Influence of the Textural Parameters of LDH-TiO₂ Composites on Phenol Adsorption and Photodegradation Capacities

Abstract

Layered double hydroxides (LDH) M2+M3+CO32− were synthesized following the sol-gel methodology using Mg-Al, Mg-Fe, and Zn-Al as cation pairs for subsequent use in the preparation of TiO2/LDH materials. The samples were characterized by infrared spectroscopy (IR), scanning electron microscopy (SEM), and the Brunauer–Emmett–Teller (BET) technique to determine the surface area (SA); the results of which were used to determine the roughness of the samples in terms of surface fractal dimension (D). The prepared materials exhibited both adsorption and photocatalytic properties in the removal of phenol in aqueous solution under ultraviolet irradiation. This work studies the relationship between the textural parameters of the materials obtained in relation to their photocatalytic efficiency and adsorption capacity, finding that the surface of the solids, their structural heterogeneity, and roughness condition the photodegradation and adsorption processes, using phenol as reference organic pollutant. The results show that different cation in LDH influences in photocatalytic capacity; the TiO2/ZnAl was the best material in one test, but after 10 times of test, the TiO2/MgFe gave the better photodegradation material. In adsorption capacity, TiO2/ZnAl and TiO2/MgFe have a close rate for phenol adsorption and both were better than TiO2/MgAl. The differences in textural characteristics (surface area, surface roughness, and pore-size distribution) affected phenol adsorption and photodegradation efficiency.

Modification of pristine layered double hydroxide to form metal oxide composites as an anionic dye photodegradation catalysts

“…TiO2 material has a relatively low energy band gap of around 3.22. Similarly, the band gap energy of ZnO is only 3.21 eV; while ZnS is 3.54 eV [18,19]. Meanwhile, the band gap energy of NiO is higher around 3.6 -4 eV [20].…”

Improvement of Congo Red Photodegradation Performance Through Zn/Al-TiO2 and Zn/Al-ZnO Preparation

“…Negatively charged anions can be intercalated between the structure of the cation layer. LDH materials can be prepared by varying the content of cation elements to produce di erent physical and chemical properties as needed (Li et al, 2020;Contreras-Ruiz et al, 2019).…”

“…LDH composited with TiO 2 or ZnO has advantages. LDH is a dispersant for TiO 2 owing to the surface hydroxyl group, thereby simultaneously generating and enhancing photocatalytic properties (Contreras-Ruiz et al, 2019) . Meanwhile, ZnO is often considered an alternative to TiO 2 because it can absorb a wider spectrum of energy than TiO 2 (Amor et al, 2018) .…”

Photocatalytic Degradation of Malachite Green by NiAl-LDH Intercalated Polyoxometalate Compound

“…Pseudo-first-order kinetics model allowed that reaction rate (r) is comparable to the catalyst's surface covered with pollutants when the pollutant solutions are not concentrated. Therefore, because the kap rate constant is proportional to the reaction rate (r), the higher the kap value indicates, the more efficient the degradation [37]. The comparison shows that all composite kap values in this study are higher or better than all other research results.…”