acid to Synthesize Economical Tanninate‐Chitosan and Its Use in Fluoride Ions Adsorption from Aqueous Solution

Abstract

The multi‐functional, green and environmental acceptable adsorbents were synthesized from activated chitosan for fluoride ions via mild‐strategies. Chloroacetylation reaction was performed to integrate an active group to the chitosan structural unit. Subsequently, the integrated active group was derivatized with tannin acid, an environmental‐friendly natural polyphenol via a simple reaction. The synthesized products were evaluated for their structures via FTIR, 1H‐NMR, UV, SEM‐EDS, elemental mapping, BET surface analysis, and XPS. The capability of the synthesized green products was appraised for fluoride ions sorption in circumneutral conditions. The results confirmed the maximum sorption capability of ≥97 % even at trace level and also proved remarkable results in competition with competitive ions. The equilibrium sorption data supported the maximum adsorption capacity of 28.57 mg g−1 by the Langmuir model within 60 min at pH 7.0, which is nearly analogous to the experimental data of 22.02 mg g−1 at 10 ppm. Therefore, in conclusion, the proposed green adsorbent is economical, and is even appropriate at almost neutral pH, which designates its applicability for treating drinking water.

Selectivity enhancement of oxidative degraded reverse osmosis membrane by chitosan–tannic acid treatment

“…The band appeared at 564, 711, and 1174 cm −1 corresponds to out‐of‐plane CN bending, out‐of‐plane bending NH, CNC stretching, and so forth. The significant peak noticed at 1586 cm −1 ascribed the bonding vibration of NH in amide II 42,43 . The split peaks at 1645 and 1617 cm −1 represented the CN stretching of acetyl group of amide I ‐‐ 36,44 .…”

“…The significant peak noticed at 1586 cm À1 ascribed the bonding vibration of N H in amide II. 42,43 The split peaks at 1645 and 1617 cm À1 represented the C N stretching of acetyl group of amide I --. 36,44 Disappearance of peak in modified membrane 1645 cm À1 , which is appearing in virgin membrane indicated that C N was used form the bridge with chitosan tannic acid assembly.…”

Natural polyphenol tannin-immobilized composites: rational design and versatile applications

“…Very recently, the Chauhan group 61 developed a method for the fabrication of a tannate–chitosan composite via a chloroacetylation reaction (Fig. 4(b)).…”

“…117 Moreover, tannin-immobilized composites were used to remediate other contaminants. Sen and co-authors 61 synthesized a tanninate-chitosan composite for the adsorption of fluoride ions from an aqueous solution, which showed a maximum adsorption capacity of 28.57 mg g À1 . Tanninimmobilized composites were used as potential adsorbents for removing methylene blue (MB), 84,215,223 Congo Red, 314 methyl orange, and rhodamine B 148 dyes.…”

Disposable Waste Aluminium Pan Derived Pseudoboehmite Nanoparticles for Concurrent Removal of Fluoride and Arsenate from Aqueous Medium

“…Both fluoride and arsenic are naturally occurring elements that can be found in groundwater due to geological processes or human activities. So far, millions people in many countries including India, China, USA, Pakistan and Bangladesh have been severely affected by presence of fluoride and arsenate in high concentrations in drinking water [7–12] . The concentration of As(V) and F − in groundwater in some regions far exceed the maximum concentration limits set by the World Health Organization (WHO), indicating the severity of the problem.…”