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[Display omitted] • Amino modified MWCNT sorbents are prepared with different structural properties. • Amino modified materials show CO 2 selectivity on CO 2 /N 2 adsorption-separation tests. • Higher N content and microporosity is linked with the best CO 2 up-take profiles. • The best amino-modified MWCNT material is water-resistant and multicycle reusable. Multi-walled carbon nanotubes (MWCNT) with different functionalities (standard–; OH–; and COOH– functionalized) are chemically modified with N1-(3-trimethoxysilylpropyl)diethylenetriamine (DETASi) aiming to enhance their CO 2 adsorption/separation properties. The grafting of the DETASi groups to the surface of the MWCNT samples is studied by X-ray photoelectron spectroscopy (XPS), operando thermogravimetric analysis - infrared spectroscopy (TGA-IR), –196 °C N 2 -sorption isotherms, and scanning electron microscopy (SEM). A comprehensive overview of the reaction mechanism and samples structure/composition is provided. It was found that the aforementioned functionalities highly influence the physical–chemical and the textural properties of the DETASi modified-MWCNT materials, impacting in the DETASi functionalization degree and its distribution on the sample. Amount (by TGA-IR) and homogeneity (by SEM) of the organosilicon group in the functionalized samples increases with the increase of the functionalities in the parent MWCNT materials. Standard-MWCNT and OH– functionalized MWCNT showed to be unable to adsorb CO 2 , while COOH– modified MWCNT adsorbed just 0.1% at 1 bar and 30 °C. At the same adsorption conditions, DETASi modification of the MWCNT materials enhanced the CO 2 adsorption capacity, with the maximum CO 2 uptake (2.11%) for COOH-MWCNT functionalized with DETASi. The selectivity for CO 2 /N 2 separation was also improved after DETASi grafting reaction, with the highest value (1.89%) observed for the standard-MWCNT material modified with DETASi. In general, the increase of the DETASi amount and of the microporosity in the functionalized MWCNT sorbents is accompanied by an improvement of the CO 2 adsorption-separation properties. The water vapor adsorption indicated that the standard-MWCNT sample modified with DETASi is resistant to the presence of water and its presence (water vapor of ~3.2 kPa) can improve the CO 2 uptake. [ABSTRACT FROM AUTHOR]

[Display omitted] • Reverse micelle synthesis fosters Fe doping of nanocrystalline CeO 2. • 2.5 mol % iron-doped ceria leads to high charge delocalization. • Efficient visible-light photodegradation of ibuprofen with 2.5 mol % Fe-CeO 2. • Substitutional Fe favours the oxygen vacancies formation and ibuprofen adsorption. • The by-product of the ibuprofen degradation is 1-ethenyl-4-(2-methylpropyl)benzene. Reverse micelle nanoreactors were successfully designed to synthesize small-sized ceria nanocrystals (3.5–4.2 nm) with a sizeable amount of substitutional iron. Undoped and doped CeO 2 catalysts with an iron content (0.50–10 mol %) compliant with the nominal value were prepared and tested for the first time for the removal of ibuprofen both in the dark and under UV or visible light irradiation. The effective inclusion and distribution of iron in the ceria lattice were ascertained through in-depth physicochemical characterization. In particular, X-ray diffraction suggested the formation of an F-type crystal structure, ruling out the formation of separate iron-containing crystalline phases. On the other hand, substitutional doping of CeO 2 with Fe atoms favoured the formation of Ce3+ defects and vacancy sites (VOs) with a maximum for the sample with 2.5 mol % iron (Fe2.5), as evidenced by X-ray photoelectron spectroscopy (XPS) measurements and Raman spectroscopy. UV–Vis spectroscopy showed that the optical properties were successfully modified by the presence of iron, which causes a gradual decrease in band gap as iron content increases. The experimental evidence was further verified and supported by density functional theory calculations. DFT calculations also revealed that the surface iron and oxygen vacancies are the preferential sites for ibuprofen adsorption. Nevertheless, it was found under dark conditions that adsorption capacity does not monotonically increase with iron content, revealing contrasting roles of surface characteristics. Indeed, catalytic experiments have identified a trade-off between adsorption and photodegradation, identifying Fe2.5 as the best-performing catalyst for ibuprofen removal under visible light irradiation. These results were discussed by considering the key properties of the catalysts as well as their different surface charge determined by ζ potential measurements. The best catalyst was tested through reuse experiments that proved its stability over 4 cycles. Finally, an attempt was made to identify the photodegradation by-products, allowing the detection of 1-ethenyl-4-(2-methylpropyl)benzene as the main by-product. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe and/or Cr doped TiO 2 photocatalysts were successfully prepared by sol–gel method. • The photocatalytic process made the effluent suitable for MBBR treatment. • Fe-doped TiO 2 showed the highest TPHs removal efficiency. • H 2 O 2 addition drastically improved TPHs removal (97%) from OMW. • Post-treatment is the best option for application of photocatalysis to OMW. TiO 2 based-photocatalysts doped with Fe and/or Cr was evaluated as pre- and post-treatment method of a moving bed biofilm reactor (MBBR) as possible solution for the treatment of real olive oil mill wastewater (OMW). Photocatalysts were synthesized by wet chemical method and their chemical-physical properties were accurately investigated through X-ray diffraction (XRD), Raman spectroscopy, UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS) and specific surface area measurements. UV–Vis DRS measurements evidenced that the simultaneous doping of TiO 2 lattice with Fe and Cr improves the optical absorption into the visible region leading to a narrow band gap (2.1 eV) with respect to undoped TiO 2 (3.2 eV) and Fe-doped TiO 2 (2.8 eV) while, Cr-doped TiO 2 showed the lowest bandgap value (1.9 eV). XRD patterns and Raman spectra showed that anatase is the predominant crystalline phase for all the prepared photocatalysts and Fe and Cr ions were effectively inserted into the TiO 2 lattice. The TiO 2 doping with Cr did not change the average crystallites size that was equivalent to that of TiO 2 (8 nm), whereas, for Fe- doped TiO 2 , it was lower than the others and equal to 6 nm. The specific surface area values of doped catalysts were higher than TiO 2 and the value for Fe-Cr-codoped TiO 2 resulted to be 97 m2 g−1. Photocatalytic treatment of OMW was evaluated in terms of total polyphenols (TPHs), Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD 5) and biodegradability (as BOD 5 /COD ratio) in 3 h of treatment under simulated solar light irradiation. Fe-doped TiO 2 showed the highest TPHs removal for both un-treated and biologically treated OMW. When H 2 O 2 was added (optimum dosage 0.5 g L-1), Fe-Cr-TiO 2 resulted in the best photocatalytic performance with TPHs removal as high as 97% and increased biodegradability (0.22 to 0.33), making the effluent suitable for the subsequent biological process. When photocatalytic process was investigated as post-treatment of OMW, Fe-TiO 2 showed the best activity and the addition of 0.5 g L-1 of H 2 O 2 was sufficient to make the effluent in compliance with Italian regulation for effluent disposal into surface water. [ABSTRACT FROM AUTHOR]

Commercial Mn 2 O 3 , Mn 3 O 4 and MnO 2 and the same after thermal or ball-milling treatments have been examined as catalysts for the photocatalytic water oxidation reaction, using [Ru(bpy) 3 ] 2+ as photosensitizer and S 2 O 8 2− as sacrificial electron acceptor. Tests were performed in a bubbling reactor, allowing the calculation of the actual rate of O 2 evolution as a function of time from raw data (oxygen flow, concentration of dissolved oxygen, DO) through a model able to take into account mass transfer phenomena Hernández et al. [19]. A few parameters are proposed for measuring activity, and comparison among them is made. The activity per unit mass of commercial samples is Mn 2 O 3 > MnO 2 > Mn 3 O 4 , in agreement with the literature. Increase in the surface area brought about by milling correspond, as expected, to a steady increase in activity in the case of Mn 3 O 4 , whereas had no effect with Mn 2 O 3 . The markedly higher specific surface of Mn 2 O 3 and Mn 3 O 4 samples obtained by thermal treatment of MnO 2 and a home-made sample, respectively, correspond surprisingly to activities lower than low surface area ball milled samples. Reasons for this are proposed to be a different nature of the surfaces arrived at, because of the different preparation route. A similar study of the effect of surface area for MnO 2 specimens is prevented by their largely amorphous nature. Comparison of present data with those already reported gives further support to the bounty of the model taking into account mass transfer. [ABSTRACT FROM AUTHOR]