Surface Modification of a Magnetic SiO2 Support and Immobilization of a Nano-TiO2 Photocatalyst on It

Iron Molybdate Fe2(MoO4)3 Nanoparticles: Efficient Sorbent for Methylene Blue Dye Removal from Aqueous Solutions

The present study investigated iron molybdate (Fe₂(MoO₄)₃), synthesized via a simple method, as a nanosorbent for methylene blue (MB) dye removal from aqueous solutions. Investigations of the effects of several parameters like contact time, adsorbent dose, initial dye concentration, temperature and pH were carried out. The results showed that MB removal was affected, significantly, by adsorbent dose and pH. Interestingly, lower values of adsorbent dose resulted in the removal of higher amounts of MB. At the optimum pH, the removal efficiency of 99% was gained with an initial MB concentration of ≤60 ppm. The kinetic study specified an excellent correlation of the experimental results with the pseudo-second-order kinetics model. Thermodynamic studies proved a spontaneous, favorable and endothermic removal. The maximum amount of removal capacity of MB dye was 6173 mg/g, which was determined from the Langmuir model. The removal efficiency was shown to be retained after three cycles of reuse, as proven by thermal regeneration tests. The presence and adsorption of the dye onto the Fe₂(MoO₄)₃ nanoparticle surface, as well as the regeneration of the latter, was ascertained by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). These findings are indicative that the investigated nanosorbent is an excellent candidate for the removal of MB in wastewater.

Enhanced Photoluminescence and Photocatalytic Efficiency of La-Doped Bismuth Molybdate: Its Preparation and Characterization

Herein, a systematic study of the enhanced physicochemical properties of lanthanide doped (La-doped) bismuth molybdate (Bi₂MoO₆) is performed. For this purpose, Bi₂MoO₆ and La-doped Bi₂MoO₆ were prepared by the sol-gel method. BiCl₃, Na₂MoO₄^·2H₂O, and LaCl₃·7H₂O were taken as the main precursors while sodium dodecyl sulfate was used as a surfactant. Both Bi₂MoO₆ and La-doped Bi₂MoO₆ were calcined at 650 °C for 2 h. These prepared materials were characterized by spectroscopic techniques such as UV–VIS, FT-IR, XRD, photoluminescence, XPS, along with other techniques such as SEM, TEM, TGA, etc. The investigation of luminescence behavior revealed that the La-doped Bi₂MoO₆ nanocomposite exhibited much greater luminescence compared to the undoped Bi₂MoO₆. The photocatalytic behavior of the prepared materials was explored by studying the degradation of methylene blue (MB) at room temperature. The degradation of MB with Bi₂MoO₆ and La-doped bismuth molybdate were observed to be 68% and 75% @ 45 s, respectively, indicating an enhancement of catalytic performance due to the La doping.

Magnetite hybrid photocatalysis: advance environmental remediation

One of the main public concerns is the aquatic habitat and its corresponding issues because of the incessant contamination of the ecological water systems. In recent years, research attention has been focused on processes that lead to an improved oxidative degradation of organic pollutants. Therefore, semiconductor photocatalysis technology has aroused scientists’ interest in environmental remediation. Although several semiconductors have proven to be ideal candidates for the treatment of water pollution, the efficient separation and recycling of this fine-powdered photocatalyst is still a scientific problem when applied in practice, including separation process, selectivity, and dispersion. A photocatalyst with magnetic properties allows the use of the technique of magnetic separation, which is one of the most effective and simple methods for removing suspended solids from wastewater without the need for further separation processes. The magnetic photocatalyst allows its use as a suspended material, providing the advantage to have a high surface area for reaction. This review highlights the advantages and disadvantages of current photocatalyst systems. Moreover, it focuses on hybrid magnetic photocatalysts, including metals and nonmetals, metal oxides, carbon-based materials, and ceramics.

An efficient synthesis of perhydro[1,2,4]triazolo[1,2-a][1,2,4]triazole-1,5-dithiones catalyzed by TiO2-functionalized nano-Fe3O4 encapsulated-silica particles as a reusable magnetic nanocatalyst

A nano-TiO₂ catalyst on was immobilized on a magnetic SiO₂ support to form a robust and magnetically recoverable Fe₃O₄@SiO₂–TiO₂ catalyst for the synthesis of perhydrotriazolotriazole derivatives by the condensation of aldazines at room temperature.