Nano-Pyroxene for Adsorption and Catalytic Thermal Decomposition of Visbroken Residue Asphaltenes

Oil will continue to be a major source of future non-renewable energy, and hence new cost-effective technologies for upgrading and recovery of conventional and unconventional oils are needed. This study presents a new environmentally sound and low-cost, yet highly efficient pyroxene nanoparticles (NaFeSi2O6, PY). Low temperature hydrothermal synthesis route was used to prepare different sized and surface-structural-modified PY nanoparticles, which were characterized by different characterization techniques like XRD, BET, FTIR, TGA, TPD-CO2, TPD-NH3, XPS, SEM and HRTEM. These nanoparticles were applied for the adsorptive removal of violanthrone-79 (VO-79) as an asphaltene model molecule. The adsorption isotherms were described by the Sips isotherm model. Similarly, the prepared nanoparticles were employed for the adsorptive removal of visbroken residue (VR-C5) asphaltenes, and the solid-liquid-equilibrium (SLE) model was used to describe the adsorption isotherms. The promising catalytic effect of PY nanoparticles towards adsorbed VR-C5 asphaltenes was investigated using TGA coupled with mass spectrometry

Heterogeneous Photodegradation for the Abatement of Recalcitrant COD in Synthetic Tanning Wastewater

Tannery wastewater is considered one of the most contaminated and problematic wastes since it consists of considerable amounts of organic and inorganic compounds. These contaminants result in high chemical oxygen demand (COD), biochemical oxygen demand (BOD), and total suspended solids (TSS). In this work, the heterogeneous photodegradation of recalcitrant COD in wastewater from the tanning industry was investigated, in particular the recalcitrant COD due to the presence of vegetable tannins extracted from mimosa and chestnut and from synthetic tannins based on 4,4′ dihydroxy phenyl sulfone. TiO2 Aeroxide P-25 was employed to study the photodegradation of model molecules in batch conditions under different parameters, namely initial concentration of COD, temperature, and catalyst dose. The maximum COD abatement reached was 60%. Additionally, preliminary kinetic investigation was conducted to derive the main kinetic parameters that can be useful for process scale-up. It was found to be independent of the temperature value but linearly dependent on both catalyst loading and the initial COD value

Heterogeneous Photodegradation for the Abatement of Recalcitrant COD in Synthetic Tanning Wastewater

Tannery wastewater is considered one of the most contaminated and problematic wastes since it consists of considerable amounts of organic and inorganic compounds. These contaminants result in high chemical oxygen demand (COD), biochemical oxygen demand (BOD), and total suspended solids (TSS). In this work, the heterogeneous photodegradation of recalcitrant COD in wastewater from the tanning industry was investigated, in particular the recalcitrant COD due to the presence of vegetable tannins extracted from mimosa and chestnut and from synthetic tannins based on 4,4′ dihydroxy phenyl sulfone. TiO2 Aeroxide P-25 was employed to study the photodegradation of model molecules in batch conditions under different parameters, namely initial concentration of COD, temperature, and catalyst dose. The maximum COD abatement reached was 60%. Additionally, preliminary kinetic investigation was conducted to derive the main kinetic parameters that can be useful for process scale-up. It was found to be independent of the temperature value but linearly dependent on both catalyst loading and the initial COD value

Photodegradation of ibuprofen using CeO2 nanostructured materials: Reaction kinetics, modeling, and thermodynamics

International audienceIbuprofen is one the most used non-steroidal anti-inflammatory drug, which is considered an emerging pollutant that may contaminate surface and underground water. Photodegradation using nanomaterials is one of the most sustainable and cheap technologies that can be used in water purification. In this study, the photodegradation efficiency of in-house prepared ceria (CeO2) nanostructured materials towards ibuprofen was assessed under UV irradiation. CeO2 nanoparticles (NPs) were prepared through wet-chemical synthesis and characterized by several techniques. The photodegradation activity of the synthesized CeO2-NPs was compared to the commercial Aeroxide TiO2-P25. Small crystalline CeO2-NPs were obtained with about 15 nm particle size, band-gap of 3.1 eVwith irregular morphology. The surface area of CeO2-NPs was estimated to be 76 ± 5 m2/g. Dynamic light scattering analysis revealed that these nanoparticles have a strong tendency to self-aggregate and to form clusters in aqueous suspension. The results showed a slightly better performance of Aeroxide TiO2-P25 compared to CeO2-NPs. On the other hand, five reusability tests confirmed the stability of CeO2-NPs in the reaction conditions,without any significant effect on their photodegradation activity. The goodness of the kinetic modeling of the experimental data was proven through the estimated kinetic parameters, together with the statistical information. The temperature effect confirmed that the higher the temperature, the greater the dissociation rate. Thus, there is a direct relationship between temperature, reaction rate, and the activation energy for each reaction.Furthermore, the thermodynamic parameters, namely: changes in Gibbs free energy (ΔG◦), enthalpy (ΔH◦), and entropy (ΔS◦) have been reported revealing the efficient photodegradation performance of CeO2-NP

Competitive adsorption of Alizarin Red S and Bromocresol Green from aqueous solutions using brookite TiO2 nanoparticles: experimental and molecular dynamics simulation

In this work, the effective adsorption and the subsequent photodegradation activity, of TiO2 brookite nanoparticles, for the removal of anionic dyes, namely, Alizarin Red S (ARS) and Bromocresol Green (BCG) were studied. Batch adsorption experiments were conducted to investigate the effect of both dyes' concentration, contact time, and temperature. Photodegradation experiments for the adsorbed dyes were achieved using ultraviolet light illumination (6 W, λ = 365 nm). The single adsorption isotherms were fitted to the Sips model. The binary adsorption isotherms were fitted using the Extended-Sips model. The results of adsorption isotherms showed that the estimated maximum adsorption uptakes in the binary system were around 140 mg g-1 and 45.5 mg g-1 for ARS and BCG, respectively. In terms of adsorption kinetics, the uptake toward ARS was faster than BCG molecules in which the equilibrium was obtained in 7 min for ARS, while it took 180 min for BCG. Moreover, the thermodynamics results showed that the adsorption process was spontaneous for both anionic dyes. All these macroscopic competitive adsorption results indicate high selectivity toward ARS molecules in the presence of BCG molecules. Additionally, the TiO2 nanoparticles were successfully regenerated using UV irradiation. Moreover, molecular dynamics computational modeling was performed to understand the molecules' optimum coordination, TiO2 geometry, adsorption selectivity, and binary solution adsorption energies. The simulation energies distribution exhibits lower adsorption energies for ARS in the range from - 628 to - 1046 [Formula: see text] for both single and binary systems. In addition to that, the water adsorption energy was found to be between - 42 and - 209 [Formula: see text]