Removal of basic blue 3 and basic yellow 51 dyes from aqueous solutions using synthesis of magnetic-dehydrated tea pulp

In this thesis study, the removal of C.I. Basic Blue 3 (BB3) and C.I. Basic Yellow 51 (BY51) dyes, which are frequently encountered in textile industry wastewaters, was investigated using magnetic dehydrated tea pulp (Fe3O4-DHÇP). The effects on the removal of dyes, initial dye solution pH, initial dye concentration, adsorbent concentration and temperature, of adsorption yield and capacity, were examined in a batch system. In the adsorption of BB3 and BY51 dyes onto Fe3O4-DHÇP sorbents, the optimum pH value was determined as 10.0. Optimum temperature is 20 ºC. The removal percentage of BB3 and BY51 dyes were reduced by increasing the of the dye concentration and increased by increasing the adsorbent concentrations. The kinetic constants were evaluated by applying different kinetic models to experimental data in order to investigate the adsorption mechanism. It was determined that the adsorption data showed on excellent description to the pseduo-second-order model. The results of the experiments carried out at various fixed temperatures (20, 30, 40 and 50 ºC) the Langmuir, Freundlich and Redlich-Peterson adsorption isotherm models were applied to each dye-sorbent system in order to define the adsorption equilibrium data mathematically. The model constants were determined and it was determined that the adsorption equilibrium data showed on description to the Redlich-Peterson isotherm model. In the study enthalpy changes (∆Hº) for adsorption processes of BB3 and BY51 dyes were calculated as 24.59 and 22.47 kJ/mol, respectively. The enthalpy changes of process for are positive a with that the adsorption process of BB3 and BY51 dyes by Fe3O4-DHÇP is endothermic. The free energy changes related to the BB3 and BY51 dyes adsorption by Fe3O4-DHÇP have negative sign and the absolute values of them increased with increasing the temperature of the solutions.