Reduce Energy Requirements Research Articles

Reviewing the potential of anaerobic membrane bioreactors in wastewater treatment

Anaerobic membrane bioreactors (AnMBRs) represent an innovative approach to wastewater treatment, combining anaerobic digestion with membrane filtration to achieve efficient organic pollutant removal and resource recovery. This review critically examines the potential of AnMBRs in wastewater treatment, highlighting their principles, advantages, challenges, recent advancements, and future prospects. AnMBRs offer several advantages over traditional aerobic treatment methods, including higher organic loading rates, reduced energy requirements, and biogas production through methane generation. However, challenges such as membrane fouling, reactor complexity, and operational costs have limited their widespread adoption. Recent advancements in membrane materials, fouling mitigation strategies, and process optimization have improved AnMBR performance and feasibility. Novel membrane materials with enhanced fouling resistance and durability have been developed, while innovative cleaning techniques and operational protocols have been implemented to mitigate membrane fouling and prolong membrane lifespan. Process optimization strategies, including reactor design modifications and operational parameter adjustments, have enhanced treatment efficiency and reduced energy consumption in AnMBRs. Future research directions in AnMBR technology focus on optimizing reactor configurations, exploring novel membrane materials and fouling control strategies, and conducting comprehensive techno-economic assessments to evaluate the environmental and economic sustainability of AnMBRs. Integration of AnMBRs with emerging technologies such as membrane distillation, forward osmosis, and bioelectrochemical systems holds promise for further enhancing treatment performance and resource recovery capabilities. Additionally, addressing knowledge gaps in membrane fouling mechanisms, microbial community dynamics, and long-term system stability is crucial for advancing AnMBR technology and facilitating its widespread implementation in wastewater treatment. Overall, AnMBRs offer significant potential for sustainable wastewater treatment, providing opportunities for organic pollutant removal, energy recovery, and resource reuse. By addressing technical challenges, optimizing process parameters, and conducting interdisciplinary research, AnMBRs can contribute to the development of efficient, cost-effective, and environmentally friendly wastewater treatment solutions, ultimately supporting the goal of achieving cleaner water resources and a more sustainable future.

Biochar-mediated release of CO2 from monoethanolamine/H2O solution with low energy requirement over ZrO2/SiO2/biochar ternary catalysts

CO2 absorption technology based on amine solutions has sustained appeal due to its high efficiency in post-combustion capture of CO2. However, the high energy penalty of solvent regeneration limits its large-scale industrial application. Therefore, designing inexpensive catalysts to reduce solvent regeneration energy consumption remains challenging. This study reports a recyclable ternary catalyst, ZrO2/SiO2/biochar, which was synthesized by co-pyrolysis of zirconium oxychloride and wheat flour in the presence of SiO2 nanoparticles. The incorporation of biochar improved the distribution of Lewis acidic sites (LAS) and Brønsted acidic sites (BAS). The improved BASs and LASs of ZrO2/SiO2/biochar catalyst were conductive to donate protons or accept electrons and thus, the amount and rate of CO2 desorption from CO2-saturated monoethanolamine (90 °C) were more than 24% and 26% higher, respectively, to compare with the catalyst-free system at the same conditions. As a result, the energy penalty was decreased by about 31%. A biochar-mediated proton-transfer mechanism that the presence of biochar increased the mesoporous proportion, the BAS and L/B ratio as well as the favorable charge transfer was inferred for the ZrO2/SiO2/biochar-catalyzed CO2 release through experimental evidence. The results reveal the role of biochar in solid acid catalysts for CO2 desorption, which will provide a novel strategy for building solid acid catalysts to reduce energy requirements in CO2 capture.

Process systems engineering perspectives on eco-efficient downstream processing of volatile biochemicals from fermentation

Increasing concerns over environmental pollution, climate change and energy security are driving a necessary transition from fossil carbon sources to more sustainable alternatives. Due to lower environmental impact, biochemicals are rapidly gaining significance as a potential renewable solution, particularly of interest in Europe. In this context, process systems engineering (PSE) helps with the decision-making at multiple scales and levels, aiming for optimum use of (renewable) resources. Fermentation using waste biomass or industrial off-gases is a promising way for the production of these products. However, due to the inhibitory effects or low substrate concentrations, relatively low product concentrations can be obtained. Consequently, significant improvements in downstream processing are needed to increase the competitiveness of the overall bioprocesses. This paper supports sustainable development by providing new PSE perspectives on the purification of volatile bioproducts from dilute fermentation broths. Since purification significantly contributes to the total cost of biochemical production processes (20%–40% of the total cost), enhancing this part may substantially improve the competitiveness of the overall bioprocesses. The highly advanced downstream process offers the possibility of recovering high-purity products while enhancing the fermentation step by continuously removing inhibitory products, and recycling microorganisms with most of the present water. Besides higher productivity, the upstream process can be greatly improved by avoiding loss of biomass, enabling closed-loop operation and decreasing the need for fresh water. Applying heat pumping, heat integration and other methods of process intensification (PI) can drastically reduce energy requirements and CO2 emissions. Additionally, the opportunity to use renewable electricity instead of conventional fossil energy presents a significant step toward (green) electrification and decarbonization of the chemical industry.

Energy-oriented optimization of the task allocation for mobile robots

Production systems need to be flexible in order to handle increasingly complex operational requirements. In many cases, mobile robots are used to flexibly connect production facilities. In this case, task allocation is a challenging procedure and should be optimized to ensure that processing deadlines are met and processing times are minimized. For this purpose, it is essential to be able to accurately predict the energy and time requirement of each action that the mobile robots could execute. This paper investigates how detailed modelling of mobile robots can reduce energy requirements and optimize planning of the logistics. Two concepts for task allocation are examined and one is presented in detail due to its applicability: global optimization by use of an open source software library and local optimization by use of an auction procedure. The global optimization method is suitable for small problems of low complexity, while the auction procedure can handle scenarios that are more complex. In this case, a central entity selects the mobile robot with the lowest bid to complete the task based on a developed prediction model for time and energy requirements.

Beyond absorption maxima: the impact of wavelength-resolved photochemistry on materials science.

Reflecting on Giacomo Ciamician's revolutionary vision of harnessing sunlight to drive photochemical transformations, the field of materials science has evolved significantly, yet it has been constrained by the misconception that the highest reactivity in photochemical systems is achieved at the absorption maxima. Here, we explore this notion further with evidence from photochemical action plots, demonstrating that reactivity can indeed be maximal at wavelengths significantly separated from the absorption peak. By examining the implications of the disparity between absorptivity and photochemical reactivitiy, we explore its impact for the enhanced penetration depth of light in photoresists, the reduction of energy requirements for photochemical reactions, and its transformative potential for volumetric 3D printing. Ultimately, we argue for a renewed appreciation of light's capability to facilitate photochemical reactions across the entire volume of a material.

Energy Performance and Thermal Comfort Assessment of an Educational Building in Northern Italy: The Importance of Climatic Files in Energy Simulations

Energy efficiency and thermal and acoustic comfort play crucial roles in the design and management of educational buildings. The literature underscores their influence on students’ and teachers’ well-being and productivity. Additionally, numerous works emphasise the growing environmental awareness among children attending sustainably designed or adapted buildings. In light of these considerations, the present study aims to evaluate the dynamic energy performance of a school located in Northern Italy, conceived as a Nearly Zero Energy Building (NZEB). The school integrates various technologies, intelligent systems, and renewable sources to reduce energy requirements. A second aspect under evaluation involves using both real and virtual anemometers to generate crucial weather data for energy simulations. Dynamic analyses often rely on traditional meteorological year (Typical Meteorological Year) datasets derived from outdated sources, leading to inaccuracies in representing current climatic conditions, especially in the case of results related to a specific period.

Integrated Experimental Phase Equilibria and Thermodynamic Modelling Research and Implementation in support of progress of process pyrometallurgy towards sustainability

Responding to the many sustainability challenges facing the metallurgical industry, we report progress that has been made on the development of predictive tools that can be applied to a wide range of technologies. The aim is to provide accurate, fundamentally-based thermodynamic tools that can be used by industry to improve process efficiencies, metal recoveries and productivities, and reduce energy requirements of pyrometallurgical systems. The program involves an integrated experimental and thermodynamic modelling research on phase equilibria in complex multi-component, multi-phase gas-slag-matte-speiss-metal-solids system with the Cu2O-PbO-ZnO-FeO-Fe2O3-CaO-Al2O3-MgO-SiO2-S major and As-Sn-Sb-Bi-Ag-Au-Ni-Co-Cr-Na minor elements. The experiments involve high temperature equilibration in controlled gas atmospheres, rapid quenching and direct measurement of equilibrium phase compositions with quantitative microanalytical techniques, including electron probe X-ray microanalysis and Laser Ablation ICP-MS. The thermodynamic modelling is undertaken using FactSage software package with advanced thermodynamic solution models. The continuing development of analytical and research methodologies has resulted in significant advances in predictive capability. Implementation of the results of fundamental studies involves ongoing collaboration of researchers and industry technologists, and the provision of advanced professional training. An overview of recent progress in research, implementation and applications in industrial practice will be presented in the paper.

Advanced purification of isopropanol and acetone from syngas fermentation

AbstractBACKGROUNDIsopropanol and acetone production by syngas fermentation is a promising alternative to conventional fossil carbon‐dependent production. However, this alternative technology has not yet been scaled up to an industrial level owing to the relatively low product concentrations (about 5 wt% in total). This original research aims to develop cost‐effective and energy‐efficient processes for the recovery of isopropanol and acetone from highly dilute fermentation broth (>94 wt% water) for large‐scale production (about 100 ktIPA+AC y−1).RESULTSVacuum distillation and pass‐through distillation enhanced with heat pumps or multi‐effect distillation were efficiently coupled with regular atmospheric distillation and extractive distillation in several innovative intensified downstream processes. Over 99.2% of isopropanol and 100% of acetone were recovered as high‐purity end‐products (>99.8 wt%). Advanced heat pumping (mechanical vapor recompression) and heat integration techniques were implemented to decrease total annual costs (0.109–0.137 USD kgIPA+AC−1), reduce energy requirements (1.348–2.043 kWth h kgIPA+AC−1) and lower CO2 emissions (0.067–0.191 kgCO2 kgIPA+AC−1), resulting in highly competitive recovery processes.CONCLUSIONThe proposed three novel isopropanol and acetone recovery processes from dilute broth significantly contribute to the expansion of sustainable industrial fermentation. Furthermore, this original research is the first one to develop novel pass‐through distillation technology for the complex isopropanol–acetone–water system. All the designed processes are highly economically competitive and environmentally viable. In addition to recovering efficiently both isopropanol and acetone, the designed downstream processes offer the possibility to enhance the fermentation process by recycling all the present microorganisms and reducing fresh‐water requirements. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).

Enhanced isobutanol recovery from fermentation broth for sustainable biofuels production

Isobutanol is a highly attractive renewable alternative to conventional fossil fuels, with superior fuel properties as compared to ethanol and 1-butanol. Even though the isobutanol production by fermentation has significant potential, complex downstream processing is limiting the wide-spreading of this technology. Accordingly, this original research significantly contributes to the advancement in industrial biofuel production by developing two eco-efficient downstream processes for the industrial-scale recovery of isobutanol (production capacity 50 ktonneIBUT/y), from a highly dilute fermentation broth (>98 wt% water). Vacuum distillation and a novel hybrid combination of gas stripping and vacuum evaporation were coupled with atmospheric azeotropic distillation to recover over 99.9 % of isobutanol as a high-purity product (100 wt%). Advanced heat pumping and heat integration techniques were further implemented to allow the complete electrification of these recovery processes. Furthermore, implementation of these techniques significantly decreased total annual costs (0.131–0.161 $/kgIBUT), reduced energy requirements (0.488–0.807 kWeh/kgIBUT) and lowered CO2 emissions (0.303–0.449 kgCO2/kgIBUT), resulting in highly competitive purification processes. In addition to efficiently recovering isobutanol, the designed downstream processes provide the potential to enhance the fermentation process by recycling all present microorganisms and reducing water demand. Therefore, the results of this original research substantially contribute to the advancement in industrial biotechnology and the wide-spreading of biofuel production.

Boosting solar vapor generation and desalination by low-cost reduced graphene oxide/cellulose aerogel and multiple energy utilization

Solar interfacial vapor generation provides one of promising pathways for seawater desalination and wastewater treatment with minimized carbon footprint. There are still great challenges in architecting low-cost solar evaporators for rapid water transfer channels and high-throughput evaporation rate. Herein, an aerogel with reduced graphene oxide and cellulose nanofibers (rGC) was fabricated by one step self-assembly method. The rGC possessed excellent light absorption, superhydrophilic ability, and reduced energy requirement of water evaporation. The evaporation rate of rGC-3 (height of 3 cm) achieved 3.19 kg m−2 h−1 with the evaporation efficiency of 114.3% under 1 sun irradiation. The suspended vapor was timely diffused by directional convection, so as to minimize the stagnation of vapor in openly channels and continuously harvest additional environmental energy. The water evaporation behavior was improved to 9.40 kg m−2 h−1 under a convective flow of 2.5 m s−1, well beyond 200.3% of non-convective condition. Additionally, the three-dimensional rGC-3 consistently evaporated in 3.5 wt% brine and the evaporation rate kept at 8.61 - 9.39 kg m−2 h−1. In the outdoor solar water desalination, rGC-3 had excellent desalination behavior and evaporative performance in weak sunlight and relative low temperature. The realization of enhanced evaporation rate, overall seawater purification capability, and high cost-effectiveness of the nanofiber aerogel provide a new inspiration for designing high-throughput solar interfacial evaporator.

Electrochemical Dewatering of Cellulosic Nanomaterials

Cellulose is the most abundant biomass material in nature utilized for the manufacturing of cellulosic nanomaterials that exhibit great potential in a variety of industrial applications. Although cellulosic nanomaterial is cost-effective to produce, it is not economical to ship long distances while containing significant water content (>95 wt.%). Therefore, a need has been identified by manufacturers to develop energy-efficient, dewatering or drying of cellulosic nanomaterials.Accordingly, Faraday Technology in collaboration with GranBio USA, manufacturers of cellulosic nanomaterials, is addressing this need by developing electrochemical based dewatering system and process to dewater cellulosic nanomaterials while maintaining material properties when dried and re-dispersed. Energy-efficient (70% reduction in energy requirements compared to thermal dewatering), environmentally beneficial (51% reduction in greenhouse gas emissions), economical (31% reduction in cost/ton of dried material), and industrially viable electrochemical based dewatering approach to process up to 2 tons/year of dried nanocellulose at alpha-scale has been demonstrated. The approach is capable of achieving >50 wt.% final solids and 18 wt.% final solids, that could be rehydrated under vortex and confirmed for re-dispersibility. Material properties (structure, particle size) were maintained by the dewatered cellulosic nanomaterials. Specifically, this talk will discuss the results of these advancements. Acknowledgements: The financial support of DOE Contract No. DE-SC0018787 is acknowledged.

Dynamically reprogrammable stiffness in gecko-inspired laminated structures

Adaptive structures are of interest for their ability to dynamically modify mechanical properties post fabrication, enabling structural performance that is responsive to environmental uncertainty and changing loading conditions. Dynamic control of stiffness is of particular importance as a fundamental structural property, impacting both static and dynamic structural performance. However, existing technologies necessitate continuous power to maintain multiple stiffness states or couple stiffness modulation to a large geometric reconfiguration. In this work, reversible lamination of stiff materials using gecko-inspired dry adhesives is leveraged for bending stiffness control. All stiffness states are passively maintained, with electrostatic or magnetic actuation applied for ∼1 s to reprogram stiffness. We demonstrate hinges with up to four passively maintained reprogrammable states decoupled from any shape reconfiguration. Design guidelines are developed for maximizing stiffness modulation. Experimentally, the proposed method achieved a stiffness modulation ratio of up to 14.4, with simulations showing stiffness modulation ratios of at least 73.0. It is anticipated that the stiffness reprogramming method developed in this work will reduce energy requirements and design complexity for adaptation in aerospace and robotics applications.

AI-Based Geometry Recognition for Evaluating the Feasibility of Intensified Reaction and Separation Systems.

Reactive distillation (RD) provides notable advantages over conventional processes, regarding reduced energy requirements and CO2 emissions. However, as the benefits of RD may not be universally applicable, a comprehensive feasibility assessment is necessary. This study introduced an automated feasibility evaluation procedure for an RD column using an AI-based region recognition approach, reducing the reliance on expert knowledge and heuristics in graphical methods. Through k-means clustering-based image segmentation, topological information on the reaction and separation reachable region was extracted from ternary diagram landscapes. Subsequently, the extracted information was integrated into tray-by-tray calculations to automate the evaluation. This geometric calculation procedure was applied to assess the feasibility of RD columns with different types of reactions. The feasibility results were obtained within seconds, demonstrating the efficiency of the proposed approach. Furthermore, case studies validated the feasibility of the evaluation results for three practical examples using rigorous simulations, confirming its reliability and applicability.

Insight on characterization through porosity-to-lime index of a stabilized soil for the long-term

The strength of lime-cemented soils has received significant attention in previous studies. However, limited research has focused on studying soil mixtures for extended durations beyond 365 days, which is essential for understanding shear strength, microstructure, unconfined compressive, and matric suction. Consequently, there is a need to explore the long-term behavior and unsaturated properties of soil specimens cured for up to 500 days using appropriately hydrated lime, considering the semi-empirical porosity/lime index. By investigating various curing times ranging from 15 to 500 days, as well as employing different compaction energies (standard, intermediate, and modified) and lime content ranging from 3% to 9% by weight, this study aims to characterize the evolution of resistance and unsaturated properties of lime-cemented soils. The semi-empirical porosity/lime index is employed to guide the characterization and analysis of the mixtures' resistance properties. By developing equations to estimate the resistance of these mixtures, the study contributes to reducing lime consumption (and reducing CO2 emissions during its production) and optimizing curing time, leading to environmentally friendly geotechnical projects. Due to the utilization of the porosity/lime ratio, lime consumption can be minimized, and curing time can be fixed, resulting in a significant reduction in energy requirements, which is beneficial for the environment. The outcomes of this research have profound implications for the design and construction of sustainable structures such as dams, pavements, and slope protection systems, ensuring their long-term stability, resilience, and ecological balance.

Thermal and energy efficiency study of passive heating and cooling systems in Morocco's cold desert climate

This research aims to showcase the imperative of integrating passive cooling and heating techniques within buildings to effectively decrease energy consumption. To accomplish this objective, numerical simulations were conducted on a representative double-walled brick building in two cold desert climates using TRNSYS software. The simulations were performed to compare and evaluate the thermal and energy performance of two distinct passive techniques, one for cooling the reflective roof and the other for heating the Trombe wall (TW). The findings demonstrate that employing a reflective roof building with an air gap significantly reduces indoor temperatures by 3 °C during the hottest weekdays of summer, as compared to the reference building, across the two studied Moroccan climates. Moreover, this approach decreases the demand for cooling energy by an impressive 69–78 %. Similarly, the passive heating technique proves highly effective during winter, reducing energy requirements by 26–30 % while increasing indoor temperatures by over 2.9 °C. Combining both techniques proves to be the most efficient solution, resulting in a 37.87 % reduction in total annual energy consumption for cooling and heating in Er-Rachidia and a 30 % reduction in Ifran. These results strongly support the suggestion that Moroccan thermal regulations should incentivize the adoption of passive cooling and heating systems, particularly in cold desert climates.

Process modeling, environmental and economic sustainability of the valorization of whey and eucalyptus residues for resveratrol biosynthesis

Biomass is one of the renewable resources with the greatest potential, not only because of the possibility of energy recovery but also because of its content in components of interest. In this context, the regions of Galicia and Portugal have large areas of land dedicated to forestry, agriculture and livestock, and the large amount of waste generated represents a cost for the producer. The importance of these facts has aroused great interest in society to focus its interest on improving the current situation while seeking a benefit, both environmental and economic, from existing resources. That is why the integration of biotechnological processes and biorefinery for their valorization are considered key aspects in the way of producing bioproducts and bioenergy. This research article proposes a process for producing resveratrol from whey from the dairy industry and eucalyptus residues from forestry exploitation. In order to evaluate its suitability, a techno-economic analysis and an environmental assessment have been carried out using the Life Cycle Assessment (LCA) methodology. The results obtained show the potential of these scenarios both from the economic point of view, by obtaining a minimum sale price of resveratrol to ensure the viability of the process below the market average, and from the environmental point of view, being eucalyptus residues those that result in a lower contribution to the environment per unit of resveratrol produced. Future research should focus on increasing the throughput of the production process to increase its profitability and on reducing energy requirements throughout the process, as these have been the main critical points identified. In addition, following the sensitivity assessment, it has been concluded that opting for renewable energy is the most sustainable option.

A COMPREHENSIVE REVIEW STUDY ON HEAT TRANSFER IMPROVEMENT TECHNIQUES WITHIN TWISTED TUBES

Heat transfer equipment has been used in many different domestic and industrial applications. There has been a concentrated effort to create a heat exchanger design that will reduce energy requirements while saving materials and other costs. Increasing the effective heat transfer surface area or creating turbulence are two common ways to improve heat transfer and hence lower thermal resistance. The thermal Performance Factor is the ratio of the difference in heat transfer rate to the difference in friction factor and serves as a metric to assess the efficiency of heat transfer enhancement technologies. Different types of twisted tubes are used in many heat transfer improvement devices. geometrical parameters of the twisted tube encompassing the aspect ratio, twist ratio, twist direction, twist length, etc. impact the heat transfer. For Instance, oval pipes with unequal twist pitches have a thermal performance factor (1.75) and equal twist pitches have a thermal performance factor (1.98). furthermore, the thermal performance factor of the twisted tube with oval dimples is equal to 1.19 compared with the twisted tube without dimples. The thermal performance factor of the twisted tube with oval dimples is equal to 1.38 compared with the straight tube, with another improvement to the twisted tube that improves the heat transfer properties by disrupting the thermal boundary layer and destabilizing it. This paper presents a comprehensive investigation of passive heat transfer devices (twisted tubes) and their relative merits in a myriad of commercial applications.

Winery and olive mill wastewaters treatment using nitrilotriacetic acid/UV-C/Fenton process: Batch and semi-continuous mode

In this work, both red and white winery wastewaters (WW) and olive mill wastewater (OMW) were submitted to a treatment by Fenton-based processes (FBPs). The main aim was to evaluate the most efficient and economic process. Initial tests, resorting to a batch reactor, demonstrated that UV-C/Fenton (λ = 254 nm) was the most effective process. Operational conditions such as pH, H2O2 and Fe2+ concentrations revealed to have a superior influence within dissolved organic carbon (DOC) removal as well as regarding the reactor's energy consumption. As a means to prevent iron precipitation, the addition of nitrilotriacetic acid (NTA) was tested. With experimental conditions pH = 3.0, [H2O2] = 194 mM, [Fe2+] = 1.0 mM, [NTA] = 1.0 mM, radiation UV-C (254 nm), time = 240 min, the kinetic rate related with DOC removal showed a kredWW = 0.0128 min−1 > kOMW = 0.0124 min−1 > kwhiteWW = 0.0104 min−1 and both the WW and OMW achieved the Portuguese legal limit values for wastewater discharge. Furthermore, comparative experiments were performed in a semi-continuous reactor, being that the results put in evidence that the concentration of H2O2 added and the flow rate of reagents' addition (F) had a significant effect on the efficiency of the reactor. Under an optimum experimental procedure pH = 3.0, [H2O2] = 97 mM, [Fe2+] = 1.0 mM, [NTA] = 1.0 mM, radiation UV-C (254 nm), F = 1 mL min−1, time = 240 min, there were observed higher DOC removal kinetic rates (kOMW = 15.20 × 10−3 min−1 > kredWW = 11.64 × 10−3 min−1 > kwhiteWW = 11.57 × 10−3 min−1) and a cost ranging between 0.0402 and 0.0419 €/g.DOC. These results showed that semi-continuous reactors have the potential to be applied to large scale treatments, with low reagents consumption and reduced energy requirements.

Impact of organic matter on transformation during thermal remediation of pyrene-contaminated substrates

Thermal remediation (TR) is a broadly applicable technology that is effective at removing volatile and semi-volatile contaminants from soil. However, TR can be costly and inefficient in practice, with underlying removal and transformation mechanisms poorly understood. To better understand the role organic matter plays in removal, a series of experiments was performed with a humic substance, humic modified silica, and a natural soil in the presence of pyrene from 100 to 500 °C and compared to prior experiments using pure minerals. Detection of by-products confirmed that pyrene was removed by transformation in addition to volatilization. Oxidation via hydroxyl radical formation and reductive hydrogenation were both indicated as possible reaction mechanisms promoted by organic matter. Because the presence of bulk water did not impact the extent of pyrene degradation or transformation, it is hypothesized that hydroxyl radicals were produced from soil organic matter functional groups, such as carboxyl and phenol groups, and possibly bound water at elevated temperatures in dry experiments. Additionally, the average oxidation state of carbon in detected by-products increased with temperature in experiments with humic modified silica and soil but not humic substance alone, though the extent of degradation did not significantly change. This shift in oxidation state may indicate that attachment of organic matter to another surface may increase interaction between reactive species. The results of this study show that contaminant transformation in soils during TR significantly contributes to removal, even at temperatures lower than those used in traditional treatment. This information will help to guide the design and operation of TR systems, potentially reducing energy requirements and highlighting the necessity of testing for transformation by-products.

Hydrophobicity Tuned Polymeric Redox Materials with Solution-Specific Electroactive Properties for Selective Electrochemical Metal Ion Recovery in Aqueous Environments.

Adaptable redox-active materials hold great potential for electrochemically mediated separation processes via targeted molecular recognition and reduced energy requirements. This work presents molecularly tunable vinylferrocene metallopolymers (P(VFc-co-X)) with modifiable operating potentials, charge storage capacities, capacity retentions, and analyte affinities in various electrolyte environments based on the hydrophobicity of X. The styrene (St) co-monomer impedes hydrophobic anions from ferrocene access, providing P(VFc-co-St) with specific response capabilities for and greatly improved cyclabilities in hydrophilic anions. This adjustable electrochemical stability enables preferential chromium and rhenium oxyanion separation from both hydrophobic and hydrophilic electrolytes that significantly surpasses capacitive removal by an order of magnitude, with a robust perrhenate uptake capacity of 329 mg/g VFc competitive with established metal-organic framework physisorbents and 17-fold selectivity over 20-fold excess nitrate. Pairing P(VFc-co-X) with other solution-specific electroactive macromolecules such as the pH-dependent poly(hydroquinone) (PHQ) and the cesium-selective nickel hexacyanoferrate (NiHCF) generates dual-functionalized electrosorption cells. P(VFc-co-X)//PHQ offers optimizable energetics based on X and pH for a substantial 4.6-fold reduction from 0.21 to 0.04 kWh/mol rhenium in acidic versus near-neutral media, and P(VFc-co-St)//NiHCF facilitates simultaneous extraction of rhenium, chromium, and cesium ions. Proof-of-concept reversible perrhenate separation in flow further highlights such frameworks as promising approaches for next-generation water purification technologies.