New trends in the synthesis of nanoparticles by green methods

In this brief survey, we deal with green processes concerning the synthesis of zerovalent nanoparticles, enlighting some aspects motivating their choice with respect to traditional techniques generally relying upon toxic or noxious reactants and stabilizing agents. After a short discussion about health and environmental safety related to the use of standard reductants, we run through several green methods for metal nanoparticle synthesis and we split them into two basic classes, according to the electropositivity of the elements which the nanoparticles are made of. This classification has been proposed in order to account for strengths and weaknesses of processes based on active substances of biological origin that, though being effective in the production of noble metal nanoparticles, proved to be much less suitable when tested in the synthesis of nanoparticles made of more electropositive elements. The goal of this work is essentially oriented to stimulating new research trends for the eco-friendly production of nanosized non-noble elements deserving more attention by current nanobiotechnology

Chromium(III) Removal from Wastewater by Chitosan Flakes

Chitosan is very effective in removing metal ions through their adsorption. A preliminary investigation of the adsorption of chromium(III) by chitosan was carried out by means of batch tests as a function of contact time, pH, ion competition, and initial chromium(III) concentration. The rate of adsorption was rather rapid (t1/2 < 18 min) and influenced by the presence of other metal ions. The obtained data were tested using the Langmuir and Freundlich isotherm models and, based on R2 values, the former appeared better applicable than the latter. Chitosan was found to have an excellent loading capacity for chromium(III), namely 138.0 mg Cr per g of chitosan at pH = 3.8, but metal ions adsorption was strongly influenced by the pH. About 76% of the recovered chromium was then removed simply by washing the used chitosan with 0.1 M EDTA (Ethylenediaminetetraacetic acid) solution. This study demonstrates that chitosan has the potential to become an effective and low-cost agent for wastewater treatment (e.g., tannery waste) and in situ environmental remediation

Microbial colonization patterns and biodegradation of petrochemical and biodegradable plastics in lake waters: insights from a field experiment

IntroductionOnce dispersed in water, plastic materials become promptly colonized by biofilm-forming microorganisms, commonly known as plastisphere.MethodsBy combining DNA sequencing and Confocal Laser Scanning Microscopy (CLSM), we investigated the plastisphere colonization patterns following exposure to natural lake waters (up to 77 days) of either petrochemical or biodegradable plastic materials (low density polyethylene - LDPE, polyethylene terephthalate - PET, polylactic acid - PLA, and the starch-based MaterBi® - Mb) in comparison to planktonic community composition. Chemical composition, water wettability, and morphology of plastic surfaces were evaluated, through Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), and static contact angle analysis, to assess the possible effects of microbial colonization and biodegradation activity.Results and DiscussionThe phylogenetic composition of plastisphere and planktonic communities was notably different. Pioneering microbial colonisers, likely selected from lake waters, were found associated with all plastic materials, along with a core of more than 30 abundant bacterial families associated with all polymers. The different plastic materials, either derived from petrochemical hydrocarbons (i.e., LDPE and PET) or biodegradable (PLA and Mb), were used by opportunistic aquatic microorganisms as adhesion surfaces rather than carbon sources. The Mb-associated microorganisms (i.e. mostly members of the family Burkholderiaceae) were likely able to degrade the starch residues on the polymer surfaces, although the Mb matrix maintained its original chemical structure and morphology. Overall, our findings provide insights into the complex interactions between aquatic microorganisms and plastic materials found in lake waters, highlighting the importance of understanding the plastisphere dynamics to better manage the fate of plastic debris in the environment

Polypropylene Recovery and Recycling from Mussel Nets

Mussels represent about one-third of all aquaculture products sold in the European Union. Theoretically, mussel production should be an environmentally friendly and sustainable activity (0.252 kg CO2 eq. per 1 kg of mussel produced against over 20 kg CO2 eq. per 1 kg of beef produced) but the abandoned plastic “socks” on the seabed and along beaches represent a significant environmental problem. The recovery and recycling of those polymer materials represents the proper management of the waste issue due to mussel farming. This study was performed to investigate, for the first time, the roles of the chemical oxidation actions on the detachment (and destruction) of organic matter (biofilm in particular) from the surface of the polypropylene “socks” used in sea farms in order to recover the polymer material and recycle it. In the experiments, oxidation by H2O2 and HNO3 was performed on the studied samples. The effects of the particle size of the fragments, oxidant concentration, agitation time and ultrasound application were determined. FTIR spectra and tensile mechanical properties of the samples after treatment were measured and compared with the virgin polymer material. The biodiversity and structure of the plastic-associated biofilm was also determined before and after the oxidation process. Based on the results of the characterization of the recovered polymer material, a process scheme was designed. The application of the developed process could significantly reduce the environmental risk associated with used mussel socks. The One LIFE (the EU’s funding instrument for the environment and climate action) Project was recently founded based on this research

Nuovi materiali per il trattamento di reflui dell'industria tessile: le fibre di carbone attivato

Activated Carbon Fibers (ACF) can adsorb a wide range of organic contaminants and may be also used to treat air, drinking waters and wastewater. Within ENEA, ACF have been applied to the treatment of wastewater coming from textile industriesI tessuti a base di fibre di carbonio (FCA) sono caratterizzati da una elevata superficie specifica e sono in grado di adsorbire un largo spettro di inquinanti organici da matrici gassose ed acquose. Le FCA sono state applicate, in ambito ENEA, nel trattamento di acque reflue derivanti dall’industria tessil

Occhione: ricerca,monitoraggi,conservazione di una specie a rischio

Dalla prefazione: I gruppi specialistici costituiscono la forza propulsiva della ricerca e della conservazione per molte specie di uccelli. È attraverso la passione, la determinazione e la professionalità delle persone che si dedicano allo studio di una specie o di un gruppo di specie che si forma quel retroterra di conoscenze necessario a sviluppare linee e progetti di ricerca e a indirizzare le politiche di conservazione. L’uscita di questo libro è la dimostrazione di quanto un gruppo tematico di lavoro possa produrre. Questa felice raccolta di contributi ci mostra quanta attenzione sia ora rivolta all’Occhione; la sua presenza è capillarmente studiata in tutta Italia e nuove segnalazioni ampliano ogni anno la nostra conoscenza sulla sua distribuzione. Ma c’è di più in questo volume. C’è la dimostrazione della capacità di andare oltre la semplice documentazione della presenza, ci sono studi sul comportamento, sul canto e sull’ecologia. Mi auguro quindi di vedere ingrossate le fila di questo gruppo di ornitologi dediti all’Occhione e di poter leggere, nei prossimi anni, studi sempre più approfonditi sulla biologia di questa bellissima specie che sta coraggiosamente riconquistando il nostro Paese. A noi spetta il compito di ammirarla e difenderla

Searching Nanoplastics: From Sampling to Sample Processing

Nanoplastics (NPs) are considered emerging pollutants, namely unregulated contaminants whose toxic effect on humans and the environment has been demonstrated or suspected. They are the result of the physical fragmentation of the plastics that over time reach smaller dimensions (<100 nm). The issues related to the characterization and quantification of NPs in the environmental matrices are mainly related to the infinitepsimal size, to the fact that they are found in bulk, and to the different physico-chemical forms in which the same polymer can evolve over time by degradation. To deal with the study of a new class of pollutants it is necessary to assess the entire analytical method, carefully considering every single step (sampling, cleanup, qualitative, and quantitative analysis) starting from the validation method in the laboratory. This paper reviews the analytical method steps, focusing on the first ones, which the current literature often underestimates: laboratory tests, sampling, and sample processing; in fact, most errors and the quality of the analyses often depend on them. In addition, all newly introduced sample processing methods were examined