Glutaraldehyde-cross-linked chitosan–alginate composite for organic dyes removal from aqueous solutions

• Published in: International journal of biological macromolecules Vol. 190; pp. 862 - 875
• Main Authors: Khapre, Maithili A., Pandey, Sadanand, Jugade, Ravin M.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.11.2021
• Subjects: Adsorption; Alginate; Alginates - chemistry; Azo Compounds - isolation & purification; Chitosan; Chitosan - chemistry; Coloring Agents - isolation & purification; Composite; Cross-linking; Cross-Linking Reagents - chemistry; Glutaral - chemistry; Hydrogen-Ion Concentration; Kinetics; Organic Chemicals - isolation & purification; Organic dyes; Solutions; Spectrometry, X-Ray Emission; Spectroscopy, Fourier Transform Infrared; Temperature; Thermogravimetry; Time Factors; Water Pollutants, Chemical - isolation & purification; X-Ray Diffraction; Alginate; Chitosan; Composite; Adsorption; Cross-linking; Organic dyes
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2021.09.026

We present an approach for synthesis of a micro-porous composite of two well-known biopolymers, namely chitosan and alginate, using glutaraldehyde as the cross-linking agent. Alginate and chitosan were pre-treated before being mixed, and the two biopolymers' proportions were also monitored. Chitosan was modified using aniline with the help of formaldehyde crosslinker and then the twizer was further crosslinked with alginate using glutaraldehyde. The synthesized composite, glutaraldehyde cross-linked chitosan–alginate composite [(Cs-F-An)-G-Al] was characterized using spectral techniques and employed as a potential adsorbent for three dyes namely Brilliant green, Methyl orange and Patent Blue V. The pHPZC of the material was 7.5 and the maximum monolayer adsorption capacity (Qmax) was found to be 235.82, 198.09 and 117.34 mg g−1 for BG (at pH 8.0), MO (at pH 6.0) and PBV (at pH 3.0) respectively. It was found that the adsorption process follows a Freundlich adsorption isotherm and pseudo second order kinetics. A thermodynamic study revealed that the process of adsorption was enthalpy-driven and spontaneous in nature. Interestingly, the values of the adsorption capacity obtained in column adsorption method are in close agreement with those obtained in batch adsorption experiments, which shows the potential of the synthesized composite for uptake of dyes. [Display omitted] •Novel chitosan-alginate composite with aniline molecular tweezer has been reported.•Composite was characterized and applied for removal of three cationic dyes.•Adsorption capacities for BG, MO and PBV are 235.82, 198.09 and 117.34 mg g−1 respectively.•Batch and column adsorption studies have been reported and showed excellent results.•Synthesize material has been showed better efficiency compared to other reported work.