Spent FCC catalyst: Potential anti-corrosive and anti-biofouling material

Photocatalytic degradation of methylene blue with spent FCC catalyst loaded with ferric oxide and titanium dioxide

The spent fluid catalytic cracking (FCC) catalyst has been loaded with ferric oxide (Fe2O3) and titanium dioxide (TiO2). Fe-Ti/SF composite (loaded with 5 wt% TiO2 and 5 wt% Fe2O3), Fe/SF composite (loaded with10 wt% Fe2O3) and Ti/SF composite (loaded with 10 wt% TiO2) have been fabricated via a modified-impregnation method. The band gaps of the Fe-Ti/SF, Fe/SF and Ti/SF composites (evaluated by the energy versus [F(R∞)hv]n) are 2.23, 1.98 and 3.0 eV, respectively. Electrochemical impedance spectroscopy shows that the Fe-Ti/SF has lower electron transfer resistance, it has the small charge transfer resistance and fast charge transfer rate. The interparticle electrons transfer between the Fe2O3 and TiO2, which can improve the separation of the photo-electrons and holes. The holes transfer from valence band of TiO2 to the valence band of Fe2O3, which can provide more active sites around the adsorbed molecules. The methylene blue degradation efficiencies (with the Fe-Ti/SF, Fe/SF and Ti/SF composites) are ~ 94.2%, ~ 22.3% and ~ 54.0% in 120 min, respectively. This work reveals that the spent FCC catalyst as supporter can be loaded with Fe2O3 and TiO2. This composite is highly suitable for degradation of methylene blue, which can provide a potential method to dispose the spent FCC catalyst in industry.

Fabrication of spent FCC catalyst composites by loaded V2O5 and TiO2 and their comparative photocatalytic activities

The spent fluid catalytic cracking catalyst (FCC) has been loaded with different content of V₂O₅ and TiO₂ through a modified-impregnation method. X-ray Diffraction (XRD), ultraviolet-visible spectrophotometry (UV-Vis), Scanning Electron Microscope (SEM), and Fourier Transform Infrared spectroscopy (FT-IR) are used to characterize the structure and morphology of these samples. Their photocatalytic activity was evaluated by degradation of methylene blue (MB) solution under 300 W Xenon lamp irradiation. The interplanar spacing of the zeolite Y (111) plane is affected by the amount of the loaded V₂O₅ on spent FCC catalyst. The (111) plane of spent FCC catalyst loaded with V₂O₅ and TiO₂ sample is 1.404 nm, which is higher than that of the zeolite Y (1.395 nm). The amount of adsorption of MB and the photocatalytic activity for the degradation increased with increasing the interplanar spacing of the (111) plane of sample. We fabricated of spent FCC catalyst composites by loaded V₂O₅ and TiO₂, which effectively solved the spent FCC catalyst disposal problem. The efficiency of the developed sample provides a potentially economical way of degrading MB.

Reuse of spent FCC catalyst, waste serpentine and kiln rollers waste for synthesis of cordierite and cordierite-mullite ceramics

Spent fluid catalytic cracking (FCC) was gathered from several petrochemical plants and calcined in a rotary furnace between 1000 and 1100°C in order to remove sulphur and hydrocarbon based impurities. Calcining process on FCC led to formation of AlVO₄ ceramic phase, so converted the hazardous waste to non-hazardous applicable raw material. In this study, two ceramic bodies as cordierite and cordierite-mullite were synthesized with calcined spent FCC, waste serpentine, kiln rollers waste and high grade kaolin as raw materials. The XRD results showed that the cordierite and cordierite-mullite were synthesized successfully so that 96.4% of F1 (cordierite) sample fired at 1400°C was cordierite phase and F2 (cordierite-mullite) sample fired at 1450°C was completely cordierite and mullite phases. The synthesized cordierite and cordierite-mullite samples had lower porosity values and coefficient of thermal expansion (CTE) than similar industrial products. The negative CTE value that obtained from the cordierite sample up to 800°C is favorable for some applications. The considerable results of the synthesized cordierite and cordierite-mullite from this work present cost reduction of the two ceramic bodies production and may help to solve the environmental problems with the use of three waste sources in large scales.

Nanopatterning of steel by one-step anodization for anti-adhesion of bacteria

Surface nanopatterning of metals has been an effective technique for improved performance and functionalization. However, it is of great challenge to fabricate nanostructure on carbon steels despite their extensive use and urgent needs to maintain the performance reliability and durability. Here, we report a one-step anodization technique to nanopattern a carbon steel in 50 wt.% NaOH solution for highly effective anti-adhesion by sulphate reducing bacteria (SRB), i.e., Desulfovibrio desulfuricans subsp. desulfuricans (Beijerinck) Kluyver and van Niel. We characterize the morphology, structure, composition, and surface roughness of the nanostructured film formed on the steel as a function of anodizing potential. We quantify the surface hydrophobicity by contact angle measurements, and the SRB adhesion by fluorescent analysis. The optimal anodization potential of 2.0 V is determined for the best performance of anti-adhesion of SRB to the steel, resulting in a 23.5 times of reduction of SRB adhesion compared to bare steel. We discuss the mechanisms for the film formation on the steel during anodization, and the high-performance anti-adhesion of bacteria to nanopatterned steels. Our technique is simple, cost-effective and environment-friendly, providing a promising alternative for industry-scale surface nanopatterning of carbon steels for effective controlling of bacterial adhesion.