Biosorbed Ferro Nano Particles as Potential Agents for the Removal of Synthetic Food Dyes in Effluents

Abstract

This thesis work focused on liquid phase adsorptive removal of synthetic food dyes viz. Allura Red and Tartrazine where they represent the class of an azo dyes. The goal of this research work was to prepare and optimize an activated carbon (AOSP, AMC and AWH) made from okra seed, mustard oil cake and water hyacinth.and biosorbed ferro nano-particles (FOSP, FMC and FWH) using activated carbon (AC) made-up from above mentioned different agricultural based materials. Biosorbed ferro nano-particles shows unique properties toward the adsorption process at the nanoscale and this is due to large specific surface area and presence of more active group on the surface. The effects of operating conditions on adsorption were also studied (contact time, initial concentration, rpm, particle size, adsorbent dosage, temperature, and pH). The characterization of all the adsorbents were carried out using advanced conventional techniques like FT-IR, UV-visible spectroscopy, XRD, FESEM, EDX, AFM, BET, DLS, Mossbauer spectroscopy, VSM, TGA, DSC, and XPS spectroscopy to analyze their crystallography, morphological, topological, and other physical properties. The optimum pH for removal of Allura Red and Tartrazine was around 2-5. Investigation on the role of adsorption behavior is successfully analyzed using Langmuir, Freundlich and Temkin isotherm models. The obtained results are well fitted in the linear forms of Langmuir and Temkin more than Freundlich adsorption isotherms for all the adsorbents. The kinetic and the mechanism study also discussed in detail by using pseudo first-order and pseudo second-order kinetic models. The adsorption kinetics data were best fitted with pseudo second-order kinetic type. Thermodynamic study also discussed in detail by using Gibbs free energy, enthalpy and entropy (and#916;So) parameters. The negative value of enthalpy changes (and#916;Ho) indicate that the adsorption process was exothermic in nature. The negative values of the entropy (and#916;So) indicate the decrease of randomness at the solid/liquid interface during the adsorption process. The desorption study was also investigated with four different desorbing solutions (methanol, ethanol, acetone, and tetrahydrofuran). The maximum recovery in percentage is achieved using tetrahydrofuran that is probably due to the higher solubility of Allura Red and Tartrazine in this media. newline