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Search Results (1,003)

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Keywords = industrial waste disposal

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23 pages, 10836 KiB  
Article
Potential Utilization of End-of-Life Vehicle Carpet Waste in Subfloor Mortars: Incorporation into Portland Cement Matrices
by Núbia dos Santos Coimbra, Ângela de Moura Ferreira Danilevicz, Daniel Tregnago Pagnussat and Thiago Gonçalves Fernandes
Materials 2025, 18(15), 3680; https://doi.org/10.3390/ma18153680 - 5 Aug 2025
Abstract
The growing need to improve the management of end-of-life vehicle (ELV) waste and mitigate its environmental impact is a global concern. One promising approach to enhancing the recyclability of these vehicles is leveraging synergies between the automotive and construction industries as part of [...] Read more.
The growing need to improve the management of end-of-life vehicle (ELV) waste and mitigate its environmental impact is a global concern. One promising approach to enhancing the recyclability of these vehicles is leveraging synergies between the automotive and construction industries as part of a circular economy strategy. In this context, ELV waste emerges as a valuable source of secondary raw materials, enabling the development of sustainable innovations that capitalize on its physical and mechanical properties. This paper aims to develop and evaluate construction industry composites incorporating waste from ELV carpets, with a focus on maintaining or enhancing performance compared to conventional materials. To achieve this, an experimental program was designed to assess cementitious composites, specifically subfloor mortars, incorporating automotive carpet waste (ACW). The results demonstrate that, beyond the physical and mechanical properties of the developed composites, the dynamic stiffness significantly improved across all tested waste incorporation levels. This finding highlights the potential of these composites as an alternative material for impact noise insulation in flooring systems. From an academic perspective, this research advances knowledge on the application of ACW in cement-based composites for construction. In terms of managerial contributions, two key market opportunities emerge: (1) the commercial exploitation of composites produced with ELV carpet waste and (2) the development of a network of environmental service providers to ensure a stable waste supply chain for innovative and sustainable products. Both strategies contribute to reducing landfill disposal and mitigating the environmental impact of ELV waste, reinforcing the principles of the circular economy. Full article
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25 pages, 4475 KiB  
Article
Physical, Mechanical, and Durability Behavior of Sustainable Mortars with Construction and Demolition Waste as Supplementary Cementitious Material
by Sandra Cunha, Kubilay Kaptan, Erwan Hardy and José Aguiar
Buildings 2025, 15(15), 2757; https://doi.org/10.3390/buildings15152757 - 5 Aug 2025
Abstract
The construction industry plays a major role in the consumption of natural resources and the generation of waste. Construction and demolition waste (CDW) is produced in substantial volumes globally and is widely available. Its accumulation poses serious challenges related to storage and disposal, [...] Read more.
The construction industry plays a major role in the consumption of natural resources and the generation of waste. Construction and demolition waste (CDW) is produced in substantial volumes globally and is widely available. Its accumulation poses serious challenges related to storage and disposal, highlighting the need for effective strategies to mitigate the associated environmental impacts of the sector. This investigation intends to evaluate the influence of mixed CDW on the physical, mechanical, and durability properties of mortars with CDW partially replacing Portland cement, and allow performance comparisons with mortars produced with fly ash, a commonly used supplementary binder in cement-based materials. Thus, three mortar formulations were developed (reference mortar, mortar with 25% CDW, and mortars with 25% fly ash) and several characterization tests were carried out on the CDW powder and the developed mortars. The work’s principal findings revealed that through mechanical grinding processes, it was possible to obtain a CDW powder suitable for cement replacement and with good indicators of pozzolanic activity. The physical properties of the mortars revealed a decrease of about 10% in water absorption by immersion, which resulted in improved performance regarding durability, especially with regard to the lower carbonation depth (−1.1 mm), and a decrease of 51% in the chloride diffusion coefficient, even compared to mortars incorporating fly ash. However, the mechanical performance of the mortars incorporating CDW was reduced (25% in terms of flexural strength and 58% in terms of compressive strength), but their practical applicability was never compromised and their mechanical performance proved to be superior to that of mortars incorporating fly ash. Full article
(This article belongs to the Special Issue Research on Sustainable Materials in Building and Construction)
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22 pages, 7391 KiB  
Article
Advanced Sustainable Epoxy Composites from Biogenic Fillers: Mechanical and Thermal Characterization of Seashell-Reinforced Composites
by Celal Kıstak, Cenk Yanen and Ercan Aydoğmuş
Appl. Sci. 2025, 15(15), 8498; https://doi.org/10.3390/app15158498 - 31 Jul 2025
Viewed by 148
Abstract
Tidal seashell waste represents an abundant, underutilized marine resource that poses environmental disposal challenges but offers potential as a sustainable bio-filler in epoxy composites. This study investigates its incorporation into bio-based epoxy systems to reduce reliance on non-renewable materials and promote circular economy [...] Read more.
Tidal seashell waste represents an abundant, underutilized marine resource that poses environmental disposal challenges but offers potential as a sustainable bio-filler in epoxy composites. This study investigates its incorporation into bio-based epoxy systems to reduce reliance on non-renewable materials and promote circular economy objectives. Processed seashell powder was blended into epoxy formulations, and response surface methodology was applied to optimize filler loading and resin composition. Comprehensive characterization included tensile strength, impact resistance, hardness, density, and thermal conductivity testing, along with microscopy analysis to evaluate filler dispersion and interfacial bonding. The optimized composites demonstrated improved hardness, density, and thermal stability while maintaining acceptable tensile and impact strength. Microscopy confirmed uniform filler distribution at optimal loadings but revealed agglomeration and void formation at higher contents, which can reduce interfacial bonding efficiency. These findings highlight the feasibility of valorizing marine waste as a reinforcing filler in sustainable composite production, supporting environmental goals and offering a scalable approach for the development of durable, lightweight materials suitable for structural, coating, and industrial applications. Full article
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25 pages, 4297 KiB  
Article
Application of Carbon–Silicon Hybrid Fillers Derived from Carbonised Rice Production Waste in Industrial Tread Rubber Compounds
by Valeryia V. Bobrova, Sergey V. Nechipurenko, Bayana B. Yermukhambetova, Andrei V. Kasperovich, Sergey A. Yefremov, Aigerim K. Kaiaidarova, Danelya N. Makhayeva, Galiya S. Irmukhametova, Gulzhakhan Zh. Yeligbayeva and Grigoriy A. Mun
Polymers 2025, 17(15), 2070; https://doi.org/10.3390/polym17152070 - 29 Jul 2025
Viewed by 330
Abstract
The disposal of agro-industrial waste is a pressing environmental issue. At the same time, due to the high silica content in specific agricultural residues, their processed products can be utilised in various industrial sectors as substitutes for commercial materials. This study investigates the [...] Read more.
The disposal of agro-industrial waste is a pressing environmental issue. At the same time, due to the high silica content in specific agricultural residues, their processed products can be utilised in various industrial sectors as substitutes for commercial materials. This study investigates the key technological, physico-mechanical, and viscoelastic properties of industrial elastomeric compounds based on synthetic styrene–butadiene rubber, intended for the tread of summer passenger car tyres, when replacing the commercially used highly reinforcing silica filler (SF), Extrasil 150VD brand (white carbon black), with a carbon–silica filler (CSF). The CSF is produced by carbonising a finely ground mixture of rice production waste (rice husks and stems) in a pyrolysis furnace at 550–600 °C without oxygen. It was found that replacing 20 wt.pts. of silica filler with CSF in industrial tread formulations improves processing parameters (Mooney viscosity increases by up to 5.3%, optimal vulcanisation time by up to 9.2%), resistance to plastic deformation (by up to 7.7%), and tackiness of the rubber compounds (by 31.3–34.4%). Viscoelastic properties also improved: the loss modulus and mechanical loss tangent decreased by up to 24.0% and 14.3%, respectively; the rebound elasticity increased by up to 6.3% and fatigue resistance by up to 2.7 thousand cycles; and the internal temperature of samples decreased by 7 °C. However, a decrease in tensile strength (by 10.7–27.0%) and an increase in wear rate (up to 43.3% before and up to 22.5% after thermal ageing) were observed. Nevertheless, the overall results of this study indicate that the CSF derived from the carbonisation of rice production waste—containing both silica and carbon components—can effectively be used as a partial replacement for the commercially utilised reinforcing silica filler in the production of tread rubber for summer passenger car tyres. Full article
(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)
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13 pages, 756 KiB  
Article
Sustainability in Beverage Packaging Technology: Life Cycle Analysis and Waste Management Scenarios
by Patrycja Walichnowska, Andrzej Tomporowski, Zbigniew Kłos, Anna Rudawska and Michał Bembenek
Sustainability 2025, 17(14), 6594; https://doi.org/10.3390/su17146594 - 19 Jul 2025
Viewed by 344
Abstract
Due to increasing environmental concerns and the constant development of the bottling industry, research into the environmental impact of beverage packaging processes is crucial. The aim of this article is to determine the environmental impact, in selected aspects, of automated beverage bottling and [...] Read more.
Due to increasing environmental concerns and the constant development of the bottling industry, research into the environmental impact of beverage packaging processes is crucial. The aim of this article is to determine the environmental impact, in selected aspects, of automated beverage bottling and packaging processes using life cycle analysis (LCA). The analysis covers key process stages, such as filling, packaging and internal transport, in the context of raw material consumption, but also energy and waste generation. This work focuses primarily on the impact of changing the raw material used for bottle and shrink film production on the environmental impact of the studied technical facility within the adopted system boundaries and on analyzing scenarios for the management of these post-consumer materials. This research has shown that the stage associated with the greatest negative environmental impact is the shrinking of the film around the bottles. Furthermore, it has been demonstrated that recycling plastic film and bottle waste is a more environmentally friendly solution than landfill disposal. The analysis shows that using recycled materials in the tested production line allows for the reduction of harmful emissions and a reduction in the overall environmental footprint of the tested system. Full article
(This article belongs to the Special Issue Sustainable Waste Utilisation and Biomass Energy Production)
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14 pages, 1175 KiB  
Article
Recovery of Natural Pyrazines and Alcohols from Fusel Oils Using an Innovative Extraction Installation
by Waldemar Studziński, Michał Podczarski, Justyna Piechota, Marzena Buziak, Myroslava Yakovenko and Yurii Khokha
Molecules 2025, 30(14), 3028; https://doi.org/10.3390/molecules30143028 - 18 Jul 2025
Viewed by 294
Abstract
The production of spirits generates significant amounts of waste in the form of fusel oils-previously treated mainly as an environmental problem. This paper presents an innovative installation designed to recover valuable components from this difficult waste. The key achievement is the effective separation [...] Read more.
The production of spirits generates significant amounts of waste in the form of fusel oils-previously treated mainly as an environmental problem. This paper presents an innovative installation designed to recover valuable components from this difficult waste. The key achievement is the effective separation and recovery of pyrazine derivatives-natural aromatic compounds with high utility value in the food, cosmetics and pharmaceutical industries. The designed system allows for the recovery of as much as 98% of pyrazines and isoamyl alcohol and isobutanol fractions with a purity above 96%, which is a significant advance compared to previous disposal methods. The installation was designed to be consistent with the idea of a circular economy, maximizing the use of by-products and minimizing losses. The results of the work indicate that fusel oils, previously perceived as waste, can become a source of valuable secondary raw materials, and the presented solution opens up new possibilities for the sustainable development of the alcohol industry. Full article
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19 pages, 6727 KiB  
Article
Soil Contamination and Related Ecological Risks: Complex Analysis of the Defor Petrila Tailings Dump, Romania
by Emilia-Cornelia Dunca, Mădălina-Flavia Ioniță and Sorin Mihai Radu
Land 2025, 14(7), 1492; https://doi.org/10.3390/land14071492 - 18 Jul 2025
Viewed by 250
Abstract
Assessing the risks associated with waste disposal is essential for environmental protection and sustainable development, especially given concerns about the impact of industrial activities on the environment. This study analyses soil contamination in the Defor Petrila tailings-dump area caused by the deposition of [...] Read more.
Assessing the risks associated with waste disposal is essential for environmental protection and sustainable development, especially given concerns about the impact of industrial activities on the environment. This study analyses soil contamination in the Defor Petrila tailings-dump area caused by the deposition of waste material resulting from coal exploitation. To characterise the heavy-metal contamination in detail, we applied a comprehensive methodology that includes the calculation of the geo-accumulation index (Igeo), contamination factor (Cf), and potential ecological risk index (PERI), along with an analysis of the heavy-metal concentration isolines and a statistical analysis using the Pearson correlation coefficient. The results reveal varying levels of heavy-metal concentrations, as indicated by the calculated indices. The findings underscore the need for remediation and ongoing monitoring to mitigate the environmental impacts. This study provides a scientific basis for decision making in environmental management and highlights the importance of assessing mining-waste disposal near human settlements using various contamination-assessment methods. Full article
(This article belongs to the Section Land Use, Impact Assessment and Sustainability)
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21 pages, 1583 KiB  
Review
Valorization of Agricultural Ashes from Cold and Temperate Regions as Alternative Supplementary Cementitious Materials: A Review
by A. Sadoon, M. T. Bassuoni and A. Ghazy
Clean Technol. 2025, 7(3), 59; https://doi.org/10.3390/cleantechnol7030059 - 11 Jul 2025
Viewed by 263
Abstract
The pursuit of sustainable alternatives to portland cement has become a global imperative within the construction sector, driven by the need to reduce carbon dioxide emissions and energy consumption. Among the promising alternatives, agricultural ashes have garnered attention for their potential as alternative [...] Read more.
The pursuit of sustainable alternatives to portland cement has become a global imperative within the construction sector, driven by the need to reduce carbon dioxide emissions and energy consumption. Among the promising alternatives, agricultural ashes have garnered attention for their potential as alternative supplementary cementitious materials (ASCMs), owing to their inherent pozzolanic properties when appropriately processed. However, the availability and utilization of these ashes have predominantly been concentrated in tropical and subtropical regions, where such biomass is more abundant. This review offers a comprehensive bibliometric analysis to identify and assess agricultural ashes (specifically switchgrass, barley, sunflower, and oat husks) that are cultivated in temperate and cold climates and exhibit potential for SCM application. The analysis aims to bridge the knowledge gap by systematically mapping the existing research landscape and highlighting underexplored resources suitable for cold-region implementation. Key processing parameters, including incineration temperature, retention duration, and post-combustion grinding techniques, are critically examined for their influence on the resulting ash’s physicochemical characteristics and pozzolanic reactivity. In addition, the effect on fresh, hardened, and durability properties was evaluated. Findings reveal that several crops grown in colder regions may produce ashes rich in reactive silica, thereby qualifying them as viable ASCM candidates and bioenergy sources. Notably, the ashes derived from switchgrass, barley, oats, and sunflowers demonstrate significant reactive silica content, reinforcing their potential in sustainable construction practices. Hence, this study underscores the multifaceted benefits of contributing to the decarbonization of the cement industry and circular economy, while addressing environmental challenges associated with biomass waste disposal and uncontrolled open-air combustion. Full article
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22 pages, 3865 KiB  
Article
An Assessment of Bio-Physical and Social Drivers of River Vulnerability and Risks
by Komali Kantamaneni, John Whitton, Sigamani Panneer, Iqbal Ahmad, Anil Gautam and Debashish Sen
Earth 2025, 6(3), 77; https://doi.org/10.3390/earth6030077 - 11 Jul 2025
Viewed by 723
Abstract
In recent decades, the River Ganges in India has been heavily contaminated with domestic waste and industrial toxins because of cultural activities, a lack of community awareness, an absence of sewage disposal facilities, and rapid population growth. Previous studies have focused separately on [...] Read more.
In recent decades, the River Ganges in India has been heavily contaminated with domestic waste and industrial toxins because of cultural activities, a lack of community awareness, an absence of sewage disposal facilities, and rapid population growth. Previous studies have focused separately on either the physical or social factors associated with River Ganges pollution but have not combined these elements in a single study. To fill this research gap, our study assesses the bio-physical and social vulnerability of the River Ganges by using a holistic approach. The following four sampling stations were selected: Rishikesh, Haridwar, Kanpur, and Varanasi. These locations were chosen to test the water quality in bio-physical aspects and to assess the social perceptions of river vulnerability among the residents and visitors. Perceptions of river water quality and likely sources of pollution were gathered via the distribution of over 1000 questionnaires. Data collection took place in the winter and summer of 2022 and 2023. The results showed that river water quality is not suitable for drinking purposes at any of the four cities without conventional treatment, and that the river is unsuitable for bathing at all locations, except upstream of Rishikesh. Nearly 50% of those questioned agreed that the river is polluted, whilst 74% agreed that pollution has increased in recent decades, particularly in the last 10 years. These compelling results are critical for policymakers and decision makers. They highlight the urgent need for novel strategies that address Ganges pollution while fostering community health education and environmental management. By dispelling myths surrounding river quality, this study strengthens the ongoing efforts to restore the Ganges, ensuring that it remains a vital lifeline for present and future generations. Full article
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25 pages, 11157 KiB  
Review
Reuse of Retired Wind Turbine Blades in Civil Engineering
by Xuemei Yu, Changbao Zhang, Jing Li, Xue Bai, Lilin Yang, Jihao Han and Guoxiang Zhou
Buildings 2025, 15(14), 2414; https://doi.org/10.3390/buildings15142414 - 9 Jul 2025
Viewed by 390
Abstract
The rapid growth of the wind energy sector has led to a rising number of retired wind turbine blades (RWTBs) globally, posing significant environmental and logistical challenges for sustainable waste management. Handling enormous RWTBs at their end of life (EoL) has a significant [...] Read more.
The rapid growth of the wind energy sector has led to a rising number of retired wind turbine blades (RWTBs) globally, posing significant environmental and logistical challenges for sustainable waste management. Handling enormous RWTBs at their end of life (EoL) has a significant negative impact on resource conservation and the environment. Conventional disposal methods, such as landfilling and incineration, raise environmental concerns due to the non-recyclable composite material used in blade manufacturing. This study explores the upcycling potential of RWTBs as innovative construction materials, addressing both waste reduction and resource efficiency in the construction industry. By exploring recent advancements in recycling techniques, this research highlights applications such as structural components, lightweight aggregates for concrete, and reinforcement elements in asphalt pavements. The key findings demonstrate that repurposing blade-derived materials not only reduces landfill dependency but also lowers carbon emissions associated with conventional construction practices. However, challenges including material compatibility, economic feasibility, and standardization require further investigation. This study concludes that upcycling wind turbine blades into construction materials offers a promising pathway toward circular economy goals. To improve technical methods and policy support for large-scale implementation, it recommends collaboration among different fields, such as those related to cementitious and asphalt materials. Full article
(This article belongs to the Section Building Materials, and Repair & Renovation)
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19 pages, 3169 KiB  
Article
Investigation of the Effects of Almond Husk Ash on the Engineering Properties of Expansive Soil
by Abdulkadir Ürünveren, Baki Bağrıaçık and Esma Kahraman
Buildings 2025, 15(14), 2384; https://doi.org/10.3390/buildings15142384 - 8 Jul 2025
Viewed by 253
Abstract
In recent years, the use of waste materials for soil improvement has gained increasing importance due to sustainability concerns and the need for effective waste disposal. Almond husk ash (AHA), though considered a major environmental pollutant, is classified as a non-hazardous and noninert [...] Read more.
In recent years, the use of waste materials for soil improvement has gained increasing importance due to sustainability concerns and the need for effective waste disposal. Almond husk ash (AHA), though considered a major environmental pollutant, is classified as a non-hazardous and noninert waste. One of the primary challenges associated with such industrial wastes is their storage; therefore, environmentally safe disposal methods are essential. This study aimed to investigate the potential of AHA in improving expansive soil (ES). The findings revealed that ES can be effectively stabilized using AHA and geogrids, both individually and in combination. The optimal conditions for soil improvement were identified as follows: 25% AHA content, a zone depth of 1.5 units, and three layers of geogrids. The bearing capacity ratios showed significant improvement under various conditions: a 2.56-fold increase with AHA alone, a 2.87-fold increase with geogrids alone, and a 5.60-fold increase when both AHA and geogrids were used together. The greatest enhancement was achieved through the combined application of AHA and geogrids. AHA was thus demonstrated to be an effective, economical, and environmentally sustainable additive for the stabilization of expansive soils. Furthermore, microstructural analyses using scanning electron microscopy (SEM), X-ray fluorescence (XRF), and X-ray diffraction (XRD) supported the improvements observed in the experimental results. Full article
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18 pages, 2645 KiB  
Review
Pre-Treatment Equipment for Processing Grape Marc into Valorised By-Products: A Review
by Stepan Akterian, Kostadin Fikiin, Georgi Georgiev and Angel Terziev
Sustainability 2025, 17(13), 6188; https://doi.org/10.3390/su17136188 - 5 Jul 2025
Viewed by 483
Abstract
While traditional disposal of solid waste from the global wine industry causes significant environmental burden and hazards, a range of value-added by-products can be produced from the grape marc. This review focuses therefore on crucial sustainability-enhancing technologies for pomace dewatering and separation, which [...] Read more.
While traditional disposal of solid waste from the global wine industry causes significant environmental burden and hazards, a range of value-added by-products can be produced from the grape marc. This review focuses therefore on crucial sustainability-enhancing technologies for pomace dewatering and separation, which constitute a mandatory stage in obtaining storage-stable by-products and final value-added commodities. A number of dryers and separators were considered for pre-treatment of wet grape marc and analysed in terms of their design characteristics, functionality, feasibility, throughput and efficiency. A multi-criteria decision analysis was carried out to compare, rank and select the equipment which is most suitable for the purpose. It was found out that the rotary drum dryer and the drum screen separator with internal blade rotor are the best candidates to fulfil the technology requirements, while the flowsheet that includes an initial separation followed by drying of the resulting fractions is a rather attractive option. Valorising grape waste worldwide contributes substantially to achieving the United Nations Sustainable Development Goals for responsible consumption and production, mitigating climate change, caring for health and well-being, preserving land life and combating hunger. Full article
(This article belongs to the Section Sustainable Food)
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19 pages, 2149 KiB  
Article
Feather Waste Biodegradation and Biostimulant Potential of Gordonia alkanivorans S7: A Novel Keratinolytic Actinobacterium for Sustainable Waste Valorization
by Katarzyna Struszczyk-Świta, Piotr Drożdżyński, Paweł Marcinkowski, Aleksandra Nadziejko, Magdalena Rodziewicz, Bartłomiej Januszewicz, Magdalena Gierszewska and Olga Marchut-Mikołajczyk
Int. J. Mol. Sci. 2025, 26(13), 6494; https://doi.org/10.3390/ijms26136494 - 5 Jul 2025
Viewed by 410
Abstract
The poultry industry produces significant quantities of keratin-rich waste, primarily feathers, whose traditional disposal methods—incineration or chemical treatment—result in environmental damage and resource depletion. This research introduces a sustainable biotechnological method for the valorization of feather waste utilizing Gordonia alkanivorans S7, an actinomycete [...] Read more.
The poultry industry produces significant quantities of keratin-rich waste, primarily feathers, whose traditional disposal methods—incineration or chemical treatment—result in environmental damage and resource depletion. This research introduces a sustainable biotechnological method for the valorization of feather waste utilizing Gordonia alkanivorans S7, an actinomycete strain extracted from petroleum plant sludge. This is the inaugural publication illustrating keratinolytic activity in the Gordonia genus. The optimization of the degradation process via the Taguchi approach led to the effective biodegradation of untreated home chicken feathers, achieving dry mass loss of up to 99% after 168 h in a mineral medium. The agricultural potential of the obtained keratin hydrolysate, which was high in organic components (C 31.2%, N 8.9%, H 5.1%, and S 1.7%), was assessed. Phytotoxicity tests demonstrated that the feather hydrolysate led to better growth of the indicator plants—Sorghum saccharatum and Lepidium sativum. The highest values of root growth stimulation were 26% for S. saccharatum and 31% for L. sativum, at a dose of 0.01%. Shoot growth stimulation was noted only for L. sativum, reaching 38% (0.01%), 53% (0.05%), and 37% (0.1%), as compared to the control sample. These results demonstrate the process’s combined economic and environmental benefits, providing a fresh approach to the production of bio-based plant biostimulants and sustainable keratin waste management. Full article
(This article belongs to the Special Issue Microbial Enzymes for Biotechnological Applications: 2nd Edition)
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32 pages, 11334 KiB  
Article
Photocatalytic Degradation of Petroleum Wastewater Using ZnO-Loaded Pistachio Shell Biochar: A Sustainable Approach for Oil and COD Removal
by Eveleen A. Dawood, Thamer J. Mohammed, Buthainah Ali Al-Timimi and Eman H. Khader
Reactions 2025, 6(3), 38; https://doi.org/10.3390/reactions6030038 - 4 Jul 2025
Viewed by 600
Abstract
The disposal of wastewater resulting from petroleum industries presents a major environmental challenge due to the presence of hard-to-degrade organic pollutants, such as oils and hydrocarbons, and high chemical oxygen demand (COD). In this study, an efficient and eco-friendly method was developed to [...] Read more.
The disposal of wastewater resulting from petroleum industries presents a major environmental challenge due to the presence of hard-to-degrade organic pollutants, such as oils and hydrocarbons, and high chemical oxygen demand (COD). In this study, an efficient and eco-friendly method was developed to treat such wastewater using a photocatalyst composed of biochar derived from pistachio shells and loaded with zinc oxide (ZnO) nanoparticles. The biochar-ZnO composite was prepared via a co-precipitation-assisted pyrolysis method to evaluate its efficiency in the photocatalytic degradation of petroleum wastewater (PW). The synthesized material was characterized using various techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy, to determine surface morphology, crystal structure, and functional groups present on the catalyst surface. Photocatalytic degradation experiments were conducted under UV and sunlight for 90 h of irradiation to evaluate the performance of the proposed system in removing oil and reducing COD levels. Key operational parameters, such as pH (2–10), catalyst dosage (0–0.1) g/50 mL, and oil and COD concentrations (50–500) ppm and (125–1252) ppm, were optimized by response surface methodology (RSM) to obtain the maximum oil and COD removal efficiency. The oil and COD were removed from PW (90.20% and 88.80%) at 0.1 g/50 mL of PS/ZnO, a pH of 2, and 50 ppm oil concentration (125 ppm of COD concentration) under UV light. The results show that pollutant removal is slightly better when using sunlight (80.00% oil removal, 78.28% COD removal) than when using four lamps of UV light (77.50% oil removal, 75.52% COD removal) at 0.055 g/50 mL of PS/ZnO, a pH of 6.8, and 100 ppm of oil concentration (290 ppm of COD concentration). The degradation rates of the PS/ZnO supported a pseudo-first-order kinetic model with R2 values of 0.9960 and 0.9922 for oil and COD. This work indicates the potential use of agricultural waste, such as pistachio shells, as a sustainable source for producing effective catalysts for industrial wastewater treatment, opening broad prospects in the field of green and nanotechnology-based environmental solutions in the development of eco-friendly and effective wastewater treatment technologies under solar light. Full article
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19 pages, 1797 KiB  
Article
From Agricultural Waste to Functional Tea: Optimized Processing Enhances Bioactive Flavonoid Recovery and Antioxidant Capacity with Multifaceted Health Benefits in Loquat (Eriobotrya japonica Lindl.) Flowers
by Mingzheng Duan, Xi Wang, Jinghan Feng, Xu Xiao, Lingying Zhang, Sijiu He, Liya Ma, Xue Wang, Shunqiang Yang and Muhammad Junaid Rao
Horticulturae 2025, 11(7), 766; https://doi.org/10.3390/horticulturae11070766 - 2 Jul 2025
Cited by 1 | Viewed by 335
Abstract
The large-scale disposal of loquat (Eriobotrya japonica Lindl.) flowers during fruit thinning represents a significant waste of bioactive resources. This study systematically evaluated how three processing methods—fresh (FS), heat-dried (HD), and freeze-dried (FD) treatments—affect the flavonoid composition and antioxidant capacity of loquat [...] Read more.
The large-scale disposal of loquat (Eriobotrya japonica Lindl.) flowers during fruit thinning represents a significant waste of bioactive resources. This study systematically evaluated how three processing methods—fresh (FS), heat-dried (HD), and freeze-dried (FD) treatments—affect the flavonoid composition and antioxidant capacity of loquat flower extracts, with the aim of developing value-added, sugar-free functional tea ingredients. Using UPLC-MS/MS and DPPH assays, we analyzed both pre-(FS/HD/FD) and post-extraction samples (FSP/HDP/FDP) to assess processing-specific metabolic signatures and extraction efficiency. The results revealed that heat-dried powder (HDP) exhibited the highest total flavonoid content and DPPH scavenging capacity (615.24 µg Trolox/g), attributed to enhanced release of stable compounds like quercetin. Freeze-dried powder (FDP) better preserved heat-sensitive flavonoids, such as catechin-(4α→8)-gallocatechin and naringenin, but showed lower overall antioxidant activity. Multivariate analysis confirmed distinct clustering patterns, with heat-drying favoring flavonoid extractability while freeze-drying maintained metabolic diversity. These findings demonstrate that processing methods significantly influence bioactive compound retention and functionality, with heat-drying offering optimal balance between yield and practicality for industrial applications. This work provides a scientific foundation for upcycling loquat flowers into standardized nutraceutical ingredients, addressing both agricultural waste reduction and the growing demand for natural functional foods. Full article
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