297 research outputs found

    Kinetic study of tire carbon black and biomass soot steam activation used for the removal of phenol and chlorine from drinking water

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    This study aims to demonstrate a novel method for removing toxic chemicals using soot produced from wood and herbaceous biomass pyrolyzed in a drop tube reactor and tire pyrolytic carbon black. In order to improve the economic performance and reliability of entrained flow gasification, biomass soot has the potential to be captured, activated and further used as a sorbent to remove a broad range of pollutants from wastewater. In recent years, the disposal of waste tires has become an important issue. The liquid hydrocarbons and solid char residue from thermal conversion of waste tires have potential to be used as environmentally benign fuel and activated carbon. In the present work, the influence of ash content, nanostructure, particle size, and porosity on the filter efficiency of steam activated carbon materials was studied. It has been shown for the first time that steam activated soot and carbon black can remove phenol and chloride with the filter efficiencies as high as 95 %. The correlation of the filter efficiency to material properties showed that the presence of alkali and steam activation time were the key parameters affecting filter efficiencies. Kinetic parameters for the steam activation of tire pyrolytic carbon black and biomass soot have been determined by thermogravimetric analysis using steam as an activation agent. The feedstock for the soot production, activation temperatures and residence time were varied. The results showed that the rate of steam activation is 10 times faster than the activation at lower temperature. This study demonstrated that the steam activation process is suitable to prepare activated soot with the high surface area at the short residence time and at temperatures below 800°C. Reaction evolution has successfully been modelled, including the maximum reaction rate obtained in experimental results. Moreover, intrinsic kinetic parameters of the activation reaction order, activation energy and pre-exponential factor – were calculated

    Special Issue: Biochemical and thermochemical conversion processes of lignocellulosic biomass fractionated streams

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    peer-reviewedGlobal consumption of materials such as forest resources, fossil fuels, earth metals and minerals are expected to double in the next 30 years, while annual waste production is estimated to increase by approximately 70% by 2050 [1]. Keeping the resource consumption within planetary boundaries, we strive to minimize the carbon and environmental footprint and concurrently double the waste material use in the coming decades. Preventing food waste from being generated could have a major impact on waste collection systems and on the capacity of bio-waste management facilities worldwide [2]. Therefore, sustainable food waste management is a key part of any green business strategy to convert food waste into green fuels

    Charcoal as an alternative reductant in ferroalloy production: A review

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    peer-reviewedThis paper provides a fundamental and critical review of biomass application as renewable reductant in integrated ferroalloy reduction process. The basis for the review is based on the current process and product quality requirement that bio-based reductants must fulfill. The characteristics of different feedstocks and suitable pre-treatment and post-treatment technologies for their upgrading are evaluated. The existing literature concerning biomass application in ferroalloy industries is reviewed to fill out the research gaps related to charcoal properties provided by current production technologies and the integration of renewable reductants in the existing industrial infrastructure. This review also provides insights and recommendations to the unresolved challenges related to the charcoal process economics. Several possibilities to integrate the production of bio-based reductants with bio-refineries to lower the cost and increase the total efficiency are given. A comparison of challenges related to energy efficient charcoal production and formation of emissions in classical kiln technologies are discussed to underline the potential of bio-based reductant usage in ferroalloy reduction process

    Secondary comminution of wood pellets in power plant and laboratory-scale mills

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    peer-reviewedThe full text of this article will not be available in ULIR until the embargo expires on the 14/03/2019This study aims to determine the influence of mill type and pellet wood composition on particle size and shape of milled wood. The size and shape characteristics of pellets comminuted using power plant roller mills were compared with those obtained by using laboratory-scale roller- and hammer mills. A 2D dynamic imaging device was used for particle characterization. It was shown that mill type has a significant impact on particle size but an almost negligible effect on the shape of milled wood. Comminution in the pilot plant using a Loesche roller mill requires less energy than using a hammer mill, but generates a larger fraction of coarse particles. The laboratory-scale roller mill provides comparable results with the power plant roller mill with respect to particle size and shape

    Life cycle assessment of renewable reductants in the ferromanganese alloy production: a review

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    peer-reviewedThis study examined the literature on life cycle assessment on the ferromanganese alloy production route. The environmental impacts of raw material acquisition through the production of carbon reductants to the production of ferromanganese alloys were examined and compared. The transition from the current fossil fuel-based production to a more sustainable production route was reviewed. Besides the environmental impact, policy and socioeconomic impacts were considered due to evaluation course of differences in the production routes. Charcoal has the potential to substantially replace fossil fuel reductants in the upcoming decades. The environmental impact from current ferromanganese alloy production can be reduced by ≥20% by the charcoal produced in slow pyrolysis kilns, which can be further reduced by ≥50% for a sustainable production in high-efficient retorts. Certificated biomass can ensure a sustainable growth to avoid deforestation and acidification of the environment. Although greenhouse gas emissions from transport are low for the ferromanganese alloy production, they may increase due to the low bulk density of charcoal and the decentralized production of biomass. However, centralized charcoal retorts can provide additional by-products or biofuel and ensure better product quality for the industrial application. Further upgrading of charcoal can finally result in a CO2 neutral ferromanganese alloy production for the renewable power supply

    Trade Liberalization and the Social Determinants of Health: A Case Study of NAFTA\u27s Impact on Mexico from 1994 to 2005

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    Given the increased transnationalization of borders and economic interdependence between countries in the Global North and South, it is imperative to address how these trends impact the health and well being of the populations involved. The conventional neoliberal economic framework, however, falls short in explaining these dynamics due to its overemphasis of proximal determinants of health as direct consequences of commodification and free market activities. In congruence with those theoretical limitations, there is a limited assessment of more distal determinants – the social determinants of health (SDOH) – that are arguably more consequential for health and are interrelated with the dynamics of domestic, regional, and global political economies. The relationship between trade liberalization and SDOH, therefore, deserves greater examination through a critical political economy oriented framework that accounts for the shortcomings of the conventional neoliberal framework. This thesis seeks to address the aforementioned gaps by assessing the impacts of trade liberalization on SDOH within a case-study analysis of the North American Free Trade Agreement (NAFTA) and its impact on Mexican SDOH pathways in the period between 1994 and 2005. I identify three SDOH pathways for the analysis of NAFTA: employment (with respect to income and economic insecurity), regulation (with respect to occupational safety and environmental health), and agricultural commerce (with respect to food insecurity and sovereignty). By analyzing the intended impacts of NAFTA and Mexican policies, the quantitative primary, and the qualitative secondary data of the actual outcomes, I find that NAFTA’s impact on SDOH was incredibly nuanced

    Polyacrylamide gel electrophoresis of humic and fulvic acids after acid hydrolysis

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    Two soil humic acids (HA), a marine sediment HA, and a soil fulvic acid (FA), were fractionated by polyacrylamide gel electrophoresis in the presence of denaturing agents before and after 6N HCl hydrolysis. After acid hydrolysis, the intensity of the high molecular size (MS) fraction decreased considerably in all HAs. On the other hand, a new high-MS fraction appeared in the FA after hydrolysis. The electrophoretic data indicate that acid hydrolysis produced a transformation in the humic macromolecule, inducing either depolymerization or condensation, depending on the nature of the humic fraction. Therefore, the advantages and disadvantages of using acid hydrolysis should be carefully considered before this treatment is carried out.Peer Reviewe
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