We show that phenol can be effectively degraded by magnetite in the presence of persulfate (S2O8(2–)) under UVA irradiation. The process involves the radical SO4(–•), formed from S2O8(2–) in the presence of Fe(II). Although magnetite naturally contains Fe(II), the air-exposed oxide surface is fully oxidized to Fe(III) and irradiation is required to produce Fe(II). The magnetite + S2O8(2–) system was superior to the corresponding magnetite + H2O2 one in the presence of radical scavengers and in a natural water matrix, but it induced phenol mineralization in ultrapure water to a lesser extent. The leaching of Fe from the oxide surface was very limited, and much below the wastewater discharge limits. The reasonable performance of the magnetite/persulfate system in a natural water matrix and the low levels of dissolved Fe are potentially important for the removal of organic contaminants in wastewater.

Polypropylene nets are widely used as hernioplasty prostheses. The reproduction of bacteria within the net fibers intersections can occur after the application of the prosthesis causing infections. For this reason, bacteria have to be removed in the very early stage of surgical implantation. Activation of the prosthesis surface was done by an innovative oxidizing plasma treatment (APP-DBD) working under atmospheric conditions in order to favor the deposition of an antibacterial coating of chitosan (biocompatible carbohydrate) and ciprofloxacin (broad spectrum antibiotic). Two different coating mixtures were realised and the antibacterial properties of such functionalised nets were investigated, together with their effectiveness. Physico-chemical characterisations of meshes were carried out before and after functionalisation by SEM-EDS and infrared spectroscopy. The release of both chitosan and ciprofloxacin, under controlled experimental conditions, was followed respectively by colorimetric determination (using UV-Visible spectroscopy) and chromatographic analysis (using HPLC). In vitro tests allow verifying antimicrobial activity (inoculation of specimens in a Staphylococcus aureus suspension).

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Soluble bio-based substances (SBO) have been isolated from urban waste. Their structural similarity with natural organic matter suggested exploring their activity in the photodegradation of organic substrates. In this work, they are shown to promote the photodegradation of monochlorophenols. Experiments performed with 1.0 × 10 −4 M substrate solutions irradiated by simulated solar light in the presence of SBO showed the progressive degradation of all the probe substrates. The experimental data were fitted to a pseudo-first-order kinetics, and the rate constant was found to decrease in the following order: 2-chlorophenol > 3chlorophenol > 4-chlorophenol. The effect of pH and SBO concentration on chlorophenols degradation was assessed. Experiments performed in the presence of selective scavengers along with EPR measurements supported the main role of singlet oxygen in the substrate photodegradation mechanism. Toxicity assays showed that the photodegradation of chlorophenols in the presence of SBO is accompanied with a progressive up to complete detoxification of the system. Moreover, no significant contribution of SBO to the whole system toxicity was observed. The results show how urban wastes can be a resource of photosensitizing bio-based substances to be explored in wastewater treatments.

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A LaFeO3 photocatalyst is obtained by solution combustion synthesis from a bio-based substance extracted from urban wastes and tested for its catalytic activity.

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Urban waste-derived bioorganic substances (UW-BOS) have shown promise as chemical auxiliaries for a number of technological applications in the chemical industry and in environmental remediation. In this study, the application of these substances in the photodegradation of organic pollutants is addressed. The experimental work is specifically focused on the photolysis mechanism promoted by AC8, a UW-BOS isolated from a 2:1 w/w mixture of food and green residues, composted for 110 days, using 4-chlorophenol (4-CP) as probe molecule. The production of (⋅)OH and the ¹O₂ is monitored by EPR spectroscopy. The correlation between radical species evolution and photodegradation of 4-CP is investigated. The effect of ¹O₂ and (⋅)OH scavengers on the 4-CP degradation process is also checked. The results suggest that the role of these species in the photodegradation of 4-CP depends on AC8 concentration. AC8 is thereby proven to be a photosensitizer for applications in environmental remediation. The results on AC8 further support the use of urban bio-waste as a versatile source of chemical auxiliaries of biological origin for use in diversified applications.