Fe-TiO₂ Nanoparticles Synthesized by Green Chemistry for Potential Application in Waste Water Photocatalytic Treatment

Abstract

Anatase TiO2 nanoparticles doped with iron ions have been synthesized via the green chemistry method using aqueous extract of lemongrass (Cymbopogon citratus) obtained from Soxhlet extraction and doped by wet impregnation. The TiO2 anatase phase has been doped with Fe3+ (0.05, 0.075, and 0.1 Fe3+ : Ti molar ratio) at 550°C and 350°C, respectively. The scanning electron microscopy with energy-dispersive X-ray (SEM-EDS) shows nanoparticle clusters and efficiencies of impregnations between 66.5 and 58.4% depending on the theoretical dopant amount. The electron transmission microscopy (TEM) reveals final particle sizes ranging between 7 and 26 nm depending on the presence or not of the dopant. The cathodoluminescence (CL) and photoluminescence (PL) studies of the doped and undoped nanoparticles show a luminescence signal attributed to surface oxygen vacancies (visible CL emission 380–700 nm and PL emission 350–800 nm); additionally, a decrease in emission intensity is observed due the inhibition of the recombination of the photogenerated electron-holes pairs; moreover, nanopowders were analyzed by UV-Vis spectrophotometry of diffuse reflectance, and the absorption edge of the Fe-TiO2 in comparison to undoped TiO2 is extended greatly toward the visible light. The six bands (A1g + 2B1g + 3Eg) found by Raman spectroscopy and the x-ray diffraction pattern (XRD) confirm that synthesized TiO2 is only anatase phase, which is commonly used as a catalyst in waste water treatment, specifically in heterogeneous photocatalytic processes.

Ionic Cross-Linking Fabrication of Chitosan-Based Beads Modified with FeO and TiO2 Nanoparticles: Adsorption Mechanism toward Naphthalene Removal in Seawater from Cartagena Bay Area

“…TiO 2 nanoparticles were synthesized via green synthesis using the as-prepared C. citratus extract as a capping agent. 71 Here, 50 mL of titanium isopropoxide (5 mM) was added to 15 mL of C. citratus extract under continuous stirring for 15 min. Afterward, the pH was adjusted to 8 using NaOH (1 M).…”

Synthesis and Characterization of Visible Light Active Fe-TiO2 using Hydrothermal Method

“…As-prepared samples were characterized by x-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and ultraviolet-visible spectrophotometer (UV-Vis). The XRD was performed on a D8 Advanced Bruker System with Cu kα radiation as the x-ray source [16,17]. The crystallite size of the studied samples was calculated using Debye-Scherrer equation with a correction for instrumental line broadening.…”

“…The optical profile as shown in Figure 3 supported this finding as Fe modification resulted in narrowing of the band gap, thus allowing the visible light absorption. It was believed that the Fe modification of the anatase samples successfully inhibited the recombination process and allowed more efficient photocatalytic reaction of MO degradation [16]. In short, the obtained apparent quantum efficiency values were very high, especially in the visible region.…”

Preparation of modified paints with nano-structured additives and its potential applications

“…The procedure for the preparation of aqueous extract of lemongrass, and then the green synthesis of TiO 2 nanoparticles, was according to the methodology reported previously. 71 Lemongrass leaves were cut, washed, and dried to remove impurities, and then crushed manually. One hundred grams of biomass was added in cloth bags for further solvent extraction using 500 mL of distilled water for 6 h. The lemongrass extract thus prepared was then placed in a storage at 4 C. Afterward, 100 mL of this extract was mixed with 20 mL of the precursor C 12 H 28 O 4 Ti by dropwise addition in a 250 mL beaker.…”