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Global increase of composite waste urgently requires innovative recycling technology. The three dimensional cross-linked structure makes melting and remoulding of thermoset composite impossible. In this study, high voltage fragmentation, originally conceived for fracturing rocks was investigated as a potential process for composite recycling. It was then benchmarked against its competitor, mechanical recycling. The investigation covered effectiveness in separating composite phases, energy demand and recyclate quality. The work is a new contribution to the performance evaluation of key technologies for rapid recycling glass fibre thermoset composites, a major challenge for manufacturing and end-of-life product waste. [ABSTRACT FROM AUTHOR]

Worldwide waste is increasing and can contain engineered nanoparticles (ENP) made from almost the entire spectrum of the periodic table. An increasing amount of waste (including nanowaste) is incinerated. A full-scale experiment in a modern waste incineration plant showed that even inert nanoparticles (nano-CeO2) are successfully removed from the flue gas and transferred to the solid incineration residues. Predicting the fate of nanomaterials in incineration plants with models based on real measurements would reduce the immense efforts (time and resources) for real-scale experiments. Here, we develop a model for the ENP fate in incineration plants, based on the data of the nanoCeO2-experiment. We investigated all possible transfers and sinks of ENP throughout the incineration by linking ENP concentration measurements to the nanomaterial flows and retention times. The model also delivers information on the associated uncertainties and how they propagate through the incineration system by using a fully probabilistic material flow analysis. The model can be generalized to other ENP and also to other incineration plants. We show that the output of the measurements was consistent albeit relying on multiple measurement methods, and that a one day sampling period is sufficient to obtain an overview on the fate of nanoparticles in incineration plants. In addition to the dynamic results, a generalized steady state mass flow with transfer factors is provided and can be used for modeling purposes of CeO2 or other nano sized metals with similar physic-chemical properties. [ABSTRACT FROM AUTHOR]

Concerns about the environmental risks of engineered nanomaterials (ENM) are growing, however, currently very little is known about their concentrations in the environment. Here, we calculate the concentrations of five ENM (nano-TiO2, nano-ZnO, nano-Ag, CNT and fullerenes) in environmental and technical compartments using probabilistic material-flow modelling. We apply the newest data on ENM production volumes, their allocation to and subsequent release from different product categories, and their flows into and within those compartments. Further, we compare newly predicted ENM concentrations to estimates from 2009 and to corresponding measured concentrations of their conventional materials, e.g. TiO2, Zn and Ag. We show that the production volume and the compounds' inertness are crucial factors determining final concentrations. ENM production estimates are generally higher than a few years ago. In most cases, the environmental concentrations of corresponding conventional materials are between one and seven orders of magnitude higher than those for ENM. [Copyright &y& Elsevier]

Abstract: Scientific consensus predicts that the worldwide use of engineered nanomaterials (ENM) leads to their release into the environment. We reviewed the available literature concerning environmental concentrations of six ENMs (TiO2, ZnO, Ag, fullerenes, CNT and CeO2) in surface waters, wastewater treatment plant effluents, biosolids, sediments, soils and air. Presently, a dozen modeling studies provide environmental concentrations for ENM and a handful of analytical works can be used as basis for a preliminary validation. There are still major knowledge gaps (e.g. on ENM production, application and release) that affect the modeled values, but over all an agreement on the order of magnitude of the environmental concentrations can be reached. True validation of the modeled values is difficult because trace analytical methods that are specific for ENM detection and quantification are not available. The modeled and measured results are not always comparable due to the different forms and sizes of particles that these two approaches target. [Copyright &y& Elsevier]

Abstract: An elementary step towards a quantitative assessment of the risks of new compounds or pollutants (chemicals, materials) to the environment is to estimate their environmental concentrations. Thus, the calculation of predicted environmental concentrations (PECs) builds the basis of a first exposure assessment. This paper presents a probabilistic method to compute distributions of PECs by means of a stochastic stationary substance/material flow modeling. The evolved model is basically applicable to any substance with a distinct lack of data concerning environmental fate, exposure, emission and transmission characteristics. The model input parameters and variables consider production, application quantities and fate of the compounds in natural and technical environments. To cope with uncertainties concerning the estimation of the model parameters (e.g. transfer and partitioning coefficients, emission factors) as well as uncertainties about the exposure causal mechanisms (e.g. level of compound production and application) themselves, we utilized and combined sensitivity and uncertainty analysis, Monte Carlo simulation and Markov Chain Monte Carlo modeling. The combination of these methods is appropriate to calculate realistic PECs when facing a lack of data. The proposed model is programmed and carried out with the computational tool R and implemented and validated with data for an exemplary case study of flows of the engineered nanoparticle nano-TiO2 in Switzerland. [Copyright &y& Elsevier]

• Environmental impacts induced by innovative recycling processes applied to epoxy / carbon fiber composites. • Supercritical hydrolysis and electrodynamic fragmentation versus pyrolysis, incineration and landfilling. • Reduction of the supercritical hydrolysis and electrodynamic fragmentation environmental impact through optimization. Global consumption of carbon fibers reinforced polymer (CFRP) is rising and the management of waste is an issue of high concern. In order to implement a sustainable carbon fiber recycling sector, there is a need to evaluate the potential environmental impacts of recycling processes. In this context, we compared current end-of-life scenarios (landfilling and incineration) with recycling technologies: pyrolysis, supercritical solvolysis and electrodynamic fragmentation using life cycle assessment. We conducted two analyses: a comparison between the CFRP end-of-life processes and a comparison including the substituted products from the recycled carbon fibers. When only considering the end-of-life processes, recycling processes have a higher environmental impact as they require higher energy demand than incineration or landfilling. When considering product substitution, recycling is environmentally beneficial since they replace the production of virgin products. Results are variable depending on the technology readiness level and the quality of fibers recovered from the recycling processes. [ABSTRACT FROM AUTHOR]

Abstract: Carbon nanotubes (CNT) are expected to be applied in a wide range of industrial applications and consumer products. As a consequence of widespread usage and their supposed persistence against degradation, human and environmental exposure to CNT is likely to increase. There are still many open questions regarding the effects of human or ecological exposure. However, the results of toxicological studies suggest that nanotubes may affect human health. Here we study possible sources of CNT-release on the basis of two case studies. In order to investigate whether and under which conditions CNT may be released from applications, we track the CNT throughout their life cycle as part of two types of consumer products: lithium-ion secondary batteries and synthetic textiles. The findings of the case studies suggest that a release of nanotubes can occur not only in the production phase, but also in the usage and disposal phases of nanotube applications. The likelihood and form of release is determined by the way CNT are incorporated into the material. A considerable part of all CNT used may finally be dispersed somewhere in the technosphere or the environment, e.g. by cross-product contamination during recycling. As long as potential adverse effects of CNT cannot be ruled out, we recommend implementing precautionary measures along the value chain (including the end-of-life treatment) in order to reduce the release and possible negative environmental or human health effects of CNT. [Copyright &y& Elsevier]