Current Opinion in Chemical Engineering最新文献

This paper reviews the latest research advancements in cathodic membrane (CM)–based electrochemical redox processes (CMERs) for water treatment. The water purification mechanisms by CMERs, including CMER reduction, CMER Fenton, and CMER coupling other oxidant processes (CMEOs), are explained. Especially, the pathways of formation of reactive species (e.g. •OH, ¹O₂, and O₂^•) are presented in detail. Besides, the effects of different CMs and operating conditions are considered. The applications extending to refractory pollutants removal, disinfection, membrane fouling alleviation, and resource recovery are well presented and analyzed. CMER reactors are also discussed for their potentials of scale up for water treatment. Finally, the trends in the field encompassing current knowledge gaps are highlighted, and the recommendations for future research are proposed.

Advanced reduction processes (ARPs) have demonstrated efficient degradation of poly- and perfluoroalkyl substances (PFAS). This paper describes the maturity level of more established ultraviolet (UV)-based ARPs, along with other reductive processes in the research stage. Commercial ARP vendors offer varying formats of UV-activated photosensitization of chemical additives to generate hydrated electrons in batch mode. These systems are typically coupled with preliminary separation processes and treat a concentrated PFAS waste stream. Other reduction approaches such as metal catalytic reduction have not yet left the academic space. Key areas of progress needed include cost-effective pretreatment approaches, and, relatedly, demonstration of ARPs in complex waste concentrates. Further improvement in reaction kinetics and developing an effective process for treating the most recalcitrant PFAS will also increase adoption of ARPs.

Metal sulfides (MSs) have been explored extensively as promising semiconductors for photocatalytic applications in pollutant degradation, CO₂ reduction, and H₂ production. However, pure MSs suffer from several drawbacks, especially rapid electron–hole recombination. The construction of S-scheme heterojunctions has been recommended as one of effective strategies to improve charge separation and transfer, as well as to retain high redox potential electrons and holes to participate in reaction. This paper reviewed recent advances on the construction of MS-based S-scheme heterojunctions with high photocatalytic performances. In particular, various design and construction approaches, including integration with other semiconductors, microstructure control, and interface modulation, were covered along with mechanisms governing the boosted photocatalytic performances. The challenges and prospects in the research about MS-based S-scheme heterojunctions were discussed finally, providing our insight on future research.

High-entropy alloys (HEAs) possess unique physical and chemical properties clearly distinguishable from those of traditional alloys, making them promising candidates for various applications, including electrocatalysis. While the electrocatalytic performance of these alloys has been assessed in detail, the electrochemical stability is often assumed to be improved compared with single metals and simple alloys. Such an assumption is rarely supported by theoretical or experimental data and might be misleading for the further successful implementation of HEAs in real devices. In this review, we provide a brief overview of the current state of this research direction, identify the common pitfalls in assessing alloy stability, and discuss the need for advanced coupled experimental/computational studies directed toward understanding the partial dissolution of elements from alloys.

This work presents a bird’s eye view depicting current trends in the pharmaceutical industry and the role of mathematical modeling in process design and operation within the framework of quality by design for a general readership in the field of chemical engineering. The paper outlines the vectors of change that are moving the pharmaceutical industry toward adopting new trends. The role of mathematical modeling is fundamental in accompanying the change taking place. A brief overview of model classification from a regulatory versus engineering point of view and recent progress in modeling in different pharmaceutical manufacturing subfields is illustrated. The short review concludes with important points to consider for maximizing the benefit of modeling in the pharmaceutical manufacturing field.

Advanced reduction processes (ARPs) have emerged as promising techniques for destruction of persistent per- and polyfluoroalkyl substances (PFAS) due to the formation of highly reductive hydrated electrons (e_aq⁻). The present study provides a critical review of the progress and prospects of the field over the past three to five years categorizing topics into three main sections: i) state of the art of ARPs, comparing the promise and mechanisms of methods such as photochemical, ionizing irradiation, plasma, sonolysis, electroreduction, and zero-valent iron; ii) integration of ARPs with physical-separation methods, oxidation processes, and their role in regeneration/management of PFAS-laden media; iii) challenges/innovations in real-world application of ARPs. Three primary future research directions are also proposed in alignment with the current and upcoming research focuses.

Remediation of per- and polyfluorinated alkyl substances (PFAS) in global water systems is a critical human and environmental health challenge facing society. PFAS consumption is associated with a litany of adverse health effects, and our knowledge of these dangers is still evolving. Current techniques to remove PFAS from water include adsorption to media (e.g. granular activated carbon, ion-exchange resin), nanofiltration, and reverse osmosis. However, these processes create a concentrated PFAS residual that requires further management. Destructive techniques are therefore needed to detoxify these residuals. Oxidative techniques have garnered the most attention (e.g. supercritical water oxidation, electrochemical oxidation) but are energy intensive and potentially form toxic by-products. As an alternative, several groups have researched advanced reduction processes that form aqueous electrons, but these processes are still chemical and energy intensive (e.g. ultraviolet/SO₃²⁻, electron beam). This concise review therefore focuses on whether electrochemical reduction — a chemical-free, modular process — could be technically feasible for PFAS destruction.

The elimination of per- and polyfluoroalkyl substances (PFAS) in water continues to garner significant attention due to their enduring presence in the environment and associated health concerns. The emergence of advanced reduction processes (ARPs) holds significant promise in reducing persistent PFAS in water, primarily due to its ability to produce short-lived yet highly reductive hydrated electrons. This concise review offers insights into the latest developments in ARP-based PFAS degradation, encompassing both experimental and theoretical investigations conducted within the last 2–5 years. We conclude with an outlook on potential research avenues in this dynamic field and suggest future experimental and computational strategies to enhance ARP capabilities.

This review provides a brief overview of the electrocatalytic reduction of refractory organic contaminants in water. The electrocatalytic reduction mechanism and principle are thoroughly discussed. The role of various oxidants such as ozone, persulfate, permanganate, peracetic acid, and mixed oxidants on the electrocatalytic reduction of refractory organic contaminants was deeply explored. The impact of various operational parameters such as current density, initial concentration of oxidants, solution pH, and water matrices on the electrocatalytic degradation of refractory organic compounds has been investigated in detail. Moreover, the role of electrode materials and electrocatalytic reactor design in the electrocatalytic reduction of refractory organic contaminants in water was also discussed. Finally, the challenges and future perspectives were highlighted for the practical implementation of electrocatalytic reduction processes for water treatment.

Numerous water remediation technologies continue to be developed with the aim to mineralize contaminants with particular emphasis on eliminating perfluoroalkyl substances (PFAS). In this review, we describe recent experimental and theoretical studies pertinent to ultraviolet-advanced reduction processes (UV-ARP) in the context of the initial PFAS reduction and defluorination by hydrated electrons, e_aq^-. Specifically, we highlight approaches using transient absorption spectroscopy that measure the kinetic parameters related to the formation of e_aq^- and PFAS reduction via e_aq^- quenching. These studies provide important information, such as the rate constants corresponding to the quenching of e_aq^- by PFAS, that is crucial in developing a mechanistic framework to describe PFAS degradation by UV-ARP. Additionally, we summarize recent theoretical studies that have calculated the energetics associated with relevant reactions and provided insights regarding the mechanism of reductive defluorination in order to identify prevalent processes and chain- length dependences for electron reactions with contaminants.