Photoinduced transformation of waste-derived soluble bio-based substances

[EN] Waste-derived, soluble bin-based substances (SBO), are effective low-cost photosensitizers that could find application in pollutant photodegradation. For this reason, it is important to understand if and to what extent irradiation could modify their properties. The exposure of SBO to simulated sunlight induced important spectral and structural modifications. Both the whole material and its acid-soluble fraction were characterized, highlighting several properties in common with humic and fulvic substances, including absorption spectra, specific absorbance and fluorescence behavior. The latter was described with a three-component model using PARAFAC analysis. Irradiation induced SBO photobleaching, but the absorbance of the acid-soluble fraction increased with irradiation. This finding suggests a progressive photochemical solubilization of SBO, which is confirmed by the increase of the carboxylic groups. In addition to absorbance, the fluorescence of whole SBO was also decreased by irradiation, thereby suggesting that both chromophores and fluorophores were photodegraded. The increasingly hydrophilic character given to SBO by irradiation also accounted for the photoinduced decrease of the surfactant properties of the material. (C) 2015 Elsevier B.V. All rights reserved.This work was funded by the 7thFP IRSES-2010-269128-EnvironBos Marie Curie Action and by Ministero delle Politiche Agricole e Forestali (Agrienergia project). The authors are grateful to the following private and/or public Italian institutions: (a) Acea Pinerolese Spa in Pinerolo (TO) for supplying the SBO sourcing materials; (b) Studio Chiono ed Associati in Rivarolo Canavese (TO) for making available pilot equipment and services for the production of the SBO.Avetta, P.; Berto, S.; Bianco Prevot, A.; Minella, M.; Montoneri, E.; Persico, D.; Vione, D.... (2015). Photoinduced transformation of waste-derived soluble bio-based substances. Chemical Engineering Journal. 274:247-255. https://doi.org/10.1016/j.cej.2015.03.126S24725527

Novel magnetite nanoparticles coated with waste sourced bio- based substances as sustainable and renewable adsorbing materials

This study examines the possibility of using bio-based product isolated from urban solid wastes as a material for environmental technological applications. To this end, Fe3O4 nanoparticles coated with different amounts of soluble bio-based products (SBO) were synthesized as low-cost nanoadsorbent for the removal of pollutants in wastewater. Particles of 10 nm diameter with Fe3O4 core and SBO shell were obtained. The concentration of SBO employed in the synthesis had no effect on the size and structure of the NPs, but ruled the pHPZC and aggregation of the nanoparticles in water. The cationic dye crystal violet (CV) was used as a model pollutant to test the adsorption capacity of the nanoparticles. The results indicated that both the medium pH and NP dosage were significant parameters to enhance the removal of CV. The results contribute to the studies which show how wastes can become a source of revenue through the industrial exploitation of their chemical value.Fil: Magnacca, Giuliana. Università di Torino; ItaliaFil: Allera, Alex. Università di Torino; ItaliaFil: Montoneri, Enzo. Università di Torino; ItaliaFil: Celi, Luisella. Università di Torino; ItaliaFil: Benito, Damián Ezequiel. Universidad Nacional de La Plata. Laboratorio de Investigación y Desarrollo de Métodos Analíticos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Gagliardi, Leonardo Gabriel. Universidad Nacional de La Plata. Laboratorio de Investigación y Desarrollo de Métodos Analíticos; ArgentinaFil: Martire, Daniel Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Gonzalez, Monica Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Carlos, Luciano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentin

SrCo1−xTixO3−δ perovskites as excellent catalysts for fast degradation of water contaminants in neutral and alkaline solutions

Perovskite-like oxides SrCo1−xTixO3−δ (SCTx, x = 0.1, 0.2, 0.4, 0.6) were used as heterogeneous catalysts to activate peroxymonosulfate (PMS) for phenol degradation under a wide pH range, exhibiting more rapid phenol oxidation than Co3O4 and TiO2. The SCT0.4/PMS system produced a high activity at increased initial pH, achieving optimized performance at pH  ≥ 7 in terms of total organic carbon removal, the minimum Co leaching and good catalytic stability. Kinetic studies showed that the phenol oxidation kinetics on SCT0.4/PMS system followed the pseudo-zero order kinetics and the rate on SCT0.4/PMS system decreased with increasing initial phenol concentration, decreased PMS amount, catalyst loading and solution temperature. Quenching tests using ethanol and tert-butyl alcohol demonstrated sulfate and hydroxyl radicals for phenol oxidation. This investigation suggested promising heterogeneous catalysts for organic oxidation with PMS, showing a breakthrough in the barriers of metal leaching, acidic pH, and low efficiency of heterogeneous catalysis

Use of graphite oxide and/or thermally reduced graphite oxide for the removal of dyes from water

Two types of carbonaceous materials, graphite oxide (GOx) and thermally reduced graphite oxide (TRGO) were tested in the dyes removal from water. Two common synthetic aquatic pollutants, Orange II, an azo dye, and Rhodamine B, a xanthene dye, were selected as probe molecules and their bleaching was evaluated. We observed that the two materials act in a different way when dispersed in aqueous solution: TRGO acts as a good adsorbent material whereas GOx can be used as an efficient photosensitizer. Dye removal is almost complete in the dark in the presence of TRGO and within few minutes a steady-state concentration was achieved. On the contrary, in the case of GOx, adsorption is limited to almost 10-20% for both dyes, but this material is able to induce dyes photodegradation and almost 80% of the residual dyes are abated within 5 h of irradiation under simulated solar light. When the graphene derivatives were dispersed in UV-cured acrylic polymeric films, the reduction of the surface area dropped the adsorption properties of TRGO, whereas the photosensitizer properties of GOx were maintained and the bleaching of the two dyes was achieved.We acknowledge support from a Marie Curie International Research Staff Exchange Scheme Fellowship (PHOTOMAT, proposal no. 318899) within the 7th European Community Framework Program.Peer Reviewe