This study aims to report Batch adsorption study of hexavalent chromium, Cr (VI) on zeoliteNaX.Kinetics of Cr (VI) adsorption and adsorption isotherms were determined by varying operating parameters such as pH, initial concentration, temperature and contact time. ZeoliteNaX was found to remove Cr (VI) in acidic solutions down to ppm level at pH of about 4. Removal rate of Cr (VI) was found to decrease as pH rises above 4.0. Langmuir, Freundlich, Temkin and Redlich-Peterson models were applied to adsorption equilibrium data to find the best amongst these models. Langmuir model with R 2 = 0.9711 best fits the adsorption data. The kinetics of adsorption was found to follow the first order reversible reaction. The separation parameter, R L values of less than 1.0 i.e., 0.7369, 0.5834 and 0.4828 corresponding to initial concentrations of 10, 20 and 30 mg/L, respectively indicated that adsorption of Cr (VI) on zeoliteNaX is favoured. The estimated values of thermodynamic parameters such as heat of adsorption and standard gibbs free energy confirmed the exothermic nature of adsorption of Cr (VI) on zeoliteNaX.

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Here, we describe the synthesis of 2–3 nm, hydrophilic, blue fluorescence-emitting carbon dots (C-Dots, made using a DNA precursor) by the hydrothermal route from the gelling concentration of 2% (w/v) DNA.

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We have investigated the phonon spectra of pulsed laser deposited Sr2CoO4 thin film and its evolution with temperature using Raman spectroscopy. The magnetic measurement reveals magnetic transition at temperature TC = 255 K. No structural phase transition is observed in the investigated temperature range (100-300 K). Close correlation between the frequency shift and the magnetization across TC establishes that the anomaly in the vicinity of TC is owing to spin-phonon coupling in the material. Using two different approaches, we have calculated spin-phonon coupling strength to be in the range of 2-3.5 cm−1.