Performance of oxalic acid-chitosan/alumina ceramic biocomposite for the adsorption of a reactive anionic azo dye

PÉREZ-CALDERÓN, JOHN; SCIAN, ALBERTO; DUCOS, MARTIN; SANTOS, VICTORIA; ZARITZKY, NOEMÍ

ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH

SPRINGER HEIDELBERG

Año: 2021

0944-1344

A biocomposite system was developed and tested for the removal of the azo dye Reactive Red (RR195) from wastewater. Thebiocomposite was synthesized using ceramic particles containing 75% alumina which were coated using chitosan cross-linkedwith oxalic acid. The biocomposite showed high performance at low pH (maximum adsorption capacity = 345.3mg.g−1 atpH=2.0). The physicochemical and structure characteristics of the matrix were evaluated by Z-potential, FTIR-ATR, SEMEDS,XRD, and porosity. Langmuir sorption isotherm and pseudosecond-order model gave the best fit. The electrostaticinteraction between RR195 (due to the sulfonate groups) and the free amino groups of chitosan, enabled successivedesorption/regeneration cycles. The maximum removal percentage (>80%) occurred at pH=2.0 due to the cross-linking effect.Experiments at different temperatures allowed the calculation of thermodynamic parameters (ΔG, ΔS, ΔH); adsorption wasspontaneous, exothermic, and enthalpy controlled. The presence of inorganic ions (SO2−4 > NO−3 > Cl− ) was analyzed duringthe adsorption process. This novel biocomposite can be applied as a cost-effective and environmentally friendly adsorbent foranionic azo dye removal from wastewater. The application of chitosan cross-linked with oxalic acid as a coating of the ceramicsupport enhanced the adsorption capacity and enabled its use under acidic conditions without solubilization.