Zirconium cross-linked chitosan composite: Preparation, characterization and application in adsorption of Cr(VI)

In the present paper, a zirconium-chitosan (Zr-CTS) composite is reported for adsorption of Cr(VI). The Zr-CTS composite was synthesized through the coordination reaction between zirconium oxychloride and chitosan biopolymeric matrix. Then the prepared composite was characterized by FT-IR, XRD, SEM and EDS. The adsorption properties of the resulting composite toward Cr(VI) were systematically investigated. Various factors possibly affecting the adsorption behavior were also studied. The results demonstrated that the equilibrium adsorption behavior of Cr(VI) on the prepared Zr-CTS composite had a good agreement with the Langmuir isotherm model (R2 = 0.9993), and the maximum adsorption capacity was calculated as 175 mg g−1 for Cr(VI) with pH 5.0 at 30 °C. The thermodynamic results revealed that chromium adsorption was a spontaneous and endothermic process. Furthermore, co-existing ions including nitrate, chloride and sulfate had effects on the uptake of Cr(VI) on the Zr-CTS composite. The Cr(VI) adsorbed Zr-CTS composite was regenerated with an efficiency of greater than 91% using 0.05 mol L−1 sodium hydroxide.