Current Opinion in Chemical Engineering最新文献

The interplay of water, energy, and food resources, which are essential for human sustenance, symbolizes a complex challenge involving social, engineering, and environmental aspects. The water–energy–food (WEF) nexus, surpassing traditional process systems engineering (PSE), underscores the interconnectedness of resource decisions. Efficient WEF nexus management demands a comprehensive approach encompassing environmental, social, economic, and technical dimensions. PSE tools are vital in shaping this nexus, facilitating a deeper resource interaction and promoting sustainability. This opinion article introduces a novel classification for WEF-specific PSE, advocating for a holistic approach that acknowledges dynamic resource interdependencies. Innovative strategies addressing WEF challenges are proposed, leveraging advanced computational solutions that enhance the nexus models' realism. This trajectory promises insights into nexus intricacies and reflects a shared commitment to harmonize resource coexistence. As we explore the interrelation between water, energy, and food, a path emerges toward the alignment of human and environmental needs, offering a sustainable world trajectory.

The presence of iron in the electrolyte has a significant impact on the performance of the electrodes in alkaline water electrolysis. For nickel-based anodes, the presence of iron is needed to achieve and maintain low overpotentials in the oxygen evolution reaction (OER). In contrast, in hydrogen evolution, the presence of iron can lead to deactivation of noble metal-based cathodes, which are more active than non-noble metal cathodes. Since the catholyte and anolyte can mix through the porous separator, stack developers need to decide on the optimal iron content in their system. It seems most promising to focus further development on the ‘iron-rich’ system, also considering the costs of construction materials and water purification.

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are extensively distributed, highly persistent, and hazardous compounds in water resources threating human health and ecosystems, therefore requiring effective controlling and management systems. Machine learning (ML)-based procedures are novel approaches through which the PFAS-controlling systems can be improved cost-effectively and rapidly from different aspects. The few accomplished ML-based studies in PFAS-controlling systems showed considerable performance, with > 80% prediction strength in outputs, for example, treatment performance, identification of the susceptible groundwater resources, and PFAS defluorination energy in > 70% of the studies. Despite such a great performance, there is no systematic study of various aspects of PFAS-controlling systems, for example, modeling and analysis of PFAS degradation and distribution mechanisms, optimization, alarm management, troubleshooting, and appropriate operation and maintenance of these systems. Therefore, this study reviews key aspects and parameters that can take advantage of ML procedures in achieving cost-effective PFAS control in water resources.

Increasing carbon dioxide emissions and the resulting global warming are a critical environmental concern. Ionic liquids (ILs) have recently gained attention as promising absorbents for carbon capture due to their favorable chemical and physical properties. Consequently, there is a need to develop process modeling and mathematical optimization techniques for the design and operation of IL-based carbon capture processes to identify optimal design and operation. This review presents recent advances in modeling and optimization of carbon capture plants using ILs. We focus on flowsheet simulation, nonlinear dynamics, variations in plant load and energy prices, and multiscale design.

Electrolyzers allow for the sustainable conversion of chemical waste (e.g. nitrous oxides, NO_x, or carbon dioxide, CO₂) into valuable chemicals or building blocks (e.g. ammonia or hydrocarbons). There is a constant search for new and improved materials (electrocatalysts) that can facilitate these complex chemical reactions with optimized activity, selectivity, and stability. In order for electrolyzers to become economically feasible, it is of utmost importance that they perform at high current density >100 mA/cm² (activity), since this scales with chemical reaction rate. However, if high current density is only achieved for a short period of time (stability), the electrolyzer has to be regenerated, which is a costly endeavor. For this purpose, chemical engineers have focused on gas diffusion electrodes (GDE) or membrane electrode assemblies (MEA) in recent years, but these cell configurations are prone to rapid deactivation and salting. In situ spectroscopy and diffraction techniques can shed light on the parameters that influence catalyst (de)activation, but application of the technique of choice depends heavily on the reaction conditions and hence is not straightforwardly applied to electrolyzers that operate at high current density. This review addresses the recent developments within the community for in situ characterization of GDE and MEA electrolyzers, and opportunities for future studies are highlighted, which are aimed to stimulate discussion and advancement of the field.

Per- and polyfluoroalkyl substances’ (PFAS) unique chemical properties define modern expectations of synthetic chemistry for diverse consumer products and industrial applications. That same chemistry becomes problematic at the end of PFAS-containing material life cycles. Safe disposal of PFAS is important to mitigate adverse human health and ecotoxicological effects. Thermal treatment is reported to be effective in defluorinating and mineralizing many PFAS. However, thermal technologies are energy-intensive and have the potential to create harmful by-products, including fluorinated products of incomplete combustion. In this work, we critically review recent advances in thermal treatment, focusing on mature technologies such as combustion and pyrolysis plus other promising options such as alkaline hydrothermal processes, sonolysis, and supercritical water oxidation. Furthermore, we propose that thermal treatment not be used as a sole method for PFAS destruction but as a treatment train component following the separation and concentration of PFAS from impacted environmental media.

As one of the most successful modifications to conventional fluidized beds to intensify their operations, vibrated gas-fluidized beds (VGFBs) have been used extensively in industry. Here, we review the hydrodynamics within VGFBs and their applications to improve fluidization quality of particles that are difficult to fluidize based on gas flow alone, to control segregation and mixing among different particle types, and to enhance heat and mass transfer. Further, recent progress in creating structured flow patterns in VGFBs to facilitate the scale-up of fluidized beds and development of methods for numerical modeling of vibration in VGFBs are discussed. Finally, perspectives on the areas for future work on VGFBs are given.

This study proposes the utilization of anaerobic membrane bioreactors (AnMBRs) as a core treatment technology for future pilot-/full-scale decentralized wastewater treatment plants (DWTPs). The treatment efficiencies, technoeconomic costs, and global warming potential of AnMBRs are comparable to those of other biological technologies. To facilitate such a paradigm, we discuss the challenges associated with AnMBR application in DWTPs that need further alleviation.

Reuse of unconventional water is a promising solution to water shortage, which needs to be fit-for-purpose when engaging the treatment of advanced oxidation processes (AOPs). This article describes the application and the present challenges of AOPs in the treatment of eight types of unconventional water (i.e., seawater, brackish groundwater, produced water, mining wastewater, power and cooling water, industrial wastewater, agricultural drainage, and municipal wastewater) to help stakeholders understand how to choose AOPs for nontraditional water reuse. This article also discusses future research areas and concepts towards a better application of AOPs, including innovative ideas to overcome the weaknesses of current AOPs and new ways to incorporate AOPs into a multibarrier treatment train.

Donnan dialysis exploits electrochemical potential gradients across ion-exchange membranes to separate ions between feed and draw solutions. This technique has been applied for treatment and recovery of chemicals in water and wastewater. Previous studies have arbitrarily selected the draw solution chemistry, making it difficult to fairly compare experimental outcomes. A universal framework is needed to standardize design and interpretation of Donnan dialysis systems. We calculated the R_d/w parameter, which is related to the draw ion concentrations in the feed and draw solutions at Donnan equilibrium, for previous studies. R_d/w values were used to determine theoretical recoveries and compare them to experimental outcomes. Of the literature data, 57% matched the theoretical recovery, 37% underperformed due to operating time constraints or transport limitations, and 6% outperformed Donnan equilibrium due to use of integrated processes. Ultimately, this work highlights the benefits of the R_d/w framework for standardizing interpretation of Donnan dialysis systems.