ABSTRACT
Ionic solid (Ethylhexadecyldimethylammoniumbromide) impregnated phosphated chitosan (ISPC) was synthesized and applied for enhanced adsorption of hexavalent chromium from industrial effluent. The compound obtained was extensively characterized using instrumental techniques like FT-IR, TGA-DTA, XRD, SEM, BET and EDX. ISPC showed high adsorption capacity of 266.67mg/g in accordance with Langmuir isotherm model at pH 3.0 due to the presence of multiple sites which contribute for ion pair and electrostatic interactions with Cr(VI) species. The sorption kinetics and thermodynamic studies revealed that adsorption of Cr(VI) followed pseudo-second-order kinetics with exothermic and spontaneous behaviour. Applicability of ISPC for higher sample volumes was discerned through column studies. The real chrome plating industry effluent was effectively treated with total chromium recovery of 94%. The used ISPC was regenerated simply by dilute ammonium hydroxide treatment and tested for ten adsorption-desorption cycles with marginal decrease in adsorption efficiency.
Subject(s)
Chitosan/chemistry , Chromium/isolation & purification , Wastewater/chemistry , Water Pollutants, Chemical/isolation & purification , Water Purification/methods , Adsorption , Chromium/chemistry , Hydrogen-Ion Concentration , Kinetics , Spectroscopy, Fourier Transform Infrared , Thermodynamics , Water Pollutants, Chemical/chemistryABSTRACT
Aliquat-336 (an ionic liquid) impregnated sulphate-crosslinked chitosan (SCC) was prepared for escalating the adsorption of hexavalent chromium through concurrent interaction. The compound obtained was intensively characterized using Fourier transform infra red (FT-IR), X-ray diffraction (XRD), Scanning electron microscopic (SEM) and Energy dispersive X-ray (EDX) studies. Various isotherm studies have been carried out to understand the adsorption mechanism. Quantitative adsorption of Cr(VI) was observed at pH 3.0 with adsorption capacity of 250.90 mg g(-1) in accordance with Langmuir isotherm. The adsorption of Cr(VI) followed pseudo-second-order kinetics. The adsorption efficiency was found to decrease with increase in temperature due to increased randomness at interaction sites. The adsorption process was found to be exothermic and spontaneous in nature. Column studies were carried out to understand the applicability of the material for higher sample volumes. The adsorbent could be regenerated using sodium hydroxide treatment and the regenerated adsorbent had same efficiency towards adsorption of Cr(VI) as that of the original.
