Andrea Petrella

Photocatalytic Oxidation of Organic Micro-Pollutants: Pilot Plant Investigation and Mechanistic Aspects of the Degradation Reaction

An innovative pilot plant based on UVB and TiO2 (Anatase) allowed for photocatalytic degradation of organic micro-pollutants. The catalyst was immobilized onto a channel through which the solution containing a target molecule (methylene blue, MB) was re-circulated. Due to the cationic nature of the MB substrate, the adsorption reaction onto the catalyst surface provided a significant contribution to the overall degradation mechanism due to the negatively charged surface at neutral pH (TiO2 pHzpc = 6.8). The influence of the initial MB concentration was investigated in the range 0.3–2.0 mg L−1 with the Langmuir–Hinshelwood (LH) model showing good data correlations at concentrations up to 0.7 mg L−1, whereas at higher concentrations a pure zero-order (catalytic) kinetic trend was observed. Flow rate of the re-circulating solution sensibly influenced kinetics after the larger volumes of liquid exposed to UVB/TiO2 and to the better oxygen saturation in the liquid phase. UV−vis and HPLC-MS/MS experimental determinations allowed for identification of MB residual concentration and by-products.

Sorption of Pb(II), Cd(II), and Ni(II) From Single- and Multimetal Solutions by Recycled Waste Porous Glass

Selective sorption of lead, cadmium, and nickel ions on recycled waste porous glass beads was investigated. Single-metal equilibrations were carried out in demineralized water and ternary metal equilibrations were carried out in demi- and tap water. Freundlich isotherm gave a good correlation of the experimental data. Maximum metal retention (qmax) in single-ion solutions were 18.66 mg/gRPWG (0.090 mmol/gRPWG), 4.83 mg/gRPWG (0.043 mmol/gRPWG), 4.00 mg/gRPWG (0.068 mmol/gRPWG), respectively, for Pb+2, Cd+2, and Ni+2, and lower figures were in the case of ternary systems: 13.50 mg/gRPWG(0.065 mmol/gRPWG), 2.23 (0.020 mmol/gRPWG), 2.05 mg/gRPWG(0.034 mmol/gRPWG), respectively, for Pb+2, Cd+2, and Ni+2, with further drastic reduction in tap water. Metal exhausted beads were used as thermal insulators in cement mortars, minimizing their potential impact in the environment.

Binders alternative to Portland cement and waste management for sustainable construction—part 1:

This review presents “a state of the art” report on sustainability in construction materials. The authors propose different solutions to make the concrete industry more environmentally friendly in order to reduce greenhouse gases emissions and consumption of non-renewable resources. Part 1—the present paper—focuses on the use of binders alternative to Portland cement, including sulfoaluminate cements, alkali-activated materials, and geopolymers. Part 2 will be dedicated to traditional Portland-free binders and waste management and recycling in mortar and concrete production.

Hybrid nanocomposites based on CdS and CdSe colloidal nanocrystals in organic polymers

High quality luminescent CdS and CdSe nanocrystals, with tuneable band edge emission, were synthesized by means of thermal decomposition of precursors in organic solvents, incorporated in polystyrene and poly(methyl methacrylate) and deposited by casting, yielding optically transparent luminescent films. The obtained nanocomposite films were characterized by spectroscopical (UV-vis absorption and emission) and structural (TEM analysis) techniques. The effect of NC composition, concentration, size, and surface chemistry was evaluated in order to understand the role played by such factors in the nanocomposite optical properties for both the investigated polymers. The presence of organic ligand shell was demonstrated to be critical for the NCs incorporation into the polymer matrix.

One pot environmental friendly synthesis of gold nanoparticles using Punica Granatum Juice: A novel antioxidant agent for future dermatological and cosmetic applications

HYPOTHESIS The interesting properties of Gold Nanoparticles (AuNPs) make them attractive for different application fields such as cosmetology, medicine and clinical nanotechnologies. In this work a fast, easy and eco-friendly method for the AuNPs synthesis is proposed by using the Punica Granatum Juice (PGJ) with potential dermatological and cosmetic applications. The AuNPs antioxidant activity, due to the presence of phenols from the juice, and their use as booster for improving the Sun Protection Factor (SPF) in commercial sunscreen formulations, are thus expounded. EXPERIMENTS By using appropriate amounts of PGJ and HAuCl4, under mild work conditions, AuNPs with a mean size of 100 ± 40 nm are observed and carefully characterized. Solution pH, temperature, and volume were also changed for optimizing the AuNPs formation and features. The antioxidant activity was studied, by evaluating the AuNP ability of scavenging the radical 2,2-diphenyl-1-picrylhydrazylhydrate (DPPH). This finding was confirmed performing special experiments focused on the reaction between AuNPs and H2O2, by using suitable probes, such as 4-thiothymidine (S4TdR) and Cytochrome-c (Cyt-c). The SPF value was also calculated. FINDINGS The synthetized AuNPs showed a surface plasmon in visible range at 577 nm and resulted stable for long time in aqueous medium, also changing the pH values in the range 2-12. The studied antioxidant activity, confirmed also by performing special experiments with suitable probes, demonstrated the high performance of AuNPs. The AuNP photostability under sun irradiation is also shown. The calculated SPF values were in the range 3-18, related to AuNPs concentration in the range 1.80 × 10-12-1.00 × 10-11 M. The same AuNPs concentrations were used for cellular experiments. Indeed, since the AuNPs-PGJ mediated will be potentially introduced by dermal contact, dermal fibroblasts (Human Dermal Fibroblasts, HDF) and Human Microvascular Endothelial Cells (HMVEC) were used to evaluate the possible effects of these nanoparticles as a preliminary step. The results indicated that an AuNP concentrations in the range 1.80 × 10-12-3.60 × 10-12 M could be adopted since they do not appeared cyctotoxic.

Chemical and geochemical characterisation of a disused red brick factory area of central Italy

Characterisation and remedial actions are proposed for a polluted site enclosed within a red brick factory, located in central Italy. Approximately 22,000 t of chromium containing tannery sludge were introduced as ‘secondary raw materials’ for reuse in red brick manufacture. Preliminary geo-electric tomography was carried out on the waste bank, followed by the perforation of 14 boreholes into the bottom geological stratum. Heavy metals [B, Crtot, Cr(VI), Hg, Pb, Cu, Sn, V, Zn] and polycyclic aromatic hydrocarbons [benzo(a)pyrene; phenanthrene; dibenzo(a,h)pyrene; pyrene] were determined on solid samples. Carrots were sliced to give samples from different depths in the waste bank. The following samples were determined in the waste leachate: 1,1,2trichlorethane, phenol, 2,4,6trichlorphenol, hexachlorhexane, dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethane (DDD) and dichlorodiphenyldichloroethylene (DDE). During characterisation, laboratory experiments were also carried out on lime-treated and untreated carrot sections to evaluate heavy metal release and potential migration in the subsoil. Pollutant exposure pathways were set up, based on application of the Risk-Based Corrective Action (RBCA) model, followed by the evaluation of potential environmental and sanitary targets for site-specific risk evaluation and the proposition of scientifically based restoration scenarios. Surface capping, coupled with lateral belting of the site, were selected for the site recovery operations after extensive cost–benefit evaluations.

Gold-chlorophyll a-hybrid nanoparticles and chlorophyll a/cetyltrimethylammonium chloride self-assembled-suprastructures as novel carriers for chlorophyll a delivery in water medium: Photoactivity and photostability

The stability of Chlorophyll a in water during prolonged exposure, at room temperature, to a neon lamp has been investigated by means of UV-vis and fluorescence spectroscopies. In addition, the Chlorophyll a (photo)stability evaluation in presence of suitable carriers has been performed in order to investigate its reactivity under the same conditions, for possible and future applications in Antimicrobial Photodynamic Therapy. Cetyltrimethylammonium chloride was chosen to solubilize Chlorophyll a in water. While, cetyltrimethylammonium chloride-capped gold nanoparticles offer a great opportunity because combine the Chlorophyll a action, used as a photosensitizer in Antimicrobial Photodynamic Therapy, with gold nanoparticles effect used in photothermal therapy. Indeed, the latter ones have exhibited an interesting rise of temperature if irradiated with visible light. Overall, both examined systems, cetyltrimethylammonium chloride/Chlorophyll a and gold nanoparticles/Chlorophyll a, were able to induce the Reactive Oxygen Species formation fundamental for a potential application in Antimicrobial Photodynamic Therapy.