Process Safety and Environmental Protection最新文献

HKUST-1, as a type of metal-organic framework (MOF), has attracted significant interest for various applications. However, its use for adsorption applications is hindered by its microporous structure, which negatively impacts the diffusion and mass transfer of large particles (> 2 nm). Concurrently, waste electric cables from discarded vehicles and electronic equipment pose significant environmental challenges. To address these issues, we developed a novel recycling method using copper hydroxide recovered from waste-thin electric cables as the metal source for synthesizing hierarchical porous HKUST-1 (W) using a green approach at a low temperature. The resulting HKUST-1 (W) exhibited interesting properties compared to the typical HKUST-1 (C) synthesized from commercial precursors, showing a microporous-mesoporous structure with enhanced molecular mass transport, while HKUST-1 (C) exhibited only micropores. Moreover, the waste-derived HKUST-1 (W) formed interconnected small particles with enhanced methylene blue (MB) removal properties compared to HKUST-1 (C), mainly due to its hierarchical porous structure facilitating easy mass transfer of MB. To evaluate the industrial potential of our adsorbent, we conducted a fixed-bed adsorption column (FBAC) experiment, which showed that HKUST-1 (W) achieved a high removal efficiency of 99 %, confirming its effectiveness as a dye adsorbent in both batch experiments and a FBAC. This approach opens new perspectives in applying upcycled waste-based materials in synthesizing hierarchical porous MOFs.

Public health, potable water supplies, and ecosystems are endangered by the disposal or reuse of non-standard effluents of wastewater treatment plants. To achieve the Sustainable Development Goals (SDG 6) and USEPA quality standards, this work utilized an innovative electrochemical technique with continuous flow. Cu@Cu foam and RuO₂@Ti were prepared for NO₃ reduction and NH₄ and COD oxidation, respectively. The characterization of electrodes was performed by XRD, EDS, FTIR, FE-SEM, and CV analysis. The effects of parameters including NH₄ concentration (10–30 mg N/L), NO₃ concentration (4–12 mg N/L), current (0.5–1.5 A), and Cl^- concentration (100–400 mg/L) were examined for the removal of NH₄, NO₃, and COD. Characterization results confirmed that Cu and RuO₂ were successfully coated on the surface of electrodes. Operating parameters were optimized using response surface methodology. The ideal conditions for current, Cl^- concentration, and HRT were 1.5 A, 347.7 mg/L, and 120 min, respectively for concentrations of 9 mg /L NO₃-N, 30 mg/L NH₄-N, and 30 mg/L COD. Under these conditions, NO₃-N, NH₄-N, and COD removal efficiencies were 78 %, 97.8 %, and 61.2 %, respectively. The proposed electrochemical process was a sustainable technology for the concurrently removal nitrogen and carbon with advantages including environmental compatibility, versatility merits, and simplicity.

A three-tank microbial fuel cell (MFC) is successfully constructed to achieve electromigration and is used in the electro-Fenton process to treat bisphenol A (BPA). The MFC system exhibits excellent mobility and efficiently aggregates Cu⁺ to the cathode. Under optimal operating conditions, the MFC achieves a maximum power density of 31.4 mW/m², which is a 3.4-fold increase over that at 0.5 kΩ. Increasing the external resistance increased the MFC power output (ca 1.5 times) and copper ion migration (ca 4.6 times) while reducing the internal resistance of the system (ca 25.3 %). Surface analysis of the cathode carbon cloth shows a 5.5-fold increase in copper content at 1 kΩ over that at 0.5 kΩ. This also increases the oxygen reduction reaction rate, thereby increasing the H₂O₂ yield by 1.5 times. The recovered copper cathode at 1 kΩ exhibits the best catalytic degradation of BPA, removing 99.7 % of BPA in 180 min, increasing 1.4 and 1.8 times that obtained at 1.5 and 0.5 kΩ, respectively. The optimal operating conditions significantly increased the abundance of electrochemically active bacteria (Azospirillaceae) (3.2 %−41.7 %), indicating that the optimized MFC is favorable for the rapid acclimatization of electrochemically active bacteria.

Detecting endocrine-disrupting phenolic substances like bisphenol A (BPA) and bisphenol S (BPS) in food products due to leakage from plastic packaging is crucial due to their potential health hazards such as hormonal disruption, metabolic disorders, cancer etc. Despite a wide range of bimetallic and trimetallic MOF-based structures have been developed for the sensitive detection of these pollutants; however, achieving a highly selective and sensitive hybrid system with diverse and effective binding sites for simultaneous and selective monitoring of these pollutants remains challenging. To address this, herein we developed a novel electrode system using thiourea functionalized trimetallic (Fe, Co, and Mn) organic framework (S-FCM-MOF) coated polycaprolactone (PCL) electrospun nanofibers. Interestingly, the S-functionalization enhances adsorption capacity for BPA and BPS, whereas PCL improves electrical conductivity and charge density across the FCM-MOF-based electrode surface, thus overcoming the challenge of achieving a highly selective and sensitive hybrid system for the simultaneous and precise detection of these pollutants. This synergistic effect leads to high sensitivity (7.0479, 5.9249 μA/μM/cm²), low detection limits (2.57, 2.91 μM), and wide linear ranges (5–365, 5–360 μM) against BPA and BPS, respectively. Furthermore, the S-FCM-MOF@PCL electrode demonstrates high selectivity for BPA and BPS even in presence of interfering species including Mg²⁺, Zn²⁺, Cu²⁺, NO₃⁻, KCl, AA, CA, HQ, PNP, KBr and MgSO₄. This innovative designed electrode is effectively used for sensitive/selective monitoring of BPA and BPS from plastic bag-packaged frozen meat samples with high precision and accuracy, thus ensuring the reliability of our designed sensor.

Numerous beneficiation techniques, such as washing, grinding, flotation, digesting, and calcination, are used to concentrate the minerals found in phosphate rocks, which include apatite, carbonatites, and silicates. Significant iodine levels are often found in phosphate ore minerals, which have a distinctive geochemical occurrence. However, the exact occurrence and distribution of iodine in these minerals are not yet thoroughly understood. A study was carried out to investigate the iodine's distribution, occurrence modes (phases), and release rate in Moroccan phosphate as it undergoes the beneficiation process. The samples underwent a multi-analytical approach combining mineralogical and chemical characterization using ICP-MS, ICP-OES, XRD, elements titration, and Pearson correlation analysis for interelement relationships. Calcination, digestion, and Heavy liquid separation is used to study the fate of iodine. The analysis indicates that iodine is primarily found in fluorapatite, with local concentrations ranging from 35 to 130 ppm. The most enriched grains/zones are associated with fluorapatite, enriched in P₂O₅, F^-. in addition, iodine is positively correlated with its main components, including P₂O₅, F^-, SO₃, Na₂O, CaO, and REEs. The flotation and heavy liquid separation process used for calcite and silicate removal is acting as an iodine and P₂O₅ concentrator, given that 99 % of iodine occurs in the apatite phase. However, it has been demonstrated that iodine can be released during the digestion of phosphate rock. Where the initial iodine content is distributed among phosphoric acid, PG, and the gaseous phase, constituting 35 %, 25 %, and 40 %, respectively. Furthermore, the calcination of phosphate rock between 800–1000 °C shows that total iodine is released with gases in I₂ form, leading to an increase in the concentration of iodine in the surrounding area. In this regard, an integrated pyrometallurgical process has been proposed for the valorization of iodine as silver iodide. This process involves trapping gaseous iodine in an alkaline solution, followed by precipitation, thereby contributing to the overarching objectives of the circular economy and environmental protection.

Addressing the challenges posed by the slow reactivity of fly ash (FA) with alkali at ambient temperatures, this study delves into the enhancement of FA-based geopolymers through alkali thermal activation (ATA). The ATA process, conducted at 550°C for 1 h, significantly increases the availability of reactive silica and alumina, which are essential for geopolymerization. A critical focus of the research is the influence of FA particle size on ATA’s efficacy and the resultant mechanical properties of the geopolymers. Findings reveal that the ATA process facilitates the rapid dissolution of the vitreous phase in FA. This leads to a sequential release of silica and alumina, which is pivotal for the geopolymer’s matrix development. Notably, geopolymers synthesized from finely milled FA, post-ATA, demonstrate a marked increase in compressive strength, escalating from 30.51 MPa to an impressive 38.46 MPa. The study meticulously delineates geopolymerization into four distinct stages—initial dissolution, depolymerization, geopolycondensation and gelation, and final diffusion, with the initial dissolution and final diffusion stages being paramount in defining the reaction kinetics and the ultimate strength of the geopolymer. This enhanced understanding paves the way for optimizing FA utilization in geopolymers, promising a more sustainable and efficient pathway for producing construction materials with superior mechanical properties.

The recycling of thermosetting plastics such as discarded bakelite poses greater challenges than thermoplastic polymers like polypropylene (PP) and high-density polyethylene (HDPE), particularly through pyrolysis requiring specialized reactors. This study examines the isothermal thermal degradation kinetics and batch pyrolysis behaviors of bakelite, along with its blends with PP and HDPE, emphasizing the characterization of pyrolytic oils for designing optimized reactors. For the study on isothermal thermal degradation kinetics, isothermal thermogravimetric analysis was performed at specified temperatures (300, 350, 400, 450, and 500°C), chosen based on the predominant non-isothermal degradation behavior of bakelite. The batch pyrolysis of discarded bakelite and blended bakelite with PP/HDPE is carried out at 450°C. The chemical composition analysis of pyrolytic oils is performed using Fourier transform infrared (FTIR) spectroscopy, with comprehensive compound analysis conducted using Gas Chromatography-Mass Spectrometry (GCMS). Isothermal thermogravimetry at temperatures ranging from 300°C to 500°C reveals increased thermal degradation with rising pyrolytic temperatures, reaching maximum weight losses of 55 % for bakelite, 82.74 % for PP-bakelite blends, and 90.8 % for HDPE-bakelite blends at 500°C. The isothermal kinetics study reveals that bakelite degrades via D₁-diffusion, polypropylene-blended bakelite via A₂-Avrami-Erofeyev, and high-density polyethylene-blended bakelite via A₃-Avrami-Erofeyev, with activation energies of 17.178, 7.193, and 3.550 kJ/mol, and Arrhenius constants of 0.095, 0.042, and 0.017 min.⁻¹, respectively. The highest condensable yield of 58.76 % during PP-blended bakelite co-pyrolysis underscores its potential for resource recovery. FTIR and GC-MS confirm the presence of alkanes, cycloalkanes, alkenes, cycloalkenes, aromatic hydrocarbons, and oxygenated compounds in the pyrolytic oils, providing detailed insights into their chemical composition. These findings offer critical insights into the thermal degradation behavior and kinetics of bakelite and polypropylene/high-density polyethylene-blended bakelite, highlighting opportunities for efficient waste plastic utilization through pyrolysis for resource recovery and energy generation, and providing essential knowledge for designing isothermal pyrolysis reactors.

Coal-ammonia co-firing is a promising technology for reducing CO₂ emissions in coal-fired boilers. However, coal-ammonia co-firing may cause significant NO_x owing to the high nitrogen in ammonia. This study proposes a novel low-NO_x swirl burner with a scalable dual-channel ammonia pipe for coal-ammonia co-firing, and evaluates the combustion and NO_x formation under different ammonia ratios of the dual channels (i.e., inner and outer channels). The results show that the ammonia is injected into the low-oxygen and high-CO environment behind the internal recirculation zone, contributing to the ammonia pyrolysis and inhibiting the ammonia oxidation reaction. Low NO_x is successfully achieved with high combustion efficiency. In addition, it is observed that the effect of the ammonia ratio of the dual channels on the combustion and NO_x formation is slight for the high ammonia blending ratio (20 %), while it is prominent for the low ammonia blending ratio (10 %). Especially, for the low ammonia blending ratio, lower ammonia ratio in the outer channel can obtain high velocity of ammonia stream in the inner channel, contributing to NO_x reduction. Overall, the cases with lower R_OC (0.1, 0.2) are suggested with low NO_x (below 120 ppm) and carbon content in fly ash (below 3.50 %) for the low ammonia blending ratio in this study.

Rising worldwide energy demand and the threat of fossil fuel depletion are driving a move toward renewable energy. Research encourages the use of clean and sustainable energy sources. This review focuses on bio-hydrogen generation, nanomaterials, and future developments. Power-to-hydrogen coupled with hydrogen-to-power (P2H-H2P) systems have come a long way recently. The focus is on technology, modeling, problems, cost-effectiveness, and sector linkage for sustainability and carbon neutrality. This research focuses on the generation of hydrogen from metal trash such as scrap aluminum, magnesium, and zinc. The comparative analysis, purification approaches, and constraints are reviewed, revealing possible uses and future opportunities. In this comprehensive analysis, microalgae, particularly for hydrogen generation, provide sustainable options for carbon-neutral biofuel production, efficiency, and other problems. This review examines traditional hydrogen-generating approaches such as steam methane reforming (a coal-based biomass gasification method) and water electrolysis. This field focuses on emerging technologies such as photocatalytic water splitting, solid-state oxide electrolysis cells, hydrogen production, and chemical-based cycling. Advanced differentiation techniques are also discussed. This study continues by discussing difficulties and opportunities, with a focus on material enduring rigidity, the effectiveness of costs, expansion, and incorporation into massive amounts of hydrogen-manufacturing facilities, all of which are subjects for further research. In addition, this review discusses emerging trends and potential breakthroughs that will shape the future of hydrogen generation.

The rapid obsolescence of cell phones has led to significant challenges in electronic waste. Effective recycling processes are crucial to mitigate environmental impacts and recover valuable materials. However, consumer participation in obsolete cell phone (OCP) recycling remains suboptimal. The purpose of this research was to apply the Theory of Planned Behavior (TPB) to investigate the factors that influence the intention to recycle obsolete cell phones among Chinese consumers. By analyzing 621 valid survey responses using Partial Least Squares Structural Equation Modeling (PLS-SEM), the study identifies that attitude, perceived behavioral control, and subjective norm, as rational factors, significantly predict OCP recycling intention. Additionally, privacy concern and object attachment, as emotional factors, are found to reduce OCP recycling intention. Further analysis using Fuzzy-Set Qualitative Comparative Analysis (fs-QCA) pinpoints essential TPB configurations that enhance OCP recycling intention, highlighting that the absence of both privacy concern and object attachment contributes to high recycling intention. By introducing an emotional perspective, this study advances our understanding of the mechanisms underlying OCP recycling behavior. Strategic directions for improving cell phone recycling management are discussed.