Kinetic study of self-assembly of Ni(ii)-doped TiO₂ nanocatalysts for the photodegradation of azo pollutants

Abstract

Ni(ii)-doped TiO2 nanoparticles were fabricated by a simple and reliable hydrothermal method.

Broadband Photocatalytic Activity of Mesoporous Cd(II)‐Doped TiO2

“…[8,29] Furthermore, Table 2 summarizes the kinetic parameters of photocatalytic process expressed by three foremost kinetic models, as mentioned in the Experimental section. [30] Clearly, the first-order and Langumuir-Hinshelwood kinetic models are not in good agreement with the experimental data. The second-order kinetic model, however, reaching the higher correlation coefficient (R 2 ) at each dye concentration tested here, gives rise to a satisfactory expression in terms of photocatalytic degradationion of RB5 and 3R dyes with Cd(II)doped TiO 2 .…”

“…Furthermore, Table summarizes the kinetic parameters of photocatalytic process expressed by three foremost kinetic models, as mentioned in the Experimental section . Clearly, the first‐order and Langumuir‐Hinshelwood kinetic models are not in good agreement with the experimental data.…”

“…Considering the zero point charge in anatase TiO 2 at pH∼7.0, the surfaces of TiO 2 turn to be positively charged in acidic solutions, and negatively charged in alkaline solutions. In fact, both RB5 and 3R dyes possess the anionic groups with negative surface charges [Figure ]; thus, the TiO 2 ‐based photocatalysts involved in the acidic solutions energetically favor the adsorption of the dyes onto the surfaces of TiO 2 nanoparticles, leaving a substantially active sites for the efficient photo‐degradation of azo dyes ,…”

Kinetic Model for Simultaneous Adsorption/Photodegradation Process of Alizarin Red S in Water Solution by Nano-TiO2 under Visible Light

“…From this consideration, the transformation of ARS to adsorbed ARS (ARSTiO2) and to photodegradated products (ARSPH) could be treated in terms of two consecutive processes. The first is represented by The obtained results do not show immediate evidence in the calculation of kinetic constants because two different processes occur at the same time and correlation is never possible by using first order, second order or Langmuir-Hinshelwood kinetic models [23][24][25][26]. It is important to note that, in these simultaneous processes, obtained without a previous adsorption-desorption equilibrium in dark conditions, knowledge of the kinetic parameters of separated processes is necessary.…”

“…The second process is represented by photodegradation of ARS, process that occurs with a rate described by the first order kinetic constant k 2 expressed by the equation ln pC{C 0 q ¡k 2 t [22,23] where C 0 is the initial concentration of ARS and C the concentration of dye at t time.…”