Adsorption of cationic and anionic organic dyes from aqueous solution using silica.
The adsorption of cationic crystal violet (CV) and anionic indigo carmine (IC) has been studied on silica to identify the soil polluting nature of organic dyes. The adsorption parameters like contact time, concentration, temperature and adsorbent dosage were optimized for maximum adsorption. The adsorptions of CV and IC on silica followed Freundlich and Langmuir adsorption isotherm and pseudo second order kinetics. The deltaS degrees, deltaH degrees and deltaG degrees of adsorption on silica are calculated by using Vant Hoff's plot. The adsorption isotherms and thermodynamic studies proved that the CV was adsorbed more than IC on silica. The dyes recovery has been studied from dyes adsorbed silica in water. Very poor recovery of CV and high recovery of IC were observed. The adsorption mechanism, high adsorption and very poor recovery of CV on silica proved that the CV is polluting the soil more than IC. The poor adsorption and high recovery of IC on silica is a supportive evidence for very less soil polluting nature of the IC.
Department of Chemistry, Periyar University, Salem-636 011, TamilNadu, India.
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Buvaneswari
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Kannan
D000327:Adsorption; D004396:Coloring Agents / Q000737:chemistry*; D005840:Gentian Violet / Q000737:chemistry*; D007203:Indigo Carmine / Q000737:chemistry*; D007700:Kinetics; D012822:Silicon Dioxide / Q000737:chemistry*; D013816:Thermodynamics; D014865:Waste Disposal, Fluid / Q000379:methods; D018508:Water Purification / Q000379:methods*
D004396:Coloring Agents; D012822:Silicon Dioxide; D007203:Indigo Carmine; D005840:Gentian Violet