Journal Description
Clean Technologies
Clean Technologies
is an international, peer-reviewed, open access journal of scientific research on technology development aiming to reduce the environmental impact of human activities, and is published quarterly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, ESCI (Web of Science), Inspec, AGRIS, RePEc, and other databases.
- Journal Rank: CiteScore - Q2 (Environmental Science (miscellaneous))
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 26.6 days after submission; acceptance to publication is undertaken in 3.8 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: APC discount vouchers, optional signed peer review, and reviewer names published annually in the journal.
Impact Factor:
3.8 (2022);
5-Year Impact Factor:
3.7 (2022)
Latest Articles
Evaluation of Distillery Fractions in Direct Methanol Fuel Cells and Screening of Reaction Products
Clean Technol. 2024, 6(2), 513-527; https://doi.org/10.3390/cleantechnol6020027 - 22 Apr 2024
Abstract
Fuel cells represent an appealing avenue for harnessing eco-friendly energy. While their fuel supply traditionally stems from water electrolysis, an environmentally conscious approach also involves utilizing low-weight alcohols like methanol and ethanol. These alcohols, concentrated from sustainable sources within the enological by-product distillation
[...] Read more.
Fuel cells represent an appealing avenue for harnessing eco-friendly energy. While their fuel supply traditionally stems from water electrolysis, an environmentally conscious approach also involves utilizing low-weight alcohols like methanol and ethanol. These alcohols, concentrated from sustainable sources within the enological by-product distillation process, offer a noteworthy contribution to the circular economy. This study delved into evaluating the efficacy of distillery fractions in powering methanol fuel cells. Beyond their energy-generation potential, the performed GC-MS analysis unveiled appreciable quantities of acetic acid resulting from the partial oxidation of ethanol. This revelation opens the door to intriguing possibilities, including the recovery and repurposing of novel compounds such as short-chain fatty acids (predominantly acetic acid), ketones, and aldehydes—establishing a link between sustainable energy production and the emergence of valuable by-product applications.
Full article
(This article belongs to the Special Issue Valorization of Industrial and Agro Waste)
►
Show Figures
Open AccessArticle
Numerical Investigation for Power Generation by Microbial Fuel Cells Treating Municipal Wastewater in Guelph, Canada
by
Yiming Li and Shunde Yin
Clean Technol. 2024, 6(2), 497-512; https://doi.org/10.3390/cleantechnol6020026 - 19 Apr 2024
Abstract
►▼
Show Figures
Significant research endeavors have focused on microbial fuel cell (MFC) systems within wastewater treatment protocols owing to their unique capacity to convert chemical energy from waste into electricity while maintaining minimal nutrient concentrations in the effluent. While prior studies predominantly relied on empirical
[...] Read more.
Significant research endeavors have focused on microbial fuel cell (MFC) systems within wastewater treatment protocols owing to their unique capacity to convert chemical energy from waste into electricity while maintaining minimal nutrient concentrations in the effluent. While prior studies predominantly relied on empirical investigations, there remains a need to explore modeling and simulation approaches. Assessing MFC systems’ performance and power generation based on real wastewater data is pivotal for their practical implementation. To address this, a MATLAB model is developed to elucidate how MFC parameters and constraints influence system performance and enhance wastewater treatment efficiency. Leveraging actual wastewater data from a municipal plant in Guelph, Canada, six sets of MFC models are employed to examine the relationship between power generation and six distinct parameters (inflow velocity, membrane thickness, internal resistance, anode surface area, feed concentration, and hydraulic retention time). Based on these analyses, the final model projects a total power generation of 50,515.16 kW for the entire wastewater treatment plant in a day, capable of supporting approximately 2530 one-person households. Furthermore, the model demonstrates a notably higher chemical oxygen demand (COD) removal rate (75%) compared to the Guelph WWTP. This comprehensive model serves as a valuable tool for future simulations in similar wastewater treatment plants, providing insights for optimizing performance and aiding in practical applications.
Full article
Figure 1
Open AccessEditorial
CO2 Capture and Sequestration
by
Diganta Bhusan Das
Clean Technol. 2024, 6(2), 494-496; https://doi.org/10.3390/cleantechnol6020025 - 16 Apr 2024
Abstract
CO2 capture and sequestration (CCS) aims to capture carbon dioxide (CO2) from CO2 sources (e [...]
Full article
(This article belongs to the Special Issue CO2 Capture and Sequestration)
Open AccessArticle
Wind–PV–Battery Hybrid Off-Grid System: Control Design and Real-Time Testing
by
Miloud Rezkallah, Ambrish Chandra and Hussein Ibrahim
Clean Technol. 2024, 6(2), 471-493; https://doi.org/10.3390/cleantechnol6020024 - 15 Apr 2024
Abstract
The paper presents the design and implementation of decentralized control for a PV–wind–battery hybrid off-grid system with limited power electronics devices and sensors. To perform well without using any maximum power point tracking (MPPT) technique from the wind turbine (WT) based on a
[...] Read more.
The paper presents the design and implementation of decentralized control for a PV–wind–battery hybrid off-grid system with limited power electronics devices and sensors. To perform well without using any maximum power point tracking (MPPT) technique from the wind turbine (WT) based on a permanent-magnet brushless DC generator (PMBLDCG) and solar panels (PVs) and balance the power in the system, a cascade control structure strategy based on a linear active disturbance rejection controller (LADRC) is developed for the two-switch DC-DC buck-boost converter. Moreover, to ensure an uninterruptible power supply to the connected loads with a constant voltage and frequency, a cascade d-q control structure based on LADRC is developed for the interfacing single-phase inverter. Furthermore, the modeling and controller parameters design are presented. The performance under all operation conditions of the hybrid off-grid configuration and its decentralized control is validated by simulation using MATLAB/Simulink and in real-time using a small-scale hardware prototype.
Full article
(This article belongs to the Topic Clean Energy Technologies and Assessment)
►▼
Show Figures
Figure 1
Open AccessArticle
Biogas as Alternative to Liquefied Petroleum Gas in Mauritania: An Integrated Future Approach for Energy Sustainability and Socio-Economic Development
by
Sidahmed Sidi Habib and Shuichi Torii
Clean Technol. 2024, 6(2), 453-470; https://doi.org/10.3390/cleantechnol6020023 - 11 Apr 2024
Abstract
The global shift from conventional energy sources to sustainable alternatives has garnered significant attention, driven by the promise of economic benefits and environmental sustainability. The current study rigorously investigated the economic advantages and sustainability achieved from the transition of households in Mauritania from
[...] Read more.
The global shift from conventional energy sources to sustainable alternatives has garnered significant attention, driven by the promise of economic benefits and environmental sustainability. The current study rigorously investigated the economic advantages and sustainability achieved from the transition of households in Mauritania from liquefied petroleum gas (LPG) to biogas utilization. The study constitutes a robust case study that centers on assessing the multifaceted impacts of this transition on household finances and overall quality of life in Mauritania. This case focuses on biogas technology adoption and its role as a competitor of LPG in Mauritania. The energy poverty portfolio of the nation has been explored and livestock waste generation and biogas production potential have been estimated at 2451 million cubic meters annually. Biogas production can fulfill 50% of the energy requirement for cooking purposes within the country. The community scale fixed-dome-type biogas digesters have been recommended for Mauritania by considering a community of 100 families. The calculated payback period for the community project is 74 months, and after the payback period, continuous monthly benefits of USD 1750 will be started. Livestock manure is directly utilized for farming practices in Mauritania, which produces 10.7 Gg of methane emissions per year. Biogas production is a clean and economically viable option for Mauritania, which can also be beneficial for reducing the methane emissions footprints of the livestock sector. This case study will prove as a vital project for other African nations if successfully implemented. Multiple recommendations for the policy-makers of Mauritania have also been formulated, like tariffs on biogas production facilities and swift financing schemes, which can further strengthen the biogas production on a national scale. International funders should also take part in coping with the energy demand of Mauritania and its mission to mitigate climate change rather than utilizing LPG on a national scale. Biogas production and utilization are much cheaper compared with the fluctuating prices of LPG and ensure health when cooking.
Full article
(This article belongs to the Collection Bioenergy Technologies)
►▼
Show Figures
Figure 1
Open AccessReview
Sustainable Treatment of Spent Photovoltaic Solar Panels Using Plasma Pyrolysis Technology and Its Economic Significance
by
Ping Fa Chiang, Shanshan Han, Mugabekazi Joie Claire, Ndungutse Jean Maurice, Mohammadtaghi Vakili and Abdulmoseen Segun Giwa
Clean Technol. 2024, 6(2), 432-452; https://doi.org/10.3390/cleantechnol6020022 - 09 Apr 2024
Abstract
In the past few decades, the solar energy market has increased significantly, with an increasing number of photovoltaic (PV) modules being deployed around the world each year. Some believe that these PV modules have a lifespan of around 25–30 years. As their lifetime
[...] Read more.
In the past few decades, the solar energy market has increased significantly, with an increasing number of photovoltaic (PV) modules being deployed around the world each year. Some believe that these PV modules have a lifespan of around 25–30 years. As their lifetime is limited, solar panels wind up in the waste stream after their end of life (EoL). Several ecological challenges are associated with their inappropriate disposal due to the presence of hazardous heavy metals (HMs). Some studies have reported different treatment technologies, including pyrolysis, stabilization, physical separation, landfill, and the use of chemicals. Each proposed treatment technique pollutes the environment and underutilizes the potential resources present in discarded solar panels (DSPs). This review recommends thermal plasma pyrolysis as a promising treatment technology. This process will have significant advantages, such as preventing toxic HMs from contaminating the soil and groundwater, reducing the amount of e-waste from DSPs in an environmentally friendly and economical way, and allows the utilization of the valuable resources contained in EoL photovoltaic solar panel modules by converting them into hydrogen-rich syngas to generate thermal energy, electricity, and non-leachable slag that can be used as an additive in other treatment processes or as a conditioner to improve soil properties. However, plasma pyrolysis uses a high temperature to break down waste materials, a challenge which can be offset by the integration of this process in anaerobic digestion (AD), as the slag from plasma pyrolysis can be used as an additive in AD treatments to produce high yields of biogas and improve nutrient recovery. Moreover, the produced energy from both processes can operate the entire plant in which they take place and increase the net energy production, a resource which can be sold for an additional income. Future challenges and recommendations are also highlighted.
Full article
(This article belongs to the Collection Review Papers in Clean Technologies)
►▼
Show Figures
Figure 1
Open AccessArticle
Forecasting Pitch Response of Floating Offshore Wind Turbines with a Deep Learning Model
by
Mohammad Barooni and Deniz Velioglu Sogut
Clean Technol. 2024, 6(2), 418-431; https://doi.org/10.3390/cleantechnol6020021 - 29 Mar 2024
Abstract
The design and optimization of floating offshore wind turbines (FOWTs) pose significant challenges, stemming from the complex interplay among aerodynamics, hydrodynamics, structural dynamics, and control systems. In this context, this study introduces an innovative method for forecasting the dynamic behavior of FOWTs under
[...] Read more.
The design and optimization of floating offshore wind turbines (FOWTs) pose significant challenges, stemming from the complex interplay among aerodynamics, hydrodynamics, structural dynamics, and control systems. In this context, this study introduces an innovative method for forecasting the dynamic behavior of FOWTs under various conditions by merging Convolutional Neural Network (CNN) with a Gated Recurrent Unit (GRU) network. This model outperforms traditional numerical models by delivering precise and efficient predictions of dynamic FOWT responses. It adeptly handles computational complexities and reduces processing duration, while maintaining flexibility and effectively managing nonlinear dynamics. The model’s prowess is showcased through an analysis of a spar-type FOWT in a multivariate parallel time series dataset using the CNN–GRU structure. The outcomes are notably promising, underscoring the model’s proficiency in accurately forecasting the performance of FOWTs.
Full article
(This article belongs to the Topic Advances in Wind Energy Technology)
►▼
Show Figures
Figure 1
Open AccessArticle
Optimizing Renewable Energy Integration through Innovative Hybrid Microgrid Design: A Case Study of Najran Secondary Industrial Institute in Saudi Arabia
by
Mana Abusaq and Mohamed A. Zohdy
Clean Technol. 2024, 6(2), 397-417; https://doi.org/10.3390/cleantechnol6020020 - 25 Mar 2024
Abstract
►▼
Show Figures
Amidst a growing global focus on sustainable energy, this study investigates the underutilization of renewable resources in the southern region of Saudi Arabia, with a specific emphasis on the Najran Secondary Industrial Institute (NSII). This research presents an in-depth analysis of installing a
[...] Read more.
Amidst a growing global focus on sustainable energy, this study investigates the underutilization of renewable resources in the southern region of Saudi Arabia, with a specific emphasis on the Najran Secondary Industrial Institute (NSII). This research presents an in-depth analysis of installing a hybrid microgrid (MG) system on the roofs of NSII buildings, exploring six cases with varying tilt and azimuth angles. The study innovatively integrates architectural design and system administration, a novel approach for this location, and benchmarks the optimal angles against Hybrid Optimization of Multiple Energy Resources (HOMER) software defaults. The proposed system consists of solar photovoltaic (PV) panels, a battery storage system (BSS), a converter, a diesel generator (DG), and a grid. The selected model balances technological and economic viability with environmental considerations, ensuring a reliable power supply within the NSII’s roof area constraints. An extensive sensitivity analysis evaluates the system’s resilience across different scenarios. The current system, which is grid-only, has an estimated Net Present Cost (NPC) of about USD 7.02M and emits 1.81M kg/yr of CO2. The findings point to installing a microgrid with a 20.97° tilt and 50° azimuth angle as optimal, demonstrating 54.69% lower NPC and 92% lower CO2 emissions, along with zero kWh/year unmet electrical load when applying the resilience assessments. This outcome highlights Saudi Arabia’s southern region’s renewable energy potential, aligning with national mega-projects and energy initiatives.
Full article
Figure 1
Open AccessArticle
Design of a Solar Dish Receiver and Life Cycle Assessment of a Hot Water System
by
Ibrahim Tursunović and Davide Papurello
Clean Technol. 2024, 6(1), 379-396; https://doi.org/10.3390/cleantechnol6010019 - 19 Mar 2024
Abstract
The energy sector is the main source of greenhouse gases, so it has the highest potential for improvement. The improvements can be achieved by generating energy from renewable sources. It is necessary to combine production from renewable sources with storage systems. Thermal energy
[...] Read more.
The energy sector is the main source of greenhouse gases, so it has the highest potential for improvement. The improvements can be achieved by generating energy from renewable sources. It is necessary to combine production from renewable sources with storage systems. Thermal energy storage using concentrated solar power systems is a promising technology for dispatchable renewable energy that can guarantee a stable energy supply even in remote areas without contributing to greenhouse gas emissions during operation. However, it must be emphasised that greenhouse gases and other impacts can occur during the production process of concentrating solar system components. This paper analyses the receiver design to produce thermal energy for the existing CSP dish plant at the Energy Center of the Politecnico di Torino. The plant is designed to produce electrical energy in the spring and summer periods. In addition to this energy production, the CSP can be adopted to produce thermal energy, through hot water, during the less favourable periods of the year in terms of global solar radiation. The surface heat flux is calculated in the first part of the analysis to obtain the maximum internal temperature in the receiver, which is 873.7 °C. This value is a constraint for the choice of material for the solar receiver. A life cycle assessment is performed to compare the emissions generated during the production of the main components of the CSP system with the emissions generated by the methane-fuelled water heater to produce the same amount of thermal energy. It can be concluded that the production of the main components of the CSP system results in lower greenhouse gas emissions than the operational phase of a conventional system. Given the assumptions made, the utilization of methane leads to the emission of approximately 12,240 kg of CO2, whereas the production of the CSP system results in emissions totalling 5332.8 kg of CO2 equivalent
Full article
(This article belongs to the Collection Brilliant Young Researchers in Clean Technologies)
►▼
Show Figures
Figure 1
Open AccessReview
Status of Concentrated Solar Power Plants Installed Worldwide: Past and Present Data
by
Sylvain Rodat and Richard Thonig
Clean Technol. 2024, 6(1), 365-378; https://doi.org/10.3390/cleantechnol6010018 - 19 Mar 2024
Abstract
Solar energy is not only the most abundant energy on earth but it is also renewable. The use of this energy is expanding very rapidly mainly through photovoltaic technology. However, electricity storage remains a bottleneck in tackling solar resource variability. Thus, solar thermal
[...] Read more.
Solar energy is not only the most abundant energy on earth but it is also renewable. The use of this energy is expanding very rapidly mainly through photovoltaic technology. However, electricity storage remains a bottleneck in tackling solar resource variability. Thus, solar thermal energy becomes of particular interest when energy storage is required, as thermal energy storage is much cheaper than electricity storage. The objective of this paper is to make a short update on the CSP (Concentrated Solar Power) market as of the year 2023. It is based on the CSP-GURU database, which lists information on CSP power plants all over the world. Although this database is open, it is not easy to find UpToDate analysis. An overview of this expanding technology is presented and offers readable figures with the most important information. This includes the evolution of installed capacities worldwide along with upcoming projects (under construction) and technological trends. The evolution of storage capacities and operating temperatures is discussed. Investment costs and levelized cost of electricity are also provided to obtain reliable data for comparison with other energy technologies. Specific land requirements are highlighted, along with overall efficiency. Relevant examples are discussed in this paper. Eventually, it outlines the evolution of the CSP landscape with useful information for scientific and educational purposes.
Full article
(This article belongs to the Collection Review Papers in Clean Technologies)
►▼
Show Figures
Figure 1
Open AccessArticle
Ammonium Removal in Wastewater Treatments by Adsorbent Geopolymer Material with Granite Wastes: Full-Scale Validation
by
M. Otero, L. Freire, S. Gómez-Cuervo and C. Ávila
Clean Technol. 2024, 6(1), 339-364; https://doi.org/10.3390/cleantechnol6010017 - 07 Mar 2024
Abstract
Elevated ammonium (NH4+) concentrations in untreated waterways contribute to eutrophication and dissolved oxygen depletion. Geopolymer (GP) materials are introduced as sustainable, straightforward operation and low-cost option for pollutant adsorption through ion exchange mechanism. In the present study, a porous metakaolin-based
[...] Read more.
Elevated ammonium (NH4+) concentrations in untreated waterways contribute to eutrophication and dissolved oxygen depletion. Geopolymer (GP) materials are introduced as sustainable, straightforward operation and low-cost option for pollutant adsorption through ion exchange mechanism. In the present study, a porous metakaolin-based geopolymer with granite waste additions was synthetized, characterised and validated as adsorbent material for NH4+ pollution in water. At this point, treatments to reduce GP alkalis leaching were also considered to comply with the water discharge regulations. The adsorption mechanism was analysed by Redlich-Peterson isotherm model concluding that NH4+ was disposed on the GP surface as a monolayer with strong physical-chemical attraction between molecules. Kinetics of the process followed the Weber-Morris rate equation being the intraparticle diffusion the limiting process. Continuous experiments at lab-scale suggested a maximum removal of 97% during the first hours and an adsorption capacity (q) of 25.24 mg/g. Additionally, as a main novelty of the work, the GP was validated in a full-scale pilot plant monitoring pH, electrical conductivity and NH4+ concentration. The obtained data revealed that the GP is high selective in a real wastewater stream and removed 81% of NH4+, higher adsorption values than those reported for natural and some synthetic zeolites.
Full article
(This article belongs to the Collection Water and Wastewater Treatment Technologies)
►▼
Show Figures
Figure 1
Open AccessArticle
Reinforcement Fiber Production from Wheat Straw for Wastepaper-Based Packaging Using Steam Refining with Sodium Carbonate
by
Sebastian Hagel and Fokko Schütt
Clean Technol. 2024, 6(1), 322-338; https://doi.org/10.3390/cleantechnol6010016 - 05 Mar 2024
Abstract
Locally sourced agricultural residues are a promising feedstock for the production of reinforcement fibers for wastepaper-based packaging papers. An eco-friendly high yield process to generate fibers from wheat straw using high pressure steam and sodium carbonate is presented. The wheat straw was impregnated
[...] Read more.
Locally sourced agricultural residues are a promising feedstock for the production of reinforcement fibers for wastepaper-based packaging papers. An eco-friendly high yield process to generate fibers from wheat straw using high pressure steam and sodium carbonate is presented. The wheat straw was impregnated with up to 16% of sodium carbonate and steam treated for 10 min at temperatures from 148 °C to 203 °C. The pulps were characterized concerning their chemical composition and test sheets with 100% straw fibers and with 15% and 30% straw fibers blended with recycled pulp were prepared. Fiber yields ranged from 70% to 45%, wherein more severe treatment conditions contributed to increased paper strength but lower yields. At comparable fiber yields, treatments featuring a higher chemical input, coupled with lower treatment temperatures, resulted in improved paper strength. By blending recycled pulp with up to 30% of straw fibers with a beating degree of roughly 45 °SR, the burst, compression and tensile strength was enhanced by up to 66%, 74% and 59%, respectively. As the enhancement effect decreases with a high steam treatment intensity and a high proportion of wheat straw, a moderate treatment and limited use of wheat straw may be the best choice.
Full article
(This article belongs to the Special Issue Valorization of Industrial and Agro Waste)
►▼
Show Figures
Figure 1
Open AccessReview
Superhydrophobic Materials from Waste: Innovative Approach
by
Maria Cannio, Dino Norberto Boccaccini, Stefano Caporali and Rosa Taurino
Clean Technol. 2024, 6(1), 299-321; https://doi.org/10.3390/cleantechnol6010015 - 04 Mar 2024
Abstract
Superhydrophobic materials, known for their exceptional water-repellent properties, have found widespread applications in diverse fields such as self-cleaning surfaces, anti-icing coatings, and water-resistant textiles. In recent years, researchers have explored a sustainable approach by repurposing waste materials to create superhydrophobic surfaces. This eco-friendly
[...] Read more.
Superhydrophobic materials, known for their exceptional water-repellent properties, have found widespread applications in diverse fields such as self-cleaning surfaces, anti-icing coatings, and water-resistant textiles. In recent years, researchers have explored a sustainable approach by repurposing waste materials to create superhydrophobic surfaces. This eco-friendly approach not only reduces environmental impact but also aligns with circular economy principles, contributing to a more sustainable future. Creating superhydrophobic materials from waste involves a combination of surface modification techniques and hierarchical structuring, with rigorous characterization to ensure the desired properties. These materials showcase their potential in various industries, opening doors to more environmentally friendly technologies. This review delves into the concept of superhydrophobic materials derived from waste and the methods used for their synthesis. It begins by defining superhydrophobicity and highlighting its unique characteristics. It emphasizes the pivotal role played by superhydrophobic materials across industries. The review then explores waste materials’ untapped potential, discussing the advantages of harnessing waste for superhydrophobic material development. Concrete examples of promising waste materials are provided, including agricultural residues and industrial byproducts. The review outlines five key sections that will be further developed to offer a comprehensive understanding of this innovative and sustainable approach to superhydrophobic materials.
Full article
(This article belongs to the Special Issue Valorization of Industrial and Agro Waste)
►▼
Show Figures
Graphical abstract
Open AccessReview
Delamination Techniques of Waste Solar Panels: A Review
by
Ali Ghahremani, Scott D. Adams, Michael Norton, Sui Yang Khoo and Abbas Z. Kouzani
Clean Technol. 2024, 6(1), 280-298; https://doi.org/10.3390/cleantechnol6010014 - 29 Feb 2024
Abstract
Solar panels are an environmentally friendly alternative to fossil fuels; however, their useful life is limited to approximately 25 years, after which they become a waste management issue. Proper management and recycling of end-of-life (EOL) solar panels are paramount. It protects the environment
[...] Read more.
Solar panels are an environmentally friendly alternative to fossil fuels; however, their useful life is limited to approximately 25 years, after which they become a waste management issue. Proper management and recycling of end-of-life (EOL) solar panels are paramount. It protects the environment because of the high energy consumption of silicon production. We can effectively decrease energy and cost requirements by recovering silicon from recycled solar panels. This is one-third of those needed for manufacturing silicon directly. Moreover, solar panels include heavy metals, such as lead, tin, and cadmium, which pose risks to human health and the environment. Empirical evidence suggests that the costs of mining materials can exceed those of recycled materials, thereby making recycling a more cost-effective means of resource harvesting. This review paper focuses on the techniques developed to delaminate solar panels, which are considered a crucial step in the recycling of EOL solar panels. Initially, various classifications of solar panels are given. Subsequently, an analysis of the diverse methods of solar panel delamination and their efficacy in the retrieval of valued materials is presented. This investigation has identified three primary modes of delamination, namely mechanical, thermal, and chemical. Among these, mechanical delamination is deemed to be a sustainable and cost-effective option when compared to thermal and chemical delamination. The current most popular method of thermal delamination is characterized by its high energy consumption and potential emission, and the chemical delamination generates hazardous liquids that pose their own threat to the environment. This study emphasizes the mechanical delamination techniques, characterized by their environmentally friendly nature, minimal ecological footprint, and capacity to retrieve entire glass panels intact. This paper also discusses the current gaps and potential enhancements for mechanical delamination techniques. For example, some delamination techniques result in crushed materials. Thus, the handling and recovery of materials such as glass and silicon cells require the implementation of an appropriate sorting technique. Also, the value obtained from recovering crushed materials is lower than that of intact glass and silicon cells.
Full article
(This article belongs to the Collection Brilliant Young Researchers in Clean Technologies)
►▼
Show Figures
Figure 1
Open AccessReview
Wastewater Treatment Utilizing Industrial Waste Fly Ash as a Low-Cost Adsorbent for Heavy Metal Removal: Literature Review
by
Waleed Jadaa
Clean Technol. 2024, 6(1), 221-279; https://doi.org/10.3390/cleantechnol6010013 - 28 Feb 2024
Abstract
Wastewater discharges from industrial processes typically include elevated concentrations of contaminants, which largely consist of potentially harmful chemicals such as heavy metals. These contaminants are characterized by their slow rate of decomposition. Hence, the removal of these metallic ions from effluents poses a
[...] Read more.
Wastewater discharges from industrial processes typically include elevated concentrations of contaminants, which largely consist of potentially harmful chemicals such as heavy metals. These contaminants are characterized by their slow rate of decomposition. Hence, the removal of these metallic ions from effluents poses a challenge. Among different treatments, the adsorption approach has considerable potential due to its ability to effectively eliminate both soluble and insoluble pollutants from effluent, even at lower levels of concentration. Of various wastes, fly ash (FA) material has been the subject of attention because it is abundant, has favorable qualities, and contains a high percentage of minerals. This review investigates multiple facets, with a specific focus on the application of FA, an industrial byproduct, as an adsorbent in removing heavy metals. A comprehensive examination was conducted on a range of concerns pertaining to the pollution caused by metallic ions, including the underlying causes, levels of contamination, health implications of heavy metals, and removal methods. Multiple factors were found to affect the adsorption process. Of all the factors, the pH value considerably influences the elimination of heavy metals. An acidic pH range of 2.5–4.5 was found to be optimal for achieving the highest possible elimination of As(V), Cu(II), Hg(II), and Cr(VI). The latter elimination rate reached 89% at the optimal pH level. Most heavy metals’ adsorption isotherms conformed to the Langmuir or Freundlich models, while the pseudo-second-order kinetics provided a satisfactory match for their removal. Using a raw FA, adsorption capacities were achieved in the removal of metallic ions, Ni(II), Pb(II), and Cr(VI), that ranged from 14.0 to 23.9 mg g−1. Meanwhile, the FA-zeolite showed a remarkable capacity to adsorb ions Mn(II), Ni(II), Cd(II), Cu(II), and Pb(II), with values ranging from about 31 to 66 mg g−1. The cost analysis showed that the treatment of FA is economically advantageous and may result in significant cost reductions in comparison to commercial adsorbents. In summary, FA is an inexpensive waste material with potential for water treatment applications and several other purposes due to its excellent chemical and mineralogical composition.
Full article
(This article belongs to the Collection Brilliant Young Researchers in Clean Technologies)
►▼
Show Figures
Figure 1
Open AccessFeature PaperArticle
Insights into the Adsorption of Cr(VI) on Activated Carbon Prepared from Walnut Shells: Combining Response Surface Methodology with Computational Calculation
by
Hicham Yazid, Taoufiq Bouzid, El mountassir El mouchtari, Lahoucine Bahsis, Mamoune El Himri, Salah Rafqah and Mohammadine El haddad
Clean Technol. 2024, 6(1), 199-220; https://doi.org/10.3390/cleantechnol6010012 - 26 Feb 2024
Abstract
Walnut shells were used to produce highly microporous activated carbon. The prepared activated walnut shells were found to be an efficient adsorbent for removing Cr(VI). The study used the response surface methodology to investigate four independent variables effect: Cr(VI) concentration, pH, AC-Ws dose,
[...] Read more.
Walnut shells were used to produce highly microporous activated carbon. The prepared activated walnut shells were found to be an efficient adsorbent for removing Cr(VI). The study used the response surface methodology to investigate four independent variables effect: Cr(VI) concentration, pH, AC-Ws dose, and temperature on the Cr(VI) removal efficiency, which was studied in the concentration range of 0.1 to 0.3 g/L, 4 to 10, 15 to 35 °C and 1 to 5 mg/L, respectively. Through experiments designed, the optimum conditions were determined to be 4, 0.23 g/L, 298 k, and 2 g/L, respectively. At these conditions, the efficiency of removal was found to be 93%. The thermodynamic study of the adsorption process showed a spontaneous and exothermic nature. The kinetic model that explains the experimental data is the pseudo-second-order model. Furthermore, the Langmuir isotherm model was estimated to be an excellent representation of the equilibrium data. Quantum calculations and NCI analyses were also performed to get more light on the adsorption mechanism of the Cr(VI) atom and its complex form on the prepared AC-Ws surface.
Full article
(This article belongs to the Special Issue Recent Advances in Applied Activated Carbon Research)
►▼
Show Figures
Figure 1
Open AccessReview
Innovative Approaches to an Eco-Friendly Cosmetic Industry: A Review of Sustainable Ingredients
by
Rafaela Sasounian, Renata Miliani Martinez, André Moreni Lopes, Jeanine Giarolla, Catarina Rosado, Wagner Vidal Magalhães, Maria Valéria Robles Velasco and André Rolim Baby
Clean Technol. 2024, 6(1), 176-198; https://doi.org/10.3390/cleantechnol6010011 - 08 Feb 2024
Abstract
►▼
Show Figures
Sustainable ingredients in cosmetics have been discussed for the past decade, and the COVID-19 pandemic has increased awareness of this significant topic. Consumers are informed and vigilant about clean labels, driving the necessity for sustainability throughout the cosmetic production chain. Moreover, nanotechnology and
[...] Read more.
Sustainable ingredients in cosmetics have been discussed for the past decade, and the COVID-19 pandemic has increased awareness of this significant topic. Consumers are informed and vigilant about clean labels, driving the necessity for sustainability throughout the cosmetic production chain. Moreover, nanotechnology and green chemistry approaches have emerged as innovative perspectives to develop sustainable and eco-friendly cosmetic ingredients. In this sense, in this review, we present examples and applications of sustainable ingredients derived from several types of sources (i.e., plants, animals, microorganisms, cell cultures, and recycled materials/biomaterials). The benefits and drawbacks of all classes of compounds were organized and discussed in relation to novel formulations/products. Finally, we addressed perspectives on cosmetic ingredients that prioritize sustainability and safety, with an emphasis on exploring sustainable ingredients, compounds, or molecules as promising areas for research and development.
Full article
Figure 1
Open AccessReview
Review of the Current State of Pyrolysis and Biochar Utilization in Europe: A Scientific Perspective
by
Maria P. C. Volpi, Jean C. G. Silva, Andreas Hornung and Miloud Ouadi
Clean Technol. 2024, 6(1), 152-175; https://doi.org/10.3390/cleantechnol6010010 - 04 Feb 2024
Abstract
This scientific paper provides an overview of the current state of pyrolysis in Europe, with a focus on mapping the key research areas and technologies employed. This research relied on search equations that centered on the utilization of biomass and plastics as primary
[...] Read more.
This scientific paper provides an overview of the current state of pyrolysis in Europe, with a focus on mapping the key research areas and technologies employed. This research relied on search equations that centered on the utilization of biomass and plastics as primary feedstocks in pyrolysis, with a particular emphasis on biochar generation and different technologies applied. The results showed that both plastic and biomass pyrolysis can contribute to reducing waste and mitigating greenhouse gas emissions. However, plastic pyrolysis can release harmful pollutants due to the presence of chlorine and other additives in plastics, which requires sophisticated emission control systems to be implemented. The production of biochar from sewage sludge is identified as a promising approach for phosphorus recovery, which can subsequently be utilized as a valuable fertilizer in agricultural applications. The data from this study contribute to exploring future applications at pilot and industrial scales for pyrolysis, with a critical assessment of the use of feedstocks. Moreover, this work provides information about current companies that are already operating on a large scale with pyrolysis and a map of the principal countries in Europe engaged in pyrolysis research, correlating the characteristics of the pyrolysis processes investigated.
Full article
(This article belongs to the Special Issue Gasification and Pyrolysis of Biomass and Waste)
►▼
Show Figures
Figure 1
Open AccessArticle
Ranking of Independent Small-Scale Electricity Generation Systems
by
Janis Kramens, Megija Valtere, Guntars Krigers, Vladimirs Kirsanovs and Dagnija Blumberga
Clean Technol. 2024, 6(1), 140-151; https://doi.org/10.3390/cleantechnol6010009 - 02 Feb 2024
Abstract
The EU’s energy targets are to achieve at least 32% renewables in the energy mix by 2030. Part of the solution is strengthening consumer rights by empowering individuals to generate their own electricity. The aim of this study was to identify the most
[...] Read more.
The EU’s energy targets are to achieve at least 32% renewables in the energy mix by 2030. Part of the solution is strengthening consumer rights by empowering individuals to generate their own electricity. The aim of this study was to identify the most suitable energy system for electricity generation of up to 50 kW in the EU residential sector. Multi-Criteria Decision Analysis was used to compare four systems: proton exchange membrane fuel cell with photovoltaic panels, photovoltaic panels, biomass-powered Stirling engine, and solar-powered Stirling engine. Based on the results, the most beneficial system for household electricity generation is the biomass-fueled Stirling engine system due to its affordability, reliability, and low environmental impact. Governments and businesses can use these findings to improve information for the residential sector and enable the transition to renewable energy.
Full article
(This article belongs to the Topic Sustainable Energy: Efficient Technological Solutions Combining Environmental, Economic, Political and Social Aspects)
►▼
Show Figures
Figure 1
Open AccessArticle
Biodegradation of 17α-Ethinylestradiol by Strains of Aeromonas Genus Isolated from Acid Mine Drainage
by
Tânia Luz Palma and Maria Clara Costa
Clean Technol. 2024, 6(1), 116-139; https://doi.org/10.3390/cleantechnol6010008 - 01 Feb 2024
Abstract
►▼
Show Figures
17α-ethinylestradiol (EE2), a synthetically derived analogue of endogenous estrogen, is widely employed as a hormonal contraceptive and is recognized as a highly hazardous emerging pollutant, causing acute and chronic toxic effects on both aquatic and terrestrial organisms. It has been included in the
[...] Read more.
17α-ethinylestradiol (EE2), a synthetically derived analogue of endogenous estrogen, is widely employed as a hormonal contraceptive and is recognized as a highly hazardous emerging pollutant, causing acute and chronic toxic effects on both aquatic and terrestrial organisms. It has been included in the initial Water Watch List. The aim of this study was to isolate bacteria from consortia recovered from mine sediments and acid mine drainage samples, both considered extreme environments, with the ability to degrade EE2. From the most promising consortia, isolates affiliated with the Aeromonas, Rhizobium, and Paraburkholderia genera were obtained, demonstrating the capability of growing at 50 mg/L EE2. Subsequently, these isolates were tested with 9 mg/L of EE2 as the sole carbon source. Among the isolated strains, Aeromonas salmonicida MLN-TP7 exhibited the best performance, efficiently degrading EE2 (95 ± 8%) and reaching concentrations of this compound below the limits of detection within 7 and 9 days. The final metabolites obtained are in accordance with those of the TCA cycle; this may indicate EE2 mineralization. As far as is known, Aeromonas salmonicida was isolated for the first time and identified in acid mine drainage, demonstrating its capacity to degrade EE2, making it a promising candidate for bioaugmentation and suggesting its possible applicability in low pH environments.
Full article
Figure 1
Highly Accessed Articles
Latest Books
E-Mail Alert
News
Topics
Topic in
Clean Technol., Energies, Environments, Processes, Sustainability
Sustainable Energy: Efficient Technological Solutions Combining Environmental, Economic, Political and Social Aspects
Topic Editors: Fabio Orecchini, Adriano Santiangeli, Fabrizio ZuccariDeadline: 15 June 2024
Topic in
Buildings, Clean Technol., Materials, Recycling, Sustainability
Circular Economy Innovations and Breakthroughs for Built Environments
Topic Editors: Sakdirat Kaewunruen, Katerina Tsikaloudaki, Ruben P. Borg, Yunlong GuoDeadline: 31 August 2024
Topic in
Clean Technol., Environments, Pollutants, Sustainability, Toxics
New Advances in Adsorptive and Extractive Methods for Pollutant Removal
Topic Editors: Rui Wang, Xinpeng Liu, Yunqian Ma, Kai ZhangDeadline: 29 September 2024
Topic in
Clean Technol., Energies, Materials, Solar, Sustainability
Smart Solar Energy Systems
Topic Editors: Venizelos Efthymiou, Minas PatsalidesDeadline: 15 November 2024
Conferences
Special Issues
Special Issue in
Clean Technol.
Simulations of Photovoltaic and Thermophotovoltaic Solar Cells—Transport and Optics
Guest Editor: Atilla Ozgur CakmakDeadline: 31 May 2024
Special Issue in
Clean Technol.
Decentralised Water Treatment Technologies
Guest Editors: Diganta B. Das, Kashyap Kumar Dubey, Lipika DekaDeadline: 30 June 2024
Special Issue in
Clean Technol.
Environmental Engineering Perspectives on Waste Management, Nature-Based Solutions (NbS) and Green/Blue Infrastructure
Guest Editors: Joseph Akunna, Kiran Tota-MaharajDeadline: 31 July 2024
Special Issue in
Clean Technol.
Thermal Storage Power Plants (TSPP)
Guest Editor: Franz TriebDeadline: 31 August 2024
Topical Collections
Topical Collection in
Clean Technol.
Brilliant Young Researchers in Clean Technologies
Collection Editor: Patricia Luis Alconero
Topical Collection in
Clean Technol.
Water and Wastewater Treatment Technologies
Collection Editor: Susana Rodriguez-Couto
Topical Collection in
Clean Technol.
Clean Catalytic Technologies
Collection Editor: Dmitry Yu. Murzin