Depletion Of Fossil Resources Research Articles

An integrated approach for sewage diversion: Case of the Huayuan mine, Hunan Province, China

Environment protection is a core priority for many governments in this century. Most environmental problems have diverse causes: emission of greenhouse gases from fossil fuels, resource depletion, or intense mining activities such as the Huayuan manganese mine. The positioning of mining factories and water treatment stations impacts the surrounding groundwater reservoir. As the mine expands, the environmental impact also increases, and the previous plan based on monitoring wastewater leakage has become inappropriate. Therefore, to solve this issue, a new study is required to understand the lateral resistivity distribution underground and to define a new station location for water treatment and divert the sewage to that station. In this study, the audio-frequency magnetotelluric method is used. Surveys of two long lines that cross the mining area to its boundaries are carried out. Data are robustly processed and inverted. Based on the inverted models, in addition to the geologic information, drilling inspections, and solid waste distributions map, the integrated interpretation develops two sites on the top of impermeable layers, which constitute a buffer point between the unsafe (high concentration of pollutants) and the safe zones in the northwestern part of the mine. From the resistivity distribution combined with the water quality analysis, a relationship between the fault structures reveals an interconnected conductive zone (CZ) in the southeastern part. As the main channels for water circulating underground, these CZs delineate the main groundwater reservoir with a clastic aquifer layer. However, close to factories, the water from faults contains solid wastes, thereby making the groundwater in that zone nonpotable, unlike the safety zone located in the northwestern part. This workflow can become a field guide to improve the environment of mines and the deployment of hydrogeologic drilling in a safe area.

How does plastic compare with alternative materials in the packaging sector? A systematic review of LCA studies.

In the recent years, packaging made of conventional plastics has been increasingly replaced by materials believed to be more sustainable. However, perceived sustainability must align with scientific assessments, such as life cycle assessments (LCAs). This review analysed 53 peer-reviewed studies published in the time range 2019-2023, aiming at understanding the state of the art in LCA about the environmental impacts of packaging by focusing on the comparison between plastics and alternative materials. The literature showed that consumer perceptions often differ from LCA findings and revealed that, frequently, conventional plastics are not the least environmentally friendly choice. Bioplastics typically show benefits only in the climate change and the fossil resource depletion impact categories. The heavy weight of glass turns out to affect its environmental performances with respect to the light plastics, with reuse being an essential strategy to lower the burdens. The comparison between plastics and metals is more balanced, leaning more towards plastics for food packaging. Similarly, article resulted often preferable than plastics. Finally, for the other materials (i.e. wood and textiles), the picture is variable. To be competitive with plastics, the alternative materials require improvements like the optimisation of their production processes, their reuse and enhanced end-of-life options. At the same time, recycled polymers could boost the eco-performance of virgin plastics.

Comparative techno-economic and life cycle assessments of single and intercropped-mixed feedstocks-based biorefineries for profitable and cleaner production of energy

The role of intercropped mixed feedstocks (IMF) in advancing biorefineries is rarely studied. However, as opposed to conventional single feedstocks (SF) from monocropping systems (MCS), IMFs could potentially enhance the economic profitability of biorefineries by reducing the cost of feedstock transportation and overall operations due to high feedstock yield/ha and fewer inputs e.g., diesel. In addition, IMFs could improve environmental performance by minimizing emissions associated with feedstock farming inputs (e.g., fertilizer), transportation (e.g., diesel, and tear & wear), and overall operational requirements. Furthermore, intercropping systems (ICS) could mitigate feedstock yield uncertainties and ensure stable feedstock supply because legumes (e.g., pigeon peas) are drought-resistant and inhibit pests & diseases when intercropped with maize. Nonetheless, the actual benefits of IMFs must be quantified. Therefore, techno-economic and life cycle assessments were done, using the Malawian economic context, to evaluate IMFs of maize stover (MS) and pigeon pea stalks and leaves (PPSL) for ethanol, electricity, and biogas production in varying biorefinery capacities of 156 000 and 2184 000 mt/y. Four scenarios were investigated; MS from MCS (S1), MS from ICS (S2), MS and PPSL from ICS (S3), where PPSL was dedicated for combined heat & power (CHP), and MS and PPSL from ICS where MS was dedicated to CHP (S4). The biorefinery systems were simulated in Aspen Plus ® to obtain mass and energy balances (MEB) which were used in assessing economic performance via biorefinery gate feedstock cost (BGFC), net present value (NPV), and minimum product selling price (MPSP). BGFC was evaluated by aggregating the cost of buying feedstocks, labor, milling, baling, and transportation. Transportation cost was computed via summation of the cost of fuel, driving labor, depreciation, and maintenance influenced by transportation distance and feedstock yield/ha. MEBs were also used as input and output data in SimaPro software to estimate emissions in terms of fossil resource depletion (FRD), global warming potential (GWP), terrestrial acidification (TA), and freshwater eutrophication (FWE). The IMFs improve biorefineries' economic performance by reducing feedstock logistical cost and MPSP, and environmental performance by reducing FRD, GWP, TA, and FWE. For example, BGFC, MPSP & FRD for IMF's S3 were $228 million/t, $2.28/L & 135 kg oil eq/mt, respectively, compared to $258 million/t, $2.37/L, and 146 kg oil eq/mt respectively for MSF's S1 at 2184 000 mt/y. Thus, IMF improved BGFC, MPSP, and FRD by 12, 5, and 8%, respectively. Therefore, utilization of the IMFs can boost the economic and environmental performances of biorefineries.

Environmental Impacts of Rice Intensification Using High-Yielding Varieties: Evidence from Mazandaran, Iran

This article aims to show the potential contribution of high-yielding rice varieties to achieve sustainable intensification in paddy farming, by focusing on a developing country. A comparative life cycle assessment of traditional vs. high-yielding varieties is carried out by comparing the area-based and yield-based results. Primary data are collected through a farm survey (49 farms in the Mazandaran province, Iran; spring 2018). The results highlight that high-yielding varieties can reduce the yield-scaled impacts. However, area-scaled impacts are subject to increase for most impact categories. Statistically significant trade-offs involve global warming potential (+13% per ha and −28% per t in high-yielding varieties) and fossil resource depletion (+15% per ha and −26% per t in high-yielding varieties). Pesticide management is the most alarming practice. High-yielding varieties increase pesticide consumption and related toxicity impacts both per t and per ha. This study is a new contribution to the literature by improving and broadening the mainstream productivity perspective of current life cycle assessment research about crop varieties. The lessons learnt from this study suggest that the trade-offs between yield-scaled and area-scaled impacts should be carefully considered by decision-makers and policymakers, especially in developing countries that, like Iran, are affected by the overexploitation of natural resources. Targeted policy and the development of farmer education and advisory services are needed to create the enabling conditions for farm management changes, including conscious use of production inputs while avoiding heuristics.

Life Cycle Assessment of Exopolysaccharides and Phycocyanin Production with Arthrospira platensis

In the pursuit of sustainable solutions for contemporary environmental challenges arising from the increasing global demand for energy, this study delves into the potential of cyanobacteria, specifically Arthrospira platensis (commonly known as “spirulina”), as a versatile resource. Employing a life cycle assessment (LCA) in accordance with the ISO 14044:2006 standard and employing both midpoint and endpoint indicators, the study comprehensively evaluates environmental impacts. The research explored a range of scenarios, specifically investigating variations in light intensity and harvesting volume. These investigations were carried out using a pilot-scale photobioreactor, specifically an airlift reactor system featuring a horizontal tubular downcomer. The primary focus is on extracting valuable compounds, namely exopolysaccharides and phycocyanin. It emphasized the extraction of value-added products and strategic integration with a biogas plant for process heat, contributing to developing a sustainable supply network and offering insights into environmentally conscious algae cultivation practices with implications for renewable energy and the production of valuable products. The results emphasize the project’s potential economic feasibility with minimal energy impact from by-product extraction. The environmental assessment identifies marine ecotoxicity and fossil resource depletion as principal impacts, predominantly influenced by upstreaming and harvesting stages. After conducting comparisons across various scenarios, it was found that cultivations under higher light intensities have a lower environmental impact than cultivations with low light supply. However, regardless of light intensity, processes with shorter harvesting cycles tend to have a smaller environmental impact compared to processes with longer harvesting cycles. Overall, this research contributes a nuanced and realistic perspective, fostering informed decision-making in sustainable algae cultivation practices, with implications for renewable energy and valuable compound production.

Unveiling the potential of starch-blended biodegradable polymers for substantializing the eco-friendly innovations

The extensive industrialization of polyethylene during the 1950s resulted in the mass production of petrochemical-derived plastics that remain widely used today. However, the harmful environmental impact of these non-biodegradable plastics has become increasingly evident. The non-degradability of conventional plastics has led to the filling of landfill sites, raising water and land pollution, and rapid depletion of fossil resources. As a result, there is an urgent need to develop sustainable alternatives that can reduce the environmental impact of plastic waste. One promising solution is the production of starch-blended biodegradable polymers. These polymers are produced from renewable resources such as corn and have the potential to be biodegradable or compostable. The compatibility between starch and other biopolymers, like polybutylene succinate (PBS), polylactic acid (PLA), and polyhydroxyalkanoates (PHAs) is being researched in several areas of food processing. The environmental impact and sustainability aspects of starch-blended biodegradable polymers are addressed, emphasizing their renewable nature, reduced carbon footprint, and potential to mitigate plastic waste. They offer a sustainable and eco-friendly alternative that can significantly reduce plastic waste and minimize the reliance on fossil resources. Studying starch-blended biodegradable polymers as a sustainable alternative to conventional plastics is crucial in addressing the detrimental environmental effects of non-degradable plastics. The review discusses the influences of starch content, compatibilizers, and plasticizers on the mechanical, thermal, and barrier characteristics of the blends also provides valuable insights into the current research trends and applications of starch-blended biodegradable polymers, highlighting their potential to contribute to sustainability and environmentally friendly polymer materials in various industries.

The environmental impacts of reusable rice packaging: An extended comparative life cycle assessment

Plastic packaging recycling has gained momentum as it can improve the circularity of this typical linear product. However, reuse ranks as a preferred strategy over recycling because product reuse can reduce material usage compared to product recycling and keeps material value higher for a longer time. Such reusable plastic packaging requires, besides a more robust product design, an additional return system. It is crucial to minimize the impact of this product system and ensure that reusable plastic packaging is not only more circular, but also more environmentally friendly than its single-use alternative. For this purpose, understanding the factors contributing to its environmental impact is key. In this paper, a new design of reusable packaging for two kilogram rice is compared with a conventional fully-optimized single-use packaging using a prospective extended life cycle assessment, including a circularity (using material flow analysis and specific circularity indicators, among which the Material Circularity Index), environmental impact (using a life cycle assessment with 16 midpoint indicators) and packaging-related food losses and waste assessment (using the food-to-packaging ratios). On average, the reusable rice packaging could be reused five times, due to losses at the distribution, use, and reuse preparation phase. While the reusable packaging scores better on the circularity indicators (a Material Circularity Index of 91 %, compared with 39 % for single-use packaging), its global warming and fossil resource depletion impact are respectively two and three times higher, considering a functional unit of one kilogram cooked rice to be consumed. The reusability and return rate, providing the retention of reusable packaging at the reuse preparation and use phase, respectively, were identified as the most determinative parameters by the sensitivity analysis. If these parameters could be optimized to a value of 99.75 %, corresponding to a total of 16 uses, the climate change impact of reusable packaging would be lower than its conventional single-use counterpart. The high food-to-packaging ratios (more than 18 for all impact categories) point to the importance of reducing food waste. If the packaging design could reduce food losses in the product system with 0.2 %, the reusable packaged rice would have a lower water use and mineral and metal resource use impact compared to the single-use packaged rice, despite the higher environmental impact of the reusable packaging unit itself. Therefore, this should be prioritized when further optimizing the reusable packaging design.

Cultivation of forage maize in boreal conditions – Assessment of trade-offs between increased productivity and environmental impact

The cultivation of whole crop forage maize (Zea mays L.) for cattle feed has a potential for increased forage yield while reducing nitrogen (N) fertilisation compared to perennial grass-based systems. However, the possible environmental trade-offs of forage maize cultivation remain unknown in the boreal region due to the short growing season which limits cultivation practices. The aim of this study was to compare the environmental impact of forage maize with more widely cultivated forage crops in Finland that include perennial silage grass mixtures and whole crop spring cereal harvested as silage. The use of plastic mulch film in forage maize cultivation was included in the assessment as well. A life cycle assessment (LCA) was conducted including impact categories for global warming potential; marine and freshwater eutrophication; terrestrial acidification; freshwater, marine and terrestrial ecotoxicity; land use; and fossil resource depletion. Additionally, soil organic carbon (SOC) stock changes under long-term cultivation of the studied forage crops were simulated with the C-TOOL and Yasso20 models with methodological comparisons. The only clear differences between the studied crops were that the land use was lower (−26–48%) for forage maize, and the freshwater eutrophication (+59–67%) and terrestrial acidification (+10–57%) were higher for perennial grasses compared with other forages. A risk for decreased SOC stock under continuous forage maize cultivation was observed. Forage maize could be used to supplement perennial grass cultivation without major associated environmental risks. Future research shall be conducted on the effect of forage choices on the environmental impact of boreal dairy milk production and on decreasing the current high uncertainty associated with nitrous oxide (N2O) emission factors and SOC stock modelling choices.

Biomass Resources and Biofuel Technologies: A Focus on Indian Development

As a result of the depletion of fossil resources, ongoing population growth, and the industrialized economy, energy demand has been rising quickly throughout the world. India is now the world’s third-largest oil consumer, surpassing Japan and Russia. Today, biofuel research is conducted worldwide because surrounding two essential characteristics: sustainability and renewability. Biofuels have gained considerable significance as a result of dwindling oil sources, worries about energy security, and the escalating environmental issues associated with climate change and greenhouse gas emissions. In most cases, biofuels are produced by subjecting materials that have been densified to the process of heat conversion. In the disciplines of research and development, alternative energy development is a top focus. Due to the depletion of fossil fuel resources, it has become important to find innovative replacements for fossil fuels, such as biofuels, to generate heat and power. Biofuels may be generated using several methodologies, encompassing biological, chemical, and physical approaches. The three steps of densification systems’ pre-, during-, and post-pelletization procedures convert biomass into pellets. Several agricultural wastes, such as grain dust, crop leftovers, and fruit tree residues, are available as sources of agricultural energy. Bioenergy from biomass, such as leftovers and energy crops, can be used to produce contemporary energy carriers. This article focuses on an overview of sustainable and renewable biofuel resources and their commercialization.

Crop residue heterogeneity: Decomposition by potential indigenous ligno-cellulolytic microbes and enzymatic profiling

The continuous depletion of fossil resources, energy-crisis and environmental pollution has gained popularity for careful selection of suitable microbial consortium to efficiently decompose crop residue and facilitate nutrient cycling. While crop residue is commonly incorporated into soil, the impact of the heterogeneity of residue on decomposition and biological mechanisms involved in extracellular carbon (C) cycle related enzyme activities remain not fully understood. To address this problem, an incubation study was conducted on chemical heterogeneity of straw and root residue with indigenous ligno-cellulolytic microbial consortium on extracellular enzymes as their activity is crucial for making in-situ residue management decisions under field condition. The activity of extracellular enzymes in different substrates showed differential variation with the type of enzyme and ranged from 16.9 to 77.6 µg mL−1, 135.7 to 410.8 µg mL−1, 66.9 to 177.1 µg mL−1 and 42.1 to 160.9 µg mL−1 for cellulase, xylanase, laccase and lignin peroxidase, respectively. Extracellular enzyme activities were sensitive to heterogeneity of biochemical constituent's present in straw and root residues and enhanced the decomposition processes with indigenous ligno-cellulolytic microbial consortium (Bacillus altitudinis, Streptomyces flavomacrosporus and Aspergillus terreus). Correlation matrix elucidated A. terreus and B. altitudinis as potential indigenous ligno-cellulolytic microbial inoculant influencing soil enzymatic activity (p < 0.001). This research work demonstrates a substantial impact of chemically diverse crop residues on the decomposition of both straw and root. It also highlights the pivotal role played by key indigenous decomposers and interactions between different microorganisms in governing the decomposition of straw and root primarily through release of extracellular enzymes. Consequently, it is novel bio-emerging strategy suggested that incorporation of the crop residues under field conditions should be carried out in conjunction with the potential indigenous ligno-cellulolytic microbial consortium for efficient decomposition in a short period of time under sustainable agriculture system.

Potential and Achievement of Floating Solar Photo Voltage in India

India’s contributions to the development of alternative energy sources are substantial. India has almost tripled the capacity of its renewable energy installations over the last five to six years, with coastal wind and solar photovoltaic (PV) installations accounting for the vast bulk of this growth. Since land scarcity is a big challenge nowadays, it is an excellent idea to construct solar plants on rivers, lakes, and dams, which are otherwise idle water bodies. The progressive depletion of fossil resources and the ever-increasing need for electricity both pose serious obstacles to progress. The electricity generated by floating solar photovoltaic systems is significant. India has completed a number of large-scale projects, including the 100MW Ramagundam, Telangana project and the NTPC Simhadri Solar Plant. This investigation highlights the potential benefits and challenges of these plants. Feasibility analysis of 5MW FSPV at Somasila Dam, Andhra Pradesh is also done in this paper. Additional to this, the article gave the economic and technological analysis of floating solar photovoltaics, in addition to discussing several case studies.

LaVO4 with alkali metal doping for enhanced photocatalytic water splitting

LaVO4 with alkali metal doping for enhanced photocatalytic water splitting

Scheduling of mobile charging stations with local renewable energy sources

Due to the depletion of fossil resources and increasing environmental concerns, electric vehicles (EVs) have been attracting more attention at the last decade. Their extensive integration into the energy systems, however, has led to numerous operational and technological challenges, especially during their bulk charging. In this study, an optimization algorithm based on mixed integer linear programming is proposed to dispatch mobile charging stations (MCSs), which have emerged as both an alternative and supplement to permanent charging stations (PCSs). It is aimed to mitigate the number of EVs that cannot be charged in PCSs, due mostly to the limited charging unit capacity and prolonged waiting times, by using an MCS. Five determinative cases involving a combination of different operating and pricing mechanisms are evaluated. The results reveal that the use of the MCS provides both economic and operational benefits. In the best case determined according to the result of the comparisons with various pricing mechanisms, the MCS provides an operational improvement of 64.3 % compared to the case without the MCS. The quantity of EVs requesting service is 1074 in all cases, while 986 EVs are served in the case with the best results. Besides, a profit increase of 46 % is achieved for the cases in which dynamic pricing is applied. An important point to note is that with the incentive mechanism applied, there is a significant increase in the profit in Case 5, while the number of EVs served is 967. In case 4, without incentive mechanism, the number of EVs served is 968.

Active sites engineered biomass-carbon as a catalyst for biodiesel production: Process optimization using RSM and life cycle assessment

Herein, we aimed at the production of porous biochar by simultaneous activation-graphitization. The active sites engineered biochar catalyst was functionalized using 4-DBS, which possessed a high surface area, and sulfur content of 1196.13 m2 g−1 and 1.9 mmol g−1, respectively. We extensively analyzed the catalyst using various techniques such as XRD, FTIR, TGA, NH3-TPD, SEM-EDS, TEM, BET, and XPS. We used this catalyst to optimize Jatropha curcas oil (JCO) transesterification, achieving a 97.1 ± 0.4% yield with the RSM-CCD method. Kinetic studies showed pseudo-first-order kinetics, and thermodynamics indicated an endothermic, nonspontaneous process.. A life cycle assessment was conducted to assess the environmental impacts of producing biodiesel from JCO, using 1 kg of biodiesel as the reference unit. The findings revealed that the total abiotic depletion of fossil resources throughout the entire biodiesel production process amounted to 52.1 MJ, the global warming potential was equivalent to 3.17 kg of CO2 emissions, the acidification potential was comparable to 0.027 kg of SO2 emissions, and the eutrophication potential was 0.016 kg of PO43−, human toxicity level 1.89 kg 1,4-DP eq and freshwater ecotoxicity to kg 1,4-DP equivalent for every 1 kg of biodiesel manufactured. The estimated cost of biodiesel produced was 1.3 USD ($) per kg, which mainly attributed to the high reusability of catalyst (82.5 ± 0.4% yield in 7th cycle), indicating high commercial applicability. Finally, the study proposes future recommendations based on identified gaps in the literature through innovative bibliometric analysis.

Catalysis in Biomass Valorization—Preface to the Special Issue

Biomass valorization has been the focus of substantial efforts in the industry and academia, addressing the issues of global warming and depletion of fossil resources [...]

A tasty solution to packaging waste? Life cycle assessment of edible coffee cups

Edible cups have been proposed as a solution to littering and plastic pollution arising from disposal of 500 billion beverage cups each year. We applied life cycle assessment and a littering indicator to benchmark the environmental performance of edible cups against mainstream cup types made from paper, polylactic acid (PLA), polystyrene (PS) and reusable cups made from polypropylene (PP) and steel. Various end-of-life treatment scenarios were analysed. Across most impact categories, edible cups incur the largest burdens, and reusable cups the smallest (if reused at least 54 times). Under default assumptions, per cup use, climate change burdens ranged from 0.004 to 0.1 kg CO2 equivalent, eutrophication burdens ranged from 6.26 × 10–6 to 4.21 × 10–4 kg N, fossil resource depletion burdens ranged from 0.05 to 0.284 MJ and water depletion burdens ranged from 0.002 to 0.437 m3. However, if edible cups are eaten after use and substitute a similar snack then their use could incur negligible environmental impact. Furthermore, edible cups demonstrate low littering potential and thus could play a role in transition towards more sustainable coffee consumption.

Non-isocyanate polyurethanes synthesized from terpenes using thiourea organocatalysis and thiol-ene-chemistry

The depletion of fossil resources as well as environmental concerns contribute to an increasing focus on finding more sustainable approaches for the synthesis of polymeric materials. In this work, a synthesis route towards non-isocyanate polyurethanes (NIPUs) using renewable starting materials is presented. Based on the terpenes limonene and carvone as renewable resources, five-membered cyclic carbonates are synthesized and ring-opened with allylamine, using thiourea compounds as benign and efficient organocatalysts. Thus, five renewable AA monomers are obtained, bearing one or two urethane units. Taking advantage of the terminal double bonds of these AA monomers, step-growth thiol-ene polymerization is performed using different dithiols, to yield NIPUs with molecular weights of above 10 kDa under mild conditions. Variation of the dithiol and amine leads to polymers with different properties, with Mn of up to 31 kDa and Tg’s ranging from 1 to 29 °C.

Structure-activity relationships of ZrO2 crystalline phases in the catalytic transfer hydrogenation of methyl levulinate with ethanol

The depletion of fossil resources is driving the research towards renewable alternatives, like lignocellulosic biomass. Therefore, the development of efficient continuous-flow processes, allowing to achieve better productivity compared to batch processes, will play a crucial role in promoting a sustainable transition. In this context, we report on the continuous-flow, gas-phase, catalytic transfer hydrogenation (CTH) of methyl levulinate and ethanol over zirconia catalysts, in particular focusing on the effect of two different crystalline phases (i.e. monoclinic, m-ZrO2, and tetragonal, t-ZrO2) on catalyst performance. An in-depth catalyst characterisation was coupled with both computational and 1H NMR relaxation studies to assess the structure-activity relationship, providing fundamental insights into the catalytic process and future catalyst optimization. The results, indicate that the higher Lewis acidity and basicity along with the lower affinity with ethanol of m-ZrO2 with respect to t-ZrO2 are responsible for the promotion of undesired oligomerisation reactions of angelica lactones responsible for catalyst deactivation.

CO rich syngas production from catalytic CO2 gasification-reforming of biomass components on Ni/CeO2

The advancement of biomass utilization technology is vital for addressing global climate change and the depletion of fossil resources. CO rich syngas production from the CO2 gasification-reforming of biomass components (cellulose, xylan, lignin, and starch) was investigated by a two-stage fixed bed reactor. The four biomass components were heated from room temperature to 600 °C in a CO2 atmosphere, among which lignin exhibited the highest residue fraction (51.6 wt.%) and the lowest gas yield (5.7 mmol gbiomass−1), whereas cellulose demonstrated the highest gas yield from CO2 gasification-reforming (14.6 mmol gbiomass−1). Nanorod CeO2 supported Ni catalysts were used to enhance volatile (tar) CO2 reforming reactions, and the gas yield increased by 104.3 % for cellulose, 103.3 % for xylan, 149.3 % for lignin, and 128.3 % for starch compared with noncatalytic CO2 gasification-reforming. Furthermore, the structure of fresh and used catalysts were characterized by X-ray diffraction (XRD), N2 adsorption/desorption isotherm, scanning electron microscope (SEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), H2-temperature programmed reduction (H2-TPR), and thermogravimetry (TGA). For the CO2 gasification-reforming of cellulose, the optimum CO yield of 27.6 mmol gbiomass−1 was achieved at a gasification/reforming temperature of 600/700 °C and a biomass/catalyst ratio of 6.25 using 2 %Ni/CeO2 catalyst. The stability tests of catalysts showed an approximately linear decrease in CO yield with the increase of the number of cycles, and catalyst deactivation resulted from Ni sintering and coke deposition.

Life cycle assessment of advanced grade PLA product with novel end-of-life treatment through depolymerization

Using biobased plastics has the potential to avoid fossil resource depletion and fossil CO2 emissions. Polylactic acid (PLA) is a fast-growing bio-based plastic made from fermented sugars. Nowadays, PLA is used to replace fossil-based polymers in healthcare and single-use applications, such as for packaging applications. However, PLA offers a much broader application range with the targeted use of a combination of its stereoisomers; PL(L)A and PL(D)A. A variety of these advanced grades of PLA can be used for multiple purposes in durable consumer products such as furniture. Recycling complex, mixed material and advanced grades of PLA is currently limited, as mechanical recycling has limitations in recycling mixed PLA grades. Using a depolymerization technology, products of such advanced grades of PLA can be recycled to form high-quality recycled PLA. A cradle-to-grave life cycle assessment study was executed to evaluate the sustainability of high-end durable product (a rug) with mixtures of PLA grade and the novel depolymerization technology. The findings of the study showed a 70 % reduction in CO2-eq. emissions compared to a conventionally designed rug. However, an increase is indicated in the following environmental impact categories: land use, eutrophication, and environmental toxicity. Sensitivity analyses for collection rates showcased that design for collection and recycling are key to obtaining a more sustainable biobased products. Additionally, scenario analysis supported depolymerization for PLA as recycling technology with low CO2-eq. emissions. Based on the results of the LCA and additional scenario analysis, the use of PLA is encouraged to be used in more durable and lasting products, such as furniture, from an environmental perspective, provided that the products are designed for collection and high-quality recycling to ensure material circularity.