2024-02-162024-02-162014-07Kara, A. vd. (2014). "Kinetic, isothermal, and thermodynamic studies of Cr(VI) adsorption on L-tryptophan-containing microspheres". Environmental Engineering Science, 31(6), 261-271.1092-8758https://www.liebertpub.com/doi/full/10.1089/ees.2013.0413https://hdl.handle.net/11452/39811Poly(ethylene glycol dimethacrylate-N-methacryloyl-(L)-tryptophan) [poly(EGDMA-MATrp)] microspheres containing L-tryptophan (average diameter = 106-300 mu m) were synthesized and characterized; their use as adsorbents in removal of Cr(VI) from aqueous solutions was investigated. The poly(EGDMA-MATRP) microspheres were prepared by copolymerizing of ethylene glycol dimethacrylate (EGDMA) with N-methacryloyl-( L)-tryptophan methyl ester (MATrp). The poly(EGDMA-MATrp) microspheres were characterized by N-2 adsorption-desorption isotherms, elemental analysis, scanning electron microscope, and swelling studies. At fixed solid/solution ratio, various factors affecting the adsorption of Cr(VI) ions from aqueous solutions, such as pH, initial concentration, contact time, and temperature, were analyzed. Cr(VI) adsroption kinetic data followed pseudo-second-order kinetics. Experimental isotherms of Cr(VI) ions were successfully fit to both the Langmuir and the Dubinin-Radushkevich isotherm models. Thermodynamic aspects of the adsorption process, such as Gibbs free energy, enthalpy, and entropy changes, were investigated.eninfo:eu-repo/semantics/closedAccessAdsorption isothermAdsorption kineticAdsorption thermodynamicCr(vi) ionsL-tryptophan microspheresEnvironmental sciences & ecologyChromium(vi) ionsEngineeringActivated carbonChitosanAqueous-solutionAcidRemovalCu(ii)EquilibriumHg(ii)BiosorptionArticle0003379110000012-s2.0-84904182698261271316Engineering, environmentalEnvironmental sciencesAqueous Solution; Biosorbents; Second-Order ModelAdsorptionAdsorption kineticsAqueous solutionArticleConcentration (parameters)Controlled studyDesorptionDiffusionEnthalpyEntropyEquilibrium constantIsothermNuclear magnetic resonance spectroscopyPhPolymerizationProton transportRoom temperatureScanning electron microscopyTemperature dependenceChromiumEthylene glycol dimethacrylateMicrosphereTryptophan derivative1557-9018https://doi.org/10.1089/ees.2013.0413