The continued accumulation of post-consumer plastic waste underscores the limitations of current recycling technologies, particularly when applied to heterogeneous and contaminated waste. These challenges are amplified in geographically isolated economies such as New Zealand, where centralised recycling infrastructure is often impractical. This review examines recent developments in reactive extrusion (REX) as a versatile, intermediate strategy that bridges conventional mechanical and energy-intensive chemical recycling approaches. Four REX-enabled strategies are highlighted: (1) dry-chemical approaches, (2) dynamic networks and structure control, (3) universal compatibilisers for multi-component blends and (4) partial depolymerisation and reconstruction. Together, these approaches provide pathways to recycle immiscible and contaminated plastic waste into economically valuable materials without requiring complete separation. As a next step, achieving industrial viability necessitates transitioning from laboratory-scale to pilot-scale demonstrations with real-world feedstocks containing additives and multi-phase polymer mixtures. Such targeted approaches are significant for aligning with market realities and ensuring the retention of material resources locally.
The environmental persistence of extracellular antibiotic resistance genes (eARGs) after wastewater effluent discharge raises significant ecological and public health concerns. Photochemical degradation is considered as a key mechanism for natural attenuation of eARGs, however, its effectiveness is highly variable depending on the composition of dissolved organic matter (DOM) in aquatic systems. This perspective highlights that disinfection applied in wastewater treatment plants could be an important process that fundamentally reprograms the photochemical reactivity of DOM toward eARGs, in particular in wastewater effluent-receiving aquatic environments. Such reprogramming reshapes both the photosensitizing capacity and antioxidant properties of DOM, thereby altering the balance between photochemical damage and repair of eARGs. This perspective outlines a mechanistic framework linking DOM composition, disinfection mechanism, and photochemical fate of eARGs. Also, key knowledge gaps towards photodegradation of eARGs in wastewater-impacted environments are identified for future studies.
Photocatalytic (PC) and photoelectrocatalytic (PEC) disinfection are promising technologies for inactivating antibiotic-resistant bacteria (ARB) and degrading antibiotic resistance genes (ARGs). However, their role in the spread of antimicrobial resistance (AMR) is complex and ambiguous. This review provides a comprehensive summary of the dual role of PC/PEC technologies in controlling AMR dissemination. The significant effect of PC/PEC in eliminating ARB and destroying ARGs through mechanisms such as oxidative damage to cell membranes, proteins, and genetic material is first summarized. Furthermore, although optimal lethal treatment can inhibit horizontal gene transfer by inactivating donor/recipient cells and degrading genetic vectors, sub-lethal or non-optimal PC/PEC exposures may enhance ARGs transfer. Finally, key future research perspectives are highlighted, with emphasis on enhancing reactive oxygen species efficiency, mitigating dissolved organic matter fouling and mass-transfer constraints, and developing integrated strategies to ensure these technologies mitigate rather than exacerbate AMR spread.
The field of CO2 electrolysis stands at an inflection point. Electrocatalytic performance on the lab scale has already achieved current densities above 1 A cm-2, operational times > 1000 hours, Faradaic efficiencies exceeding 80% for CO, formate, and ethylene. Now the field requires rigorous pilots to demonstrate the technology on a large scale to allow industrial uptake. Here, we argue that stack-level operation reveals critical challenges hindering the industrialization of this technology. When cells are assembled into stacks, issues present at the bench scale are amplified: electrodes flood, salts precipitate, thermal gradients develop, and current distributes unevenly. For each challenge, we identify the mitigation strategies demonstrated in the literature and the operational parameters that must be actively controlled. We extend this analysis beyond the technical hurdles, examining the political, regulatory, and societal barriers that will play an equally determining and frequently underestimated role in shaping whether this technology reaches the scale required for commercialization.
Repurposing CO2 into renewable carbon sources is a critical path towards a sustainable future. Here, we review the recent advances in rewiring cellular metabolism for the biological conversion of CO2. We highlight the principles and endeavors of metabolic engineering in reconnecting metabolic pathways for CO2 fixation, where the essential metabolic nodes produced or involved in such pathways can be diverted for the production of diverse value-added products. We underscore the interactions between CO2 fixation pathways and central metabolism and discuss the energy demands and approaches to fulfill the requests for CO2 reduction. Finally, we review recent progress in diverting carbon from these metabolic nodes, including pyruvate, PEP, and acetyl-CoA, towards intended products.
The increasing demand for decentralized public health surveillance, particularly in resource-limited settings, highlights the urgent need for point-of-care testing (POCT) technologies. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-based diagnostics (CRISPR-Dx) have emerged as powerful alternatives to conventional pathogen detection methods, offering high sensitivity, programmability, and compatibility with portable platforms. In this work, we review various CRISPR-Cas systems to develop CRISPR-Dx, ranging from fundamental mechanisms to practical applications. We discuss advances in CRISPR-Dx, focusing on paper-based devices, microfluidic systems, electrochemical sensors, and wearable sensors. We also assess their applications in pathogen detection and discuss technical challenges, translational feasibility, and future development directions. This work provides a framework to support the continued advancement and real-world implementation of CRISPR-based POCT technologies for public health surveillance.
The accelerating discharge of wastewater pollutants poses long-term threats to public health and global ecosystems. Developing technologies that integrate enrichment, sensing, separation, and degradation is therefore of importance for achieving low-energy, high-efficiency removal of wastewater pollutants. However, conventional approaches remain constrained by the lack of synergistic effects of unit operations. Two-dimensional (2D) nanofluidics has emerged as a promising methodology addressing these issues because of its extreme nanoconfinement, ultrafast mass transport, and integrated advantages in the removal of wastewater pollutants. Here, we propose future pathways for the underlying mechanisms, strategies, and processes of enrichment, sensing, separation, and degradation using 2D nanofluidics. The advances in integrated system design and identifying key challenges are highlighted. We propose that AI-driven intelligent feedback and multidisciplinary system integration will be essential to translating this technology toward next-generation wastewater treatment.
Plastic pollution has emerged as one of the most urgent environmental concerns of the twenty-first century, with over 430 million tons produced globally each year and production expected to rise further. Despite decades of recycling efforts, less than 10% of global plastic trash is successfully recycled, emphasizing the critical need for advanced technologies that enable a shift from linear consumption to real material circularity. This review critically focuses on recent advances in plastic recycling systems, namely mechanical, chemical, and developing dynamic chemistry-based approaches to enhancing polymer circularity. It addresses advances in mechanical recycling, such as enhanced sorting technologies, process optimization, and the use of reactive additives to reduce polymer degradation and improve recycling performance. The review further examines chemical recycling pathways such as pyrolysis, solvolysis, and catalytic depolymerization, with a focus on catalyst design and process advances that allow for the recovery of monomers, fuels, and value-added chemicals from complex plastic waste. It also investigates dynamic covalent chemistry techniques, including vitrimerization and universal dynamic compatibilization, which enable reversible bond exchange and interfacial interactions to aid in the recycling of crosslinked and mixed polymer systems. Finally, the review anticipates how combining these techniques might lead to more efficient, sustainable, and scalable recycling technologies, therefore facilitating the transition to a circular plastics economy.
Flowability and fluidization quality of bulk solids are closely interlinked and decisive for the processing behavior and homogeneity of product quality in many applications, ranging from fine chemicals to energy generation. In this perspective, we summarize recent advances in the modification of flowability towards the improvement of fluidization quality, with a special focus on cohesive (Geldart-C) particles. Furthermore, open challenges are named, directions are given, and methods (e.g. machine learning and AI) are discussed to address them.
We summarize advances in technologies that assist fluidization of cohesive gas–solid mixtures over a broad range of interfacial velocities. Periodic external forcing, through oscillatory gas flow, vibration, acoustics, or other force fields, can reduce apparent cohesion and lower the minimum fluidization velocity. This enables low-stress, low-velocity fluidization with reduced gas demand for drying, adsorption, and other processes requiring enhanced heat or mass transfer. When external heat or mass transfer resistance dominates over intrinsic kinetics and intraparticle transport, centrifugal fluidization can boost overall transport at very high interfacial velocities, which enables short gas–solid contact, enhancing selectivity, for example, in oxidative coupling of methane. This article surveys progress in assisted fluidization methods. It discusses advances in regime mapping, structured flow control, predictive modeling, and scale-up strategies. Remaining challenges include robustness, control, and moving beyond ad hoc design. We advocate transferable operating guidelines, hybrid assisted units, and data-assisted design frameworks to improve economic viability.
Plastic waste can be recycled into resins with near-virgin properties by solution-based purification processes that selectively dissolve polymers, remove contaminants, or detach printing residues. In this review, we examine computational methods for predicting the behavior governing solution-based plastic purification, motivated by the vast polymer–solvent–contaminant compositional space. We discuss thermodynamic and machine learning methods for predicting polymer–solvent and polymer–contaminant interaction and review physics-based molecular dynamics simulations that resolve molecular-scale phenomena within polymer matrices inaccessible to screening methods. We highlight how these methods have informed experimental design for dissolution-based recycling and solvent-based contaminant removal. Finally, we discuss the prospective role of agentic AI in integrating these computational tools with real-time sorting data to adapt purification conditions to the compositional variability of real post-consumer feedstocks. This review charts a path toward computationally guided solution-based purification workflows that can respond to the complexity inherent in plastic waste streams.
Microbial electrochemical systems for wastewater treatment and CO2 valorization are gaining attention as an integrated route to pollutant removal and chemical production, where bioanodes oxidize organics in wastewater to recover electrons that can drive cathodic reduction reactions. Hybrid microbial electrosynthesis (MES) processes, which couple abiotic electrocatalysis with microbial upgrading at the cathode, offer a route to overcome the product selectivity and diversity limitations of abiotic electrochemical CO2 reduction. However, H2-mediated MES targeting acetate faces increasing pressure from rapidly advancing abiotic electrolysis in productivity and scalability, motivating exploration of alternative electron and carbon carriers (e.g. CO/H2 syngas or formate) that can better match microbial uptake kinetics and redox demands. Using isopropanol as a representative C3+ product, we illustrate the challenges and opportunities of advancing toward higher-value CO2-derived products. Future research should focus on improving catalyst-electrolyte compatibility, enhancing mediator transfer efficiency, and engineering microbial pathways for complex product formation, while in parallel optimizing bioanode configurations for stable and efficient electron supply from real wastewater streams.
Environmental monitoring is essential to protect the ecosystem and human health. Currently, there is a limited number of deployable sensors for emerging contaminants. Biology-enabled sensing methods are addressing this gap by using biological components as sensors. This review provides a perspective on recent advances in biology-enabled sensors, with a focus on cell-free sensors, whole-cell sensors, and multicellular sensors. These tools can be leveraged to produce sensitive, deployable, and at times rapid sensing technologies. Many sensor-related studies have focused on deployment in aqueous matrices that are optically transparent. This perspective paper extends beyond aqueous environments to examine emerging approaches for biology-enabled monitoring of analytes in soil and air. By comparing sensing mechanisms, sensitivity, limit-of-detection, and response time across different matrices, this review highlights tradeoffs in sensor performance. Finally, this review outlines future directions for improving biology-enabled sensors to make them more robust, scalable, and capable of real-time sensing for comprehensive environmental monitoring.
Bioelectrochemical systems provide a platform for microbial CO2 reduction to organic compounds such as acetate or methane. However, their performance is limited by low CO2 solubility, mass transfer limitations, and significant pH gradients at electrode surfaces. Recently, Microbial Electrochemical Fluidized Bed Reactors (ME-FBRs) have emerged as an alternative configuration to mitigate these limitations. ME-FBR uses electroconductive particles as fluidized electrodes for enhancing surface area, mixing, mass transfer, and microbe–electrode interactions.This review covers current knowledge on CO2 fixation in ME-FBR, including similar concepts like moving electrodes, slurry electrodes, and capacitor granular beds. The conductive material is key, and activated carbon showed promise; however, chemical modifications of alternative materials (e.g. glassy carbon) are opening new opportunities to improve electron transfer and catalytic performance.Finally, the use of ME-FBR for growing autotrophic photosynthetic microorganisms like purple phototrophic bacteria expands the scope of biorefinery applications from CO2.
In the literature, there is a large variety of different equations that are claimed to be the ‘governing equations’ of gas–solid flows. One reason for the large variety of governing equations is that there exist many different ways to define a ‘resolved’ flow quantity that all come with different properties and implications. In the present paper, the existing approaches are structured, and it is clearly distinguished which parts of the governing equations are exact and which are modeled and therefore only valid under certain circumstances. We discuss what the different definitions of ‘resolved’ flow quantities mean physically and how they differ from the instantaneous flow quantities. We further discuss common misconceptions in closure modeling and how to preserve consistency throughout the simulation process, from the governing equations, over the discretization, to the interpretation of the results.
High gravity (HiGee) technology, implemented in rotating packed beds (RPBs), creates a centrifugal field several hundred to several thousand times Earth’s gravity. This field breaks the liquid phase into thin films, ligaments, and droplets, and continuously renews the gas–liquid interface, which strongly intensifies mass transfer and micromixing. As a result, HiGee equipment can overcome the large volume, high energy consumption, and low mass transfer efficiency of conventional packed and tray columns. This perspective summarizes recent industrial deployments of RPBs in decarbonization and desulfurization implemented by Beijing University of Chemical Technology. It focuses on postcombustion CO₂ capture, deep removal of H₂S and SO₂ from various gas streams, and regeneration of spent caustic from LPG desulfurization. Industrial demonstrations from the last two decades show that RPB can reduce equipment volume and footprint, lower steam consumption for solvent regeneration, and ultra-high removal efficiency of H₂S and SO₂ under a wide range of operating conditions. With its strong process intensification capability and stable long-term operation, RPB has become a practical option for carbon mitigation and industrial flue gas treatment, and has clear potential for broader deployment.
A spinning disc reactor (SDR) is an intensified chemical reactor renowned for its excellent heat and mass transfer performance. Its applications have expanded to a wide range of chemical processes, including nanoparticle synthesis and both chemical and photochemical reactions. Computational fluid dynamics (CFD) has become an essential tool for understanding SDR hydrodynamics and guiding reactor design, optimization, and scale-up. This review critically examines the development of models for predicting liquid film thickness and the key CFD modeling approaches, including multiphase flow, turbulence modeling, and mixing characterization. It also discusses current challenges in SDR scale-up and proposes future research directions to support the broader industrial implementation of this promising SDR technology.
Energy systems based on the use of concentrated solar irradiation are one of the key players in the current energy transition to a defossilized world. Directly irradiated solar reactors are of great interest for high-temperature thermochemical processes involving solid particles, such as cement production. Compared to indirectly heated reactors, directly irradiated reactors allow reaching higher temperatures, and also avoid additional heat transfer steps, which result in lower energy efficiency and the need for high-temperature standing material. However, the main bottleneck of these reactor concepts is very often the need for a window. This component is necessary to control the reaction atmosphere and to reduce thermal losses while allowing the solar irradiation to enter the reactor chamber. Nevertheless, the window easily heats up and breaks when particulate material deposits on its surface. Several studies have been carried out to tackle this problem, proposing solutions based on aerodynamic protection systems. These could mitigate the problem, but in many cases, particle deposition was observed, and the large amount of inert gas required for the system decreased the efficiency of the processes. Recent studies propose the implementation of existing technologies for high-temperature gas cleaning (e.g. electrostatic separation of particles) to find another option to protect the window, but their development is only in the initial phase. This article makes a detailed review of the main methods of solar reactor window protection, showing the complexity of the problem, the advances in recent years, and suggesting possible future developments.
