Abstract Isolated regions face significant challenges in managing water, energy, and waste due to their inherent geographic and resource constraints. This study evaluates the energy and economic viability of an integrated forward osmosis, anaerobic digestion, and reverse osmosis (FO-AD-RO) process for the simultaneous treatment of wastewater, valorization of brine streams, and generation of biogas, using the Canary Islands as a representative case study. Three real draw solutions (DS) were assessed, brine from a brackish water desalination plant (BWB), seawater (SW), and brine from a seawater reverse osmosis plant (SWB), across a wide range of FO and RO recovery rates. The results show that the combined use of FO and RO, when BWB and SW are used as DS, reduces the specific energy consumption of the RO stage by 14 to 28% relative to the baseline scenario, depending on the FO recovery rate. For BWB, the integrated process achieves an overall recovery rate close to 97%, approaching zero liquid discharge, while for SWB, overall seawater recovery above 70% is reached. The incorporation of an AD stage to treat the FO concentrate allows part of the RO energy demand to be offset through biogas-based energy recovery, an effect that is more pronounced for BWB and diminishes with increasing recovery rates. From an economic standpoint, the levelized cost of water remains below or close to 0.8 €/m3 for RO recovery rates below 50% across all scenarios, which is competitive with other brine minimization strategies. Overall, the integrated FO-AD-RO process proves to be a technically and economically viable strategy for reducing desalination energy consumption, valorizing waste streams, and supporting the decarbonization of water and wastewater treatment in isolated, energy-dependent regions.
Abstract Gallium nitride (GaN) epitaxial film properties depend critically on deposition uniformity and growth efficiency. While metal-organic chemical vapor deposition (MOCVD) is the dominant industrial technology, traditional vertical rotating disk reactors generate complex centrifugal fields, edge vortices, and gas short-circuiting. These flow instabilities degrade film purity, limit precursor utilization, and complicate process control, creating bottlenecks for large-scale, high-throughput integration. To address these limitations, a novel, rotation-free MOCVD reactor architecture designed for high-capacity batch scale-up is proposed. By eliminating the high-speed rotating susceptor (core moving component of traditional MOCVD) and adopting advanced structural flow control, the proposed static chamber accommodates six symmetrically arranged stationary substrates, which removes centrifugal flow disturbances induced by mechanical rotation. The system utilizes 12 independently distributed annular inlets to deliver trimethylgallium (TMGa) and ammonia (NH3) isolated by inert carrier gases (H2/N2), successfully eliminating gas-phase prereactions at the source. Such units can be stacked up to increase throughput. Using an experimentally validated 3D multiphysics coupled model, the chamber height and exhaust outlet layout were optimized to suppress parasitic vortices. Numerical simulations demonstrate that the optimized design (75 mm chamber height) dramatically improves growth uniformity (GU) by 77.4% (from 0.04746 to 0.01074) compared to traditional rotating systems, while slightly increasing the average growth rate (GR) to 0.4774 μm/h. Furthermore, process parameter optimization (V/III ratio = 700, substrate temperature = 1373 K) enhances the growth rate to 0.509 μm/h while maintaining excellent uniformity. This rotation-free, multisubstrate design strategy offers a highly stable, low-complexity framework for next-generation, high-throughput semiconductor manufacturing equipment.
Abstract An environmentally friendly magnetic metal–organic framework (MMOF) based on MIL-53(Al) was synthesized using terephthalic acid (TPA) recovered from polyethylene terephthalate (PET) waste as the organic linker. The Fe2O3@MIL-53(Al) adsorbent was fabricated through a layer-by-layer assembly, with polyethylenimine (PEI) bridging the Fe2O3 core (∼200 nm) and MIL-53(Al) shell (∼25 nm). A uniform MOF layer was achieved in a single cycle under green synthesis conditions with PEI concentrations ≥ 10 g/L. The MMOF efficiently removed organophosphate pollutants, particularly 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC), a common scale and corrosion inhibitor. Adsorption kinetics across a pH range of 3–10.5 closely match the pseudo-second-order kinetic model, indicating chemisorption. The adsorption capacity ranged from 250 to 460 mg/g, with a maximum surface-normalized capacity of 0.44 mg/m2 at pH 5.5, attributed to favorable electrostatic interactions. Adsorption performance was strongly influenced by both the MMOF zeta potential and the ionization state of PBTC. The well-fitted adsorption isotherms (R2 > 0.9) to the Freundlich, Temkin, and Henry models indicate heterogeneous surface adsorption mechanisms. Electrostatic attraction, hydrogen bonding, and surface complexation are proposed as the dominant mechanisms. Overall, the Fe2O3/PEI/MIL-53(Al) composite exhibits high adsorption capacity, broad pH stability, and low toxicity, highlighting its promise for efficient PBTC antiscalant removal applications.
Abstract A pilot-scale pyrolysis process was designed to produce gasoline and diesel-range fuels from waste plastic bags through pyrolysis reaction, ex-situ catalytic cracking, and staged condensation. The catalytic upgrading unit was operated at 400–440 °C and consisted of different catalysts such as ZSM-5, dolomite, or kaolin catalysts. The surface properties of the catalysts were analyzed using Brunauer–Emmett–Teller (BET) and scanning electron microscopy (SEM) techniques. The products were highly temperature-dependent, with a maximum liquid yield at 420 °C, above which secondary cracking led to increased gas yield. ZSM-5 catalysts facilitated extensive aromatization, yielding gasoline-range plastic pyrolysis oil (G-PPO) with a high heating value of 44.5 MJ kg–1 and high benzene and toluene content, while dolomite catalysts facilitated the production of stable diesel-range hydrocarbons with high cycloalkane content, whereas kaolin catalysts inhibited heavy wax production with high liquid yield. Gas chromatography mass spectrometer (GC–MS) analysis validated that radical cracking, β-scission, cyclization, and dehydrogenation were the dominant product evolution pathways, which were highly dependent on catalyst acidity and structure. Engine testing with a 20% G-PPO blend showed a predictable rise in the brake thermal efficiency with increasing load, with exhaust gas temperature and emissions correlating with the aromatic composition of the fuel. Exergy analysis showed that ZSM-5-derived G-PPO had the lowest exhaust exergy and irreversibility losses, suggesting a more efficient conversion of chemical energy to useful work. Although pyrolysis can help with waste disposal of plastic bag, but emission data from blend fuel (20% G-PPO) revealed higher NOx and particulate emissions compared to commercial gasoline.
Nanostructured NiO electrodes fabricated using glancing angle deposition (GLAD) are promising platforms for nonenzymatic electrochemical glucose sensing, owing to their high surface area and tunable morphology. With GLAD, adjusting the deposition angle and substrate rotation rate can significantly affect electrochemical performance; however, identifying optimal GLAD structures for specific use cases is still largely experimental, relying on trial and error. Here, we develop a multiscale modeling framework that links the GLAD film growth process to glucose electro-oxidation performance by combining on-lattice kinetic Monte Carlo (kMC) simulations with morphology characterization and a coupled reaction-diffusion electrochemical model. Key morphological features, including surface area, porosity, and directional tortuosities, are quantified from kMC-generated structures across a wide range of GLAD geometries, such as slanted posts, helical shapes, and vertical nanocolumns. These features are then incorporated into a homogenized porous electrode model for glucose electro-oxidation on Ni-based catalysts. The model clarifies how the trade-off between surface area and mass transport governs electrode sensitivity. We identify a slanted-post morphology deposited at 72.5° as the optimal design for maximizing glucose electro-oxidation, and we find that physical electrodes formed with similar geometries were approximately 25% more sensitive to glucose than those formed with the vertical post morphology previously considered to be the optimum (i.e., 1.38 mA/mM·cm2 vs 1.12 mA/mM·cm2). Beyond glucose, this modeling workflow provides general guidelines for designing GLAD-fabricated electrodes for other biosensing targets and for electrochemical applications, including energy conversion and hydrogen generation.
