Search Results (63)

Nitrogen dioxide (NO₂) is a major atmospheric pollutant and also a recoverable nitrogen resource, for which adsorption offers a promising technical pathway. This review systematically summarizes the recent progress in the removal of NO₂ from flue gas by adsorption methods, with a focus on material-level and process-level advancements. From the material perspective, three representative adsorbents—zeolites, activated carbons, and metal oxides—are comparatively evaluated in terms of their physicochemical properties, active sites, and adsorption mechanisms. Emphasis is placed on their adsorption capacity, selectivity, and hydrothermal stability, supported by both experimental and theoretical insights. From the process perspective, four adsorption-based technologies—Pressure Swing Adsorption (PSA), Temperature Swing Adsorption (TSA), Vacuum Pressure Swing Adsorption (VPSA), and Vacuum Temperature Swing Adsorption using multiple Gas circulations (GVTSA)—are analyzed regarding their principles, operational workflows, and engineering applications, with particular attention to the process intensification potential of GVTSA. The review identifies existing challenges in terms of material stability under complex conditions and process scalability, especially for severe environments such as nuclear reprocessing tail gases. Finally, future research directions are proposed toward developing multifunctional composite adsorbents with high capacity, strong environmental tolerance, and excellent regenerability, along with optimized and integrated adsorption processes, to achieve efficient NO₂ abatement and high-value recovery. Full article

Phenolic compounds are widespread environmental contaminants whose removal from water and wastewater is essential for ecosystem protection. Among the several purification technologies, the use of zero-valent metals has gained increasing interest in recent years. The identification of effective and environmentally friendly materials is a key issue for the development of this technology. In this study, zero-valent magnesium (ZVMg), a highly reactive non-toxic material, was used for the first time for the degradation of gallic acid (GA), chosen as a model phenolic compound, in an aqueous system. Several tests were conducted in order to identify the effect of pH, ZVMg amount, and temperature on the process performance. Moreover, the reusability of the reactive material in subsequent treatment cycles was assessed. Optimal operational conditions were achieved with a ZVMg amount of 0.3 g, corresponding to a ratio of 0.33 g_GA/g_Mg, reaching a removal efficiency of almost 90% in about 180 min. The performance was clearly favored by an alkaline environment, and yields close to the maximum values were reached under uncontrolled pH conditions. The increase in temperature significantly accelerated the reaction rate, which followed pseudo-first-order kinetic law, achieving high abatement percentages with a reduced quantity of ZVMg. Finally, Mg⁰ demonstrated good reusability, maintaining high efficiency, close to 78%, for up to four cycles, with the possibility of restoring the material’s activity through acid washing. The detected results confirm that ZVMg is a promising and sustainable reactive material for environmental remediation processes, offering an effective alternative for the treatment of water contaminated by phenolic compounds. Full article

Papermaking sludge, rich in intrinsic resource value, is effectively barred from direct deployment in environmental remediation, agriculture, or energy generation by its pronounced contaminant burden. Pyrolytic conversion into high-value paper sludge biochar, such as papermaking sludge biochar (PSBC) provides a green, efficient portal for closing its resource loop. In this study, papermaking sludge was converted into a series of paper sludge biochars (PSBCs) via oxygen-limited pyrolysis at 500–900 °C. The porous architecture, surface physicochemical properties, and crystalline structure of the biochars were comprehensively characterized, and their performance for aqueous tetracycline (TC) removal was systematically quantified. Pyrolysis at 900 °C afforded PSBC 900 with the lowest yield (36.05%) yet the highest Brunauer–Emmett–Teller (BET) surface area (79.53 m²/g), an extensively developed mesopore network, and the greatest degree of graphitization. Across an initial tetracycline (TC) concentration window of 20–160 mg/L, PSBC 900 delivered an equilibrium capacity (q_e) of 72.22 mg/g, outperforming PSBC 700 and PSBC 500 by factors of 1.3 and 1.8, respectively. Optimal uptake was achieved at a dosage of 1.0 g/L, pH 7, and 120 min contact time. Among the background cations examined, Mg²⁺ exerted a pronounced inhibitory effect, whereas Na⁺, K⁺, and Ca²⁺ exerted negligible interference. The adsorption process was accurately described by the pseudo-second-order kinetic model and the Langmuir isotherm (R² > 0.999), yielding a theoretical maximum capacity (q_m) of 76.39 mg/g for PSBC 900 at 313 K. Thermodynamic parameters ($∆{\mathrm{G}}^{\mathsf{\theta }}$ < 0, $∆{\mathrm{H}}^{\mathsf{\theta }}$ > 0, $∆{\mathrm{S}}^{\mathsf{\theta }}$ > 0) confirm a spontaneous, endothermic, and entropy-driven process. After five consecutive adsorption–desorption cycles, PSBC 900 retained >64.68% of its original efficiency, demonstrating excellent regenerability. Paper sludge biochar enables a “waste-to-treat-waste” strategy for the efficient abatement of tetracycline, offering an economically viable and high-performance technology that advances the remediation of tetracycline-laden wastewaters. Full article

Non-thermal plasma (NTP) is a fast, reagent-free technology for dye removal, yet its performance is highly dependent on the operating conditions and on plasma–catalyst interactions. In this work, a coaxial falling-film dielectric barrier discharge (DBD) reactor was optimized for the degradation and decolorization of organic dyes, with ceria (CeO₂) employed as a catalyst. For the first time, CeO₂ prepared via a supercritical antisolvent (SAS) micronization route was tested in plasma-assisted dye decolorization and directly compared with its non-micronized counterpart. Optimization of plasma parameters revealed that oxygen feeding, an input voltage of 12 kV, a gas flow of 0.2 NL·min⁻¹, and an initial dye concentration of 20 mg·L⁻¹ resulted in the fastest decolorization kinetics. While the anionic dye Acid Yellow 36 exhibited electrostatic repulsion and negligible plasma–ceria synergy, the cationic dyes Crystal Violet and Methylene Blue showed strong adsorption on the negatively charged CeO₂ surface and pronounced plasma–catalyst synergy, with SAS-derived CeO₂ consistently outperforming the non-micronized powder. The SAS catalyst, characterized by a narrow particle size distribution (DLS) and spherical morphology (SEM), ensured improved dispersion and interaction with plasma-generated species, leading to significantly shorter decolorization radiation times compared to the literature benchmarks. Importantly, this enhancement translated into higher energy efficiency, with complete dye removal achieved at a lower specific energy input than both plasma-only operation and non-micronized CeO₂. Scavenger tests confirmed •OH radicals as the dominant oxidants, while O₃, O₂•⁻, and e⁻_a played secondary roles. Tests on binary dye mixtures (CV + MB) revealed synergistic decolorization under plasma-only conditions, and the CeO₂-SAS catalyst maintained high overall efficiency despite competitive adsorption effects. These findings demonstrate that SAS micronization of CeO₂ is an effective material-engineering strategy to unlock plasma–catalyst synergy and achieve rapid, energy-efficient dye abatement for practical wastewater treatment. Full article

Climate change mitigation demands scalable, technologically mature solutions capable of addressing emissions from hard-to-abate sectors. Carbon Capture and Storage (CCS) offers one of the few ready pathways for deep decarbonization by capturing CO₂ at large point sources and securely storing it in deep geological formations. The long-term viability of CCS depends on well control strategies/injection schedules that maximize storage capacity, maintain containment integrity, ensure commercial deliverability and remain economically viable. However, current practice still relies heavily on manual, heuristic-based well scheduling, which struggles to optimize storage capacity while minimizing by-products such as CO₂ recycling within the high-dimensional space of interdependent technical, commercial, operational, economic and regulatory constraints. This study makes two contributions: (1) it systematically reviews, maps and characterizes these multidimensional constraints, framing them as an integrated decision space for CCS operations, and (2) it introduces an industry-ready optimization framework—Automated Optimization of Well control Strategies through Dynamic Time–Space Discretization—which couples reservoir simulation with constraint-embedded, hierarchical refinement in space and time. Using a modified genetic algorithm, injection schedules evolve from coarse to fine resolution, accelerating convergence while preserving robustness. Applied to a heterogeneous saline aquifer model, the method was tested under both engineering and financial objectives. Compared to an industry-standard manual schedule, optimal solutions increased net stored CO₂ by 14% and reduced recycling by 22%, raising retention efficiency to over 95%. Under financial objectives, the framework maintained these technical gains while increasing cumulative cash flow by 23%, achieved through leaner, smoother injection profiles that minimize costly by-products. The results confirm that the framework’s robustness, scalability and compatibility with commercial simulators make it a practical pathway to enhance CCS performance and accelerate deployment at scale. Full article

Crude oil accounts for approximately 40% of global energy consumption, and the refining sector is a major contributor to greenhouse gas (GHG) emissions, particularly through the production of hard-to-abate fuels such as aviation fuel and fuel oil. This study disaggregates the refinery into its key process units to identify decarbonization opportunities along the entire production chain. Units are categorized into combustion-based processes—including crude and vacuum distillation, hydrogen production, coking, and fluid catalytic cracking—and non-combustion processes, which exhibit lower emission intensities. The analysis reveals that GHG emissions can be reduced by up to 60% with currently available technologies, without requiring major structural changes. Electrification, residual heat recovery, renewable hydrogen for desulfurization, and process optimization through digital twins are identified as priority measures, many of which are also economically viable in the short term. However, achieving full decarbonization and alignment with net-zero targets will require the deployment of carbon capture technologies. These results highlight the significant potential for emission reduction in refineries and reinforce their strategic role in enabling the transition toward low-carbon fuels. Full article

Cardiac devices have transformed the management of heart failure, ventricular arrhythmias, ischemic cardiomyopathy, and valvular heart disease. Technologies such as cardiac resynchronization therapy (CRT), conduction system pacing, left ventricular assist devices (LVADs), and implantable cardioverter-defibrillators have contributed to abated global cardiovascular risk through action onto pathophysiological processes such as mechanical unloading, electrical resynchronization, or hemodynamic optimization, respectively. While their clinical benefits are well established, their long-term molecular and structural effects on the myocardium remain under investigation. Cardiac devices dynamically interact with myocardial and vascular biology, inducing molecular and extracellular matrix adaptations that vary by pathology. CRT enhances calcium cycling and reduces fibrosis, but chronic pacing may lead to pacing-induced cardiomyopathy. LVADs and Impella relieve ventricular workload yet alter sarcomeric integrity and mitochondrial function. Transcatheter valve therapies influence ventricular remodeling, conduction, and coronary flow. Understanding these remodeling processes is crucial for optimizing patient selection, device programming, and therapeutic strategies. This narrative review integrates the current knowledge on the molecular and structural effects of cardiac devices, highlighting their impact across different disease settings. Full article

A mass abatement scalable system through managed aquifer recharge (MAR-MASS) improves mass extraction from groundwater with a variable-density flow. This method is superior to conventional injection systems because it promotes uniform mass displacement, reduces density gradients, and increases mass extraction efficiency over time. Simulations of various scenarios involving hydrogeologic variables, including hydraulic conductivity, vertical anisotropy, specific yield, mechanical dispersion, molecular diffusion, and mass concentration in aquifers, have identified critical variables and parameters influencing mass transport interactions to optimize the system. MAR-MASS is adaptable across hydrogeologic conditions in aquifers that are 25–75 m thick, comprising unconsolidated materials with hydraulic conductivities between 5 and 100 m/d. It is effective in scenarios near coastal areas or in aquifers with variable-density flows within the continent, with mass concentrations of salts or solutes ranging from 3.5 to 35 kg/m³. This system employs a modular approach that offers scalable and adaptable solutions for mass extraction at specific locations. The integration of programming tools, such as Python 3.13.2, along with technological strategies utilizing parallelization techniques and high-performance computing, has facilitated the development and validation of MAR-MASS in mass extraction with remarkable efficiency. This study confirmed the utility of these tools for performing calculations, analyzing information, and managing databases in hydrogeologic models. Combining these technologies is critical for achieving precise and efficient results that would not be achievable without them, emphasizing the importance of an advanced technological approach in high-level hydrogeologic research. By enhancing groundwater quality within a comparatively short time frame, expanding freshwater availability, and supporting sustainable aquifer recharge practices, MAR-MASS is essential for improving water resource management. Full article

The construction sector makes a major contribution to global greenhouse gas emissions, in which cement alone produces approximately 7–8% of global CO₂ emissions. To abate environmental impact and promote sustainable construction, alternative low-carbon cementitious materials are gaining attention. Biochar (BC), a carbon-rich material obtained from biomass sources through the process of pyrolysis, has surfaced as a capable supplementary cementitious material due to its carbon capture capabilities and positive impact on the characteristics of cement composites. This review investigates the role of BC in cement composites, including its effects on hydration kinetics, microstructural development, fresh-state properties, and its optimal utilisation. The study also highlights the internal curing capabilities of BC when used in cement composites, its role in promoting hydration product formation, and its dual function in enhancing mechanical performance while facilitating carbon capture. Despite the benefits, there are some challenges such as variable BC properties, optimal dosage, and scalability. The review highlights the need for standardisation and further research to fully harness BC’s potential as a sustainable component in low-carbon construction technologies. Full article

Against the backdrop of increasing extreme weather events associated with global climate change, regulating carbon dioxide emissions, a primary contributor to atmospheric warming, has emerged as a pressing global challenge. Focusing on China as a representative case study of major developing economies, this research examines industrial carbon emission patterns during 2001–2022. Methodologically, it introduces an innovative analytical framework that integrates the Generalized Divisia Index Method (GDIM) with the Low Emissions Analysis Platform (LEAP) to both decompose industrial emission drivers and project future trajectories through 2040. Key findings reveal that:the following: (1) Carbon intensity in China’s industrial sector has been substantially decreasing under green technological advancements and policy interventions. (2) Industrial restructuring demonstrates constraining effects on carbon output, while productivity gains show untapped potential for emission abatement. Notably, the dual mechanisms of enhanced energy efficiency and cleaner energy transitions emerge as pivotal mitigation levers. (3) Scenario analyses indicate that coordinated policies addressing energy mix optimization, efficiency gains, and economic restructuring could facilitate achieving industrial carbon peaking before 2030. These results offer substantive insights for designing phased decarbonization roadmaps, while contributing empirical evidence to international climate policy discourse. The integrated methodology also presents a transferable analytical paradigm for emission studies in other industrializing economies. Full article

Is it possible to control NPS (non-point source) pollution whose sources, sizes, and origins are difficult to identify? This study provides a positive answer in a non-cooperative n-firm oligopoly model in which the firms determine levels of differentiated goods and abatement technologies. It first derives a Cournot–Nash equilibrium in which the firms maximize their profit and emit pollution under the ambient charge scheme, combining rewards from the total NPS concentration less than a given standard with the penalties above. The effect of the ambient charge is then analytically shown in homogeneous and heterogeneous duopoly and triopoly. Further, possible controllability is numerically examined in the case of $n\ge 4$. Full article

In the context of mounting concerns over carbon emissions and the need to accelerate the energy transition, green hydrogen has emerged as a strategic solution for decarbonizing hard-to-abate sectors. This paper introduces a methodological innovation by proposing the Green Hydrogen Efficiency Index (GHEI), a unified and quantitative framework that integrates multiple stages of the hydrogen value chain into a single comparative metric. The index encompasses six core criteria: electricity source, water treatment, electrolysis efficiency, compression, end-use conversion, and associated greenhouse gas emissions. Each are normalized and weighted to reflect different performance priorities. Two weighting profiles are adopted: a first profile, which assigns equal importance to all criteria, referred to as the balanced profile, and a second profile, derived using the analytic hierarchy process (AHP) based on structured expert judgment, named the AHP profile. The methodology was developed through a systematic literature review and was applied to four representative case studies sourced from the academic literature, covering diverse configurations and geographies. The results demonstrate the GHEI’s capacity to distinguish the energy performance of different green hydrogen routes and support strategic decisions related to technology selection, site planning, and logistics optimization. The results highlight the potential of the index to contribute to more sustainable hydrogen value chains and advance decarbonization goals by identifying pathways that minimize energy losses and maximize system efficiency. Full article

To address the challenge of abatement of volatile organic compounds (VOCs) in environmental catalysis, this study developed a temperature-gradient hydrothermal strategy to fabricate SrSn(OH)₆ nanocatalysts and systematically investigatd their photocatalytic performance and mechanisms for gaseous toluene degradation. SrSn(OH)₆ (SSH) was synthesized via a simple hydrothermal method with optimal preparation conditions identified as a reaction temperature of 140 °C and duration of 12 h. The crystallinity of SrSn(OH)₆ was modulated by adjusting the pH of the precursor solution, yielding materials with distinct morphologies, specific surface areas, and band gaps. The narrowed band gap of SrSn(OH)₆ nanocatalysts facilitated electron excitation to generate additional photogenerated electron-hole pairs. The SSH-10.5 sample with ordered planar and hole-like structures promoted carrier migration, effectively suppressed electron-hole recombination, and enhanced the conversion of abundant surface hydroxyl groups into hydroxyl radicals. Under UV irradiation, SSH-10.5 achieved a toluene degradation efficiency of 69.56% and showed excellent stability after five reuse cycles. Electron spin resonance analysis confirmed the presence of •OH and •O₂⁻ radicals in the reaction system, with •OH identified as the dominant active species. In situ FT-IR spectroscopy revealed that •OH and •O₂⁻ radicals attacked the methyl group of toluene, converting it into intermediates including benzyl alcohol, benzaldehyde, and benzoic acid. This work provides a novel design of high-efficiency VOC-photocatalytic materials and shows significant implications for advancing industrial exhaust gas purification technologies. Full article

Volatile organic compound (VOC) emissions have become a critical environmental concern due to their contributions to photochemical smog formation, secondary organic aerosol generation, and adverse human health impacts in the context of accelerated industrialization and urbanization. Catalytic oxidation over perovskite-type catalysts is an attractive technological approach for efficient VOC abatement. This review systematically evaluates the advancements in perovskite-based catalysts for VOC oxidation, focusing on their crystal structure–activity relationships, electronic properties, synthetic methodologies, and nanostructure engineering. Emphasis is placed on metal ion doping strategies and supported catalyst configurations, which have been demonstrated to optimize catalytic performance through synergistic effects. The applications of perovskite catalysts in diverse oxidation systems, including photocatalysis, thermal catalysis, electrocatalysis, and plasma-assisted catalysis, are comprehensively discussed with critical analysis of their respective advantages and limitations. It summarizes the existing challenges, such as catalyst deactivation caused by carbon deposition, sulfur/chlorine poisoning, and thermal sintering, as well as issues like low energy utilization efficiency and the generation of secondary pollutants. By consolidating current knowledge and highlighting future research directions, this review provides a solid foundation for the rational design of next-generation perovskite catalysts for sustainable VOC management. Full article

The COVID-19 pandemic highlighted the urgent need for sustainable and scalable air disinfection technologies in HVAC systems, addressing the limitations of energy-intensive and chemically intensive conventional methods. This study developed and evaluated a pilot experimental installation integrating plasma chemistry and photocatalysis for airborne pathogen and pollutant mitigation. The installation, designed with a modular architecture to simulate real-world HVAC dynamics, employed a bipolar plasma ioniser, a TiO₂ photocatalytic module, and an adsorption-catalytic module for ozone abatement. Characterization techniques, including SEM and BET analysis, were used to evaluate the morphology and surface properties of the catalytic materials. Field tests in a production room demonstrated a 60% reduction in airborne microflora in three days, along with effective decomposition of ozone. The research also determined the optimal electrode geometry and interelectrode distance for stable corona discharge, which is essential for efficient plasma generation. Energy-efficient design considerations, which incorporate heat recovery and heat pump integration, achieved a 7–8-fold reduction in air heating energy consumption. These results demonstrate the potential of integrated plasma photocatalysis as a sustainable and scalable approach to enhance indoor air quality in centralised HVAC systems, contributing to both public health and energy efficiency. Full article