Facile and Bioinspired Approach from Gallic Acid for the Synthesis of Biobased Flame Retardant Coatings of Basalt Fibers.

A sustainable, bioinspired approach to functionalize basalt fibers with an innovative gallic acid (GA)-iron phenyl phosphonate complex (BF-GA-FeP), for the purpose of improving the flame retardancy in composite materials, is developed. BFs were at first pretreated with O3, obtaining surface free hydroxyl groups that allowed the subsequent covalent immobilization of biosourced GA units on the fiber through ester linkages. Phenolic -OH groups of the GA units were then exploited for the complexation of iron phenyl phosphonate, resulting in the target-complex-coated BF fiber (BF-GA-FeP). Microwave plasma atomic emission spectroscopy and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy analyses of BF-GA-FeP highlighted an increase in iron content, modification of fiber morphology, and occurrence of phosphorus, respectively. BFs, modified with a low amount of the developed complex, were used to reinforce a poly(lactic acid) (PLA) matrix in the production of a biocomposite (PLA/BF-FeP). PLA/BF-FeP showed a higher thermal stability than neat PLA and PLA reinforced with untreated BFs (PLA/BF), as confirmed by thermogravimetric analysis. The cone calorimeter test highlighted several advantages for PLA/BF-FeP, including a prolonged time to ignition, a reduced time to flame out, an 8% decrease in the peak heat release rate, and a 15% reduced fire propagating index compared to PLA/BF.

Copper-Decorated Titanium Electrodes: Impact of Surface Modifications of Substrate on the Morphology and Electrochemical Performance.

This study investigates the effect of surface modifications of the titanium substrate on the growth of electrochemically deposited copper. These materials are intended to serve as cathodes in the electroreduction of nitrates in aqueous solutions. Surface modifications included the use of hydrogen fluoride for titanium etching and anodization to promote the growth of a structured titania nanotube array. The effect of an intermediate calcination step for the nanotubes before deposition was assessed along with a comparison to an untreated substrate electrode. The materials were comprehensively characterized by SEM, XRD, contact angle, potentiodynamic tests, EIS, and cyclic voltammetry. Their electrocatalytic ability was tested in the reduction of aqueous solutions containing nitrates. The results reveal that surface finishing impacted the shape and size of the Cu microparticles, as well as the nucleation mechanism enabling a crystal-facet-controllable synthesis. All the materials exhibited microsized copper particles with a spherical shape with some clusters. On the etched titanium surface, a high number of heterogeneous submicroscopic particles were also present. The thermally treated anodized substrate promoted the development of a combination of sparse microparticles corresponding to defect sites in amorphous titanium and the presence of a diffuse coating of octahedral nanosized particles whose growth was promoted by the tetragonal structure of anatase crystals. Electrochemical tests display reduced charge transfer resistance upon copper deposition on the modified substrates, which is indicative of the enhanced conductivity of the coated materials. Additionally, cyclic voltammetry and electrolysis experiments reveal the electrodes' potential for nitrate reduction, showing a better response for the etched titanium substrate (30% nitrate removal, after 2 h at 25 mA cm-2).

Stigmatizing attitudes toward Internet gaming disorder, Problematic smartphone use and Problematic social networking site use: An experimental vignette study.

Public stigma on substance and gambling disorders have been well documented. Negative effects of stigma include shame, embarrassment, fear being judged and the determent of help-seeking behaviors among stigmatized individuals. Less is known about the public perception toward Internet gaming disorder (IGD) and other widespread problematic behaviors that share some characteristics with established behavioral addictions, such as Problematic smartphone use (PSU) and Problematic social networking sites use (PSNSU). The purpose of this study is to compare the public perception of problematic Internet gamers, problematic smartphone users and problematic social networking sites users using an experimental within-group vignette study design. A sample of 280 adults (F = 72.1%; Mage = 32.84, SD = 13.85) was recruited and completed the study online. Participants were presented with male OR female vignettes (i.e. the gender of the target in the vignette was randomized) describing an individual with IGD, PSU, and PSNSU. A repeated-measures ANOVA followed by post hoc tests using Bonferroni's correction was used. IGD was seen as more serious, more noticeable, and less understandable than both PSU and PSNU. Moreover, participants' emotional reaction (e.g., anger and sadness) and desired social distance were significantly stronger toward IGD. However, vanity attributions were higher for individuals with PSNSU, which were also more blamed compared to both IGD and PSU. PSU was seen as more controllable than both IGD and PSNSU. The results, taken together, suggest that IGD is perceived as more inherently problematic, but PSNSU also seem to deserve scientific attention as individuals showing symptoms of PSNSU are blamed more than problematic Internet gamers. Our findings provide initial information that can be used when developing interventions to impact stigma toward technological addictions.

Effect of Precursors on the Electrochemical Properties of Mixed RuOx/MnOx Electrodes Prepared by Thermal Decomposition.

Growing thin layers of mixed-metal oxides on titanium supports allows for the preparation of versatile electrodes that can be used in many applications. In this work, electrodes coated with thin films of ruthenium (RuOx) and manganese oxide (MnOx) were fabricated via thermal decomposition of a precursor solution deposited on a titanium substrate by spin coating. In particular, we combined different Ru and Mn precursors, either organic or inorganic, and investigated their influence on the morphology and electrochemical properties of the materials. The tested salts were: Ruthenium(III) acetylacetonate (Ru(acac)3), Ruthenium(III) chloride (RuCl3·xH2O), Manganese(II) nitrate (Mn(NO3)2·4H2O), and Manganese(III) acetylacetonate (Mn(acac)3). After fabrication, the films were subjected to different characterization techniques, including scanning electron microscopy (SEM), polarization analysis, open-circuit potential (OCP) measurements, electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), cyclic voltammetry (CV), and galvanostatic charge-discharge (GCD) experiments. The results indicate that compared to the others, the combination of RuCl3 and Mn(acac) produces fewer compact films, which are more susceptible to corrosion, but have outstanding capacitive properties. In particular, this sample exhibits a capacitance of 8.3 mF cm-2 and a coulombic efficiency of higher than 90% in the entire range of investigated current densities.

Pyrolysis wastewater treatment by adsorption on biochars produced by poplar biomass.

Pyrolysis is a widely studied thermochemical process, however the disposal of the produced byproducts is an unexplored field. In particular, the acqueous phase, characterized by a high organic load (TOC), must be necessarily treated. Aims of this work is to study the potentiality of biochar as adsorbent material for the treatment of this wastewater. For this aim, pyrolysis wastewater and biochar produced in the same plant were used. Two biochars produced at different temperatures (550 and 750 °C) and an activated biochar produced by chemical activation with NaOH of the raw biomass were tested. The study shows that higher temperature in the biochar production leads to higher sorption capacity of the organic compounds due to an increase of the surface area. The activation process further increases the surface area of the biochar that becomes similar to that of a commercial activated carbon while the sorption capacity exceeds that of commercial activated carbon of 2.5 times.

Tetrachloroethene recovery and hazard reduction of spent powders from dry cleaning process.

Dry cleaning facilities using perchloroethylene produce a solid waste consisting of spent filtering powders with a high content of residual perchloroethylene, together with dyes and non-volatile residues. Untreated spent powders, classified as hazardous waste, cannot be disposed in landfill and incineration represents the only viable alternative. In this study, together with a full characterisation of the waste, the removal and recovery of the residual perchloroethylene by means of different heat treatments was investigated. In particular, tests of distillation and stripping with air and steam were carried out, evaluating the effectiveness of the treatments by quantifying the residual perchloroethylene in the samples treated. The results obtained show that the spent filtering powders contained about 25% wt. of perchloroethylene and that the maximum perchloroethylene recovery was obtained by steam stripping; approximately 98% after only 50 minutes. However, this treatment accounted for the production of a liquid mixture containing perchloroethylene and of a solid waste that required a further washing with boiling water to decrease the residual organic content below the eligibility criteria for landfill disposal.

Environmental effects of using chelating agents in polluted sediment remediation.

The results of laboratory scale experimental tests of contaminant extraction from marine sediment slurries are presented and discussed. The objective of this study was to compare the effectiveness of EDTA and rhamnolipid in copper removal from an artificially contaminated sediment. The comparison was made in terms of metal extraction yield, and in the evaluation of its mobilization towards the more exchangeable fractions in the sediment. Results show that, under acidic conditions established during washing, EDTA ensured higher extractions efficiencies of Cu (up to 95 %) than rhamnolipid, although there was less mobilization into bioavailable forms with the use of rhamnolipid. In addition, in the view of a biological treatment of the spent solution, the use of rhamnolipid resulted in a lower decrease of the specific oxygen uptake rate with respect to EDTA. In fact, the low surfactants concentration required, partially compensated the toxic effect of Cu towards biomass.

Fenton-type treatment: state of the art.

The different currently used Fenton-type treatments, either chemically or electrochemically generated, are reviewed. A particular attention is devoted to the traditional Fe++/H2O2 chemical process and to the indirect electrochemical oxidation which uses in situ generated hydrogen peroxide. Mechanisms and experimental conditions employed for the optimisation of each technology are reported; moreover advantages and main limitations are discussed.

Oxidation of phosphorus compounds by Fenton's reagent.

In the present work a Fenton's treatment for the oxidation of a phosphorous compounds mixture, simulating a match manufacturing industry wastewater, were studied. Experimental tests were performed on three sample solutions at a phosphorus concentration of 250, 500 and 750 mg/l. In each solution an equal amount of sodium phosphite and sodium hypophosphite was dissolved. The investigation of pH, temperature and reagents ratio on the oxidation rate led to the individuation of the optimal process operating conditions. The results show that Fenton's reagent provides a powerful conversion to phosphate of the phosphorous solution. In particular at pH=3.5 and 20 degrees C a residual concentration of non oxidized phosphorus in compliance with the Italian regulation limits for industrial wastewater disposal. Tests performed on sample solution of 500 mg/l P and 750 mg/l P by adding hydrogen peroxide and bivalent iron in three sequential steps led to similar reaction efficiencies to tests carried out adding both Fenton's reagents in one step, but with a remarkably lower reagents consumption.

Use of a standard system to evaluate the matrix effect on the treatment of a solution from atrazine contaminated soils.

The influence of humic substances on the electrochemical treatment of solutions resulting from the remediation of atrazine contaminated soil has been investigated. In particular the effect on the hydrogen peroxide production stage and the effect on the hydroxyl radical oxidation treatment have been separately studied. In order to quickly assess the possible inhibition of the removal, an inorganic system has been adopted as a standard system. The results confirm the validity of electrochemical technologies also for the treatment of a real effluent where a matrix effect is expected since the organic matter content affects only the hydrogen peroxide production.

Treatment of the solution extracted from metal contaminated soils by reverse osmosis and chemical precipitation.

In this study a process for the remediation of soils contaminated by lead or copper is proposed, consisting of the operations in sequence: soil flushing, membrane treatment, acidification, and metal precipitation. Pb(II) and Cu(II) extraction from a synthetically contaminated soil using a 0.05 M EDTA aqueous solution were investigated in column. The metal removal efficiencies and the final soil metal concentration were 98.2% and 37.96 mg/g respectively for lead and 95.4% and 59.20 mg/kg for copper. The extracted solutions were concentrated through a membrane treatment to reduce the water content up to the 75% and to obtain a permeate metal concentration in compliance with the Italian Environmental Regulation. The recovery of the used EDTA from the retentate solution, with recovery yield of at least 85.4%, was also obtained through acidification. Metal precipitation from the filtered solution was then performed according two different methods, achieving metal removal yield of more than 99.4%.

Experimental assessment of electrochemical processes in the remediation of atrazine contaminated soils.

The electrochemical oxidation of an atrazine solution obtained from a flushing treatment of a contaminated soil was investigated. The influence of ethanol on atrazine oxidation was studied. Results show that the electrogenerated Fenton's reagent provides a complete degradation of atrazine and its main chlorinated by-products via N-dehalkylation and dechlorination. This process therefore presents an effective alternative to the chemical oxidation treatment which necessarily needs a further biological state.

Treatment of industrial landfill leachate by means of evaporation and reverse osmosis.

In this paper a process for the treatment of landfill leachate involving evaporation and reverse osmosis was proposed. Experimental tests were performed on an industrial landfill leachate. The leachate was subjected to evaporation so as to obtain a distillate containing a small amount of organic material and a substantial amount of inorganic substances (consisting primarily of metals and ammonium salts). The distillate of the evaporation treatment was then subjected to reverse osmosis. The reverie osmosis tests were performed using two different membranes: the AD membrane (thin two-ply film of polyamide) and the SC membrane (thin three-ply film of polyamide). Tests carried out at different values of pH showed a reduction of organic content of about 88% when AD membranes were used and about 80% with SC membranes independently of pH. As regards ammonium, comparable reductions of over 97% were registered for both types of membrane in the optimal conditions of pH = 6.4 (97.1% for AD membranes and 97.7% for SC).