Gasification of the char derived from distillation of granulated scrap tyres

This work reports the effect of pressure on the steam/oxygen gasification at 1000 °C of the char derived from low temperature-pressure distillation of granulated scrap tyres (GST). The study was based on the analysis of gas production, carbon conversion, cold gas efficiency and the high heating value (HHV) of the product. For comparison, similar analyses were carried out for the gasification of coals with different rank.In spite of the relatively high ash (≈12 wt.%) and sulphur (≈3 wt.%) contents, the char produced in GST distillation can be regarded as a reasonable solid fuel with a calorific value of 34 MJ kg⁻¹. The combustion properties of the char (E_A ≈ 50 kJ mol⁻¹), its temperature of self-heating (≈264 °C), ignition temperature (≈459 °C) and burn-out temperature (≈676 °C) were found to be similar to those of a semi-anthracite.It is observed that the yield, H₂ and CO contents and HHV of the syngas produced from char gasification increase with pressure. At 0.1 MPa, 4.6 Nm³ kg_char⁻¹ of syngas was produced, containing 28% v/v of H₂ and CO and with a HHV around 3.7 MJ Nm⁻³. At 1.5 MPa, the syngas yield achieved 4.9 Nm³ kg_char⁻¹ with 30% v/v of H₂-CO and HHV of 4.1 MJ Nm⁻³. Carbon conversion significantly increased from 87% at 0.1 MPa to 98% at 1.5 MPa.It is shown that the char derived from distillation of granulated scrap tyres can be further gasified to render a gas of considerable heating value, especially when gasification proceeds at high pressure.     

Ozonisation coupled with biological degradation for treatment of phenolic pollutants: a mechanistically based study

Phenolic acids constitute an important group of pollutants which are reluctant to biological treatment. Solutions containing a mixture of cinnamic acid, p-coumaric acid, caffeic acid and ferulic acid were submitted to ozonisation. Then, the changes in biodegradability along the process were studied by means of respirometry. There is an optimum ozone dosage in the interval 3-5 min of treatment which allows to achieve the maximum increase in biodegradability (more than 10 times) and a high efficiency of the ozonisation process (COD decreases to a half of its initial value). Further ozonisation does not help to increase biodegradability and is clearly disadvantageous. Similar results are obtained with actual samples of olive oil wastewaters. This behaviour is explained based on the formation of highly biodegradable benzaldehydes as key ozonisation intermediates, in the early reaction stages.     

Plants against the global epidemic of arsenic poisoning

Due to the growing current trend around the world of drinking water from underground sources, in an attempt to replace heavily polluted surface water supplies, arsenic is causing a global epidemic of poisoning with hundreds of millions of people now being thought at serious risk in many countries. Phytoremediation (bioremediation mediated by plants) has been proposed as an effective tool in arsenic cleanup. Actually, some plants (most notably, the Chinese brake fern Pteris vittata) have been reported to be suitable for arsenic phytoremediation. In this respect, transgenic plants are being developed to improve their capacity to accumulate arsenic. Most interestingly, rhizofiltration (use of plants to absorb or adsorb pollutants from water) is being considered for the ex situ and in situ remediation of arsenic-contaminated water. Similarly, some plants show great potential to remove arsenic from polluted soil.     

Chemo-ecological studies on hexactinellid sponges from the Southern Ocean

Hexactinellids (glass sponges) are an understudied class with syncytial organization and poor procariotic associations, thought to lack defensive secondary metabolites. Poriferans, though, are outstanding sources of bioactive compounds; nonetheless, a growing suspicion suggests that many of these chemicals could be symbiont-derived. In Polar latitudes, sponges are readily invaded by diatoms, which could provide natural products. Hexactinellids are typical of deep waters; but in Antarctica, they dominate the upper shelf providing shelter and food supply to many opportunistic mesograzers and macroinvertebrates, which exert strong ecological pressures on them. Aiming to examine the incidence of defensive activities of hexactinellids against consumption, feeding experiments were conducted using their lipophilic fractions. Antarctic hexactinellid and demosponge extracts were tested against the asteroid Odontaster validus and the amphipod Cheirimedon femoratus as putative sympatric, omnivorous consumers. Hexactinellids yielded greater unpalatable activities towards the amphipod, while no apparent allocation of lipophilic defenses was noted. After chemical analyses on the lipophilic fractions from these Antarctic glass sponges, quite similar profiles were revealed, and no peculiar secondary metabolites, comparable to those characterizing other poriferans, were found. Instead, the lipidic compounds 5α(H)-cholestan-3-one and two glycoceramides were isolated for their particular outspread presence in our samples. The isolated compounds were further assessed in asteroid feeding assays, and their occurrence was evaluated for chemotaxonomical purposes in all the Antarctic samples as well as in glass sponges from other latitudes by NMR and MS. Characteristic sphingolipids are proposed as chemical markers in Hexactinellida, with possible contributions to the classification of this unsettled class.     

Removal of hydrogen sulfide from biogas by adsorption and photocatalysis: a review

Environmental Chemistry Letters - Biogas is a renewable fuel produced from modern biomass, yet biogas contains traces of hydrogen sulfide, a toxic compound, that must be removed before biogas...     

Auto shredder residue recycling: Mechanical separation and pyrolysis

Directive 2000/53/EC sets a goal of 85% material recycling from end-of-life vehicles (ELVs) by the end of 2015. The current ELV recycling rate is around 80%, while the remaining waste is called automotive shredder residue (ASR), or car fluff. In Europe, this is mainly landfilled because it is extremely heterogeneous and often polluted with car fluids. Despite technical difficulties, in the coming years it will be necessary to recover materials from car fluff in order to meet the ELV Directive requirement. This study deals with ASR pretreatment and pyrolysis, and aims to determine whether the ELV material recycling target may be achieved by car fluff mechanical separation followed by pyrolysis with a bench scale reactor. Results show that flotation followed by pyrolysis of the light, organic fraction may be a suitable ASR recycling technique if the oil can be further refined and used as a chemical. Moreover, metals are liberated during thermal cracking and can be easily separated from the pyrolysis char, amounting to roughly 5% in mass. Lastly, pyrolysis can be a good starting point from a "waste-to-chemicals" perspective, but further research should be done with a focus on oil and gas refining, in order both to make products suitable for the chemical industry and to render the whole recycling process economically feasible.     

An Aegean island earthquake protection strategy: an integrated analysis and policy methodology

Viewing an insular setting as a distinct risk environment, an effort is made here to develop a methodology for identifying core issues related to earthquake risk and disaster protection policy, adjusted to the 'specificities' of such a context. The methodology's point of departure is the inherent condition of the 'island operating as a closed system', requiring an attempt to assess and optimise local capacity (social, political, economic, institutional and technical) to deal with an earthquake emergency. The island is then treated as an 'open system', implying that in the event of a disaster, it should be able to maximise its ability to receive and distribute external aid and to manage effectively population evacuation and inflows/outflows of aid resources. Hence, an appropriate strategic policy approach could be developed by integrating the 'open' and 'closed' system components of an island setting. Three islands from the Aegean Archipelagos in Greece--Chios, Kos and Nissyros--serve as case study areas.     

Tree growth inference and prediction from diameter censuses and ring widths.

Estimation of tree growth is based on sparse observations of tree diameter, ring widths, or increments read from a dendrometer. From annual measurements on a few trees (e.g., increment cores) or sporadic measurements from many trees (e.g., diameter censuses on mapped plots), relationships with resources, tree size, and climate are extrapolated to whole stands. There has been no way to formally integrate different types of data and problems of estimation that result from (1) multiple sources of observation error, which frequently result in impossible estimates of negative growth, (2) the fact that data are typically sparse (a few trees or a few years), whereas inference is needed broadly (many trees over many years), (3) the fact that some unknown fraction of the variance is shared across the population, and (4) the fact that growth rates of trees within competing stands are not independent. We develop a hierarchical Bayes state space model for tree growth that addresses all of these challenges, allowing for formal inference that is consistent with the available data and the assumption that growth is nonnegative. Prediction follows directly, incorporating the full uncertainty from inference with scenarios for "filling the gaps" for past growth rates and for future conditions affecting growth. An example involving multiple species and multiple stands with tree-ring data and up to 14 years of tree census data illustrates how different levels of information at the tree and stand level contribute to inference and prediction.     

Energy consumption analysis of ABS plastic parts injected in a hybrid injection moulding machine

The energy analysis of injection moulding processes is influenced by complex interactions amongst the moulded part, its material, the injection machine, the process parameters and the environmental conditions. The availability of energy usage analyses that comprehend information on specific materials and machine kind is limited. This paper reports a study that estimates and analyses the power usage profile (PUP), the specific energy consumption (SEC), and the energy distribution at an operation level of two different injected parts made of acrylonitrile-butadiene-styrene and produced in a hybrid injection moulding machine. The methodology followed by the authors incorporates an experiment carried out in an industrial facility. A large sample size, and data-acquisition and data post-processing processes to obtain an accurate PUP and SEC are used. A breakdown of the energy consumed by the injection moulding process of the parts studied at an operation level using Sankey diagrams is discussed. The study results are used to identify strategies to reduce the energy consumed by the processes. The methodology employed, and the strategies reported could be used with other plastic parts regardless of the material and machine used. The results reported are new experimental data useful input for theoretical models.     

Microplastics in seawater: sampling strategies,laboratory methodologies,and identification techniques applied to port environment

Environmental Science and Pollution Research - The European Interreg Italy–France 2014–2020 Maritime Project SPlasH! (Stop to Plastics in H2O!) focused on the study of microplastics...