Postindustrial Jute Waste as a Support for Nano-Carbon Nitride Photocatalyst: Influence of Chemical Pretreatment.

Non-woven jute (NWJ) produced from carpet industry waste was oxidized by H2O2 or alkali-treated by NaOH and compared with water-washed samples. Changes in the structure of the NWJ, tracked by X-ray diffraction (XRD), showed that both chemical treatments disrupt hydrogen bond networks between cellulose Iß chains of the NWJ fibers. Thereafter, nano-carbon nitride (nCN) was impregnated, using a layer-by-layer technique, onto water-washed jute samples (nCN-Jw), NaOH-treated samples (nCN-Ja) and-H2O2 treated samples (nCN-Jo). Analysis of the Fourier transform infrared spectroscopy (FTIR) spectra of the impregnated samples revealed that nCN anchors to the water-washed NWJ surface through hemicellulose and secondary hydroxyl groups of the cellulose. In the case of chemically treated samples, nCN is preferentially bonded to the hydroxymethyl groups of cellulose. The stability and reusability of prepared nCN-jute (nCN-J) samples were assessed by tracking the photocatalytic degradation of Acid Orange 7 (AO7) dye under simulated solar light irradiation. Results from up to ten consecutive photocatalytic cycles demonstrated varying degrees of effectiveness across different samples. nCN-Jo and nCN-Ja samples exhibited declining effectiveness over cycles, attributed to bond instability between nCN and jute. In contrast, the nCN-Jw sample consistently maintained high degradation rates over ten cycles, with a dye removal percentage constantly above 90%.

Ecotoxicological Estimation of 4-Cumylphenol, 4-t-Octylphenol, Nonylphenol, and Volatile Leachate Phenol Degradation by the Microscopic Fungus Umbelopsis isabellina Using a Battery of Biotests.

The phenolic xenobiotics nonylphenol (NP), 4-tert-octylphenol (4-t-OP), and 4-cumylphenol (4-CP) have the potential to seriously disrupt the endocrine system. Volatile phenols (VPs), especially those present in landfill leachate, also adversely affect the health of numerous organisms. Microbial degradation of xenobiotics can result in the formation of intermediates with higher toxicity than the precursor substrates. Therefore, the main aim of this study was to assess the changes in environmental ecotoxicity during the biotransformation of nonylphenol, 4-tert-octylphenol, 4-cumylphenol and volatile phenols by Umbelopsis isabellina using a battery of biotests. The application of bioindicators belonging to different taxonomic groups and diverse trophic levels (producers, consumers, and reducers) indicated a significant reduction in toxicity during the cultivation of fungus cultures both for nonylphenol, 4-tert-octylphenol, 4-cumylphenol and volatile phenols. The rate of toxicity decline was correlated with the degree of xenobiotic biotransformation. Removal of 4-cumylphenol and 4-tert-octylphenol also led to a decrease in the anti-androgenic potential. Moreover, this is the first report demonstrating the anti-androgenic properties of 4-cumylphenol. The results showed that U. isabellina is an attractive tool for the bioremediation and detoxification of contaminated environments.

Selection of recycled waste plastic for incorporation in sustainable asphalt pavements: A novel multi-criteria screening tool based on 31 sources of plastic.

This study investigated the suitability of 31 recycled waste plastic samples obtained from 15 major recycling companies across Australia and New Zealand to be used as bitumen/asphalt modifiers. The plastics have been selected to be representative of recycled waste plastic around Australia and New Zealand. The recycled waste plastics belonged to either the post-industrial or post-consumer collection scheme. A new classification scheme was developed to rank each recycled waste plastic based on their chemical and physical properties against those of bitumen/asphalt. Specifically, density, polarity, melting point, solubility and melt flow index of the samples as well as the presence of contaminants, fillers and additives were analyzed for each recycled waste plastic material and their virgin counterpart. These 8 properties were used to rank various sources of recycled low-density poly(ethylene), linear low-density poly(ethylene), high density poly(ethylene) and poly(propylene) in addition to commingled plastics based on their suitability for bitumen modification (wet method). The modification of asphalt via replacement of virgin quarry aggregate with plastic aggregate (dry method) by recycled acrylonitrile butadiene styrene and poly(ethylene terephthalate) was also assessed by considering four criteria of purity, polarity, recycling contamination and hazardous additives. This new multi-criterion ranking approach revealed that low-density and linear low-density poly(ethylene) and acrylonitrile butadiene styrene and poly(ethylene terephthalate) should be preferentially used as bitumen/asphalt modifiers. This tool has been developed for recycling companies and bitumen/asphalt contractors to determine the suitability of recycled waste plastics within asphalt roads by a series of experimental techniques.

Heavy metals, PAHs and POPs in recycled polyethylene samples of agricultural, post-commercial, post-industrial and post-consumer origin.

In the present work, recycled polyethylene (LDPE) samples of agricultural, post-commercial, post-industrial and post-consumer origin were selected and analysed. The analysis comprised the determination of different contaminants such as metals, polycyclic aromatic hydrocarbons (PAHs), dioxin-like biphenyl polychlorides (PCBs), and polychlorinated-dibenzo-p-dioxins and furans (PCDD/Fs). A comparison with one sample of virgin plastic (unrecycled) was performed. The study aimed at stressing the importance of this type of analysis in recycled plastics. Indeed, such an examination will determine the material's final destination, and the possible origin of the pollutants analysed is investigated. Black post-industrial and post-consumer samples presented the highest concentration of PCBs and PCDD/Fs, attaining a maximum value of 2.40 pg WHO-TEQ/g, while the least toxic sample (post-commercial) presented a toxicity of 0.38 pg WHO-TEQ/g. PAHs content was also much higher in black samples, reaching 514.41 ng/g, while the lowest concentrations were obtained for the post-commercial plastic sample, which did not exceed 38.98 ng/g. The higher PAHs concentrations in the black samples were related to the carbon black content of the black samples, which was 2.00% for black post-industrial sample and 1.51% for post-consumer sample. The PCDD/Fs congener profile observed in almost all samples was very similar to the profile found in the literature on urban air samples, indicating that the plastic is mainly influenced by the environment. The presence of some metals (mainly copper) showed a slight correlation with PCDD/Fs content. The pollutants analysed were found to be significantly reduced during the cleaning processes that are generally carried out in recycling companies.

Influence of compatibilizer on the properties of low-density polyethylene/polyamide 6 blends obtained by mechanical recycling of multilayer film waste.

Polymeric wastes have caused increasing environmental problems, mainly in oceans that accumulate large amounts of non-degradable plastic waste. Particularly, waste of polymeric multilayer films for packaging presents low interest for mechanical recycling due to the poor properties and low commercial value of the recycled material generated as polymeric blends. Multilayer films of low-density polyethylene (LDPE) and polyamide 6 (PA6) is a typical material used for packaging applications. The aim of this study was to evaluate the action of the concentration of maleic anhydride grafted polyethylene (PE- g-MA) on the compatibilization of LDPE/PA6 blends generated from mechanical recycling of multilayer films containing both polymers. The action of the PE- g-MA on the properties of the LDPE/PA6 blends was evaluated by tensile tests, optical microscopy, melt flow rate, and scanning electron microscopy. The use of PE- g-MA at 2.5 wt% as a compatibilizer during reactive extrusion of the multilayer films waste has showed the best result for production of the respective recycled LDPE/PA6 blends.

Organoclay nanocomposites of post-industrial waste poly(butylene terephthalate) from automotive parts.

Polymeric nanocomposites are novel materials of huge interest owing to their favourable cost/performance ratio with low amount of nanofillers, improved thermal resistance, flame retardancy and mechanical properties in relation to their matrices. In this work, composites based on post-industrial waste or primary recycled poly(butylene terephthalate) and 5 wt.% of organic modified montmorillonite clays were melt compounded using a twin-screw extruder. A 2(2) factorial experimental design was used to study the compounding and processing variables: Organic modified montmorillonite with one or two hydrogenated tallow (initial basal spacing) and screw speed of the extruder. X-ray diffraction and transmission electron microscopy suggest that a partial exfoliation of the organoclay in the recycled poly(butylene terephthalate) matrix was achieved for organic modified montmorillonite with lower initial basal spacing. On the other hand, formulations containing organic modified montmorillonite with higher initial basal spacing showed only intercalated structure. The recycled poly(butylene terephthalate)-organic modified montmorillonite nanocomposites did not drip flaming material during burning tests. Storage of dynamic-mechanical, tensile and flexural moduli of the recycled poly(butylene terephthalate)-organic modified montmorillonite were improved when compared with both virgin and recycled poly(butylene terephthalate)s, mainly for nanocomposites formulated at a lower initial basal spacing organoclay. This could be related to a better diffusion of polymer into organic modified montmorillonite layers compared with the higher initial basal spacing organoclay. The improvements on the physical properties of recycled poly(butylene terephthalate) showed the feasibility to add value to primary recycled engineering thermoplastics with a very small amount of organic modified montmorillonite.