title: Removal kinetics and mechanism for crystal violet uptake by surfactant-modified alumina.
abstract: Sodium dodecyl sulfate (SDS), an anionic surfactant (AS) was used for the surface modification of neutral alumina. Micelle-like structures are formed on the surface of alumina, which was used for the removal of crystal violet (CV), a well-known cationic dye from aquatic environment. This process is called adsolubilization. The surfactant-modified alumina (SMA) was found to be very efficient showing >99% CV removal from a 200 ppm CV bearing solution with only 6 g/L of adsorbent dose. The kinetic studies showed that 60 minutes' shaking time was sufficient to achieve the equilibrium. The reaction kinetics data were analysed using four reaction kinetic models, viz., first-order reaction model, pseudo-first-order reaction model, second-order reaction model and pseudo-second-order reaction model, and it was found that the removal of CV followed the pseudo-second order reaction model. It was found that neither film diffusion nor pore diffusion was rate limiting for this process. Isotherm studies showed that Langmuir isotherm fitted more accurately compared to Freundlich isotherm. To test whether the removal of CV was possible from real water using SMA, the experiments were conducted using CV spiked distilled water and synthetic wastewater. It was interesting to note that the removal efficiency was better for wastewater as compared to that of distilled water.
authors.affiliation: Civil Engineering Group, Birla Institute of Technology and Science, Pilani, Rajasthan, India.
authors.forename: Asok
authors.initials: A
authors.lastname: Adak
authors.forename: Anjali
authors.initials: A
authors.lastname: Pal
mesh_terms: D000327:Adsorption; D000537:Aluminum Oxide / Q000737:chemistry*; D005840:Gentian Violet / Q000032:analysis / Q000737:chemistry*; D007220:Industrial Waste / Q000032:analysis; D007700:Kinetics; D008823:Micelles; D008956:Models, Chemical; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry*; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D007220:Industrial Waste; D008823:Micelles; D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical; D012967:Sodium Dodecyl Sulfate; D005840:Gentian Violet; D000537:Aluminum Oxide