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Abdolsamad Zarringhalam Moghaddam,Somayeh Alijani,Mohammad Vaez,Jafar Towfighi 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.10
TiO2 nanoparticles were synthesized by the P-25 powder modified sol-gel method under different TTIP (Titanium tetraisopropoxide) concentrations, P-25 loading and the gelation pHs. Structural properties of nanoparticles were characterized by XRD, FESEM and BET analysis. Results show that crystallinity level, particle size and the surface area are a function of P-25 loading and gelation pH, whereas TTIP concentration affects only the crystalline composition. Response surface methodology based on central composite design was used to optimize these synthesis parameters in photodegradation of Acid Red 73. The degradation efficiency was significantly affected by P-25 loading,pH value of gelation and the interaction effect between TTIP concentration and P-25 loading. The optimal values of parameters were found to be a pH of 1.34, a TTIP concentration of 0.25M and a P-25 loading of 39.76 g/L. At optimal synthesis conditions, TiO2 film was coated on alumina foam and its structural properties were characterized by XRD,SEM and BET technique. The photocatalytic activity of the as-prepared films was found to be higher than that of the films prepared by the sol-gel method and those made from the slurries of P-25. The reasonable photocatalytic performance and good stability offered by the optimized film make it as an effective alternative for large application of water treatment.
Parham Haghighi,Amin Bazyari,Somayeh Alijani,Fatemeh Khademian,Levi Theodore Thompson 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.5
Surface modification of a mesoporous tungsten- and bismuth-promoted titania-silica nanocomposite was conducted by a silylation method using hexamethyldisilazane (HMDS) as the silylation reagent to overcome the low adsorption capacity of TiO2-based photocatalysts for organic dyes, which subsequently enhances photodegradation of the organic dyes under visible light irradiation. The performance of the nanocomposites was evaluated by photodegradation of Rhodamine B (RhB) dye under visible light irradiation in a triple-walled immersion well reactor. The synthesized nanocomposites were characterized by N2 adsorption-desorption, FE-SEM, XRD, SAED pattern, HR-TEM, EDX, FTIR, UV-Vis DRS, PL spectroscopy, TGA, and water contact angle measurement to determine the bulk structure and surface properties before and after surface silylation. The results revealed that surface hydroxyl groups were successfully replaced by the silyl groups via the silylation process, without significant alterations in the structure and textural properties of the nanocomposite. In addition, silylation of the nanocomposite surface significantly enhanced the adsorption capacity of RhB molecules due to increased surface hydrophobicity, which accelerated the photocatalytic degradation of RhB in water. The results of the photocatalytic degradation experiments demonstrated that although all the synthesized nanocomposites were able to remove all RhB molecules from water after 240 minutes of the reaction, the optimized silylated sample with 0.15 g of HMDS (TSWBi-Sil3) was able to remove 92% of the RhB after only 90 minutes, while it was only 79% for the unmodified nanocomposite.