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This study aims to produce sustainable thermal insulation materials from waste textiles and evaluate their environmental impact using life cycle assessment (LCA). In this study, three different insulation panels were produced using textile wastes at different percentages, temperatures, and pressure conditions. They are composed of 100% recycled cotton (N1), 90% recycled cotton/10% polylactic acid (PLA) (N2), and 42.5% recycled cotton/42.5% recycled nylon/15% PLA (N3). A cradle-to-gate LCA (starting from waste textile collection to the production of thermal insulation panels) was conducted to assess the key environmental impacts based on the ISO 14040/44 guidelines. Test results revealed that insulation materials produced from waste textiles have excellent thermal insulation properties. The obtained thermal conductive values of N1, N2, and N3 insulation materials are 0.027, 0.028, and 0.036 W/mK, respectively. In the case of environmental impacts, results showed that N1 and N2 insulation materials had lower environmental impacts than N3. Environmental impacts of produced insulation panels were also compared with some commercially available insulation materials (stone wool, recycled PET bottle, and flax). During comparison, the thickness of materials is adjusted to keep their thermal resistance value same (R = 1 m2 K/W). The LCA results showed that the insulation panels N1 and N2 have eleven and three times (respectively) lower global warming (GW) potential than stone wool and sixteen and four times (respectively) lower GW potential than flax-based insulation panels and, therefore, could be considered as comparatively higher eco-friendly products. This LCA study also exposed a clear insight into the environmental impacts of several stages of the production process, which may be helpful to optimize or modify processes and produce more eco-friendlier thermal insulation material. [ABSTRACT FROM AUTHOR]

Purpose: Increased accumulation of fossil-based polymer packaging films on land and ocean surfaces poses major environmental challenges to our ecosystem. Developing alternative packaging films with no or minimal environmental burdens is critically important. Cellulose nanofibril (CNF)-reinforced chitosan biopolymer composites are the most promising bio-based alternatives for packaging applications due to their biodegradable, biocompatible, and antimicrobial properties. This study evaluates the life cycle environmental impacts of chitosan-CNF composite films to identify the environmental hotspots that can be eliminated during large-scale production. Methods: A cradle-to-gate life cycle assessment is conducted to evaluate the environmental impacts of citric acid crosslinked chitosan-CNF composite films that can be used for packaging applications. The main manufacturing operations include (i) production of chitosan from shrimp shell waste, (ii) CNF production from forest biomass, and (iii) production of citric acid crosslinked composite films by the solvent-casting method. Life cycle inventory data are obtained from published literature and laboratory experiments. The environmental impacts are evaluated by US EPA's TRACI 2.1 impact assessment method. The effects of key process parameters on the environmental impacts of composite films are also evaluated. Results and discussion: The global warming potential (GWP) of manufacturing chitosan-CNF composite films is about 3.91 kg CO2 eq./kg of the film, which is marginally lower than that of the fossil-based low-density polyethylene (LDPE) and bio-based poly(lactic acid) (PLA) films. The film casting sub-process in the composite film production contributes up to 90% of the total CO2 emissions. The amount of sodium hydroxide used in the deproteination of shrimp shells is the most sensitive factor in all impact categories. The scenario analysis shows the increase in the CNF loading rate to improve the mechanical and barrier properties does not substantially increase the global warming potential (GWP) and other environmental impacts. Conclusion: A cradle-to-gate life cycle assessment of the chitosan-CNF composite film has demonstrated that the overall environmental impacts are comparable or lower than that of fossil-based polymers and other biopolymers considered in the flexible packaging applications. The development of renewable energy-based film dryers and environmentally benign methods to extract chitosan from shrimp shell waste can further reduce the GWP of composite films. When the end of life of fossil-based polymers is considered, the biodegradable nature of chitosan-CNF composite can be an environmentally attractive film for packaging applications. [ABSTRACT FROM AUTHOR]

Subnational entities are recognizing the need to systematically examine options for reducing their carbon footprints. However, few robust and comprehensive analyses are available that lay out how US states and regions can most effectively contribute. This paper describes an approach developed for Georgia—a state in the southeastern United States called "Drawdown Georgia", our research involves (1) understanding Georgia's baseline carbon footprint and trends, (2) identifying the universe of Georgia-specific carbon-reduction solutions that could be impactful by 2030, (3) estimating the greenhouse gas reduction potential of these high-impact 2030 solutions for Georgia, and (4) estimating associated costs and benefits while also considering how the solutions might impact societal priorities, such as economic development opportunities, public health, environmental benefits, and equity. We began by examining the global solutions identified by Project Drawdown. The resulting 20 high-impact 2030 solutions provide a strategy for reducing Georgia's carbon footprint in the next decade using market-ready technologies and practices and including negative emission solutions. This paper describes our systematic and replicable process and ends with a discussion of its strengths, weaknesses, and planned future research. [ABSTRACT FROM AUTHOR]

Purpose: Napier grass, one of the high yield perennial energy crops can be grown on marginal lands with minimal inputs, but with increased soil carbon sequestration in the southeastern US. The sustainable use of Napier grass for bioenergy applications such as combined heat and power at low cost to mitigate greenhouse gas emissions needs to be investigated. Methods: In this study, an integrated life cycle assessment and techno-economic analysis approach were used to estimate the energy use, environmental emissions, and minimum selling price (MSP) of electricity and thermal heat produced from Napier grass and compared with a coal or natural gas-fired combined heat and power generation plant. Results and discussion: The use of Napier grass as a feedstock decreased the global warming potential (GWP) of the medium-sized CHP (i.e., 13 MWe) plant by 73–92 % compared to that of a coal and natural gas-fired CHP plants. Other environmental impacts were also reduced by 24–100 %. Eutrophication was the only impact comparable to that of the coal-fired CHP plant. The energy return on investment (EROI) was around 5:1. The minimum selling price of electricity generated from the CHP plant was US$0.05–0.4 MJe−1 (US$0.13–0.18 kWh−1) considering the credits for steam production, renewable electricity production tax credit (PTC), and carbon footprint from the fossil fuel-based electricity generation. Conclusions: Although the pelleting of Napier grass for the CHP plant increased the cost and GHG emissions by 38% and 55% over the non-pelleted system, the pelleting process can ensure consistent quality and uninterrupted supply of the feedstock for heat and power generation. [ABSTRACT FROM AUTHOR]

Densification of thermally treated energy crops by torrefaction is required to increase the bulk density and to reduce the handling, transport, and storage cost for bioenergy applications. In this study, we investigated the densification characteristics of thermally treated energy cane and napier grass grown on marginal lands at various applied forces and binder levels. The addition of starch (0, 10, and 15%) and lignosulfonate (0, 5, and 10%) was examined to enhance the strength and durability of raw and torrefied briquettes, respectively. Although the use of starch binder relatively increased the bulk density, it did not improve the hardness and durability of untreated energy crop briquettes. The addition of 10% lignosulfonate binder increased the torrefied briquette density of up to 11% for energy cane and up to 38% for napier grass and decreased the compression energy by up to 35% for both samples. Moreover, the hardness (compressive resistance) was tripled, and the durability was relatively improved for both torrefied briquettes. The increase in applied force not only increased the bulk density but also increased the specific energy required for densification. However, there was no substantial change in hardness and durability when the compression force was increased from 15 to 20 kN for all samples. In overall, densification of thermally treated energy crops is required, and the quality of the briquettes can be improved by the use of appropriate binders for efficient handling, transport, and storage. [ABSTRACT FROM AUTHOR]

Densification of switchgrass into consistent and high-density solid feedstock will reduce the cost of transport, handling, and storage to produce fuels and chemicals. Development a novel, low-cost densification technology is critical for reducing the delivered cost of feedstock while improving the bulk flow properties of densified products. In this paper, a novel wet granulation technology was proposed to investigate the effect of lime pretreatment on the production of switchgrass granules. Granulation is a process of agglomerating fine powders by wetting powder surfaces with liquid binders and mild application of shear/vibrating forces. Switchgrass was size reduced into fine powders using a knife mill and pretreated with three lime loading rates (0.05, 0.1, 0.2 g/g of biomass) at 121 °C for 30 min and at room temperature (25 °C) for 72 h. The structural modification of pretreated samples was analyzed by scanning electron microscopy and autofluorescence microscopy. Pretreated samples were granulated using a pan granulator with pre-formulated starch binder. Granules made from 20 % (0.2 g/g of biomass) lime loading rate had significantly higher single granule density and angle of repose with lower binder requirement than that of untreated granules. Lime treatment did not significantly increase the bulk density and hardness of granules. Lime-treated granules had significantly higher ash content and lower gross calorific value than that of untreated granules. In overall, lime treatment was not attractive to produce granules for thermochemical conversion platform, but lime-treated granules could be used to produce liquid biofuels and platform chemicals in biochemical conversion platform. [ABSTRACT FROM AUTHOR]