Mitigation of Cr (VI) from aqueous solution using jute charcoal iron composite (JC-FeCs): Response surface methodology (RSM)

Abstract

In this study potential adsorbent jute charcoal iron composite (JC-FeCs) was synthesized via co precipitation of iron composite on jute charcoal and utilized it for Cr (VI) removal from water. The surface morphology of composite were performed with advance techniques such as BET, FESEM, EDX, FTIR, XPS, AFM and HR-TEM to analyzed the surface functional groups and elements on the prepared composite. The influence of pH, JC-FeCs dose, time, and concentration on % removal of Cr (VI) were examined. Noteworthy, the JC-FeCs reveals excellent removal capacity of Cr (VI) (Qmax 92.33 mg/g) at 303K which is much better than those adsorbent reported in the literature. XPS analysis of adsorbent shows the existence of both Cr (VI) and Cr (III) peaks on JC-FeCs surface, which implied that Cr (VI) adsorption occurs on composite. Herein Cr (VI) was first adsorbed on JC-FeCs via electrostatic force of attraction, later it was partially reduced to Cr (III). Non-linear isotherm study suggests monolayer adsorption occurs on homogenous surface of JC-FeCs adsorbent due to greater value of R2 than other isotherm. Kinetic studies suggest that adsorption followed pseudo second order model with greater R2 value. Thermodynamic study indicate endothermic, spontaneous and physisorption adsorption process. The predicted result of Cr (VI) removal obtains from RSM model and the observed % removal were found close to each other indicate that quadratic model best explain the adsorption process. Desorption study shows the good regeneration ability of adsorbent in alkaline medium. Thus, this bio-composite could work as an effective adsorbent for mitigation of Cr (VI) from water in environmental pollution cleanup.