| Popis: |
High grade chitin extracted from Brachyura shell waste was successfully used for adsorptive de-colorization of highly turbid fishpond effluent. Brachyura shell chitin was characterized via Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC). Results obtained from the characterization indicated that the extracted chitin possessed significant features required for surface phenomenon driven matrices. The best efficiency obtained for turbidity and color removal were 88% and 91%, respectively, at BSC dosage of 1.8 g/L, pH of 6.0 and temperature of 45°C. The maximum adsorption capacity of the de-colorization process onto BSC was found to be 265.59 mg/g. Results from kinetic analysis suggested that pseudo-second order model was most accurate (R2 > 0.99) in predicting the experimental data. Webber-Morris intraparticle diffusion rate constant (Kipd) demonstrated that the adsorptive process depended more on film diffusion mechanism. Equilibrium study was carried out using Langmuir, Freundlich, Temkin, Dubinin Radushkevich and Brunauer-Emmett-Teller isotherm model at 30, 40 and 50°C. Fitness appraisal analysis of the isotherm models pointed out that experimental data aligned significantly with Langmuir and Temkin isotherm (R2 > 0.94), suggesting the homogenous and monolayer mode of the adsorptive process. Values of Gibbs free energy (− ΔG0= 1.7816 – 2.6706 kJ /mol), enthalpy (ΔH0= 11.6867kJ/ mol), activation energy (EA= 13.2330kJ/ mol) and entropy (ΔS0= 44.4511J / molK) obtained from thermodynamic analysis confirmed the spontaneous, endothermic, favorable and physical nature of the process. |
