Recovery Solutions Research Articles

Carbon dioxide storage and cumulative oil production predictions in unconventional reservoirs applying optimized machine-learning models

To achieve carbon dioxide (CO2) storage through enhanced oil recovery, accurate forecasting of CO2 subsurface storage and cumulative oil production is essential. This study develops hybrid predictive models for the determination of CO2 storage mass and cumulative oil production in unconventional reservoirs. It does so with two multi-layer perceptron neural networks (MLPNN) and a least-squares support vector machine (LSSVM), hybridized with grey wolf optimization (GWO) and/or particle swarm optimization (PSO). Large, simulated datasets were divided into training (70%) and testing (30%) groups, with normalization applied to both groups. Mahalanobis distance identifies/eliminates outliers in the training subset only. A non-dominated sorting genetic algorithm (NSGA-II) combined with LSSVM selected seven influential features from the nine available input parameters: reservoir depth, porosity, permeability, thickness, bottom-hole pressure, area, CO2 injection rate, residual oil saturation to gas flooding, and residual oil saturation to water flooding. Predictive models were developed and tested, with performance evaluated with an overfitting index (OFI), scoring analysis, and partial dependence plots (PDP), during training and independent testing to enhance model focus and effectiveness. The LSSVM-GWO model generated the lowest root mean square error (RMSE) values (0.4052 MMT for CO2 storage and 9.7392 MMbbl for cumulative oil production) in the training group. That trained model also exhibited excellent generalization and minimal overfitting when applied to the testing group (RMSE of 0.6224 MMT for CO2 storage and 12.5143 MMbbl for cumulative oil production). PDP analysis revealed that the input features “area” and “porosity” had the most influence on the LSSVM-GWO model's prediction performance. This paper presents a new hybrid modeling approach that achieves accurate forecasting of CO2 subsurface storage and cumulative oil production. It also establishes a new standard for such forecasting, which can lead to the development of more effective and sustainable solutions for oil recovery.

Exhaust Gas Flow Study of Electric Turbo Compounding (ETC) to Determine the Potential Electrical Energy Recovery from Exhaust Emission

Electric turbo compounding (ETC) emerges as a pivotal energy recovery solution, seamlessly combining an advanced turbocharger with a high-speed generator to harvest electrical energy from exhaust gas dynamics. This research delves into the practical application of ETC in vehicles, employing a comprehensive approach blending simulation techniques with experimental validation. The investigative process involves meticulous data collection on vehicle muffler dimensions, subsequent device modelling based on this data, and rigorous flow simulations, followed by thorough analysis. The study's key findings highlight a noteworthy 9% increase in engine back pressure at 850 rpm, counterbalanced by a 7% reduction at 2000 rpm. Despite the integration of the ETC mechanism, electric current measurements remain consistently within the range of 1.4 to 1.6 amperes at 1200-2000 rpm. This research not only unveils the tangible effects of ETC on engine performance but also underscores its viability as an efficient energy recovery solution in the automotive sector, setting the stage for advancements in sustainable transportation.

Formation mechanism of high biofilm phosphorus storage capacity and its effect on phosphorus uptake-release and carbon source consumption

Phosphorus recovery from wastewater is an effective method to alleviate the shortage of phosphorus resources. The biofilm phosphorus recovery process can realize simultaneous removal and enrichment of phosphorus in wastewater. In this study, a sequencing batch biofilm reactor was constructed to study the rapid phosphorus release and slow phosphorus release stages in the phosphorus recovery cycle. The relationship between high biofilm phosphorus storage capacity (Pbiofilm), phosphorus recovery solution concentration, phosphorus uptake-release behavior and carbon source consumption were explored. The increase in phosphorus recovery solution concentration promotes the elevation of Pbiofilm, which, conversely promotes phosphorus release in the next recovery cycle. In addition, the distinct phosphorus uptake-release characteristics of extracellular polymeric substances and cells were illustrated. This study provides a theoretical foundation to elevate the phosphorus recovery efficiency and reduce carbon source consumption in biofilm phosphorus recovery process.

Integrating local knowledge into public policy instruments for enhancing restoration: A study case from western Mexican tropical dry forest

Local knowledge (LK) is often overlooked in the decision-making process during landscape restoration process. In this study, we focus on the Zicuirán-Infiernillo Biosphere Reserve as a case study. We propose a framework to incorporate LK into public policy instruments for implementing restoration interventions in Mexican protected natural areas (PNAs). Through semi-structured interviews, participant observation, and informal talks, conducted with residents from two communities located in the buffer zone and the border area of the reserve, we gathered valuable insights regarding the following: (1) the inhabitants' LK of the ecology and contributions of tropical dry forest, (2) the socioeconomic and environmental issues identified by these communities in their localities, (3) ecological and socioeconomic actions suggested by the residents to recover the forest or halt its degradation, and (4) the role of institutions and local organizations in restoration and conservation processes. Our findings indicate that residents recognized changes in species distribution and identified native trees that are tolerant to drought. Moreover, they acknowledged the beneficial contributions provided by forests, including climate and water cycle regulation, oxygen supply, and raw materials. Local people also demonstrated their awareness of environmental and socioeconomic issues and proposed activities to reverse vegetation cover loss and halt forest degradation. While reforestation emerged as the primary solution for forest recovery, assisted natural regeneration and natural regeneration were also suggested. Based on our results, we propose a framework that emphasizes a robust knowledge exchange among stakeholders, for facilitating the inclusion of LK in an ecological restoration-based education program. It is crucial for Mexican public policy instruments operating in PNAs to consider local knowledge to enhance the effectiveness of ecological restoration.

DDQN-SFCAG: A service function chain recovery method against network attacks in 6G networks

Service Function Chain (SFC) as an effective solution can satisfy the diverse service requirements of six application scenarios in Network Function Virtualization (NFV)-enabled 6G networks. Resilience as a new key capability indicator in 6G networks puts forward higher requirements for the Quality of Service (QoS) of SFCs. In this article, we study the resilience recovery method in network attack scenarios. We make full use of the monitoring and early warning capability of the monitoring function and propose a proactive recovery method called Double Deep Q-Network based on SFC Attack Graph (DDQN-SFCAG). We fully consider the characteristics of network attacks to generate SFC attack graphs and determine the recovery strategy of SFC according to the service security requirements to provide guidance for recovery. Among them, we design three recovery modes for the recovered Virtual Network Functions (VNFs) to determine the optimal recovery strategy and avoid resource waste. We formalize the SFC recovery problem, which aims to minimize the recovery cost while meeting the recovery strategy. In order to shorten the interruption time, we use DDQN to quickly solve the recovery solution to ensure optimal recovery performance. Our extensive evaluation shows DDQN-SFCAG has excellent recovery performance in network attack scenarios and can reduce the recovery cost by at least 31% compared to the state-of-the-art methods.

PH independent adsorption: Reusable zinc-ferrite nanospheres for the selective recovery of dyes from binary mixtures

Efficient separation of colorant pollutants is a formidable challenge, prompting research into innovative materials. We developed zinc-ferrite nanoparticles via the Microwave-Assisted Solvothermal Technique (MAST), exploiting judicious solvent compositions to enhance Lewis's acidity. Upscaling to gram batches yielded nanoparticles with a higher specific surface area (149 m2g−1). These nanoparticles demonstrated selective separation of dyes from binary mixtures, including Orange-G (OG), Fluorescein-Sodium (FSS), and Methyl-Orange (MO), with their high sorption rate fitting to the pseudo-second-order kinetic model. Langmuir isotherm for OG and MO were observed with respective adsorption capacity (qm) of 94.12 mg/g, 104.28 mg/g, whereas FSS more likely matched Sips isotherm with qm = 124.31 mg/g at natural pH in room temperature (27 °C). Desorption, reliant on solution pH and OH− ions, enabled efficient regeneration and multiple reuses without significant efficiency loss over five reuse cycles. Remarkably, selective separation was independent of surface charge and remained effective across a wide pH range and in the presence of common anions, namely I−, NO3−, C2H3O2− routinely encountered in dye effluents. This ecologically safe, scalable adsorbent offers a promising solution for expensive dye recovery.

Electric stimulation mitigated the mixed microplastic inhibition to anaerobic digestion during wastewater treatment

The presence of mixed microplastics (MPs) in anaerobic wastewater treatment processes has been shown to impede fermentation performance by suppressing microbial activity. Microbial electrosynthesis (MES), with its extensive potential, offers a promising solution for refractory substances management and methane recovery, achieved through the enhancement of microbial metabolism and interspecies electron transfer. This study, therefore, delves into the functional impacts and the microbial response to MES in the remediation of wastewater contaminated with mixed-MPs. Results indicated that mixed-MPs could inhibit methane production (−52.38%) and substance removal (−26.59%), and MES could effectively mitigate this inhibitory effect (−22.86%, −19.01%). Concurrently, MES also boosts enzymatic activities pivotal for electron transfer, such as cytochrome c and nicotinamide adenine dinucleotide (NADH), as well as those linked to energy metabolism like adenosine triphosphate (ATP). Furthermore, MES bolsters microbial resistance to mixed-MPs, as evidenced by an increase in extracellular polymeric substances (EPS), albeit with a minor rise in reactive oxygen species (ROS) production and lactate dehydrogenase (LDH) release. Correspondingly, electric stimulation promoted the enrichment of functional microorganisms associated with fermentation, acetate production, electrogenesis, and methanogenesis, and stimulated elevated expression levels of genes related to methane metabolism. Notably, the Methanothrix-mediated acetoclastic pathway emerges as the predominant methanogenic route, succeeded by the Methanobacterium-driven hydrogenotrophic pathway. Lastly, the study underscores the supportive role of applied voltage and carriers in energy metabolism and substance transport, which are associated with methanogenesis. Overall, MES demonstrates efficacy in mitigating the biotoxicity induced by mixed-MPs exposure and in enhancing anaerobic wastewater treatment and methane recovery.

Towards circular economy of wasted printed circuit boards of mobile phones fuelled by machine learning and robust mathematical optimization framework

Estimating the operating conditions using conventional process analysis techniques for the maximum metal extraction from the wasted printed circuit boards (WPCB) can provide sub-optimal solutions leading to the low yield of the process. In this paper, we present a closed-loop methodological framework built on machine learning and robust mathematical optimization technique, that offers the mathematical rigour, to determine the optimum operating conditions for the maximum Cu and Ni recovery from the WPCB. Alkali leaching based novel metals recovery process from the WPCB is designed, and the experiments are conducted to collect the data on the percentage recovery of Cu and Ni against the operating levels of the process input variables (ammonia concentration (NH3 conc. (g/L)), ammonium sulfate concentration ((NH4)2SO4 conc. (g/L)), H2O2 concentration (H2O2 conc. (M)), time (h), liquid to solid ratio (L/S ratio, (mL/g)), temperature (Temp. (°C)), and stirring speed (rpm)). The experimental data is deployed to construct the functional mapping between the nonlinear output variables of metals recovery process with the hyperdimensional input space through artificial neural network (ANN) based modelling algorithm – a powerful universal function approximator. Well-predictive ANN models for Cu and Ni recovery are developed having co-efficient of determination (R2) value more than 0.90. Partial derivative-based sensitivity analysis is then carried out to establish the order of the significance of the input variables that is backed by the domain knowledge, thus promotes the interpretability of the trained ANN models. The hybridization of ANN with NLP (nonlinear programming) framework is implemented for the determination of optimized operating conditions to extract maximum Cu and Ni under separate and combined model of metal extraction. The robustness of the determined solutions is verified, the determined optimized solutions for the metal recovery are validated in the lab, and the maximum metal recovery, i.e., 100 % Cu and 90 % Ni is extracted from the WPCB. This research demonstrates the effective utilization of ANN model-based robust optimization approach for the metal recovery from the WPCB that supports the circular economy for the metal extraction industry.

In situ self-assembly of ZIF-8@sodium alginate composite hydrogels for enhanced adsorption of Cu2+ Ions

With the advancement of science and technology, the issue of wastewater pollution has escalated, necessitating urgent attention to wastewater treatment. In this study, a highly efficient adsorbent for Cu2+ was successfully synthesized through in situ self-assembly using Ca2+ as the cross-linking agent in ZIF-8@ALG composite hydrogel. The results demonstrated that the incorporation of Ca2+ as the cross-linker enhanced both adsorption capacity and swelling properties of ZIF-8@ALG composite hydrogel. Adsorption performance evaluation revealed that the hydrogel followed pseudo-second-order kinetic model for Cu2+ adsorption and Freundlich isotherm model with a theoretical maximum adsorption capacity of 309.57 m g−1. Thermodynamic analysis indicated that Cu2+ adsorption onto the hydrogel occurred spontaneously with heat absorption. Furthermore, excellent reusability was observed after five cycles of usage without significant loss in adsorption efficiency. Overall, these findings highlight the potential application of ZIF-8@ALG composite hydrogel as an effective solution for wastewater remediation and recovery of heavy metal ions.

Adsorption of Cobalt Ions by Activated Carbon Prepared from Agricultural Waste Residues and Treated with Magnetic Nanomaterials: A Review

General Background: The study of heavy metal adsorption is crucial for environmental protection and industrial wastewater management. Specific Background: The adsorption of cobalt ions (Co2+) by activated carbon derived from agricultural waste, enhanced with magnetic nanomaterials, has garnered significant interest due to its potential for cost-effective and efficient wastewater treatment. Knowledge Gap: Despite numerous studies, there remains a lack of comprehensive research on the specific combination of agricultural waste-derived activated carbon and magnetic nanomaterials for Co2+ adsorption. Aims: This study aims to meticulously review the existing literature on the preparation of activated carbon from agricultural residues, the enhancement of its properties with magnetic nanomaterials, and its effectiveness in Co2+ ion adsorption. Results: The review demonstrates that activated carbon with a large specific surface area and diverse functional groups significantly improves Co2+ adsorption. The incorporation of magnetic nanomaterials further enhances this efficiency due to increased surface area and magnetic properties. Novelty: This research uniquely combines agricultural waste valorization with advanced nanotechnology, presenting a sustainable and innovative approach to heavy metal adsorption. Implications: The findings underscore the dual environmental benefits of recycling agricultural waste and mitigating industrial pollution, offering a cost-effective and efficient solution for cobalt ion recovery from wastewater. This study serves as a valuable resource for researchers and engineers focusing on sustainable environmental remediation technologies. Highlights: Enhanced Adsorption: Magnetic nanomaterials boost activated carbon's efficiency. Sustainable Solution: Agricultural waste-derived activated carbon is eco-friendly and cost-effective. Comprehensive Insight: Review identifies research gaps and future directions. Keywords: cobalt ion adsorption, activated carbon, agricultural waste, magnetic nanomaterials, wastewater treatment

Application of nanofiltration for the recovery of nickel glycinates from alkaline glycine-based solutions using polyamide membranes: A technical note

Glycine has been intensively investigated as a “green” lixiviant for precious and base metals. Alkaline glycine solutions to extract Ni from sulfide resources has shown promising results. However, a considerable amount of Ni will be lost in the wash solutions when leaching residues are washed during solid-liquid separation of the leachates from their respective leach residues. In this context, this study explored Ni recovery from alkaline glycine-based wash solutions using a polyamide nanofiltration membrane. In the tests using synthetic single and multi-metal solutions, the membrane achieved >95% rejection of Ni in the selected ranges of glycine/Ni molar ratio (up to 5), pressure (15–30 bar), initial nickel concentration (0.5–1.5 g/L), sodium sulfate background concentration (∼30 g/L) and under the use of different pH modifiers (aqueous ammonia and caustic soda). When using a real solution, the concentrations of Ni and other major elements (Cu, S, Co, Mg, Zn) in the final retentate increased by about 5 times at 80 wt% permeate recovery, leaving <3 mg/L major elements in permeate. The permeate stream could be recycled in the washing stage, and the retentate stream could be combined with the pregnant leach solution (PLS) for metals recovery. The investigation demonstrates some of the technical optionality for nickel recovery from filter wash solutions utilising nanofiltration within the context of alkaline glycine-based leach technology and preliminarily demonstrates where it can be used in the structure of flowsheets to recover valuable base metals and reagents for recycle. However, the increased membrane resistance causing a low permeate flux should be concerned due to the considerable dissolved salts, precipitation of gypsum and the increasing feed concentration over time.

Low-carbon emitting Fe-cycle recovery of battery-grade FePO4 from biogas slurry for Li-battery application

Under the background of carbon peaking and carbon neutrality in China, anaerobic digestion of sludge to produce methane was an important way to recover biomass energy. But plenty of as-generated biogas slurry (BS) with high P concentration was valuable and difficult to dispose. Here, this work proposed a low-carbon emitting Fe-cycle strategy to recover battery-grade FePO4 from BS. At pH=1.0, the P-leaching rate of Fe-sludge (42.93 ± 1.49 mg g−1) generated by polymerized ferrous sulfate (an inorganic polymer coagulant) addition into BS was 93.46 ± 3.56% and high-purity FePO4 (99.0%) could further be obtained by Fe3+ supplement and pH adjustment (pH=2.0). The contents of all elements in recovered FePO4 product fully complied with the battery grade of national industry standard of China (HG/T 4701-2021). After battery-grade FePO4 precipitate separation, recovery solution (RS) with remaining Fe3+ was reutilized to remove 88.05 ± 1.77% of P when mixed with BS wit RS/BS ratio of 2:1, thus achieving a Fe cycle utilization. Meanwhile, the recovery cost of 5.42 $/kg P and CO2 emissions of 80.83 kg/kg P were lower than those of current FePO4 industrial production (14.60 $/kg P and 110.60 kg/kg P). Finally, the LiFePO4/C cathode material based on recovered FePO4 from BS exhibited stable discharge specific capacity of 84.6–100.2 mAh/g during 100 charge–discharge cycles. In general, this study successfully manifested the feasibility of novel Fe-cycle battery-grade FePO4 recovery strategy from wastewater, paving a viable low-carbon emitting pathway for future Li-battery manufacture industry.

The Low Survivability of Transplanted Gonadal Grafts: The Impact of Cryopreservation and Transplantation Conditions on Mitochondrial Function.

Advances in tissue preservation techniques have allowed reproductive medicine and assisted reproductive technologies (ARTs) to flourish in recent years. Because radio- and chemotherapy procedures are often gonadotoxic, irreversible damage can preclude future gamete production and endocrine support. Accordingly, in recent years, the freezing and storage of gonadal tissue fragments prior to the first oncological treatment appointment and autologous transplantation post-recovery have been considered improved solutions for fertility recovery in cancer survivors. Nevertheless, the cryopreservation and transplantation of thawed tissues is still very limited, and positive outcomes are relatively low. This review aims to discuss the limitations of oncofertility protocols with a focus on the impacts of mitochondrial dysfunction, oxidative stress, and the loss of antioxidant defense in graft integrity.

Satellite gravimetry observations on the state of groundwater level variability in the Arabian Peninsula Region and the associated socio-economic sustainability challenges

Groundwater is an important resource for the Arabian Peninsula Region. The population increase, rise in agricultural activities, and Gulf Cooperation Council (GCC) countries (Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and the United Arab Emirates) inclination towards economic diversification and tourism promotion have heightened the freshwater demand. As a result of climate change and varying weather patterns, the situation has become more complicated. Due to arid conditions, recharge is mostly less than withdrawal which consequently results in underground water level decline over time. In the research, we have used Gravity Recovery and Climate Experiment (GRACE/GRACE-FO) MASCON solutions, Global Land Data Assimilation System (GLDAS) soil moisture, and the Integrated Multi-satellite Retrievals for Global Precipitation Mission (IMERG) rainfall data to observe the Equivalent Water Thickness (EWT), and rainfall patterns in this region for the past two decades (2002–2023). The results indicate that in Saudi Arabia the water level is declining nearly at a linear rate and the linear regression model fits well with the data (R2 value, the coefficient of determination, for different cities of Saudi Arabia is ≥ 0.94). In the Al Jouf Area, the water decline is the highest at −1.69 cm/year which is 43% greater than the previous calculations. The lowest decline rate is in Sanaa (Yemen) which is −0.13 cm/year. Furthermore, all the other studied locations show a groundwater declining trend. In Saudi Arabia's Makkah, Madina, Riyadh, and Damam the reduction rate is −0.36, −0.48, −0.72, and −0.48 (cm/year) respectively. Kuwait, UAE's Dubai, and Al Ain show a similar groundwater reduction rate of −0.19 cm/year. In Oman's Masqat, the groundwater decline rate is −0.22 cm/year. Also, in the recent data, one can see the higher seasonal amplitudes that are indicative of greater fluctuations in EWT data in recent times. If water mining continues at the same pace, this important resource can become a rare commodity. Limited water supply can likely become a limiting factor for further social, agricultural, and industrial development. That's why major reviews and shifts are necessary in the current policies related to water resource management and conservation.

Turning Food Loss and Food Waste into Watts: A Review of Food Waste as an Energy Source

Food loss (FL) and food waste (FW) have become severe global problems, contributing to resource inefficiency and environmental degradation. Approximately 6% of greenhouse gas emissions (GHGs) are derived from FW, which is usually discarded in landfills, emitting methane, a gas that is 28 times more harmful than CO2. Diverting the path of FW towards the energy industry represents a promising avenue to mitigate the environmental impact and save resources while generating energy substitutes. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach was utilized to conduct a systematic literature review on 10 different conversion processes used to convert FL and FW into energy. Anaerobic bioconversion integrated with pyrolysis emerges as a potential eco-friendly and promising solution for FW management, nutrient recovery and energy production in various forms, including biogas, heat, biohydrogen and biochar. Despite its potential, the anaerobic digestion of FW still faces some challenges related to the production of intermediate harmful compounds (VOCs, NH3, H2S), which necessitate precise process control and optimization. Nonetheless, converting FW into energy can provide economic and environmental benefits in the context of the circular economy. This review offers insightful information to stakeholders, academics and policymakers who are interested in utilizing FW as a means of producing sustainable energy by summarizing the important findings of ten different waste-to-energy processing methods and their potential for improved energy recovery efficiency.

Forward osmosis membrane process: A review of temperature effects on system performance and membrane parameters from experimental studies

Forward osmosis (FO) offers a promising solution for concentration and material recovery, characterized by its low energy consumption and high separation efficiency. Temperature exerts a significant influence on FO, affecting permeation performance, membrane characteristics, and solution chemistry. The review article shows that increasing temperatures enhance forward permeate flux and solvent recovery by modifying mass transfer coefficients, membrane structure, and solution properties like osmotic pressure, diffusivity, and viscosity. This helps alleviate concentration polarization, a key challenge in FO applications. However, higher temperatures can exacerbate reverse solute flux, diminish solute rejection, and amplify membrane fouling, impacting operational efficiency and effluent quality. Studies involving thermoresponsive compounds or high-solute-content solutions yield conflicting results, further complicated by thermo-osmosis in scenarios with temperature gradients between solutions. In water and wastewater treatment, a huge quantity of solutions is treated, and temperature control is difficult. Managing solution temperatures through the utilization of waste hot streams or available heat sources can offer a viable strategy for enhancing system efficiency and mitigating the detrimental impacts of temperature fluctuations, while the solution volume should be effectively reduced before the treatment. A nuanced comprehension of temperature’s impacts is imperative for refining FO systems and addressing challenges across various industrial and environmental sectors.

A new extraction mechanism in sulfuric acid media for the recovery of aluminum

The separation of aluminum and manganese from mineral leach solutions has been a challenge at present and has attracted great interest. In this paper, the effects of different extractants on aluminum recovery as well as the effects of the concentration of the most suitable extractant, extraction temperature, initial pH and organic phase/aqueous phase ratio on the recovery of aluminum were investigated. The results showed that for chromite recovery solution(CRS) with an initial aluminum concentration of 0.1221 g/L, S-NA at 0.25 mol/L exhibited good selectivity and extraction efficiency for aluminum, and was able to separate aluminum from other elements and recover it easily for secondary use without scrubbing. The extraction mechanism of aluminum in sulfuric acid medium was investigated through various analyses including the combination of energy and bond length calculations, electrostatic potential (ESP) theory calculations, IGMH analysis, process chemistry analysis, and thermodynamic equilibrium species calculations. These analyses showed that Al(III) was distributed in the recycling solution in the form of AlSO4+ and had strong interactions with naphthenate ions, and that the combination of AlSO4+ with the naphthenate ions(R−)’s formed the stable complex molecule AlSO4R. The study provides a feasible path for the recovery of aluminum in CRS and is of guiding significance for the theoretical study of aluminum in sulfuric acid media.

Performance of a novel CO2 absorption and reverse electrodialysis system with different amine solutions for simultaneous energy and bicarbonate recovery

In this study, the performance of a novel integrated carbon dioxide (CO2) capture and reverse electrodialysis (RED) system was evaluated. The optimal operating conditions and carbon dioxide absorption and desorption mechanisms were identified. The proposed system utilizes a RED device to recover energy from the desorption step of the CO2 capture process, which is known to have high energy requirements in conventional processes. It has the potential as a hybrid process capable of recovering absorbent, energy, and bicarbonate through RED. To verify the performance of the system, CO2 loading, power density, and absorbent regeneration were evaluated using primary (monoethanolamine, MEA), secondary (diethanolamine, DEA), and tertiary (N-methyldiethanolamine, MDEA) amines. In the case of primary and secondary amines, carbamates, intermediate products, are formed and pass through the ion exchange membrane of RED, thereby achieving high power density. However, they are re-substituted with amines after passing through the ion exchange membrane (IEM), leading to the loss of absorbent. Conversely, in the case of tertiary amines, no intermediate products were formed, and excellent absorbent regeneration performance of more than 99.9% was demonstrated through multi-stage RED. Through this, the feasibility of future applications of this technology was confirmed.

All-In-One solution for simultaneous phosphonate degradation and orthophosphate recovery by NiFe-Layer double Hydroxide/PDS

Phosphate recovery presents an effective solution to address the conflicting problems of phosphorus pollution and scarcity. However, recovering organic phosphates, such as 1-hydroxyethane 1,1-diphosphonic acid (HEDP), is comparatively complex, which involves multiple processes. Herein, we developed an innovative all-in-one solution to simplify these processes by combining NiFe-layered double hydroxides (NiFe-LDH) and peroxydisulfate (PDS). This combination achieved approximately 90 % conversion of HEDP to orthophosphate, with 100 % of the resulting orthophosphate recovered in 120 min. The exceptional performance in simultaneous HEDP degradation and recovery can be attributed to dual roles of Ni and Fe in NiFe-LDH/PDS. The polyvalent Ni functions as an electron shutter (Ni2+ ⇋ Ni3+ ⇋ Ni2+) in the redox cycles between PDS and HEDP, accounting for effective HEDP degradation. The high complexation stability between Fe(Ⅲ) and orthophosphate (log K = 9.92) allows Fe(Ⅲ) to serve as binding sites for orthophosphate recovery. Moreover, NiFe-LDH/PDS effectively treats HEDP across wide pH ranges (3–––10), which can be ascribed to pH buffers originating from protonation/deprotonation in NiFe-LDH layers. The recovered phosphorus with NiFe-LDH exhibited a slow-release property under soil water solution without notable Ni release, which highlighted its potential usage as a slow-release fertilizer. These features—catalytic and binding sites, and high compatibility—allow NiFe-LDH to achieve concurrent degradation and recovery of organic phosphate in a single solution.

Multistage regulation of LiMn2O4 electrode for electrochemical lithium extraction from salt-lake

The sustainable development of future energy relies significantly on the abundant lithium resources present in salt-lake brines. LiMn2O4 (LMO) electrochemical Li+ pump has garnered substantial attention due to its capacity to efficiently extract lithium resources from aqueous solutions with minimal energy consumption. However, the industrial application of LMO electrodes is often limited by Mn dissolving during cycles, as well as the complex and variable brine environment. To address these challenges, this study conducted a multistage regulation of LMO electrodes. Originally, the sol-gel technique was used to prepare CePO4 loading LMO. Due to CePO4 rivet load reforming LMO surface charge, the best-performing 1 wt% CePO4-loaded LMO exhibited a remarkable capacity retention rate of 83.8 % after 30 cycles. Subsequently, a comprehensive hydrophilic modification was applied to the entire electrode. 20%PAA-1CP-LMO//Ag system displayed an admirably release capacity of 24.7 mg·g−1 in Zabuye real brine characterized by an ultra-low Li/Na ratio, with Li/Na ratio in recovery solution reaching as high as 0.62.