ABSTRACT A sustainable healthcare waste (HCW) management strategy for Dhaka integrating material flow analysis and comparative life cycle assessment is proposed. The current scenario (SC1), heavily reliant on landfilling, low recycling, and incineration without energy integration, is compared with the proposed alternative scenario (SC2), with higher material recycling, waste‐to‐energy conversion, and heat integration. Using gate‐to‐grave life‐cycle assessment across eighteen ReCiPe 2016 midpoint (H) impact categories, the proposed SC2 outperforms SC1 in ten categories, notably acidification potential by 96%, land‐use potential by 97%, climate change impacts by 78%, and marine eutrophication by 44%, while PM formation potential falls by 20.499 kg PM 2.5 ‐eq and energy resource depletion becomes a net credit through 20572 kWh/day of recovered electricity. However, trade‐offs are observed in the toxicity, eutrophication, and photochemical oxidant formation categories, notably carcinogenic human toxicity (∼3.8x increase), marine ecotoxicity (∼2.3x increase), freshwater eutrophication (∼97% increase), and photochemical oxidant formation potential (∼3x increase). The proposed scheme also supports Bangladesh's drive toward SDG 7 and 13 outright, and toward SDG 3, 6, 11, and 14 once the toxicity and oxidant formation burdens are controlled. Our findings can provide a substantial quantitative framework for improving existing systems to achieve sustainability with a circular economy strategy.
ABSTRACT Liquefied natural gas (LNG) regasification releases substantial cryogenic energy, presenting an opportunity to reframe LNG terminals from simple gas suppliers to integrated energy hubs. This study evaluates the system‐level integration of two parallel organic Rankine cycles (ORCs) with hydrogen production pathways—proton exchange membrane water electrolysis (PEMWE) and seawater direct electrolysis (SWDE)—to assess their economic and environmental feasibility. A comprehensive techno‐economic analysis and life cycle assessment reveal that, owing to the dominant influence of LNG feedstock costs and large LNG throughput, the integration of these systems results in only marginal variations in the minimum selling price and global warming potential of natural gas. Among the evaluated pathways, ORC–PEMWE demonstrates a more favorable balance, enabling low‐carbon hydrogen production (0.42 kg CO2‐eq/kg‐H2), whereas SWDE remains constrained under the current assumptions due primarily to the conservative replacement interval and associated replacement costs, together with its higher assumed capital requirement. Furthermore, an environmental techno‐economic assessment indicates that capital expenditure‐oriented policy support is more effective than carbon credits in improving system competitiveness. Overall, this work provides a realistic, policy‐relevant framework for transforming existing LNG infrastructure into multifunctional energy systems while maintaining economic feasibility.
ABSTRACT Cigarette butts are a persistent plastic‐rich waste stream commonly disposed of in landfill, creating environmental and resource‐recovery challenges. Their cellulose‐acetate‐rich filters and organic components, however, provide a potential precursor for waste‐derived porous carbons. Here, whole cigarette‐butt (WCB) waste was converted into hierarchical porous carbons by carbonization followed by Na 2 CO 3 activation. The pore structure was tuned from poorly developed porosity to a micro–mesoporous network whose development varied with Na 2 CO 3 loading. Pore development increased across the WCB‐ x series up to 83 wt.% Na 2 CO 3 , beyond which over‐activation reduced the effective adsorption network. WCB‐83, the highest‐uptake sample within the Na 2 CO 3 series, combined a specific surface area of 750 m 2 g − 1 with the micropore volume of 0.24 cm 3 g − 1 , delivering 3.0 mmol g − 1 CO 2 at 273 K and 1 bar. This exceeded both over‐activated WCB‐91 (2.6 mmol g − 1 ) and the NaOH‐activated counterpart WCB‐OH‐83 (1.2 mmol g − 1 ). At 298 K, WCB‐83 adsorbed 0.3 mmol g − 1 CO 2 at 0.15 bar and 1.0 mmol g − 1 at 1 bar. Temperature‐dependent adsorption gave apparent isosteric heats of approximately 53 to 59 kJ mol − 1 , while Ideal Adsorbed Solution Theory (IAST) ‐predicted CO 2 /N 2 selectivity reached 120. This work demonstrates a waste‐valorization strategy for converting cigarette‐butt waste into CO 2 ‐selective hierarchical carbon adsorbents.
ABSTRACT Lignocellulosic polylactic acid biorefineries face challenges due to high energy demand, complex downstream processing, and underutilized co‐products. Although lignocellulosic biomass is a promising feedstock, the sustainability, and economic impacts of integrating multiple value‐added products remain unclear. This study develops an integrated thermodynamic, exergoeconomic, exergoenvironmental, and renewability assessment of bagasse‐ and corn stover‐based biorefineries producing polylactic acid, electricity, and co‐products including succinic acid, xylitol, and adhesives. Sugarcane bagasse exhibits higher fuel exergy input (103.94–138.47 GJ per functional unit (FU)) than corn stover (97.41–128.49 GJ/FU), with marginally higher product exergy output. Overall exergy efficiencies remain comparable (44%–64% for corn stover and 47%–65% for bagasse). Electricity‐integrated configurations show poorer thermodynamic performance, with exergy destruction exceeding 55 GJ/FU, whereas adhesive‐integrated configurations reduce destruction to 45.45–50.75 GJ/FU (corn stover) and 47.39–47.72 GJ/FU (bagasse), achieving efficiencies up to 65%. Exergoeconomic results indicate that downstream purification dominates cost formation. Succinic acid purification costs increase from 344.19 to 958.85 USD/GJ (corn stover to bagasse), while xylitol purification reaches 566.57 and 288.04 USD/GJ, respectively. Exergoenvironmental analysis identifies purification and pretreatment as hotspots. Renewability analysis shows that electricity‐based configurations remain non‐renewable (renewability indicator (RI)<0), whereas adhesive‐integrated scenarios achieve partial renewability (RI = 0.35–0.47). Overall, co‐product strategy and downstream processing influence system performance more strongly than feedstock selection.
ABSTRACT Climate change is increasingly recognized as a determinant of metabolic health. Emerging evidence indicates that rising temperatures impair glucose homeostasis—specifically through reduced brown adipose tissue activity and increased insulin resistance—thereby exacerbating type 2 diabetes mellitus (T2DM) risk. Concurrently, food systems drive substantial greenhouse gas emissions (GHGE), with gender‐differentiated dietary patterns uniquely influencing both environmental impact and health outcomes. In this perspective, we move beyond well‐established separate links to propose an original integrated and systemic conceptual framework. This framework connects gender‐related drivers in dietary behaviors, GHGE, global warming, brown adipose tissue dysfunction, and T2DM risk into an integrated multidimensional feedback model, providing a novel basis to generate hypotheses for future mechanistic, epidemiological, and intervention studies, supporting gender‐sensitive prevention strategies.
