Hexavalent chromium removal from aqueous solutions by a novel powder prepared from Colocasia esculenta leaves

• Published in: International journal of phytoremediation Vol. 18; no. 8; pp. 812 - 821
• Main Authors: Nakkeeran, E, N. Saranya, M.S. Giri Nandagopal, A. Santhiagu, N. Selvaraju
• Format: Journal Article
• Language: English
• Published: United States Taylor & Francis 02-08-2016; Taylor & Francis Ltd
• Subjects: Absorption, Physicochemical; Adsorbents; Adsorption; agitation; Aqueous solutions; Bioremediation; biosorbents; biosorption; Carcinogens, Environmental - isolation & purification; Chromium; Chromium - isolation & purification; Colocasia; Colocasia esculenta; energy-dispersive X-ray analysis; Flowers & plants; Fourier transform infrared spectroscopy; Fourier transforms; FTIR; Hexavalent chromium; Isotherms; leaves; Mathematical models; phytoremediation; Plant Leaves; Powders; scanning electron microscopy; Solutions; sorption isotherms; temperature; thermodynamic parameters; Thermodynamics; Water Purification - methods; Colocasia esculenta; isotherms; hexavalent chromium; biosorption; FTIR; thermodynamic parameters
• ISSN: 1549-7879; 1522-6514; 1549-7879
• DOI: 10.1080/15226514.2016.1146229

In this study, batch removal of hexavalent chromium from aqueous solutions by powdered Colocasia esculenta leaves was investigated. Batch experiments were conducted to study the effects of adsorption of Cr(VI) at different pH values, initial concentrations, agitation speeds, temperatures, and contact times. The biosorbent was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier transform infrared spectrometer analysis. The biosorptive capacity of the adsorbent was dependent on the pH of the chromium solution in which maximum removal was observed at pH 2. The adsorption equilibrium data were evaluated for various adsorption isotherm models, kinetic models, and thermodynamics. The equilibrium data fitted well with Freundlich and Halsey models. The adsorption capacity calculated was 47.62 mg/g at pH 2. The adsorption kinetic data were best described by pseudo-second-order kinetic model. Thus, Colocasia esculenta leaves can be considered as one of the efficient and cheap biosorbents for hexavalent chromium removal from aqueous solutions.