The widespread presence of fluoroquinolone antibiotics (such as ciprofloxacin, CIP) in aquatic environments poses a serious threat to ecosystems and human health. Therefore, it is urgent to explore adsorbents with superior CIP removal performance and cost-effectiveness. Hence, this study employed KOH activation to convert pinecone biomass into low-cost, environmentally friendly porous carbon, which was further modified with three metal dopants (Fe, Mg, and Mn). Metal incorporation markedly enhanced porosity (up to 1530.44 m(2) g(-1)) and introduced uniformly dispersed metal-O active sites. The optimized pore size (similar to 2.1 nm) was approximately twice the molecular dimension of CIP, favoring rapid diffusion and efficient adsorption. Among these, Fe-doped porous carbon (Fe-PC) exhibited the highest CIP adsorption capacity (468.4 mg g(-1)), outperforming most reported biochar-based adsorbents. Kinetic and isotherm analyses indicated that CIP adsorption followed monolayer chemisorption behavior. FT-IR, XPS, zeta potential analyses, and DFT calculations identified Fe-O coordination sites as the dominant adsorption centers, synergistic with pi-pi interactions, electrostatic attraction, and pore filling. DFT further revealed the shortest Fe-O_CIP coordination distance (1.87 & Aring;), pronounced interfacial charge redistribution in the Fe-PC/CIP complex, and the lowest adsorption energy (-4.52 eV) compared with pristine PC, confirming enhanced chemisorptive adsorption on Fe-PC. Moreover, Fe-PC exhibited good pH adaptability, ionic stability, and reusability, indicating potential applicability in complex aqueous environments. Cost analysis revealed the competitive cost of Fe-PC (27.47 $ kg(-1)) with commercial activated carbon. This study provides mechanistic insights and scalable strategies for designing metal-modified biochar for efficient antibiotic removal.

Biomass-derived porous carbons are attractive for CO2 capture and supercapacitive energy storage because of their low cost and tunable porosity. Hierarchical porous carbons were synthesized from pinecone biomass via template-free KOH activation. The activation temperature and KOH/precursor ratio were systematically varied to tune the ultramicroporosity (<0.7 nm), specific surface area, and micropore-to-mesopore ratio of the samples. At 298 K and 1 bar, the optimized carbon exhibited a CO2 uptake of 3.83 mmol g(-1), a CO2/N-2 selectivity of 11, and excellent regenerability. As supercapacitor electrodes, they delivered a specific capacitance of 266.08 F g(-1) at 0.5 A g(-1), an energy density of 25.3 Wh kg(-1), a power density of 1600 W kg(-1), and 95.02 % capacitance retention after 10,000 charge/discharge cycles, surpassing the performance of typical porous carbons. Structure-performance analysis indicated that CO2 adsorption was governed by ultramicroporosity rather than the total surface area, whereas the rate capability depended on a well-connected micro/mesopore network. A web-like ("spider-web") architecture formed during activation provides continuous mass transfer pathways and lowers charge-transfer resistance, enabling simultaneous enhancement of CO2 capture and capacitive performance. This approach offers a scalable route to multifunctional porous carbons and a mechanistic basis for porosity-optimized design.

Layered double hydroxides (LDHs) are promising pseudocapacitive materials but suffer from poor conductivity, nanosheet restacking, and weak electrode-substrate coupling. Herein, a ZIF-67-assisted precursor conversion strategy is developed to construct hydrangea-like NiCoMn-LDH nanosheets on nickel foam through a two-step in situ growth and hydrothermal reconstruction. Nickel foam provides a conductive scaffold, while ZIF-67 acts as both a sacrificial template and a local Co source, enabling confined reconstruction of ternary LDH nanosheets into interconnected porous architecture. Benefiting from this integrated structural and compositional regulation, the optimized NCM-LDH/NF-0.5 electrode delivers 2258 F g−1 at 1 A g−1 and retains 83.2% of its capacitance after 5000 cycles. The assembled asymmetric supercapacitor maintains 81.6% capacitance retention after 5000 cycles. DFT calculations reveal interfacial charge redistribution, enhanced electronic states near the Fermi level, and favorable OH− adsorption, consistent with reduced charge-transfer resistance.

Metallic bipolar plates (BPPs) are crucial for advancing proton exchange membrane fuel cells (PEMFCs) because they dictate the stack durability, efficiency, and cost. Although stainless steel, aluminum, and titanium have been widely studied, their intrinsic trade-offs in terms of corrosion resistance, conductivity, and manufacturability remain major barriers to commercialization. This review provides a comparative framework that unifies disparate performance metrics, enabling the direct evaluation of the cost–durability–scalability balance across different metallic substrates. Particular emphasis is placed on surface engineering strategies, including carbon-based layers, nitrides/carbides, conductive polymers, and emerging MXene or high-entropy alloy coatings, which suppress interfacial contact resistance and enhance defect tolerance. Beyond short-term tests, this review systematically dissects long-term degradation mechanisms under realistic PEMFC conditions, such as humidity cycling, start–stop transients, and contaminant exposure, which are often overlooked in previous surveys. By linking material selection, coating design, and aging pathways, this study outlines critical research gaps and proposes future directions centered on scalable manufacturing, sustainable modification, and durability metrics (ΔICR@1000 h, Δjcorr@1000 h). These insights aim to guide the rational development of next-generation metallic BPPs that reconcile performance with industrial feasibility.

Reducing atmospheric CO2 requires low cost and energy efficient adsorbents, yet porous carbons are still often designed primarily based on BET surface area. Here, pinecone-derived porous carbons were synthesized via metal-assisted activation to tailor ultramicropore structure and surface chemistry. The optimized Mn-600-700 sample shows a CO2 uptake of 4.18 mmol g-1 at 298.15 K, with high CO2/N2 selectivity of 13.56 at 1 bar and a moderate adsorption heat of 21.28 kJ mol-1, together with initial adsorption-desorption regenerability. Correlation analysis reveals that CO2 uptake is governed mainly by ultramicropores rather than total surface area, indicating a confinement-controlled mechanism relevant to low pressure capture. Dual-site Langmuir fitting and DFT calculations based on an idealized metal-O-modified graphene model further suggest that polarized metal-carbon interfacial sites enhance surface polarization and CO2 affinity without inducing strong chemisorption, thereby preserving reversibility. In contrast, electrochemical charge storage depends more on ion-accessible micropores and mesopore-assisted transport. This work clarifies the distinct pore-structure requirements for CO2 capture and capacitive storage and provides a practical strategy for designing sustainable biomass-derived carbons.

ABSTRACT The emerging pollutant chloramphenicol (CAP) is highly environmentally persistent and biotoxic, causing extreme environmental harm. This study investigates the removal of CAP from aqueous solutions using biochar derived from pinecones. The biochars were activated at 800°C using KOH with different mass ratios to the carbonized sample (2:1, 4:1, and 6:1). Among them, the biochar with a KOH ratio of 4:1 (PCK4‐800) exhibits the highest pore volume (1.8 cm 3 g −1 ) and a specific surface area (3131.6 m 2 g −1 ). Batch experiments reveal that the CAP adsorption capacity of the biochar is positively correlated with its specific surface area. At pH 7, PCK4‐800 achieves a removal efficiency of up to 92% for a 100 mg L −1 CAP solution using a dosage of just 0.1 g L −1 . This performance surpasses that of recently reported adsorbents. Kinetic and thermodynamic model fitting results indicate that chemical adsorption within a monomolecular layer dominates physical adsorption. The primary adsorption mechanisms involve pore filling and π‐π interactions, while secondary mechanisms include electrostatic effects and hydrogen bonding. Thermodynamic parameters confirm that the adsorption process is endothermic and spontaneous. Moreover, the removal efficiency of PCK4‐800 remains above 80% after five regeneration cycles. In summary, the high removal efficiency and excellent regeneration potential of PCK4‐800 demonstrate its suitability as an effective adsorbent for antibiotic removal.

Download This Paper Open PDF in Browser Add Paper to My Library Share: Permalink Using these links will ensure access to this page indefinitely Copy URL Hydrophobic Shell of Bio-Based Polyurethane Coated on Hydrothermally Stable Core of Zeolite for Direct Steam Generation from Hot Water in a Solid Sorption Heat Pump 21 Pages Posted: 26 Feb 2024 See all articles by Xiaoran HeXiaoran HeZhengzhou UniversityBing XueZhengzhou University - School of Mechanical and Power EngineeringRuixun WeiZhengzhou UniversityKanglong LiaoZhengzhou UniversityGuangyao Liaffiliation not provided to SSRNTaibao ZhaoZhengzhou University of Light Industry Abstract Although the direct contact heat exchange method has been proposed in the adsorption heat pump for high-temperature steam generation, the presence of free water within the adsorbents limits the improvement of system performance. A shell-core structure was prepared using a hydrothermally stable zeolite 13X as the core and a hydrophobic bio-based polyurethane (BPU) as the shell through a drum coating method. SEM results proved the successful preparation of 13X@SBPU3 (BPU doped with 3 wt% hydrophobically modified nano-SiO2) with a shell layer thickness ranging from 7.5 to 9.0 μm. Thermogravimetric analysis results showed that the shell-core zeolite exhibited good thermal stability up to 300 °C. The water content inside the 13X@SBPU3 was measured to be 69.0 % lower than that of 13X. Cyclic operation based on a packed bed of the shell-core zeolite showed 218~233 ℃ steam generated from hot water at 72 °C, while 140 °C air was used for regeneration. The steam temperature and generation rate of the shell-core zeolite were increased by 22.7% and 21.6%, respectively. The quantity of free water in the packed bed was greatly reduced, which resulted in a 49.4% reduction in regeneration consumption. The Coefficient of Performance for Heating (COPh) and Specific Heating Power (SHP) of the shell-core zeolite were maximized by 91% and 12.3%, respectively. The tiny protrusions on the surface of the SiO2-modified shell and the air within the pores created an air film which effectively prevented liquid water. Consequently, water could only enter the adsorbent in the form of water vapor. Therefore, the reduction in free liquid water volume inside the zeolite 13X greatly reduces the regeneration energy consumption and effectively improves the system efficiency. Keywords: Shell-core structure, coating, Surface Modification, Adsorption heat pump, High-temperature steam. Suggested Citation: Suggested Citation He, Xiaoran and Xue, Bing and Wei, Ruixun and Liao, Kanglong and Li, Guangyao and Zhao, Taibao, Hydrophobic Shell of Bio-Based Polyurethane Coated on Hydrothermally Stable Core of Zeolite for Direct Steam Generation from Hot Water in a Solid Sorption Heat Pump. Available at SSRN: https://ssrn.com/abstract=4738688 Xiaoran He Zhengzhou University 100 Science AvenueZhengzhou, CO 450001China Bing Xue (Contact Author) Zhengzhou University - School of Mechanical and Power Engineering ( email ) ZhengzhouChina Ruixun Wei Zhengzhou University ( email ) 100 Science AvenueZhengzhou, CO 450001China Kanglong Liao Zhengzhou University ( email ) 100 Science AvenueZhengzhou, CO 450001China Guangyao Li affiliation not provided to SSRN ( email ) No Address Available Taibao Zhao Zhengzhou University of Light Industry ( email ) China Download This Paper Open PDF in Browser Do you have negative results from your research you’d like to share? Submit Negative Results Paper statistics Downloads 0 Abstract Views 19 39 References PlumX Metrics Related eJournals Energy Engineering eJournal Follow Energy Engineering eJournal Subscribe to this fee journal for more curated articles on this topic FOLLOWERS 157 PAPERS 18,641 Feedback Feedback to SSRN Feedback (required) Email (required) Submit If you need immediate assistance, call 877-SSRNHelp (877 777 6435) in the United States, or +1 212 448 2500 outside of the United States, 8:30AM to 6:00PM U.S. Eastern, Monday - Friday.

Adsorption heat pump is a promising technology to generate steam from the recovery of low-grade waste heat. Although the direct contact heat exchange method has been proposed in the adsorption heat pump, the presence of free water within the adsorbents limits the improvement of system performance. In this work, a shell-core structure was prepared using a hydrothermally stable zeolite 13X as the core and a hydrophobic bio-based polyurethane as the shell through a drum coating method. The Scanning Electron Microscopy results proved the successful preparation of shell-core zeolites with a shell layer thickness ranging from 7.5 to 9.0 mu m. Thermogravimetric analysis results showed that the shell-core zeolite exhibited good thermal stability up to 300 degrees C. The water content is reduced by 69 % compared to unmodified zeolite 13X. Cyclic operation based on a packed bed of the shell-core zeolite showed 218 similar to 233 degrees C steam generated from hot water at 72 degrees C, while 140 degrees C hot dry gas was used for regeneration. The steam temperature and generation rate of the shell-core zeolite were increased by 22.7 % and 21.6 %, respectively. The mass of free water within the packed bed was greatly reduced by 49.3 %, which resulted in a 49.4 % reduction in regeneration consumption. The Coefficient of Performance for Heating and Specific Heating Power of the shell-core zeolite were maximized by 91 % and 12.3 %, respectively. The tiny protrusions on the surface of the silicon dioxide-modified shell and the air within the pores created an air film that effectively prevented liquid water. Consequently, water could only enter the adsorbent in the form of water vapor. Overall, shell-core zeolite is a suitable adsorbent that can greatly reduce regeneration energy consumption and effectively improve system efficiency. It is foreseeable that the adsorbent preparation method presented in this work will provide a means for advancing the fields of coated slow-release fertilizers and gas separation.

Direct-contact method has been utilized in an open-loop adsorption heat pump based on composite adsorbent for high-temperature steam generation. Deliquescence problem arisen from the loss of salt in adsorbent under high humidity environment limits the stable performance during adsorption process. The composite zeolite was functionally modified with octyltrimethoxysilane (OTMOS) agent during water-free process based on liquid chemical grafting method. Measurement results from XRF (X-Ray Fluorescence) confirm the stable amount of salt is kept inside the modified zeolite. Characterization results from BET (Brunauer-Emmett-Teller) reveal the facts that pore volume and diameter are reduced simultaneously with the decrease in surface area. During regeneration dry air at 130 C-degrees is used for removing water out of the packed bed filled with S8-7.5 (the composite adsorbent modified with 7.5 % OTMOS). During generation process superheated steam at 200 C is obtained directly from hot water at 72 C-degrees. GTL (Gross Temperature Lift) reaches 115(degrees )C. COPh (coefficient of performance for heating) and SHP (specific heating power) for steam generation are increased by 16.2 % and 10.4 %, respectively after modification. The corresponding increases in system indicators stem from the promotion of steam mass, as adsorption abilities for composite zeolite are maintained well during direct contact with liquid water after modification.

Adsorption heat pump (AdHP) is a potential technology to recover and storage low-temperature waste heat. This paper presents an experimental research on direct low-pressure process steam generation from hot water based on superhydrophobic surface-modified zeolite 13X. The measured water contact angle of the modified zeolite is larger than 150 & DEG;, which restricts free water entering the pores inside the zeolite particles. Cyclic experiments are conducted for performance evaluation. High-temperature steam (205-229 & DEG;C, 0.1-0.3 MPa) is generated from hot water (72 & DEG;C) in the AdHP driven by dry air (130 & DEG;C). The temperature of generated steam is promoted with increasing preset steam pressure, among which the temperature is raised by about 23 & DEG;C at 0.3 MPa. As the boiling point of water rises simultaneously, the sensible heat demand is increased. Thus, the mass of the steam is accordingly decreased. GTL (gross temperature lift) reaches 130 & DEG;C. When the preset pressure is increased, COPh (coefficient of performance for heating) and SHP (specific heat power) for direct steam generation are decreased by 36% and 39%, respectively. One feasible option to elevate these two indicators is to increase the inlet water to near boiling water to match the change in the preset pressure. However, the GTL will be decreased based on the option. Balance should be made based on the choice of design for practical application.

Superhydrophobic surface-modified zeolite 13X has been utilized to regulate nonadsorbed liquid water in an open-loop adsorption heat pump system for steam generation. The zeolite is modified by vinyltrimethoxysilane to achieve a superhydrophobic surface effect. The measured static water contact angles of the modified zeolite reached 152 degrees. Thermogravimetric analysis results show good thermal stability at temperatures less than 400 degrees C. The measured adsorption capacity and adsorption heat slightly decrease for the modified zeolite. During the regeneration process dry air at 140 degrees C drives wet zeolite to remove adsorbed and free water. Then generation process proceeds for steam generation at a maximum of 220 degrees C from water at 72 degrees C. The mass and temperature of the steam generated from the modified zeolite bed increase compared with those of unmodified zeolite 13X. This is because of the apparent decrease in the total amount of free water, which allows the released adsorption heat to be transferred to passing water quickly for steam generation. Energy consumption during regeneration simultaneously reduces. System indicators such as the coefficient of performance for heating (COPh), specific heating power (SHP), gross temperature lift (GTL) and exergy efficiency (eta(e)) increase with increasing hydro-phobicity of zeolite particles. The surface hydrophobicity decreases the affinity of zeolite for useless free water which cannot contribute to increasing the overall adsorption heat.