Application of water hyacinth as a benign solid phase extractor for selective removal of cr(VI) from natural water samples: Equilibrium, isotherm and kinetics studies

Abstract

Stem of Water Hyacinth (SWH) is a low-cost, friendly solid phase extractor was used to remove Cr(VI) from natural water samples. For obtaining its maximum removal, batch experiments were carried out at different parameters including hydrogen ion concentration, initial Cr(VI) concentrations, mass of the adsorbent and equilibration times. The FT-IR spectra of SWH before and after uptake of Cr(VI) were recorded to explore the nature of the functional groups responsible for its binding onto the adsorbent. Surface morphology was also explored in parallel, using Scanning Electron Microscope (SEM). The equilibrium characteristics of Cr(VI) adsorption was described and data well fitted by Langmuir isotherms with maximum uptake capacity (4.599 mg g-1). The Cr(VI) adsorption was fast and completed within 7.5 min and the kinetics data was best fitted with the pseudo-second order type. Finally, Cr(VI) spiked natural water samples such as Doubly Distilled Water (DDW), Drinking Surface Water (DSW), Drinking Ground Water (DGW) were quantitatively recovered (>98.0%) using batch experiments.