Factors influencing the adsorption and photocatalysis of direct red 80 in the presence of a TiO₂: Equilibrium and kinetics modeling

Among the different photocatalysts, TiO 2 ( E g = 3.1 eV, zero charge point (pHpzc 6.3), and surface 55 m /g) is currently most efficient studied semiconductor due to its strong photocatalytic activity, non-toxicity, chemical stability. The elimination of DR-80 on by adsorption in batch mode application heterogeneous photocatalysis onto under UV irradiation. effects contact time (0–60 min), initial pH (3–11), dose adsorbent (0.5–3 L ?1 ), concentration (40–60 mg ) are for optimization these parameters. kinetic parameters, rate constants, equilibrium capacities calculated discussed each applied theoretical model. well described pseudo-first-order fitting isotherms shows that models Langmuir Temkin offering a better fit an 64.102 mg/g at 25 °C eliminated. results showed efficiency strongly depends while photodegradation proportional catalyst dose, becomes almost constant above threshold value. It was found favored low concentrations accordance with Langmuir–Hinshelwood model constants K ad 6.5274 L/mg L–H 0.17818 min. However, improved high concentrations. degradation both temperature temperature. photocatalyst has activity DR-80, compared some commercial catalysts have been literature.