The pressing issues of organic pollutants contamination of aquatic ecosystems challenges current research. Herein, we prepared three melamine-based POFs, to remove organic dyes from water. Melamine was polymerized with 1,4-dibromobutane (POF-1,4), terephthalaldehyde (POF-TerA) and trimesic acid (POF-TriA), obtaining POFs of different structural order degree and aromaticity. POFs were characterized using FT-IR spectroscopy, thermal gravimetric analysis, BET, powder X-ray diffraction and scanning electron microscopy. They were employed to remove cationic (Rhodamine B, RhB and Methylene Blue, MB) and anionic dyes (Methyl Orange, MO and Eosin Yellow, EY), using UV-vis investigation. The adsorption process was studied from the kinetic and thermodynamic points of view and reusing the best adsorbent was also considered. Data collected evidence that adsorption capacity depends on the POF structure, with maximum adsorption capacity, according to Langmuir isotherm model, of 329 mg/g for POF-1,4/MO and 472 mg/g for POF-TerA/RhB. Interactions involved in the adsorption were also elucidated. Comparison with reported data demonstrates that our materials show comparable performance to some previously reported systems. Furthermore, POF-TriA, is effective for dye mixtures and reusable three times without performance loss, after washing with methanol, avoiding harsh acidic/basic treatments. Results obtained systematically relate the adsorption efficiency to structural features of melamine-based POFs, representing useful support in designing such materials to remove selected classes of contaminants.

A new hybrid nanocomposite for wastewater treatment was developed using hemp shiv fibers coated with ZnO nanolayers. Macro hemp shives were selected for their adsorption capacity and sustainability, while ZnO provided photocatalytic activity. Low-temperature atomic layer deposition (ALD) anchored ZnO nanolayers with controlled thicknesses (30, 70, 90 nm) onto hydroxyl groups on the hemp shives' surface. The effect of the ZnO thickness on adsorption and photocatalytic performance toward water organic pollutants was systematically investigated. Characterization included spectroscopic ellipsometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM) with electron energy loss spectroscopy (EELS) and selected area electron diffraction (SAED), X-ray diffraction (XRD), thermogravimetric analysis (TGA), N2 adsorption-desorption analysis, and Fourier transform infrared spectroscopy (FTIR). Methylene blue (MB) adsorption kinetics showed ZnO coatings partially shield the intrinsic adsorption aptitude of pure porous fibers' surface, with a shielding increasing with the ZnO thickness. Photocatalytic activity under UV irradiation was evaluated using three emerging water pollutants: MB dye, sodium dodecyl sulfate (SDS), and phenol. Hemp shives coated with a 30 nm-thick ZnO layer exhibited the highest degradation efficiencies for all the tested pollutants (about 70% after 4 h of light irradiation). Recycling tests confirmed material stability, with preserved ZnO coating and crystal structure after repeated use. Scavenger experiments indicated both radicals and photo-generated holes contribute to photocatalytic mechanism. The synergistic combination of adsorption and photocatalysis makes ZnO-coated hemp shives a promising and sustainable material for advanced wastewater treatment.

In this work, Etna ash-derived photocatalysts were investigated for the first time for solar H2 production. Volcanic ash, commonly treated as a special waste in eastern Sicily (Italy), was modified through chemical treatment followed by microwave-assisted crystallization, avoiding the conventional high-temperature thermal route. The obtained material was tested both as a bare photocatalyst and as a support for a Nb2O5/graphitic carbon nitride composite prepared by a hydrothermal method. The Etna-derived photocatalyst exhibited a solar H2 production rate (by TEOA photoreforming) of 920 μmol/gcat∙h. Upon incorporation of the Nb-based composite, the H2 evolution rate increased by about 2.5 times, reaching 2370.5 μmol/gcat∙h, demonstrating a strong synergistic effect. Notably, the developed materials largely outperformed commercial TiO2 P25 (25 μmol/gcat∙h). The enhanced photocatalytic activity was attributed to the tailored modifications of Etna ash, which increased porosity and promoted aluminosilicate framework reorganization, favoring an optimal distribution of the photocatalytically active TiO2 and iron oxide phases. The obtained Nb oxide/carbon nitride supported on modified Etna ash also showed a remarkable stability after six consecutive runs of solar photocatalytic H2 production. This work demonstrates a sustainable strategy for converting volcanic waste into efficient multifunctional photocatalysts while minimizing the use of critical raw materials.

The development of efficient catalysts for CO₂ utilization is a key challenge for industrial sustainability. This study explores the photothermo-catalytic methanation of CO₂ using Ni-Zn-Al Layered Double Hydroxide-derived (LDHd) catalysts modified with phyllosilicates (Montmorillonite K30 and Halloysite). LDH precursors were synthesized by co-precipitation and hydrothermal treatment, then calcined and reduced leading to the formation of mixed oxides and metallic Ni and Zn nanoparticles. Catalytic performances were evaluated at 1 atm and 350 °C. The Ni-Zn-Al LDHd catalyst achieved high CO₂ conversion (86 %) and CH₄ selectivity (>99 %) under photothermo-catalytic conditions, outperforming commercial Ni systems. Incorporation of halloysite, thermally treated at 200 °C, further increased CO₂ conversion to 92 % with the same high CH₄ selectivity. This improved performance is attributed to enhanced surface area, optical absorption and moderate–strong basic sites from LDHd–Halloysite interaction. In contrast, Montmorillonite modification, despite cetyltrimethylammonium bromide (CTAB) intercalation, resulted in lower activity and selectivity, due to weaker basicity and ineffective LDHd interaction. The Ni-Zn-Al LDHd/halloysite catalyst exhibited excellent stability during 20 h of continuous photothermo-catalytic test at 350 °C. These results demonstrate the potential of phyllosilicate-modified LDH-derived catalysts, with low metals content, for efficient CO₂ methanation under solar irradiation.

Nanowires (Nws) play a crucial role in titanium dioxide's photo-physical and photochemical applications, such as photovoltaics, photocatalysis, and water splitting. Among the techniques employed to synthesise nanostructures, the Au seed-assisted thermal oxidation is the simplest and the most intriguing. TiO2 NWs, with Au-nanoparticles (AuNPs) on the tip, can be obtained by annealing in air, a thin Au film deposited on a metallic Ti. Au-NPs, formed during the annealing, act as seeds for NWs growth, while the oxide layer, formed during oxidation, inhibits the Nws growth. An in-depth investigation is conducted on the effects of various substrates, oxide layer thickness, and oxidation time. We propose a diffusion mechanism involving the transport of Ti interstitials from the metallic Ti substrate, through the TiO2, to the surface. Moreover, high-resolution conductive AFM analysis at the AuNp/TiO2 interface suggests the formation of a nanometric heterojunction. The heterojunction electric field promotes a localised enrichment of Ti interstitials close to AuNps, thereby enhancing the oxidation rate and resulting in the creation of TiO2 nanowires.

ABSTRACT Contamination of water bodies is one of the pressing issues of modern society. In this context, to achieve sustainable removal of pollutants from wastewater, the authors prepared hybrid membranes based on biomass‐derived poly(3‐hydroxybutirate) doped with hydrophobic imidazolium‐based ionic liquids differing for the alkyl chain length. Membranes were easily prepared, without synthetic steps, and were characterized by surface roughness, hydrophobicity/hydrophilicity and morphology. Then, these materials were investigated for their ability to remove cationic, neutral and anionic dye pollutants from water. The materials showed fast and thorough removal of most dyes, particularly cationic and neutral ones. Adsorption process was investigated in terms of mechanism and kinetics determining the adsorption isotherms and rate. The best results were obtained for methyl violet with maximum adsorption capacity of 132 mg/g, and the performance of the systems proved comparable to the one of related systems reported in the literature. The best‐performing membrane was reused nine times without significant loss in removal efficiency or intermediate washing. To minimize the waste generated by the adsorption process, the membranes were further doped with a photocatalyst like TiO 2 and employed to degrade dyes in water solution, finding that they are effective and recyclable catalysts, especially toward cationic dyes.

Nowadays thanks to the sustainable utilization of carbon dioxide, through its conversion into solar fuels, is possible to mitigate the impact of this greenhouse gas reducing at the same time the use of fossil fuels. In this work the conversion of the CO2 into CO and CH4 was investigated using a hybrid catalytic approach, the photothermo-catalysis, and non-critical catalysts, i.e., commercial montmorillonite (K30) modified with the intercalation of Ni and Ce and coated with Mn and Cu oxides. The best performance was obtained with the K30-Ni/Ce modified with both manganese and copper oxides that exhibited the 76.7

A novel and smart methacrylic acid (MAA) based macroporous material functionalized with thiol groups (-SH) was developed to achieve highly efficient and selective removal of toxic Hg(II) ions from water. With the aim of visualizing the saturation of the active sites of the material in real-time, a porphyrin-based co-monomer was synthesized and included (only 0.25 % w/w) as a part of the co-polymeric structure. The porphyrin ring can capture Hg(II) ions, causing a color change from red to green. However, due to the higher affinity of Hg(II) towards thiol groups, the porphyrin will be able to interact with free Hg(II) only when the adjacent thiols are no longer available and, therefore, close to the complete saturation of -SH sites. The color shift alerts that the material is approaching saturation, hence, a regeneration step is necessary for subsequent adsorption cycles. The typical interconnected macroporous (3-23 mu m) network of the cryogel allows fast water diffusion and easy access to the -SH and PORPH sites. Such design achieves an exceptional Hg(II) adsorption capacity (Q(max) > 1200 mg/g), calculated from the Langmuir isotherm model. The synthesized material shows high selectivity towards Hg(II) (S% > 95 %) in a solution with the simultaneous presence of other metal cation species. The kinetics of Hg(II) capture, pH behavior, material dosage, and regeneration cycles were tested, highlighting its potential applicability across a broad pH range and its reusability for at least five cycles. These combined features underscore the superior performance of this advanced material compared to current state-of-the-art competitors.

The photothermo-catalysis is a combined multicatalytic approach that allows to overcome some drawbacks of the respective single catalytic processes as the thermocatalysis and the photocatalysis. In this work, to efficiently exploit the potentiality of the solar photothermo-catalysis, SiC/hydrotalcites-derived catalysts were prepared with a simple hydrothermal method to exploit both the thermocatalytic properties of the formed multifunctional mixed oxides and the photo(thermo)-catalytic features of the silicon carbide. Two different hydrotalcite-derived catalysts were prepared, one with Mg-Co ions and another with Zn-Co ions. This latter sample, after the addition of SiC, showed the best performance in the CO2 methanation reaction, with a CH4 selectivity maximum of 71 % in the photothermal conditions at 250 degrees C, strongly improving the performance of the thermocatalysis (36 % at 350 degrees C). The presence of SiC permitted to increase the harvesting of the solar light, to modify the basic sites of the hydrotalcite-derived catalysts, allowing an efficient CO2 activation, and to generate self-heating effects that enhanced the photo-driven thermocatalysis. Moreover, the formation of photocatalytic active species as the ZnO and the ZnAl2O4 after the calcination of the corresponding hydrotalcite precursor, led to exploit additional photocatalytic contributions to further increase the catalytic activity in the photo-promoted thermocatalytic CO2 conversion into methane. The high versatility and the several synergisms generated by the application of this hybrid catalysis with these peculiar SiC/hydrotalcite-derived catalysts can be a sustainable strategy to efficiently valorise the carbon dioxide.

In this paper, we study the electrochemical properties of hydrogenated Au/TiO2 nanowires (NWs) synthesised by seed-assisted oxidation. Hydrogenation was performed electrochemically or by annealing in forming gas. The reduction process leads to a 20x improvement in photocurrent and introduces defects at the nanowires/water interface. At high frequencies, the usual Randles circuit is used. The depletion layer defect density is estimated to be 10(16), 10(18) and 10(20) cm(-3) for "as-grown", "Forming gas" and "electrochemically reduced" samples, respectively. At frequencies lower than the relaxation frequency, defects localised at the nanowire/water interface cause an enhancement in capacitance. Under UV irradiation, a density of 10(12) cm(-2) can be estimated for these defects at about 0 VAg/AgCl.

The solar photoreforming of some plastic materials (polylactic acid from biodegradable glasses, polystyrene from food dishes and low-density polyethylene from food packaging) to obtain H2, were investigated employing an unusual photocatalytic composite made by SiC-graphitic carbon nitride (g-C3N4) and the titanium carbonitride (TiCN). The plastic materials were pre-treated in alkaline mild conditions to favour their depolymerization. Among the investigated reactions, the solar photoreforming of polystyrene led to obtain the highest H2 production rate (371 mu molH2/gcat center dot h) using the SiC-1 wt% g-C3N4-5 wt% TiCN. The presence of graphitic carbon nitride favoured the photoelectrons mobility, generated by the absorption of the solar light by the SiC, whereas the interaction with the titanium carbonitride strongly enhanced the charge carriers separation. With this unconventional photocatalyst composite it is possible to valorise the plastics waste in a sustainable way, producing at the same time a high added value product fuel as hydrogen with a green waste-to-fuel approach.

The increasing presence of organic pollutants such as herbicides and pesticides in water, soil and air requires efficient strategies for their removal and degradation in a reliable and environmentally sound manner. This work focuses on adsorbent materials for water remediation, also addressing pollutant degradation, a critical aspect allowing adsorbent re‐use. A photo‐regenerable adsorbent based on a liquid crystal network (LCN) is proposed, consisting of a highly ordered nanoporous material obtained through the polymerization of reactive mesogenic monomers. The addition of titanium dioxide nanoparticles in the LCN matrix as photocatalyst opens to its photoregeneration, allowing degradation of the pollutants and further cycles of adsorption. The LCN‐TiO 2 composite was optimized using methylene blue (MB) as a model and then tested for a real pollutant. The adsorber proved its efficiency with a maximum pollutant uptake of 86 wt% and total photoregeneration achieved by irradiation with an ultraviolet source. The best tradeoff of adsorption capacity and photoregeneration efficacy was found for samples loaded with only 1 wt% of TiO 2 nanoparticles. This composite also exhibited a high pollutant adsorption capacity and fast and complete photo‐regeneration toward the herbicide Diquat, opening the way for a new versatile strategy for water remediation from emerging organic pollutants.

Titanium dioxide Nanowires (NWs) are particularly interesting because of their very high surface/volume ratio and their photocatalytic activity allows them to be used in a myriad of applications. This manuscript presents a study of nanowires grown on a conductive substrate making use of a seed-assisted thermal oxidation process. To obtain doped NWs, before the oxidation, metallic titanium was doped with Fe (or Cr) by ion implantation technology. Analyses showed good quality Rutile phase and light absorption in the visible range. Transport properties of the NWs/electrolyte junction were investigated by using linear sweep voltammetry and electrochemical impedance spectroscopy. They allowed us to measure the photovoltage and the barrier height of the junction. We also evaluated the density of hole trap states at the interface during illumination. Electrical results indicate that the formation of deep levels, induced by doping, influences the electron concentration in the TiO2 and the transport properties.

A hydrogel formulation of 2-hydroxy ethyl methacrylate (HEMA) containing covalently linked magnetite nanoparticles was developed to actively facilitate the selective removal and photocatalytic degradation of antibiotics. To this purpose, the hybrid materials were molecularly imprinted with Lomefloxacin (Lome) or Ciprofloxacin (Cipro), achieving a selectivity of 60% and 45%, respectively, starting from a solution of XX concentration. After the adsorption, the embedded magnetite was used with the double function of (i) magnetically removing the material from water and (ii) triggering photo-Fenton (PF) reactions assisted by UVA light and H2O2 to oxidize the captured antibiotic. The success of the material design was confirmed by a comprehensive characterization of the system from chemical–physical and morphological perspectives. Adsorption and degradation tests demonstrated the material’s ability to efficiently degrade Lome until its complete disappearance from the electrospray ionization (ESI) mass spectra. Regeneration tests showed the possibility of reusing the material for up to three cycles. Ecotoxicological tests using algae Rapidocelis subcapitata, crustaceans Daphnia magna, and bacteria Vibrio fischeri were performed to evaluate the ecosafety of our synthesized materials.

The realization of polymeric nanocomposites is a promising strategy for large-scale applications of photocatalytic nanomaterials, limiting their dispersion into the environment. In addition, in order to obtain very efficient materials, a valid solution can be the formation of heterojunctions that, reducing the electron-hole recombination phenomena, increases the performances of the photocatalysts. For this work, we have realized promising photocatalytic polymeric nanocomposites through the simple method of sonication and solution casting, using poly (methyl methacrylate) (PMMA) as supporting matrix, ZnO nanoparticles as photoactive material, and MoS2 nanoflakes as co-catalyst for the realization of the heterojunction. Materials with several quantities of MoS2 have been synthetized and characterized by scanning electron microscopy (SEM), contact angle measurements, X-ray diffraction analysis (XRD), UV–Vis spectroscopy, transmission electron microscopy (TEM), and photoluminescence (PL). The photocatalytic performances of the obtained materials were evaluated by the photodegradation under UV light irradiation of two different common pollutants: rhodamine B (RhB) and sodium dodecyl sulfate (SDS). The mechanism of the involved photocatalytic process was studied by the investigation of the main oxidants responsible of the photodegradation, using hole or radical scavengers. The antibacterial properties were investigated using Escherichia coli as a model organism. The eventual toxic effects of the prepared materials were studied on Artemia salina.

An improvement of water supply and sanitation and better management of water resources, especially in terms of water reuse, is one of the priorities of the European Green Deal. In this context, it is crucial to find new strategies to recycle wastewater efficiently in a low-cost and eco-friendly manner. The immobilization of inorganic nanomaterials on polymeric matrices has been drawing a lot of attention in recent years due to the extraordinary properties characterizing the as-obtained nanocomposites. The hybrid materials, indeed, combine the properties of the polymers, such as flexibility, low cost, mechanical stability, high durability, and ease of availability, with the properties of the inorganic counterpart. In particular, if the inorganic fillers are nanostructured photocatalysts, the materials will be able to utilize the energy delivered by light to catalyze chemical reactions for efficient wastewater treatment. Additionally, with the anchoring of the nanomaterials to the polymers, the dispersion of the nanomaterials in the environment is prevented, thus overcoming one of the main limits that impede the application of nanostructured photocatalysts on a large scale. In this work, we will present nanocomposites made of polymers, i.e., polymethyl methacrylate (PMMA), and photocatalytic semiconductors, i.e., TiO2 nanoparticles (Evonik). MoS2 nanoflakes were also added as co-catalysts to improve the photocatalytic performance of the TiO2. The hybrid materials were prepared using the sonication and solution casting method. The nanocomposites were deeply characterized, and their remarkable photocatalytic abilities were evaluated by the degradation of two common water pollutants: methyl orange and diclofenac. The relevance of the obtained results will be discussed, opening the route for the application of these materials in photocatalysis and especially for novel wastewater remediation.

Nowadays, developing countries have seen a reduction in male reproductive parameters, and it has been linked to the exposure of endocrine disrupting chemicals (EDCs), which are able to mimic or disrupt steroid hormone actions. Also, nanoparticles have shown effects on the male reproductive system, in particular the use of TiO2-NPs in drugs, cosmetics, and food as pigment additives, and, thanks to their small size (1–100 nm), provide themselves the opportunity to be internalized by the body and pass the blood–testis barrier (BTB). Therefore, TiO2-NPs can act on spermatogenesis and spermatozoa. In this study, we carried out an in vitro assay on human spermatozoa to evaluate the effects of TiO2-NPs at the concentrations of 500, 250, 100, and 50 ppm. Exposure did not statistically alter sperm parameters (e.g., motility and viability) but induced damage to sperm DNA and the expression of biomarkers by spermatozoa. This immunofluorescence investigation showed a positivity for biomarkers of stress (HSP70 and MTs) on the connecting piece of spermatozoa and also for sex hormone binding globulin (SHBG) biomarkers. The SHBG protein acts as a carrier of androgens and estrogens, regulating their bioavailability; therefore, its expression in the in vitro assay did not rule out the ability of TiO2-NPs to act as endocrine disruptors.

The photoreforming of polyethylene terephthalate and bisphenol A was here investigated using uncommon photocatalysts (SiC-g-C3N4 composites). The results showed as the addition of small amounts of g-C3N4 on SiC promoted an efficient charge carriers separation and a good interaction between the two materials, leading to a H2 production rate of 18 and 12 μmolH2/gcat∙h for the photoreforming of polyethylene terephthalate and bisphenol A, respectively. The accurate selection of different g-C3N4 precursors, combined with the appropriate control of the key reaction parameters (pH and plastic materials pretreatments) allowed to optimize the performance of the SiC-g-C3N4 composites for the photocatalytic H2 production.

Rising plastic waste from products such as contact lenses underscores the need for innovative recycling solutions. This study presents a sustainable approach to produce reusable photocatalytic hybrid nanocomposites for water treatment through the use of waste contact lenses. TiO2 nanoparticles were uniformly integrated into postused contact lenses via a controlled spray deposition technique, resulting in nanocomposites with different spray times (10, 15, or 20 min). The innovative polymeric hybrids were comprehensively characterized from a morphological, structural, and chemical standpoint using techniques such as scanning and transmission electron microscopy, thermogravimetric analysis, X-ray diffraction analysis, Raman spectroscopy, Z-potential analysis, UV-vis spectroscopy, and Fourier transform infrared spectroscopy. The UV-photocatalytic performance of the resulting systems was successfully tested on two common pollutants: methylene blue (a cationic dye) and sodium dodecyl sulfate (an anionic surfactant). The highest efficiency was obtained through the 20 min spray-coated lenses, able to degrade similar to 100% of MB and similar to 60% of SDS within 3 h of UV-light irradiation. The difference in the photocatalytic efficiency was attributed to the electrostatic interaction between the individual pollutant and the material's surface. In addition, the antibacterial activity was assessed on Escherichia coli, a well-known indicator of water fecal contamination. This research paves the way for recycling plastic waste through an affordable and cost-effective production method that aligns with the circular economy principles.