Low-cost diatomite supported binary transition metal sulfates: an efficient reusable solid catalyst for biodiesel synthesis

Using a simple method of impregnation and then calcination, diatomite supported binary transition metal sulfates (Fe and Zr, designated as Fe₂(SO₄)₃&Zr(SO₄)₂@diatomite) were prepared and used as a catalyst in the preparation of renewable biofuels. The synthesised Fe₂(SO₄)₃&Zr(SO₄)₂@diatomite catalyst (Fe₂(SO₄)₃ : Zr(SO₄)₂ : diatomite = 1 : 2 : 6, mass ratio) was thoroughly characterised using transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, microbeam X-ray fluorescence (μ-XRF) spectroscopy and thermogravimetric analysis (TG). The results demonstrated that the sulfate was successfully loaded onto the diatomite with a uniform distribution. The N₂ adsorption/desorption analysis indicated that the catalyst's specific surface area was 1.54 m² g^-1. The catalyst exhibited outstanding performance in the preparation of renewable biofuel (biodiesel) from waste fatty acids and the optimal parameters were methanol-to-oil 1.25 : 1, reaction temperature 70 °C, catalyst concentration 10 wt%, reaction time 4 h. The conversion was found to reach 98.90% under optimal parameters, which is better than that of Fe₂(SO₄)₃·xH₂O, Zr(SO₄)₂·4H₂O, Fe₂(SO₄)₃@diatomite and Zr(SO₄)₂@diatomite. Moreover, the catalyst can be recycled by simple filtration and reused for three cycles after regeneration without noticeable reduction in catalytic activity.

Preparation and Properties of g-C3N4-TiO2 Cement-Based Materials Supported by Recycled Concrete Powder

In this paper, recycled concrete powder (RCP) is used as the carrier of g-C3N4-TiO2 instead of natural minerals. The prepared g-C3N4-TiO2/RCP composites were characterized by X-ray diffractometer, scanning electron microscope, infrared spectrometer, specific surface area analyzer, UV-visible spectrophotometer, and RhB solution degradation experiments. The results show that the rough, porous structure of RCP was beneficial to the stable load of g-C3N4-TiO2. Under the condition that the content of g-C3N4-TiO2 catalyst is constant, the agglomeration of g-C3N4-TiO2 can be reduced by using RCP as a carrier, thus improving its photocatalytic efficiency. Subsequently, g-C3N4-TiO2/RCP was loaded onto the surface of cement-based materials by coating bonding method to study its photocatalytic performance. It is found that the photocatalytic cement-based material has a similar degradation effect on the degradation of surface RhB as g-C3N4-TiO2/RCP in RhB solution. Our work may open up a new field for the recycling of RCP and provide new ideas for the development of photocatalytic cement-based materials.

Photocatalytic Bacterial Inactivation of Acinetobacter baumannli on Cu/TiO2/Diatomite

Cu4Ti2O/TiO2/diatomite with double interface Cu4Ti2O/TiO2 and rutile/anatase heterojunction were fabricated, which demonstrated good antibacterial activity (100%) against Acinetobacter baumannii. Cu/TiO2/diatomite prepared under optimum preparation conditions (added diatomite, 0.005 g; Cu, 0.005 g; reaction temperature, 180 °C; reaction time, 8 h) exhibited high antibacterial activity (100%) against A. baumannii. For the Cu/TiO2/diatomite powders, their structural, compositional, optical and morphological traits were characterized by XRD, SEM, TEM, XPS, BET, FTIR, Mapping, and DRS. It was shown that Cu/TiO2/diatomite under optimum conditions consisted of the double interface Cu4Ti2O/TiO2 and rutile/anatase heterojunction with the narrowest band gap and largest BET surface area, pore size, and pore volume. Then, it could exhibit the best photocatalytic activity.