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Clean Technol., Volume 5, Issue 1 (March 2023) – 22 articles

Cover Story (view full-size image): Membrane-based operations are useful approaches for the recovery of water and primary resources from exhaust baths of beam house, tanning and post-tanning operations in the leather industry. Their integration with conventional physico-chemical and biological treatments also provide useful protocols for the treatment of global wastewaters with a significant reduction in organic compounds and the removal of refractory inorganic compounds. The global findings clearly highlight that these processes can play a key role in redesigning the conventional production cycle of the leather industry within the logics of the process intensification, zero-discharge and circular economy strategies. View this paper
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15 pages, 268 KiB  
Article
Public Acceptance and Willingness to Pay for Carbon Capture and Utilisation Products
by Tryfonas Pieri, Alexandros Nikitas and Athanasios Angelis-Dimakis
Clean Technol. 2023, 5(1), 436-450; https://doi.org/10.3390/cleantechnol5010022 - 13 Mar 2023
Cited by 1 | Viewed by 1995
Abstract
Although the significance of the social science agenda reflecting and affecting the carbon capture and utilisation (CCU) value chain has been acknowledged, there is still a scarcity of research about it. This work contributes in developing an understanding of public perceptions regarding the [...] Read more.
Although the significance of the social science agenda reflecting and affecting the carbon capture and utilisation (CCU) value chain has been acknowledged, there is still a scarcity of research about it. This work contributes in developing an understanding of public perceptions regarding the acceptance, use, and purchasing of carbon dioxide (CO2)-derived products through an online quantitative survey. Our research suggests the awareness and acceptance of such products are relatively high. Respondents were in favour of CO2-derived product promotion by policy makers and the industry, approved the funding of such schemes by government, and supported companies that use captured CO2 in their products. The product category seems to influence the willingness of people to use and buy CO2-derived products, with our respondents being more willing to use CO2-derived fuels than food or beverages, showing a caution toward health-related risks. Respondents were also more willing to buy a CO2-derived product if it was cheaper or better for the environment. Male respondents were in general less willing to pay for CCU-based products, while people aged 25 to 29 were more positive toward them. We conclude that the public will be in favour of CCU-based products and willing to buy them if the involved stakeholders do their part in delivering a safe product at a comparable quality and price to existing ones. Better information provision can also support this cause. Full article
18 pages, 7286 KiB  
Article
Unsupervised Machine Learning to Detect Impending Anomalies in Testing of Fuel Economy and Emissions of Light-Duty Vehicles
by Dhan Lord B. Fortela, Ashton C. Fremin, Wayne Sharp, Ashley P. Mikolajczyk, Emmanuel Revellame, William Holmes, Rafael Hernandez and Mark Zappi
Clean Technol. 2023, 5(1), 418-435; https://doi.org/10.3390/cleantechnol5010021 - 13 Mar 2023
Viewed by 1843
Abstract
This work focused on demonstrating the capability of unsupervised machine learning techniques in detecting impending anomalies by extracting hidden trends in the datasets of fuel economy and emissions of light-duty vehicles (LDVs), which consist of cars and light-duty trucks. This case study used [...] Read more.
This work focused on demonstrating the capability of unsupervised machine learning techniques in detecting impending anomalies by extracting hidden trends in the datasets of fuel economy and emissions of light-duty vehicles (LDVs), which consist of cars and light-duty trucks. This case study used the vehicles’ fuel economy and emissions testing datasets for vehicle model years 2015 to 2023 with a total of 34,602 data samples on LDVs of major vehicle manufacturers. Three unsupervised techniques were used: principal components analysis (PCA), K-Means clustering, and self-organizing maps (SOM). Results show that there are clusters of data that exhibit trends not represented by the dataset as a whole. Fuel CO vs. Fuel Economy has a negative correlation in the whole dataset (r = −0.355 for LDVs model year 2022), but it has positive correlations in certain sample clusters (e.g., LDVs model year 2022: r = +0.62 in a K-Means cluster where the slope is around 0.347 g−CO/mi/MPG). A time series analysis of the results of clustering indicates that Test Procedure and Fuel Type, specifically Test Procedure 11 and Fuel Type 26 as defined by the US EPA, could be the contributors to the positive correlation of CO and Fuel Economy. This detected peculiar trend of CO-vs.-Fuel Economy is an impending anomaly, as the use of Fuel 26 in emissions testing with Test Procedure 11 of US-EPA has been increasing through the years. With the finding that the clustered data samples with positive CO-vs.-Fuel Economy correlation all came from vehicle manufacturers that independently conduct the standard testing procedures and not data from US-EPA testing centers, it was concluded that the chemistry of using Fuel 26 in performing Test Procedure 11 should be re-evaluated by US-EPA. Full article
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15 pages, 4350 KiB  
Article
Graphene Embedded with Transition Metals for Capturing Carbon Dioxide: Gas Detection Study Using QM Methods
by Fatemeh Mollaamin and Majid Monajjemi
Clean Technol. 2023, 5(1), 403-417; https://doi.org/10.3390/cleantechnol5010020 - 09 Mar 2023
Cited by 10 | Viewed by 2005
Abstract
Carbon dioxide (CO2) adsorption on decorated graphene (GR) sheets with transition metals (TMs) including iron, nickel and zinc was investigated for removing this hazardous gas from the environment. TM-doped GR results in higher activity toward gas detecting than pristine graphene nanosheets. [...] Read more.
Carbon dioxide (CO2) adsorption on decorated graphene (GR) sheets with transition metals (TMs) including iron, nickel and zinc was investigated for removing this hazardous gas from the environment. TM-doped GR results in higher activity toward gas detecting than pristine graphene nanosheets. TM embedding restrains hydrogen evolution on the C sites, leaving more available sites for a CO2 decrease. The Langmuir adsorption model with ONIOM using CAM-B3LYP functional and LANL2DZ and 6-31+G (d,p) basis sets due to Gaussian 16 revision C.01 program on the complexes of CO2→(Fe, Ni, Zn) embedded on the GR was accomplished. The changes of charge density illustrated a more considerable charge transfer for Zn-embedded GR. The thermodynamic results from IR spectroscopy indicated that ΔGads,CO2Zn@CGRo has the notable gap of Gibbs free energy adsorption with a dipole moment which defines the alterations between the Gibbs free energy of the initial compounds (ΔGCO2 o and ΔGZn@CGRo) and product compound (ΔGCO2Zn@CGRo) through polarizability. Frontier molecular orbital and band energy gaps accompanying some chemical reactivity parameters represented the behavior of molecular electrical transport of the (Fe, Ni, Zn) embedding of GR for the adsorption of CO2 gas molecules. Our results have provided a favorable understanding of the interaction between TM-embedded graphene nanosheets and CO2. Full article
(This article belongs to the Special Issue Application of Porous Materials in CO2 Capture)
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51 pages, 56823 KiB  
Review
Arsenic Removal by Adsorbents from Water for Small Communities’ Decentralized Systems: Performance, Characterization, and Effective Parameters
by Roya Sadat Neisan, Noori M. Cata Saady, Carlos Bazan, Sohrab Zendehboudi, Abbas Al-nayili, Bassim Abbassi and Pritha Chatterjee
Clean Technol. 2023, 5(1), 352-402; https://doi.org/10.3390/cleantechnol5010019 - 06 Mar 2023
Cited by 5 | Viewed by 4695
Abstract
Arsenic (As), a poisonous and carcinogenic heavy metal, affects human health and the environment. Numerous technologies can remove As from drinking water. Adsorption is the most appealing option for decentralized water treatment systems (DWTS) for small communities and household applications because it is [...] Read more.
Arsenic (As), a poisonous and carcinogenic heavy metal, affects human health and the environment. Numerous technologies can remove As from drinking water. Adsorption is the most appealing option for decentralized water treatment systems (DWTS) for small communities and household applications because it is reliable, affordable, and environmentally acceptable. Sustainable low-cost adsorbents make adsorption more appealing for DWTS to address some of the small communities’ water-related issues. This review contains in-depth information on the classification and toxicity of As species and different treatment options, including ion exchange, membrane technologies, coagulation-flocculation, oxidation, and adsorption, and their effectiveness under various process parameters. Specifically, different kinetic and isotherm models were compared for As adsorption. The characterization techniques that determine various adsorbents’ chemical and physical characteristics were investigated. This review discusses the parameters that impact adsorption, such as solution pH, temperature, initial As concentration, adsorbent dosage, and contact time. Finally, low-cost adsorbents application for the removal of As was discussed. Adsorption was found to be a suitable, cost-effective, and reliable technology for DWTS for small and isolated communities. New locally developed and low-cost adsorbents are promising and could support sustainable adsorption applications. Full article
(This article belongs to the Special Issue Decentralised Water Treatment Technologies)
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23 pages, 21228 KiB  
Article
Model-Based Predictive Control of a Solar Hybrid Thermochemical Reactor for High-Temperature Steam Gasification of Biomass
by Youssef Karout, Axel Curcio, Julien Eynard, Stéphane Thil, Sylvain Rodat, Stéphane Abanades, Valéry Vuillerme and Stéphane Grieu
Clean Technol. 2023, 5(1), 329-351; https://doi.org/10.3390/cleantechnol5010018 - 02 Mar 2023
Cited by 2 | Viewed by 2189
Abstract
The present paper deals with both the modeling and the dynamic control of a solar hybrid thermochemical reactor designed to produce syngas through the high-temperature steam gasification of biomass. First, a model of the reactor based on the thermodynamic equilibrium is presented. The [...] Read more.
The present paper deals with both the modeling and the dynamic control of a solar hybrid thermochemical reactor designed to produce syngas through the high-temperature steam gasification of biomass. First, a model of the reactor based on the thermodynamic equilibrium is presented. The Cantera toolbox is used. Then, a model-based predictive controller (MPC) is proposed with the aim of maintaining the reactor’s temperature at its nominal value, thus preserving the reactor’s stability. This is completed by adjusting the mirrors’ defocusing factor or burning a part of the biomass to compensate for variations of direct normal irradiance (DNI) round the clock. This controller is compared to a reference controller, which is defined as a combination of a rule-based controller and an adaptive proportional–integral–derivative (PID) controller with optimized gains. The robustness of the MPC controller to forecast errors is also studied by testing different DNI forecasts: perfect forecasts, smart persistence forecasts and image-based forecasts. Because of a high optimization time, the Cantera function is replaced with a 2D interpolation function. The results show that (1) the developed MPC controller outperforms the reference controller, (2) the integration of image-based DNI forecasts produces lower root mean squared error (RMSE) values, and (3) the optimization time is significantly reduced thanks to the proposed interpolation function. Full article
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32 pages, 13875 KiB  
Article
Design-Based Approach to Support Sorting Behavior of Food Packaging
by Babak Nemat, Mohammad Razzaghi, Kim Bolton and Kamran Rousta
Clean Technol. 2023, 5(1), 297-328; https://doi.org/10.3390/cleantechnol5010017 - 28 Feb 2023
Cited by 3 | Viewed by 2099
Abstract
It is widely acknowledged that environmental impacts from packaging waste depend on how consumers sort this waste fraction. In this research, “design for sustainable behavior” (DfSB) strategies are used to improve a cream packaging design that can support proper sorting of packaging waste [...] Read more.
It is widely acknowledged that environmental impacts from packaging waste depend on how consumers sort this waste fraction. In this research, “design for sustainable behavior” (DfSB) strategies are used to improve a cream packaging design that can support proper sorting of packaging waste as a sustainable behavior. The application of three DfSB strategies—“match”, “steer”, and “force”—was examined through circular interviews and practical experience with two groups of participants in Karlskrona, Sweden. Prototyping was used to provide a more realistic experiment and enhance communication during the interviews. The results show that consumer-packaging interaction during the usage phase is important to enhance proper sorting behavior. The results also show the potential of a user-centered design-based approach to study consumer-packaging interaction and to understand the challenges faced by users when sorting packaging waste. It also shows the possibility of packaging design to script consumer behavior and reveals details that are important when designing packaging that was not known. In this vein, packaging form, color, and haptic attributes are the most influential design attributes that can support packaging functionalities and script consumer sorting behavior. Full article
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23 pages, 1983 KiB  
Review
Membranes and Integrated Membrane Operations as Clean Technologies in the Leather Industry
by Enrico Drioli and Alfredo Cassano
Clean Technol. 2023, 5(1), 274-296; https://doi.org/10.3390/cleantechnol5010016 - 16 Feb 2023
Cited by 3 | Viewed by 2378
Abstract
The leather industry is characterized by the production of a huge amount of wastewater with a high organic/inorganic charge, causing widespread water and soil pollution. Pressure-driven membrane operations and membrane bioreactors have long been proven to be a valid approach for the treatment [...] Read more.
The leather industry is characterized by the production of a huge amount of wastewater with a high organic/inorganic charge, causing widespread water and soil pollution. Pressure-driven membrane operations and membrane bioreactors have long been proven to be a valid approach for the treatment of tanning wastewaters aimed at the recovery of raw materials as well as for the removal of toxic and environmentally harmful substances. Such processes, opportunely integrated among themselves and/or with conventional physical-chemical and biological treatments, also provide useful protocols for the treatment of global wastewaters with significant advantages in terms of environmental protection, decrease of disposal costs, simplification of cleaning-up processes and saving of water and chemicals. This paper, as the state of the art, attempts to revise the potential and perspectives of membrane-based technologies in the leather industry with related applications in beamhouse, tanning and post-tanning operations as well as in the treatment of global wastewaters. Full article
(This article belongs to the Collection Review Papers in Clean Technologies)
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15 pages, 2402 KiB  
Article
Rheological Behavior and Characterization of Drinking Water Treatment Sludge from Morocco
by Fantasse Azeddine, Parra Angarita Sergio, Léonard Angélique, Lakhal El Khadir, Idlimam Ali and Bougayr El Houssayne
Clean Technol. 2023, 5(1), 259-273; https://doi.org/10.3390/cleantechnol5010015 - 16 Feb 2023
Cited by 1 | Viewed by 1966
Abstract
Drinking water treatment generates a high amount of pasty by-product known as drinking water treatment sludge (DWTS). The chemical composition, microstructure and rheological behavior of DWTS are of utmost importance in the calculation, design, optimization, commissioning and control of its treatment processes. The [...] Read more.
Drinking water treatment generates a high amount of pasty by-product known as drinking water treatment sludge (DWTS). The chemical composition, microstructure and rheological behavior of DWTS are of utmost importance in the calculation, design, optimization, commissioning and control of its treatment processes. The purpose of this research was to characterize the DWTS from the drinking water treatment plant of Marrakech (Morocco), aiming to help future researchers and engineers in predicting its hydrodynamic behavior. The first part of this study was devoted to the physical structure and the chemical composition of sludge. The second part was oriented towards the study of the mechanical properties; a penetration test and a rotational rheology test were performed. For the first test, a force–length penetration diagram was plotted in order to calculate the hardness, the cohesiveness and the adhesiveness of DWTS. For the second test, the shear stress and the apparent viscosity were plotted and fitted to five rheological models, as function of the shear rate, aiming to describe the rheological behavior of samples. The obtained results reveal that the drinking water treatment sludge from Marrakech is a porous, amorphous and highly adhesive material, with a shear-thinning (pseudoplastic) rheological behavior that can be described according to the Herschel–Bulkley model (better in low-rate stresses, R² = 0.98) or the Windhad model (better in high shear rates, R² = 0.96) and is mainly composed of silica, aluminum and iron oxides. Full article
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26 pages, 6176 KiB  
Article
Energetic Valorization of Bio-Waste from Municipal Solid Waste in Porto Santo Island
by Fabíola Pereira and Carlos Silva
Clean Technol. 2023, 5(1), 233-258; https://doi.org/10.3390/cleantechnol5010014 - 08 Feb 2023
Cited by 3 | Viewed by 2235
Abstract
The valorization of bio-waste as a resource for green energy production will be beneficial at a social, economic, and environmental level in different regions. The scope of this research is to develop the energetic valorization of the bio-waste fraction from municipal solid waste, [...] Read more.
The valorization of bio-waste as a resource for green energy production will be beneficial at a social, economic, and environmental level in different regions. The scope of this research is to develop the energetic valorization of the bio-waste fraction from municipal solid waste, to produce biogas from the anaerobic digestion process and electricity in a biogas CHP process, to increase the penetration of renewables in the electricity production system, with an application of these technologies on islands instead of these waste fractions being transported to other regions. The methodologies developed included: 1. Identification and mapping of resources; 2. State-of-the-art of bio-waste parameters and process solutions; 3. Pilot initiative for separation, collection, and analysis of food waste fractions; 4. Development of process solutions according to resources and needs; 5. Determination of investment, production costs, and revenues of the solution created. The case study selected was Porto Santo Island, with the potential to reduce maritime transportation costs of these undifferentiated waste fractions to Madeira Island and contribute to developing an innovative solution for the energetic valorization of bio-waste, including the participation of the local community. The results demonstrated a production of 272,221 m3 of biogas for use as fuel in a cogeneration unit to transform chemical energy into electrical and thermal energies. Furthermore, the self-consumption of the cogeneration unit is 25% of the total electricity produced and 29% of the total thermal energy produced. In conclusion, this research and solution is in compliance with PNEC, the EU Green Deal, and the European Directive 2018/851, which will make mandatory from 2024: the selective collection of bio-waste, 60% by weight of urban waste to be recycled by 2030, and only 10% of waste to be landfilled by 2035. Full article
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18 pages, 1785 KiB  
Article
Techno-Economic Efficiency Estimation of Promising Integrated Oxyfuel Gasification Combined-Cycle Power Plants with Carbon Capture
by Igor Donskoy
Clean Technol. 2023, 5(1), 215-232; https://doi.org/10.3390/cleantechnol5010013 - 06 Feb 2023
Cited by 1 | Viewed by 3428
Abstract
The study concerns promising coal-fired power plants that can gain an advantage over traditional options in the context of decarbonization. The calculations show that combined-cycle plants with integrated coal gasification and carbon dioxide recirculation may have better technical and economic characteristics compared to [...] Read more.
The study concerns promising coal-fired power plants that can gain an advantage over traditional options in the context of decarbonization. The calculations show that combined-cycle plants with integrated coal gasification and carbon dioxide recirculation may have better technical and economic characteristics compared to existing gasification processes (one- and two-stage). The recirculation of carbon dioxide improves the efficiency of the gasification process (the combustible gases yield and the fuel carbon conversion degree) and reduces the energy costs of the flue gas cleaning and carbon capture unit, thereby improving the economic performance of the plant. The estimates show that the decrease in the efficiency of electricity production associated with the removal of carbon dioxide is approximately 8% for the recirculation of combustion products and 15–16% for traditional processes, and the increase in the cost of electricity is 20–25% versus 35–40%, respectively. Full article
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12 pages, 1504 KiB  
Article
Electrochemical Treatment of Arsenic in Drinking Water: Effect of Initial As3+ Concentration, pH, and Conductivity on the Kinetics of Oxidation
by Sabrina Sorlini, Marco Carnevale Miino, Zdravka Lazarova and Maria Cristina Collivignarelli
Clean Technol. 2023, 5(1), 203-214; https://doi.org/10.3390/cleantechnol5010012 - 03 Feb 2023
Cited by 1 | Viewed by 1893
Abstract
Many technologies for the treatment of arsenic-containing drinking water are available, but most of them are more effective on arsenic oxidized forms. Therefore, the pre-oxidation of As3+ is necessary. The electrochemical processes represent a very promising method due to the simultaneous oxidation [...] Read more.
Many technologies for the treatment of arsenic-containing drinking water are available, but most of them are more effective on arsenic oxidized forms. Therefore, the pre-oxidation of As3+ is necessary. The electrochemical processes represent a very promising method due to the simultaneous oxidation of compounds using electrochemical conditions and the reactive radicals produced. In this work, As3+ oxidation was experimentally studied at a pilot scale using an electrochemical oxidation cell (voltage: 10 V; current: 1.7 A). The effect of the initial arsenite concentration, pH, and conductivity of drinking water on the oxidation of As3+ into As5+ was investigated. The results showed that the initial As3+ concentration strongly directly influences the oxidation process. Increasing the initial arsenite concentration from 500 to 5000 µg L−1, the pseudo-first order kinetic constant (k) strongly decreased from 0.521 to 0.038 min−1, and after 10 min, only 21.3% of As3+ was oxidized (vs. 99.9% in the case of As3+ equal to 500 µg L−1). Slightly alkaline conditions (pH = 8) favored the electrochemical oxidation into As5+, while the process was partially inhibited in the presence of a more alkaline or acidic pH. The increase in conductivity up to 2000 µS cm−1 enhanced the kinetic of the oxidation, despite remaining on the same order of magnitude as in the case of conductivity equal to 700 µS cm−1. After 10 min, 99.9 and 95% of As3+ was oxidized, respectively. It is the opinion of the authors that the influence of other operational factors, such as voltage and current density, and the impact of the high concentration of other pollutants should be deeply studied in order to optimize the process, especially in the case of an application at full scale. However, these results provide helpful indications to future research having highlighted the influence of initial As3+ concentration, pH, and conductivity on the electrochemical oxidation of arsenic. Full article
(This article belongs to the Special Issue Advanced Oxidation Processes for Environmental Remediation)
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13 pages, 4271 KiB  
Article
Influence of the Presence of Poly(butylene succinate) in the Poly(ethylene terephthalate) Recycling Process
by Cristina Pavon, Miguel Aldas, David Bertomeu, Harrison de la Rosa-Ramírez, María Dolores Samper and Juan López-Martínez
Clean Technol. 2023, 5(1), 190-202; https://doi.org/10.3390/cleantechnol5010011 - 31 Jan 2023
Cited by 3 | Viewed by 1847
Abstract
Poly(butylene succinate) (PBS) is one of the contaminants in the Poly(ethylene terephthalate) (PET) recycling process. It is known that high contents of PBS in PET significantly reduce PET properties, but the effect of low contents on PET has yet to be studied. This [...] Read more.
Poly(butylene succinate) (PBS) is one of the contaminants in the Poly(ethylene terephthalate) (PET) recycling process. It is known that high contents of PBS in PET significantly reduce PET properties, but the effect of low contents on PET has yet to be studied. This work studied the influence of low contents of PBS on recycled PET. Five formulations of PBS in PET were prepared, and the properties of relative affinity, mechanical, thermal, and disintegration under composting conditions were assessed. The solubility parameter indicated that PET and PBS are miscible. However, FESEM images show slight marks of immiscibility, and the mechanical characterization results showed that PBS, even in low contents, reduced the mechanical properties of recycled PET, which proves that the materials are not miscible in the studied contents. The DSC results indicated that PBS could not be quickly detected in PET. However, its presence can be inferred by the reduction in PET crystallization degree. Finally, the presence of PBS up to 15 wt.% does neither affect the disintegration under composting conditions nor the thermal stability of recycled PET. The drop in mechanical properties shows that PBS must be removed from the PET waste stream to preserve the quality of the material. Full article
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23 pages, 1292 KiB  
Systematic Review
A Literature Review on Existing Methods and Indicators for Evaluating the Efficiency of Power-to-X Processes
by Natascha Eggers, Torsten Birth, Bernd Sankol, Lukas Kerpen and Antonio Hurtado
Clean Technol. 2023, 5(1), 167-189; https://doi.org/10.3390/cleantechnol5010010 - 31 Jan 2023
Cited by 1 | Viewed by 2200
Abstract
The challenges posed by climate change have prompted significant growth in efficiency evaluation and optimization research, especially in recent years. This has spawned a variety of heterogeneous methods and approaches to the assessment of technical processes. These methods and approaches are rarely comparable [...] Read more.
The challenges posed by climate change have prompted significant growth in efficiency evaluation and optimization research, especially in recent years. This has spawned a variety of heterogeneous methods and approaches to the assessment of technical processes. These methods and approaches are rarely comparable and are usually only applicable to specific sectors. This paper provides an overview of the literature on efficiency assessment methods and KPIs, leading to a more manageable selection of an appropriate method with special regard to energy system integration technologies. In addition to reviewing the literature systematically, this paper examines existing methods and indicators’ applicability to and significance for efficiency optimization. In this context, a holistic approach to process design, evaluation, and improvement is given with particular regard to power-to-X systems. Within the framework of the study, three overarching goals could be defined as levels of efficiency evaluation of power-to-X systems: 1. identification of the process (steps) with the most significant optimization potential, 2. identification of the process phases with the greatest optimization potential (timewise considered), and 3. derivation of specific recommendations for action for the improvement of a process. For each of these levels, the most suitable evaluation methods were identified. While various methods, such as life cycle assessment and physical optimum, are particularly suitable for Level 1 and Level 2, for Level 3, even the best-identified methods have to be extended on a case-by-case basis. To address this challenge, a new approach to a holistic evaluation of power-to-X systems was developed based on the study’s findings. Full article
(This article belongs to the Collection Review Papers in Clean Technologies)
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27 pages, 12346 KiB  
Review
Synthesis of Metal Organic Frameworks (MOFs) and Their Derived Materials for Energy Storage Applications
by Sunil Dutt, Ashwani Kumar and Shivendra Singh
Clean Technol. 2023, 5(1), 140-166; https://doi.org/10.3390/cleantechnol5010009 - 20 Jan 2023
Cited by 13 | Viewed by 9543
Abstract
The linkage between metal nodes and organic linkers has led to the development of new porous crystalline materials called metal–organic frameworks (MOFs). These have found significant potential applications in different areas such as gas storage and separation, chemical sensing, heterogeneous catalysis, biomedicine, proton [...] Read more.
The linkage between metal nodes and organic linkers has led to the development of new porous crystalline materials called metal–organic frameworks (MOFs). These have found significant potential applications in different areas such as gas storage and separation, chemical sensing, heterogeneous catalysis, biomedicine, proton conductivity, and others. Overall, MOFs are outstanding candidates for next-generation energy storage devices, and they have recently attracted the greater devotion of the scientific community worldwide. MOFs can be used to enhance the ability of a device to store energy due to their unique morphology, controllable structures, high surface area, and permanent porosity. MOFs are widely used in super capacitors (SCs), metal (Li, Na, and K) ion batteries, and lithium–sulfur batteries (LSBs) and act as a promising candidate to store energy in an environmentally friendly way. MOFs are also used as efficient materials with better recyclability, efficiency, and capacity retention. In this review, first we summarize the material design, chemical compositions, and physical structure of MOFs and afterward, we highlight the most recent development and understanding in this area, mainly focusing on various practical applications of MOFs in energy storage devices. Full article
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3 pages, 180 KiB  
Editorial
Acknowledgment to the Reviewers of Clean Technologies in 2022
by Clean Technologies Editorial Office
Clean Technol. 2023, 5(1), 137-139; https://doi.org/10.3390/cleantechnol5010008 - 16 Jan 2023
Viewed by 1151
Abstract
High-quality academic publishing is built on rigorous peer review [...] Full article
21 pages, 1345 KiB  
Review
Artificial Neural Networks as Artificial Intelligence Technique for Energy Saving in Refrigeration Systems—A Review
by Mario Pérez-Gomariz, Antonio López-Gómez and Fernando Cerdán-Cartagena
Clean Technol. 2023, 5(1), 116-136; https://doi.org/10.3390/cleantechnol5010007 - 11 Jan 2023
Cited by 11 | Viewed by 3038
Abstract
The refrigeration industry is an energy-intensive sector. Increasing the efficiency of industrial refrigeration systems is crucial for reducing production costs and minimizing CO2 emissions. Optimization of refrigeration systems is often a complex and time-consuming problem. This is where technologies such as big [...] Read more.
The refrigeration industry is an energy-intensive sector. Increasing the efficiency of industrial refrigeration systems is crucial for reducing production costs and minimizing CO2 emissions. Optimization of refrigeration systems is often a complex and time-consuming problem. This is where technologies such as big data and artificial intelligence play an important role. Nowadays, smart sensorization and the development of IoT (Internet of Things) make the massive connection of all kinds of devices possible, thereby enabling a new way of data acquisition. In this scenario, refrigeration systems can be measured comprehensively by acquiring large volumes of data in real-time. Then, artificial neural network (ANN) models can use the data to drive autonomous decision-making to build more efficient refrigeration systems. Full article
(This article belongs to the Special Issue Synergistic Technologies to Advance in Sustainable Refrigeration)
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22 pages, 10074 KiB  
Article
An Enhanced Piezoelectric-Generated Power Technique for Qi Wireless Charging
by Wafa Elmannai, Khaled Elleithy, Andrew Anthony Benz, Alberto Carmine DeAngelis and Nick Weaver
Clean Technol. 2023, 5(1), 94-115; https://doi.org/10.3390/cleantechnol5010006 - 10 Jan 2023
Cited by 2 | Viewed by 3333
Abstract
This paper aims to design and implement a robust wireless charging system that utilizes affordable materials and the principle of piezoelectricity to generate clean energy to allow the user to store the energy for later use. A wireless charging system that utilizes the [...] Read more.
This paper aims to design and implement a robust wireless charging system that utilizes affordable materials and the principle of piezoelectricity to generate clean energy to allow the user to store the energy for later use. A wireless charging system that utilizes the piezoelectricity generated as a power source and integrated with Qi-standard wireless transmission would substantially affect the environment and the users. The approach consists of a full-wave-rectified piezoelectric generation, battery storage, Qi-standard wireless transmission, and Bluetooth Low Energy (BLE) as the controller and application monitor. Three main functions are involved in the design of the proposed system: power generation, power storage, and power transmission. A client application is conceived to monitor the transmission and receipt of data. The piezoelectric elements generate the AC electricity from the mechanical movements, which converts the electricity to DC using the full-wave bridge rectifiers. The sensor transmits the data to the application via BLE protocols. The user receives continuous updates regarding the storage level, paired devices, and remaining time for a complete charge. A Qi-standard wireless transmitter transfers the stored electricity to charge the respective devices. The output generates pulses to 60 voltage on each compression of a transducer. The design is based on multiple parallel configurations to solve the issue of charging up to the triggering value VH = 5.2 V when tested with a single piezoelectric transducer. AA-type battery cells are charged in parallel in a series configuration. The system is tested for a number of scenarios. In addition, we simulate the design for 11.11 h for approximately 70,000 joules of input. The system can charge from 5% to 100% and draw from 98%. Using four piezos in the designed module results in an average output voltage of 1.16 V. Increasing the number of piezos results in 17.2 W of power. The system is able to wirelessly transmit and store power with a stable power status after less than 0.01 s. Full article
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20 pages, 8054 KiB  
Article
Functional and Environmental Performances of Novel Electrolytic Membranes for PEM Fuel Cells: A Lab-Scale Case Study
by Matteo Di Virgilio, Andrea Basso Peressut, Valeria Arosio, Alessandro Arrigoni, Saverio Latorrata and Giovanni Dotelli
Clean Technol. 2023, 5(1), 74-93; https://doi.org/10.3390/cleantechnol5010005 - 09 Jan 2023
Cited by 4 | Viewed by 3876
Abstract
Despite being the most employed polymer electrolyte for proton exchange membrane fuel cells (PEMFCs), Nafion® has several limitations: expensiveness, poor performance when exposed to temperatures higher than 80 °C, and its potential as a source of environmentally persistent and toxic compounds (i.e., [...] Read more.
Despite being the most employed polymer electrolyte for proton exchange membrane fuel cells (PEMFCs), Nafion® has several limitations: expensiveness, poor performance when exposed to temperatures higher than 80 °C, and its potential as a source of environmentally persistent and toxic compounds (i.e., per- and polyfluoroalkyl substances, known as PFASs) when disposed of. This work explores the functional and environmental performances of three potential PFAS-free alternatives to Nafion® as electrolytic membranes in PEMFCs: sulfonated graphene oxide (SGO), graphene oxide-naphthalene sulfonate (GONS), and borate-reinforced sulfonated graphene oxide (BSGO). Investigated via ATR-FTIR spectroscopy, TGA, and cross-sectional SEM, the membranes show an effective functionalization of GO and good thermal stability. Functional properties are determined via Ion Exchange Capacity (IEC) evaluation, Electrochemical Impedance Spectroscopy, and tensile tests. In terms of IEC, the innovative materials outperform Nafion® 212. Proton conductivities at 80 °C of SGO (1.15 S cm−1) and GONS (1.71 S cm−1) are higher than that of the commercial electrolyte (0.56 S cm−1). At the same time, the membranes are investigated via Life Cycle Assessment (LCA) to uncover potential environmental hotspots. Results show that energy consumption during manufacture is the main environmental concern for the three membranes. A sensitivity analysis demonstrates that the impact could be significantly reduced if the production procedures were scaled up. Among the three alternatives, SGO shows the best trade-off between proton conductivity and environmental impact, even though performance results from real-life applications are needed to determine the actual environmental consequences of replacing Nafion® in PEMFCs. Full article
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23 pages, 6730 KiB  
Article
A Novel H2O/LiBr Absorption Heat Pump with Condensation Heat Recovery for Combined Heating and Cooling Production: Energy Analysis for Different Applications
by Juan Prieto, Dereje S. Ayou and Alberto Coronas
Clean Technol. 2023, 5(1), 51-73; https://doi.org/10.3390/cleantechnol5010004 - 31 Dec 2022
Cited by 3 | Viewed by 2693
Abstract
The aim of this study is to analyze the feasibility of the single-effect H2O/LiBr absorption heat pump cycle to produce combined heating and cooling. To achieve this, first, the main changes that the absorption cycle requires are described in comparison with [...] Read more.
The aim of this study is to analyze the feasibility of the single-effect H2O/LiBr absorption heat pump cycle to produce combined heating and cooling. To achieve this, first, the main changes that the absorption cycle requires are described in comparison with the conventional single-effect absorption chiller. Then, the cycle’s operational limits in terms of temperature lift and LiBr crystallization are evaluated. In this sense, driving heat temperatures required for these applications range from 85 °C to 120 °C. The energy and exergy performance (in terms of cooling and heating capacities, cooling and heating coefficient of performance, and exergy coefficient of performance) of the cycle is theoretically studied for five different types of applications that require simultaneous heating and cooling: building air conditioning, a 4th generation district heating and cooling network, a sports center with an indoor swimming pool, a hybrid air conditioning system with an absorption heat pump and a desiccant evaporative cooling system, and simultaneous cooling and water purification application for coastal areas. The system performance in terms of the cooling coefficient of performance varies in the range of 0.812–0.842, in terms of heating coefficient of performance from 0.58 to 1.842, and in terms of exergy coefficient of performance from 0.451 to 0.667. The application with the highest exergy coefficient of performance is the 4th generation district heating and cooling network. Full article
(This article belongs to the Special Issue Synergistic Technologies to Advance in Sustainable Refrigeration)
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13 pages, 4011 KiB  
Article
Using Self-Organizing Map Algorithm to Reveal Stabilities of Parameter Sensitivity Rankings in Microbial Kinetic Models: A Case for Microalgae
by Dhan Lord B. Fortela, Alyssa M. DeLattre, Wayne W. Sharp, Emmanuel D. Revellame and Mark E. Zappi
Clean Technol. 2023, 5(1), 38-50; https://doi.org/10.3390/cleantechnol5010003 - 26 Dec 2022
Viewed by 1768
Abstract
Microalgae are multi-purpose microbial agents due to their capability to efficiently sequester carbon dioxide and produce valuable biomass such as protein and single-cell oils. Formulation and tuning of microalgae kinetics models can significantly contribute to the successful design and operation of microalgae reactors. [...] Read more.
Microalgae are multi-purpose microbial agents due to their capability to efficiently sequester carbon dioxide and produce valuable biomass such as protein and single-cell oils. Formulation and tuning of microalgae kinetics models can significantly contribute to the successful design and operation of microalgae reactors. This work aimed to demonstrate the capability of self-organizing map (SOM) algorithm to elucidate the patterns of parameter rankings in microalgae models subject to stochastic variations of input forcing functions–bioprocess influent component concentration levels. These stochastic variations were implemented on a modeled chemostat with a deterministic microalgae kinetic model consists of ten time-dependent variables and eighteen model parameters. The methodology consists of two major stages: (1) global sensitivity analysis (GSA) on the importance of model parameters with stochastic sampling of bioreactor influent component concentrations, and (2) training of self-organizing maps on the datasets of model parameter rankings derived from the GSA indices. Results reveal that functional principal components analysis can project at least 99% of the time-dependent dynamic patterns of the model variables on B-splines basis functions. The component planes for hexagonal lattice SOMs reveal that the sensitivity rankings some parameters in the algae model tested can be stable over a wide range of variations in the levels of influent component concentrations. Therefore, SOM can be used to reveal the trends in multi-dimensional data arrays arising from the implementation of GSA of kinetic models under stochastic perturbation of input forcing functions. Full article
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13 pages, 4136 KiB  
Article
A Comprehensive Model to Estimate Electric Vehicle Battery’s State of Charge for a Pre-Scheduled Trip Based on Energy Consumption Estimation
by Quynh T. Tran, Leon Roose, Chayaphol Vichitpunt, Kumpanat Thongmai and Krittanat Noisopa
Clean Technol. 2023, 5(1), 25-37; https://doi.org/10.3390/cleantechnol5010002 - 23 Dec 2022
Cited by 6 | Viewed by 2260
Abstract
EV development is being prioritized in order to attain the target of net zero emissions by 2050. Electric vehicles have the potential to decrease greenhouse gas (GHG) emissions, which contribute to global warming. The driving range of electric vehicles is a significant limitation [...] Read more.
EV development is being prioritized in order to attain the target of net zero emissions by 2050. Electric vehicles have the potential to decrease greenhouse gas (GHG) emissions, which contribute to global warming. The driving range of electric vehicles is a significant limitation that prevents people from using them generally. This paper proposes a comprehensive model for calculating the amount of energy needed to charge EVs for a scheduled trip. The model contains anticipated consumption energy for the whole trip as well as contingency energy to account for unpredictable conditions. The model is simple to apply to various types of electric vehicles and produces results with sufficient precision. A number of driving tests with different road characteristics and weather conditions were implemented to evaluate the success of the proposed method. The findings could help the users feel more confidence when driving EVs, promote the usage of EVs, and advocate for the increased use of green and renewable energy sources. Full article
(This article belongs to the Topic Low-Carbon Power and Energy Systems)
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24 pages, 6711 KiB  
Review
CO2-Selective Capture from Light Hydrocarbon Mixtures by Metal-Organic Frameworks: A Review
by Hengcong Huang, Luyao Wang, Xiaoyu Zhang, Hongshuo Zhao and Yifan Gu
Clean Technol. 2023, 5(1), 1-24; https://doi.org/10.3390/cleantechnol5010001 - 20 Dec 2022
Cited by 4 | Viewed by 3694
Abstract
CO2 represents a typical impurity in light hydrocarbon feedstocks, which affects the quality of subsequent chemical products. Owing to their highly similar nature, industrial separation requires large amounts of energy. Adsorptive gas separation based on porous materials is considered an efficient alternative, [...] Read more.
CO2 represents a typical impurity in light hydrocarbon feedstocks, which affects the quality of subsequent chemical products. Owing to their highly similar nature, industrial separation requires large amounts of energy. Adsorptive gas separation based on porous materials is considered an efficient alternative, as it can offer faster kinetics, higher selectivity, long-term stability and more energy-efficient regeneration. For the adsorption separation method, preferential CO2 capture from gas mixtures in one step is more energy-efficient for direct purification than light hydrocarbons, saving about 40% energy by eliminating energy-intensive post-regeneration processes such as countercurrent vacuum blowdown. Therefore, CO2-selective adsorbents are more sought-after than light hydrocarbon-selective adsorbents. Metal-organic frameworks (MOFs) have been demonstrated as outstanding physisorbents for CO2 capture due to their configurable channels for CO2 recognition, structural flexibility and large specific surface area. Many highly selective CO2 adsorption behaviors of MOFs have been reportedly achieved by precise modulation of pore size, pore chemistry or structural flexibility. In this review, we discuss the emerging development of MOFs for CO2-selective capture from different light hydrocarbon mixtures. The challenges of CO2 recognition and the strategies employed to achieve CO2 selectivity over light hydrocarbon mixtures by MOFs are summarized. In addition, the current challenges and prospects in the field of MOFs for CO2 capture are discussed and elaborated. Full article
(This article belongs to the Special Issue Application of Porous Materials in CO2 Capture)
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