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PFASs are a variety of ecologically persistent compounds of anthropogenic origin loosely included in many industrial products. In these, the carbon chain can be fully (perfluoroalkyl substances) or partially (polyfluoroalkyl substances) fluorinated. Their ubiquitous presence in many environmental compartments over the years and their long-lasting nature have given rise to concerns about the possible adverse effects of PFASs on ecosystems and human health. Among a number of remediation technologies, adsorption has been demonstrated to be a manageable and cost-effective method for the removal of PFASs in aqueous media. This study tested two novel and eco-friendly adsorbents (pinewood and date seeds biochar) on six different PFASs (PFOS, GenX, PFHxA, PFOA, PFDA, and PFTeDA). Batch sorption tests (24 h) were carried out to evaluate the removal efficiency of each PFAS substance in relation to the two biochars. All samples of liquid phase were analyzed by a developed and then a well-established method: (i) pre-treatment (centrifugation and filtration) and (ii) determination by high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS/MS). The results evidenced a comparable adsorption capacity in both materials but greater in the long-chain PFASs. Such findings may lead to a promising path towards the use of waste-origin materials in the PFAS remediation field. [ABSTRACT FROM AUTHOR]

This study explores the use of pine wood biochar (BC) waste gasified at 950 °C as fillers in polymer matrices to create BC@biopolymer composites with perspectives in groundwater remediation. Four biochar samples underwent different sieving and grinding processes and were extensively characterized via UV–Vis, FTIR, and FESEM–EDS, highlighting the fact that that BCs are essentially graphitic in nature with a sponge-like morphology. The grinding process influences the particle size, reducing the specific surface area by about 30% (evaluated by BET). The adsorption performances of raw BC were validated via an adsorption isotherm using trichloroethylene (TCE) as a model contaminant. A selected BC sample was used to produce hydrophilic, stable polymer composites with chitosan (CS), alginate (ALG), potato starch (PST), and sodium carboxymethylcellulose (CMC) via a simple blending approach. Pilot sedimentation tests over 7 days in water identified BC@PST and BC@CMC as the most stable suspensions due to a combination of both hydrogen bonds and physical entrapment, as studied by FTIR. BC@CMC showed optimal distribution and retention properties without clogging in breakthrough tests. The study concludes that biopolymer-based biochar composites with improved stability in aqueous environments hold significant promise for addressing various groundwater pollution challenges. [ABSTRACT FROM AUTHOR]

In this work, the consolidation efficiency of SiO2 nanoparticles (synthesized in the Chemistry laboratories at the Tor Vergata University of Roma) was tested on Pietraforte sandstone surfaces belonging to the bell tower of San Lorenzo (Florence, Italy) and was fully investigated. Nanoparticles (synthesized in large-scale mass production) have been characterized by XRD—X-Ray Diffraction; Raman and FTIR—Fourier Transform Infrared spectroscopy; SEM—Scanning Electron Microscopy; while the Pietraforte sandstone morphology was examined by Porosimetry, capillary absorption test, surface hardness test, drilling resistance and tensile strength. The colorimetric measurements were also performed to characterize the optical modification exhibited by Pietraforte sandstones, especially after the SiO2 treatments. Our results show that applying to the Pietraforte, the new consolidating agent based on SiO2 nanoparticles, has several advantages, as they are more resistant to perforation, wear, and abrasion even long range (for long times of exposure and consolidating exercise against Florentine sandstone), compared to the CaCO3 nanoparticles (tested in our previous paper), which instead show excellent performance but only close to their first application. This means that over time, their resistance to drilling decreases, they wear much more easily (compared to SiO2-treated sandstone), and tend to exhibit quite a significant surface abrasion phenomena. The experimental results highlight that the SiO2 consolidation efficiency on this kind of Florentine Pietraforte sandstone (having low porosity and a specific calcitic texture) seems to be higher in terms of water penetration protection, superficial cohesion forces, and an increase in surface resistance. Comparing the performance of SiO2 nanoparticles with commercial consolidants in solvents such as Estel 1000 (tested here), we demonstrate that: (A) the restorative effects are obtained with a consolidation time over one week, significantly shorter when compared to the times of Estel 1000, exceeding 21 days; (B) SiO2 nanoparticles perform better than Estel 1000 in terms of cohesion forces, also ensuring excellent preservation of the optical and color properties of the parent rock (without altering it after application). [ABSTRACT FROM AUTHOR]

In this investigation, the crystal chemical characterization of one sample of woolly erionite-K (Lander County, NV, USA) was examined after suspension in a FeCl2 solution, in anaerobic conditions. The aim of this study was to determine the effect of the chemical composition of erionite on its efficiency to bind iron. Inductively coupled plasma (ICP) results showed that the sample bound Fe(II) through an ion-exchange mechanism mainly involving Ca. In addition, chemical and structural data indicated that Fe(II) is fixed at the Ca3 site, six-fold coordinated to water molecules. According to Brunauer--Emmett--Teller (BET) sample surface area the amount of Fe(II) bound by the fibers was comparable with that retrieved for fibrous erionite-Na sample from Rome (OR, USA) for which the ion-exchange process mainly affected Na. This finding provides clear evidence of a strong tendency of Fe(II) to bind to the erionite structure. Furthermore, considering that the woolly erionite-K from Langer County differs markedly from erionite-Na from Rome in the extra-framework cation content, our observations indicate that the Fe binding efficiency is not significantly modulated by the chemical composition. Notably, Fe ion-exchanged and/or accumulated on the fiber surface can generate hydroxyl radicals via the Fenton reaction, thus influencing the potential carcinogenicity of the different erionite species. [ABSTRACT FROM AUTHOR]

Groundwater is an extremely important resource that may, however, contain a variety of toxic and bioaccumulative contaminants. Traditional "Pump and Treat" technologies for treating contaminated groundwater are no longer time- or cost-effective; therefore, new technologies are needed. In this work, we synthesized core-shell materials of micrometric dimensions based on the interaction of iron particles (the core) and fermentable biopolymers such as polyhydroxybutyrate (PHB, the surrounding shell) to be used in permeable reactive barriers for the removal of chlorinated pollutants from contaminated groundwater. The materials were prepared by precipitation techniques that allowed stable preparations to be obtained, whose chemico-physical properties were thoroughly characterized by scanning electron microscopy, porosimetry, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analyses, disc centrifuge analysis, and dynamic light scattering. The properties of the prepared materials are very promising, and may enhance the performance of permeable reactive barriers towards chlorinated compounds. [ABSTRACT FROM AUTHOR]

The basic macrocyclic octapyridinotetrapyrazinoporphyrazine InIII complex of formula [Py8TPyzPzIn(OAc)]·8H2O, prepared by reaction of the free ligand [Py8TPyzPzH2]·2H2O with In(OAc)3, is a stable-to-air species of which the structure has been studied by its X-ray powder diffraction and mass spectra and characterization operated by IR and UV-visible spectral behavior. The complex has been further examined and proven to be of potential interest for its response as an anticancer agent in the field of photodynamic therapy (PDT), the value of ΦΔ = 0.55 (in DMF) being in the range of 0.4–0.6 at the level of similar phthalocyanine and porphyrazine analogs and qualifying the species as a highly efficient anticancer agent. Planned parallel types of investigation, including their photoactive behaviour in PDT, have been extended to the mononuclear octacation [(2-Mepy)8TPyzPzIn(OAc)]8+ (salted by iodide ions) and the heteropentanuclear derivatives [(M'Cl2)4Py8TPyzPzIn(OAc)]·xH2O (M' = PdII, x = 8; PtII, x = 1)) and [{(Pd(CBT)2)4}Py8TPyzPzIn(OAc)]·19H2O (CBT = m-carborane-1-thiolate anion). [ABSTRACT FROM AUTHOR]

Ni/ZrO2 catalysts, active and selective for the catalytic partial oxidation of methane to syngas (CH4-CPO), were prepared by the dry impregnation of zirconium oxyhydroxide (Zhy) or monoclinic ZrO2 (Zm), calcination at 1173 K and activation by different procedures: oxidation-reduction (ox-red) or direct reduction (red). The characterization included XRD, FESEM, in situ FTIR and Raman spectroscopies, TPR, and specific surface area measurements. Catalytic activity experiments were carried out in a flow apparatus with a mixture of CH4:O2 = 2:1 in a short contact time. Compared to Zm, Zhy favoured the formation of smaller NiO particles, implying a higher number of Ni sites strongly interacting with the support. In all the activated Ni/ZrO2 catalysts, the Ni–ZrO2 interaction was strong enough to limit Ni aggregation during the catalytic runs. The catalytic activity depended on the activation procedures; the ox-red treatment yielded very active and stable catalysts, whereas the red treatment yielded catalysts with oscillating activity, ascribed to the formation of Niδ+ carbide-like species. The results suggested that Ni dispersion was not the main factor affecting the activity, and that active sites for CH4-CPO could be Ni species at the boundary of the metal particles in a specific configuration and nuclearity. [ABSTRACT FROM AUTHOR]