Ertugay, Nese; Acar, Filiz Nuran

The sono, photo, and sonophotocatalytic degradations of Direct Blue 71 (DB71) in the presence heterogeneous TiO2 catalyst were studied at 20 kHz using ultrasonic (US) power of 95 W and aqueous temperature of 20°C for 20 min. The effects of various operational parameters such as the concentration of the dye, pH, and amounts of catalysts on the sonochemical degradation were also investigated. Sonochemical degradation of DB71 was strongly affected by initial substrate concentration, amounts of catalysts, and pH. Acidic pH was favored for the sonocatalytic degradation of DB71 using catalysts. The hybrid technique of sonocatalytic degradation was compared with the individual techniques of catalysis, sonolysis, and photocatalysis. The US degradation of dye was enhanced by catalyst addition. The structure and morphology of the catalyst were investigated using scanning electron microscopy and X-ray diffraction pattern.

Ertugay, Nese

In this work, the adsorption potential of sawdust of Swietenia mahagoni to remove Basic Violet 10 (BV10) from aqueous solutions was investigated by batch adsorption system. The adsorbent was characterized by Fourier transform infrared spectrophotometer, scanning electron microscope, particle size distribution, and Brunauer, Emmett, and Teller methods. The effect of various experimental parameters such as pH, initial dye concentration, adsorbent concentration, and temperature on adsorption of BV10 was investigated. The optimum pH for BV10 adsorption was found to be 4.2. Equilibrium adsorption data were analyzed by the Langmuir, Freundlich, Temkin, and Scatchard isotherm models. The results show that the best fit was achieved with the Langmuir isotherm with a maximum adsorption capacity of 222.76 mg g−1 at 50°C. Pseudo-first-order, pseudo-second-order, intraparticle diffusion, and Elovich models were used to analyze the kinetic data obtained at different BV10 concentrations. The adsorption kinetic data were well described by the pseudo-second-order model. The calculated thermodynamic parameters, namely ∆G°, ∆H°, and ∆S°, showed that adsorption of BV10 was spontaneous and endothermic under examined conditions.