Unlocking the potential of olive residues for functional purposes: update on human intervention trials with health and cosmetic products

Olive mill waste (OMW) is a promising source of valuable compounds such as polyphenols, terpenes, sterols, and other bioactive compounds, which are of interest to the pharmaceuticals and cosmeceutical industries. This review examines the potential of OMW extracts for health and beauty applications based on evidence reports from human clinical trials. The results achieved to date indicate health-enhancing properties, but little is known about the underlying mechanisms of action, dose-response relationships, and long-term impacts. Therefore, while olive by-products, extracted using eco-friendly methods, present opportunities for the development of high-value health and cosmetic products, further studies are necessary to determine the full range of their effects and establish specific therapeutic strategies. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Slags from roasting of antimony ore in the Brioude-Massiac (France) area used as aggregates: An early example of circular economy

Towards the end of the 19th century and the early 20th century, France was the world's largest producer of antimony, especially due to the rich deposits in the Brioude-Massiac area. Even though all the mining and smelting activities are long gone, there are still some remains of those activities. The most original of those is the use of roasting slags as aggregates in former plant walls or industrial building. They are macroscopically characterised by a black or red colour with a vesicular aspect similar to natural pozzolanas. Common petrography and mineralogy tools have been used to characterise those slags: optical mineralogy, scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) and X-ray diffraction (XRD). To gain an insight into their mineral complexity, a QEMSCAN map has been produced. The mineralogy is typical of high-temperature slags: cristobalite, quartz, mullite, fayalite-forsterite series and spinel. The antimony content is quite high, up to seven percent, under the form of various antimony oxides and native antimony.

A review of extant literature and recent trends in residential construction waste reduction

The residential construction sector in New Zealand and worldwide is experiencing increased criticism for generating substantial waste that poses environmental concerns. Accordingly, researchers have advocated implementing residential construction waste reduction (RCWR) strategies as a sustainable solution to managing construction waste (CW). This article aims to provide a comprehensive overview of RCWR by analysing 87 articles from the Scopus database using bibliometric and critical review methods. The co-occurrence analysis of keywords revealed five clusters, in which five main themes emerged: (i) waste generation and management performance, (ii) prefabrication and life cycle assessment concepts, (iii) design concepts, (iv) circular economy and (v) decision-making concepts. The findings suggest that sustainable practices such as designing for waste reduction, prefabrication, waste quantification, three-dimensional printing and building information modelling can effectively achieve RCWR. The study also highlights the benefits of RCWR, including reducing environmental impacts, and identifies management, economic, legislative, technology and cultural barriers that affect the implementation of RCWR strategies. These results provide valuable insights to support future policy formulation and research direction for RCWR in New Zealand.

Rare Earth Element Adsorption to Clay Minerals: Mechanistic Insights and Implications for Recovery from Secondary Sources

The energy transition will have significant mineral demands and there is growing interest in recovering critical metals, including rare earth elements (REE), from secondary sources in aqueous and sedimentary environments. However, the role of clays in REE transport and deposition in these settings remains understudied. This work investigated REE adsorption to the clay minerals illite and kaolinite through pH adsorption experiments and extended X-ray absorption fine structure (EXAFS). Clay type, pH, and ionic strength (IS) affected adsorption, with decreased adsorption under acidic pH and elevated IS. Illite had a higher adsorption capacity than kaolinite; however, >95% adsorption was achieved at pH ∼7.5 regardless of IS or clay. These results were used to develop a surface complexation model with the derived binding constants used to predict REE speciation in the presence of competing sorbents. This demonstrated that clays become increasingly important as pH increases, and EXAFS modeling showed that REE can exist as both inner- and outer-sphere complexes. Together, this indicated that clays can be an important control on the transport and enrichment of REE in sedimentary systems. These findings can be applied to identify settings to target for resource extraction or to predict REE transport and fate as a contaminant.

Applications of Plasma Technologies in Recycling Processes

Plasmas are reactive ionised gases, which enable the creation of unique reaction fields. This allows plasmas to be widely used for a variety of chemical processes for materials, recycling among others. Because of the increase in urgency to find more sustainable methods of waste management, plasmas have been enthusiastically applied to recycling processes. This review presents recent developments of plasma technologies for recycling linked to economical models of circular economy and waste management hierarchies, exemplifying the thermal decomposition of organic components or substances, the recovery of inorganic materials like metals, the treatment of paper, wind turbine waste, and electronic waste. It is discovered that thermal plasmas are most applicable to thermal processes, whereas nonthermal plasmas are often applied in different contexts which utilise their chemical selectivity. Most applications of plasmas in recycling are successful, but there is room for advancements in applications. Additionally, further perspectives are discussed.

Valorisation of metallurgical residues via carbothermal reduction: A circular economy approach in the cement and iron and steel industry

The decarbonisation of the steel and cement industry is of utmost importance in tackling climate change. Hence, steel production in modern integrated steel mills will be shifted towards electric arc furnaces in the future, in turn causing dwindling supplies of blast furnace slag, which is used as a supplementary cementitious material inter alia to reduce the CO2 emissions of cement production. Achieving a sustainable circular steel and building material economy requires the valorisation of currently landfilled steel slags and investigating utilisation options for electric arc furnace slag, which is increasingly being generated. For this purpose, different metallurgical residues and by-products were treated by carbothermal reduction in an inductively heated graphite crucible and then rapidly cooled by wet granulation, yielding a slag fraction similar to granulated blast furnace slag and a metal fraction valuable as a secondary raw material. A spreadsheet-based model was developed to calculate residue combinations to accomplish target compositions of the slag and metal fractions to fulfil previously identified requirements of the targeted cementitious and ferrous products. The results demonstrate the high accuracy of the model in predicting the properties (e.g. main oxide composition) of the generated slag and metal fraction, which fulfil the needed requirements for their use as (i) a supplementary cementitious material and (ii) a secondary raw material in steel production.

The Precursors Used for Developing Geopolymer Composites for Circular Economy-A Review

Considering recent climate changes, special importance is given to any attempt to depollute and protect the environment. A circular economy seems to be the ideal solution for the valorization of mineral waste, resulting from various industrial branches, by reintroducing them in the process of obtaining alternative building materials, more friendly to the environment. Geopolymers can be considered as a promising option compared to Portland cement. Information about the influence of the composition of the precursors, the influence of the activation system on the mechanical properties or the setting time could lead to the anticipation of new formulations of geopolymers or to the improvement of some of their properties. Reinforcement components, different polymers and expansion agents can positively or negatively influence the properties of geopolymers in the short or long term.

Environmental impacts of circularity strategies for social distancing plastic shields made of polymethyl methacrylate in the United States

One application of plastics that grew during the COVID-19 pandemic is for social distancing plastic shields, or protective barriers, made from polymethyl methacrylate (PMMA) such as transparent face guards. Although available for other applications, end-of-life impacts for barriers are currently lacking in the literature, and there is a need to fill in this gap to guide decisions. This study evaluated the end-of-life environmental impacts of PMMA barriers in the United States by using life cycle assessment. We evaluated five strategies including landfilling, waste-to-energy, mechanical recycling, chemical recycling and reuse. Data were sourced from literature and various life cycle inventory databases. The Tool for Reduction and Assessment of Chemicals and Other Environmental Impacts (TRACI) was used as the life cycle impact assessment method. Landfilling exhibited the highest impact in all indicators and reuse demonstrated optimal results for global warming potential. A scenario analysis was conducted to explore a combination of strategies, revealing that the most promising approach involved a mix of 40% reuse, 20% mechanical recycling and 40% chemical recycling. Circular economy recommendations are proposed for managing these sources of plastic waste in the United States.

A Closed-Loop Recyclable Low-Density Polyethylene

Low-density polyethylene (LDPE) is one of the most important plastics, which is produced unfortunately under extreme conditions. In addition, it consists of robust aliphatic C─C bonds which are challenging to cleave for plastic recycling. A low-pressure and -temperature (pethylene = 2 bara, T = 70 °C) macromonomer-based synthesis of long chain branched polyethylene is reported. The introduction of recycle points permits the polymerization (grafting to) of the macromonomers to form the long chain branched polyethylene and its depolymerization (branch cleavage). Coordinative chain transfer polymerization employing ethylene and co-monomers is used for the synthesis of the macromonomers, permitting a high flexibility of their precise structure and efficient synthesis. The long chain branched polyethylene material matches key properties of low-density polyethylene.

Erythrosine-Dialdehyde Cellulose Nanocrystal Coatings for Antibacterial Paper Packaging

Though paper is an environmentally friendly alternative to plastic as a packaging material, it lacks antibacterial properties, and some papers have a low resistance to oil or water. In this study, a multifunctional paper-coating material was developed to reduce the use of plastic packaging and enhance paper performance. Natural cellulose nanocrystals (CNCs) with excellent properties were used as the base material for the coating. The CNCs were functionalized into dialdehyde CNCs (DACNCs) through periodate oxidation. The DACNCs were subsequently complexed using erythrosine as a photosensitizer to form an erythrosine-CNC composite (Ery-DACNCs) with photodynamic inactivation. The Ery-DACNCs achieved inactivations above 90% after 30 min of green light irradiation and above 85% after 60 min of white light irradiation (to simulate real-world lighting conditions), indicating photodynamic inactivation effects. The optimal parameters for a layer-by-layer dip coating of kraft paper with Ery-DACNCs were 4.5-wt% Ery-DACNCs and 15 coating layers. Compared to non-coated kraft paper and polyethylene-coated paper, the Ery-DACNC-coated paper exhibited enhanced mechanical properties (an increase of 28% in bursting strength). More than 90% of the bacteria were inactivated after 40 min of green light irradiation, and more than 80% were inactivated after 60 min of white light irradiation.

Exploring the Untapped Potential of Pine Nut Skin By-Products: A Holistic Characterization and Recycling Approach

The increasing population, food demand, waste management concerns, and the search for sustainable alternatives to plastic polymers have led researchers to explore the potential of waste materials. This study focused on a waste of pine nut processing referred to in this paper as pine nut skin. For the first time, its nutritional profile, potential bioactive peptide, contaminants, and morphological structure were assessed. Pine nut skin was composed mainly of carbohydrates (56.2%) and fiber (27.5%). The fat (9.8%) was about 45%, 35%, and 20% saturated, monounsaturated, and polyunsaturated fatty acid, respectively, and Omega-9,-6, and -3 were detected. Notably, oleic acid, known for its health benefits, was found in significant quantities, resembling its presence in pine nut oil. The presence of bioactive compounds such as eicosapentaenoic acid (EPA) and phytosterols further adds to its nutritional value. Some essential elements were reported, whereas most of the contaminants such as heavy metals, polycyclic aromatic hydrocarbons, rare earth elements, and pesticides were below the limit of quantification. Furthermore, the in silico analysis showed the occurrence of potential precursor peptides of bioactive compounds, indicating health-promoting attributes. Lastly, the morphological structural characterization of the pine nut skin was followed by Fourier Transform Infrared and solid-state NMR spectroscopy to identify the major components, such as lignin, cellulose, and hemicellulose. The thermostability of the pine nut skin was monitored via thermogravimetric analysis, and the surface of the integument was analyzed via scanning electron microscopy and volumetric nitrogen adsorption. This information provides a more comprehensive view of the potential uses of pine nut skin as a filler material for biocomposite materials. A full characterization of the by-products of the food chain is essential for their more appropriate reuse.

Comparative Analysis of the Effects of Incorporating Post-Industrial Recycled LLDPE and Post-Consumer PE in Films: Macrostructural and Microstructural Perspectives in the Packaging Industry

In accordance with the Circular Economy Package of the European directive, the Spanish government compels manufacturers of plastic bags to include into their products a minimum of 70% of polyethylene (PE) waste. Following this mandate can be challenging and requires a deep knowledge of the alterations produced by the recycling in the main components of a plastic bag film: lineal low-density polyethylene (LLDPE), the LLDPE recycled post-industry, generated as waste from an industrial process (rLLDPE) and the PE recycled from post-consumer use (rPE), that has been picked up, cleaned, and reprocessed. This study provides insight in the macro and microstructural changes produced by several cycles of recycling in these materials. Specimens in the form of film for supermarket bags formed with these polymers have been subjected to several recycling sequences. The process closely mimics industrial processes. Four cycles have been applied to the samples. The evolution of mechanical properties, including tensile strength, elongation at break, and tear and impact tests, shows an obvious decrease due to degradation that is not an impediment for practical use after the four cycles of recycling according to the main specifications defined by the producer. Colorimetric measurements reveal no significant variations in the color of the films. The results of the FTIR and TGA analysis show degradation phenomena and changes in crystallinity in branching and the apparition of crosslinking that are in consonance with the mechanical data. There is also a difference between both types of recycled PE. In general, rLLDPE is more affected by the recycling than rPE. According to our findings, the limiting property would be the tearing. By comparing these values with bags available in the market, manufactured from 70-80% recycled material, we can infer that while two reprocessing cycles can lead to good results, a maximum of four cycles of recycling is advisable.

Comparison of Different Pretreatment Processes Envisaging the Potential Use of Food Waste as Microalgae Substrate

A significant fraction of the food produced worldwide is currently lost or wasted throughout the supply chain, squandering natural and economic resources. Food waste valorization will be an important necessity in the coming years. This work investigates the ability of food waste to serve as a viable nutritional substrate for the heterotrophic growth of Chlorella vulgaris. The impact of different pretreatments on the elemental composition and microbial contamination of seven retail food waste mixtures was evaluated. Among the pretreatment methods applied to the food waste formulations, autoclaving was able to eliminate all microbial contamination and increase the availability of reducing sugars by 30%. Ohmic heating was also able to eliminate most of the contaminations in the food wastes in shorter time periods than autoclave. However, it has reduced the availability of reducing sugars, making it less preferable for microalgae heterotrophic cultivation. The direct utilization of food waste containing essential nutrients from fruits, vegetables, dairy and bakery products, and meat on the heterotrophic growth of microalgae allowed a biomass concentration of 2.2 × 108 cells·mL-1, being the culture able to consume more than 42% of the reducing sugars present in the substrate, thus demonstrating the economic and environmental potential of these wastes.

Response of Pasture Grasses to Organic Fertilizer Produced from Black Soldier Fly Frass

Livestock and dairy farmers are increasingly required to maintain productivity and profitability while mitigating the environmental harm associated with high-input agriculture. Accordingly, to reduce reliance on synthetic fertilizers, a wide range of organically derived products are being evaluated for their effects on sward growth and forage quality. This study used glasshouse experiments to investigate the responses of four grass species to a novel organic fertilizer derived from the mass production of black soldier fly larvae [Hermetia illucens, HexaFrass™, Meath, Ireland]. Although there was some variability among trials, overall our results indicate that application of HexaFrass produced increased shoot growth of Perennial Ryegrass (PRG; Lolium perenne L.), Timothy (Phleum pratense L.), and Cocksfoot (Dactylis glomerata L.) compared with growth achieved in no-fertilizer control plants. In addition to increases in shoot fresh and dry weight, shoot chlorophyll content was also positively related to the HexaFrass application rate. At nitrogen-equivalent application rates, HexaFrass resulted in lower shoot growth compared with the application of urea, suggesting that the nitrogen contained in HexaFrass may not be immediately plant-available. Of relevance to grazing or silage systems, the addition of HexaFrass resulted in increased shoot regrowth of PRG and Timothy after shoots had been cut. Based on our results, insect-frass-based fertilizers may have a role in low input, organic, and/or regenerative pasture-based livestock systems, although issues may occur due to the relatively high costs and low availability compared with other organic soil amendments such as farmyard manure and slurry.

Waste Cooking Oil as Eco-Friendly Rejuvenator for Reclaimed Asphalt Pavement

Over 50 MioT of Waste Cooking Oil (WCO) was collected worldwide in 2020 from domestic and industrial activities, constituting a potential hazard for both water and land environments, and requiring appropriate disposal management strategies. In line with the principles of circular economy and eco-design, in this paper an innovative methodology for the valorisation of WCO as a rejuvenating agent for bitumen 50/70 coming from Reclaimed Asphalt Pavement (RAP) is reported. In particular, WCO or hydrolysed WCO (HWCO) was modified by transesterification or amidation reactions to achieve various WCO esters and amides. All samples were characterised by nuclear magnetic resonance, melting, and boiling point. Since rejuvenating agents for RAP Cold Mix Asphalt require a melting point ≤0 °C, only WCO esters could further be tested. Efficiency of WCO esters was assessed by means of the Asphaltenes Dispersant Test and the Heithaus Parameter. In particular, bitumen blends containing 25 wt% of WCO modified with 2-phenylethyl alcohol, showed high dispersing capacity in n-heptane even after a week, compared to bitumen alone (1 h). Additionally, the Heithaus Parameter of this bitumen blend was almost three times higher than bitumen alone, further demonstrating beneficial effects deriving from the use of WCO esters as rejuvenating agents.

The Effects of Encapsulation on the In Vitro Anti-Clostridial Activity of Olive Mill Wastewater Polyphenolic Extracts: A Promising Strategy to Limit Microbial Growth in Food Systems

Despite the technologies applied to food production, microbial contamination and chemical deterioration are still matters of great concern. In order to limit these phenomena, new natural approaches should be applied. In this context, the present study aimed to assess the antioxidant and anti-Clostridial effects of two different polyphenolic extracts derived from olive mill vegetation water, one liquid (LE) and one encapsulated (EE). The extracts have been preliminary characterized using Liquid Chromatography Quadrupole Time-Of Flight spectrometry. The Oxygen Radical Absorbance Capacity method was used to determine the antioxidant capacity, registering a higher value for EE compared to that for LE (3256 ± 85 and 2446 ± 13 µgTE/g, respectively). The antibacterial activity against C. perfringens, C. botulinum and C. difficile was studied by the agar well diffusion method, MIC and MBC determination and a time-kill test. The results confirm that EE and LE are able to limit microbial growth, albeit with minor effects when the phenolic compounds are encapsulated. Further studies are needed to evaluate the possible application of these extracts in food systems.

Eco-management of end-of-life tires: Advances and challenges for the Ecuadorian case

The aim of this research is to analyse the performance of the extended producer responsibility model for the management of end-of-life tires (ELTs) in Ecuador that has been implemented since 2013. For this research, we conducted case studies of, and subsequently, a comparative analysis between, the ELT management system in Ecuador with respect to the ELT management models in Colombia and Brazil. Our findings show that although the programme implementation represented a significant advance in Ecuador's waste management system there are important challenges that should be considered in future adaptations of the programme. Among the measures that can be adopted to improve the ELT management system are the consolidation and stimulation of the market for products made from ELT waste; promotion of other productive sectors linked to the creation of new products and sectors that generate complementary products; enhancement of the generation, socialization and access to knowledge of the waste by-products for micro-, small- and medium-sized enterprises; increase the tire consumer fee, known as 'Ecovalor' and improvement of the quality and availability of information and indicators regarding ELT management. In this sense, the experiences of Colombia and Brazil show important lessons for the Ecuadorian case.

Optimizing Agroecological Measures for Climate-Resilient Olive Farming in the Mediterranean

In order to evaluate the potential of climate change mitigation measures on soil physiochemical properties, an experiment based on the application of five agroecological practices such as the addition of composted olive-mill wastes, recycling pruning residue, cover crops, organic insect manure, and reduced soil tillage, solely or combined, was conducted over two years (2020 to 2022) in a 48-year-old olive plantation. The results showed significant increases in soil water content during the spring and summer periods for the combined treatment (compost + pruning residue + cover crops) (ALL) compared to the control (CONT) by 41.6% and 51.3%, respectively. Also, ALL expressed the highest soil organic matter (4.33%) compared to CONT (1.65%) at 0-10 cm soil depth. When comparing soil nutrient contents, ALL (37.86 mg kg-1) and cover crops (COVER) (37.21 mg kg-1) had significant increases in soil nitrate compared to CONT (22.90 mg kg-1), the lowest one. Concerning exchangeable potassium, ALL (169.7 mg kg-1) and compost (COMP) (168.7 mg kg-1) were higher than CONT (117.93 mg kg-1) at the 0-10 cm soil depth and had, respectively an increase of 100.9% and 60.7% in calcium content compared to CONT. Over the experimental period, the implementation of the five agroecological management practices resulted in enhanced soil fertility. In a long-term Mediterranean context, this study suggests that these sustainable practices would significantly benefit farmers by improving agroecosystem services, reducing reliance on synthetic fertilizers, optimizing irrigation water use, and ultimately contributing towards a circular economy.

Long-Term Robustness and Failure Mechanisms of Electrochemical Stripping for Wastewater Ammonia Recovery

Nitrogen in wastewater has negative environmental, human health, and economic impacts but can be recovered to reduce the costs and environmental impacts of wastewater treatment and chemical production. To recover ammonia/ammonium (total ammonia nitrogen, TAN) from urine, we operated electrochemical stripping (ECS) for over a month, achieving 83.4 ± 1.5% TAN removal and 73.0 ± 2.9% TAN recovery. With two reactors, we recovered sixteen 500-mL batches (8 L total) of ammonium sulfate (20.9 g/L TAN) approaching commercial fertilizer concentrations (28.4 g/L TAN) and often having >95% purity. While evaluating the operation and maintenance needs, we identified pH, full-cell voltage, product volume, and water flux into the product as informative process monitoring parameters that can be inexpensively and rapidly measured. Characterization of fouled cation exchange and omniphobic membranes informs cleaning and reactor modifications to reduce fouling with organics and calcium/magnesium salts. To evaluate the impact of urine collection and storage on ECS, we conducted experiments with urine at different levels of dilution with flush water, extents of divalent cation precipitation, and degrees of hydrolysis. ECS effectively treated urine under all conditions, but minimizing flush water and ensuring storage until complete hydrolysis would enable energy-efficient TAN recovery. Our experimental results and cost analysis motivate a multifaceted approach to improving ECS's technical and economic viability by extending component lifetimes, decreasing component costs, and reducing energy consumption through material, reactor, and process engineering. In summary, we demonstrated urine treatment as a foothold for electrochemical nutrient recovery from wastewater while supporting the applicability of ECS to seven other wastewaters with widely varying characteristics. Our findings will facilitate the scale-up and deployment of electrochemical nutrient recovery technologies, enabling a circular nitrogen economy that fosters sanitation provision, efficient chemical production, and water resource protection.

Advances in Biological Wastewater Treatment Processes: Focus on Low-Carbon Energy and Resource Recovery in Biorefinery Context

Advancements in biological wastewater treatment with sustainable and circularity approaches have a wide scope of application. Biological wastewater treatment is widely used to remove/recover organic pollutants and nutrients from a diverse wastewater spectrum. However, conventional biological processes face challenges, such as low efficiency, high energy consumption, and the generation of excess sludge. To overcome these limitations, integrated strategies that combine biological treatment with other physical, chemical, or biological methods have been developed and applied in recent years. This review emphasizes the recent advances in integrated strategies for biological wastewater treatment, focusing on their mechanisms, benefits, challenges, and prospects. The review also discusses the potential applications of integrated strategies for diverse wastewater treatment towards green energy and resource recovery, along with low-carbon fuel production. Biological treatment methods, viz., bioremediation, electro-coagulation, electro-flocculation, electro-Fenton, advanced oxidation, electro-oxidation, bioelectrochemical systems, and photo-remediation, are summarized with respect to non-genetically modified metabolic reactions. Different conducting materials (CMs) play a significant role in mass/charge transfer metabolic processes and aid in enhancing fermentation rates. Carbon, metal, and nano-based CMs hybridization in different processes provide favorable conditions to the fermentative biocatalyst and trigger their activity towards overcoming the limitations of the conventional process. The emerging field of nanotechnology provides novel additional opportunities to surmount the constraints of conventional process for enhanced waste remediation and resource valorization. Holistically, integrated strategies are promising alternatives for improving the efficiency and effectiveness of biological wastewater treatment while also contributing to the circular economy and environmental protection.

Thermodynamic model of MSWI flue gas cooling path: Effect of flue gas composition on heavy metal binding forms

In the context of circular economy and heavy metal (HM) recovery from municipal solid waste incineration (MSWI) fly ash (FA), detailed knowledge of HM binding forms is required for achieving higher extraction rates. The FA mineralogy is still poorly understood due to its low grain size and low metal concentration. To investigate the HM binding forms, a sophisticated thermodynamic reactive transport model was developed to simulate ash-forming processes. The stability of different binding forms was investigated at different flue gas conditions (varying ratios of HCl, SO2, O2) by simulating the gas cooling path in closed system and dynamic open system, where the gas composition is changing upon cooling due to precipitation of solids. The simulations predict that at flue gas conditions of molar ratio S/Cl < 1, Cu and Zn precipitate as oxides (and Zn silicates) at approximately 650°C. At temperatures <300°C, Zn, Cu, Pb and Cd are predicted to precipitate as easily soluble chlorides. In flue gas with molar ratio S/Cl > 1, the HM precipitate as less soluble sulphates. The results indicate that the less soluble HM fraction in the electrostatic precipitator ash represent oxides and silicates that formed in the boiler section but were transported to the electrostatic precipitator. The model provides insight into the physical-chemical processes controlling the metal accumulation in the flue gas and FA during the cooling of the flue gas. The obtained data serve as valuable basis for improving metal recovery from MSWI FA.

Chitosan- and gallic acid-based (NPF) displayed antibacterial activity against three Pseudomonas spp. plant pathogens and boosted systemic acquired resistance in kiwifruit and olive plants

BACKGROUD

Pseudomonas syringae pv. actinidiae (Psa), P. syringae pv. tomato (Pst) and P. savastanoi pv. savastanoi (Psav) are bacterial plant pathogens with worldwide impact that are mainly managed by the preventive application of cupric salts. These are dangerous for ecosystems and have favoured the selection of resistant strains, so they are candidates to be replaced in the next few years. Thus, there is an urgent need to find efficient and bio-based solutions to mitigate these bacterial plant diseases. Nanotechnology could represent an innovative way to control plant diseases, providing alternative solutions to the agrochemicals traditionally employed, thanks to the formulation of the so-called third-generation and nanotechnology-based agrochemicals.

RESULTS

In this work, a novel nanostructured formulation (NPF) composed of cellulose nanocrystals (CNC) as carrier, high amylose starch (HAS) as excipient, and chitosan (CH) and gallic acid (GA) as antimicrobials, was tested at 2% in vitro and in vivo with respect to the three different Pseudomonas plant pathogens. In vitro agar assays demonstrated that the NPF inhibited ≤80% Psa, Pst and Psav. Moreover, the NPF did not decrease biofilm synthesis and it did not influence bacterial cells flocculation and adhesion. On plants, the NPF displayed complete biocompatibility and boosted the transcript levels of the major systemic acquired resistance responsive genes in kiwifruit and olive plants.

CONCLUSION

This works provides novel and valuable information regarding the several modes-of-action of the novel NPF, which could potentially be useful to mitigate Psa, Pst and Psav infections even in organic agriculture. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Swine slaughterhouse biowaste: an environmental sustainability assessment of composting, amended soil quality, and phytotoxicity

In this article, the environmental sustainability of a circular economy concept applied to the management of biowaste was studied. To achieve this goal, the composting performance, compost-amended soil health, and phytotoxicity were assessed in the case of management of solid waste from a small swine slaughterhouse. Microorganisms present in a similar composting process were used as inoculums to improve the efficiency of composting. Addition of the inoculum promoted a faster and more efficient composting process than composting without the inoculum. The physical, chemical, and microbiological characteristics of soil were considered to be improved after compost application. Phytotoxicity tests in soils with and without compost amendment showed that a soil-compost mixture (90:10 and 70:30 mass ratios) was not phytotoxic to the plant species Sorghum saccharatum and Lepidium sativum, and that soil with compost showed higher plant biomass growth than that without compost amendment. The triple bottom line methodology used in this study can help in the assessment of circular economy activity in relation to the environmentally sustainable management of solid waste generated in small swine slaughterhouses.

Factors influencing the fate of chemical food safety hazards in the terrestrial circular primary food production system-A comprehensive review

Food safety is recognized as a major hurdle in the transition toward circular food production systems due to the potential reintroduction and accumulation of chemical contaminants in these food systems. Effectively managing these hazardous contaminants in a risk-based manner requires quantitative insights into the factors influencing the presence and fate of contaminants in the entire circular food chain. A systematic literature review was performed to gain an up-to-date overview of the known factors and their influence on the transfer and accumulation of contaminants. This review focused on the terrestrial circular primary food production system, including the pathways between waste- or byproduct-based fertilizers, soil, crops, animal feed, and farmed animals. This review revealed an imbalance in research regarding the different pathways: studies on the soil-to-crop pathway were most abundant. The factors identified can be categorized as compound-related (intrinsic) factors, such as hydrophobicity, molecular weight, and chain length, and extrinsic factors, such as soil organic matter and carbon, pH, milk yield of cows, crop age, and biomass. Quantitative data on the influence of the identified factors were limited. Most studies quantified the influence of individual factors, whereas only a few studies quantified the combined effect of multiple factors. By providing a holistic insight into the influential factors and the quantification of their influence on the fate of contaminants, this review contributes to the improvement of food safety management for chemical hazards when transitioning to a circular food system.

Waste cooking oil and molasses for the sustainable production of extracellular lipase by Saitozyma flava

Organic waste valorization is one of the principal goals of the circular economy. Bioprocesses offer a promising approach to achieve this goal by employing microorganisms to convert organic feedstocks into high value products through their metabolic activities. In this study, a fermentation process for yeast cultivation and extracellular lipase production was developed by utilizing food waste. Lipases are versatile enzymes that can be applied in a wide range of industrial fields, from detergent, leather, and biodiesel production to food and beverage manufacturing. Among several oleaginous yeast species screened, Saitozyma flava was found to exhibit the highest secreted lipase activity on pNP-butyrate, pNP-caproate, and pNP-caprylate. The production medium was composed of molasses, a by-product of the sugar industry, which provided nutrients for yeast biomass formation. At the same time, waste cooking oil was employed to induce and enhance extracellular lipase production. After 48 h of process, 20 g/L of yeast biomass and 150 mU/mgdw of lipase activity were achieved, with a productivity of 3 mU/mgdw /h. The purified lipase from S. flava showed optimal performances at temperature 28°C and pH 8.0, exhibiting a specific activity of 62 U/mg when using p-NPC as substrate.

Sensor-based characterization of construction and demolition waste at high occupancy densities using synthetic training data and deep learning

Sensor-based monitoring of construction and demolition waste (CDW) streams plays an important role in recycling (RC). Extracted knowledge about the composition of a material stream helps identifying RC paths, optimizing processing plants and form the basis for sorting. To enable economical use, it is necessary to ensure robust detection of individual objects even with high material throughput. Conventional algorithms struggle with resulting high occupancy densities and object overlap, making deep learning object detection methods more promising. In this study, different deep learning architectures for object detection (Region-based CNN/Region-based Convolutional Neural Network (Faster R-CNN), You only look once (YOLOv3), Single Shot MultiBox Detector (SSD)) are investigated with respect to their suitability for CDW characterization. A mixture of brick and sand-lime brick is considered as an exemplary waste stream. Particular attention is paid to detection performance with increasing occupancy density and particle overlap. A method for the generation of synthetic training images is presented, which avoids time-consuming manual labelling. By testing the models trained on synthetic data on real images, the success of the method is demonstrated. Requirements for synthetic training data composition, potential improvements and simplifications of different architecture approaches are discussed based on the characteristic of the detection task. In addition, the required inference time of the presented models is investigated to ensure their suitability for use under real-time conditions.

Recycled Waste as Polyurethane Additives or Fillers: Mini-Review

The intensive development of the polyurethanes industry and limited resources (also due to the current geopolitical situation) of the raw materials used so far force the search for new solutions to maintain high economic development. Implementing the principles of a circular economy is an approach aimed at reducing the consumption of natural resources in PU production. This is understood as a method of recovery, including recycling, in which waste is processed into PU, and then re-used and placed on the market in the form of finished sustainable products. The effective use of waste is one of the attributes of the modern economy. Around the world, new ways to process or use recycled materials for polyurethane production are investigated. That is why innovative research is so important, in which development may change the existing thinking about the form of waste recovery. The paper presents the possibilities of recycling waste (such as biochar, bagasse, waste lignin, residual algal cellulose, residual pineapple cellulose, walnut shells, silanized walnut shells, basalt waste, eggshells, chicken feathers, turkey feathers, fiber, fly ash, wood flour, buffing dust, thermoplastic elastomers, thermoplastic polyurethane, ground corncake, Tetra Pak®, coffee grounds, pine seed shells, yerba mate, the bark of Western Red Cedar, coconut husk ash, cuttlebone, glass fibers and mussel shell) as additives or fillers in the formulation of polyurethanes, which can partially or completely replace petrochemical raw materials. Numerous examples of waste applications of one-component polyurethanes have been given. A new unexplored niche for the research on waste recycling for the production of two components has been identified.

A Network of Processes for Biorefining Burdock Seeds and Roots

In this work, a novel sustainable approach was proposed for the integral valorisation of Arctium lappa (burdock) seeds and roots. Firstly, a preliminary recovery of bioactive compounds, including unsaturated fatty acids, was performed. Then, simple sugars (i.e., fructose and sucrose) and phenolic compounds were extracted by using compressed fluids (supercritical CO2 and propane). Consequently, a complete characterisation of raw biomass and extraction residues was carried out to determine the starting chemical composition in terms of residual lipids, proteins, hemicellulose, cellulose, lignin, and ash content. Subsequently, three alternative ways to utilise extraction residues were proposed and successfully tested: (i) enzymatic hydrolysis operated by Cellulases (Thricoderma resei) of raw and residual biomass to glucose, (ii) direct ethanolysis to produce ethyl levulinate; and (iii) pyrolysis to obtain biochar to be used as supports for the synthesis of sulfonated magnetic iron-carbon catalysts (Fe-SMCC) to be applied in the dehydration of fructose for the synthesis of 5-hydroxymethylfurfural (5-HMF). The development of these advanced approaches enabled the full utilisation of this resource through the production of fine chemicals and value-added compounds in line with the principles of the circular economy.

Semi-industrial ultrasound-assisted extraction of grape-seed proteins

BACKGROUND

To manage industrial waste in accordance with the circular bioeconomy concept it is sometimes necessary to handle grape seeds, an abundant by-product of the wine-making process. This study presents a process based on ultrasound technology for the extraction of grape-seed proteins, due to their nutritional and techno-functional properties. The protein content of extracts obtained under silent and lab-scale conditions was compared with that obtained under semi-industrial ultrasound conditions, and the chemical composition (carbohydrates, total phenols, and lipids) and the elemental profiles of the final, up-scaled downstream extracts were characterized.

RESULTS

This work found that the maximum amount of protein in the final product was 378.31 g.kg-1 of the extract. Chemical characterization revealed that each 1 kg of extract had an average content of 326.19 g gallic acid equivalent as total phenols, 162.57 g glucose equivalent as carbohydrates, and 382.76 g of lipophilic compounds. Furthermore, when the extract was checked for hazardous elements, none were found in levels that could be considered a risk for human health.

CONCLUSION

The proposed semi-industrial strategy has the potential to contribute greatly to the valorization of grape seeds through the preparation of a protein-rich extract that can be used as an alternative to synthetic wine stabilizers and for the development of novel food and nutraceutical products. © 2024 Society of Chemical Industry.

Improving Tenebrio molitor Growth and Nutritional Value through Vegetable Waste Supplementation

Huge amounts of vegetable wastes are generated by the food industry. Their bioconversion into valuable products (e.g., insect flours or biofertilizer) through insect farming is a promising solution to reduce their negative environmental and economic impacts. This study evaluates the growth of Tenebrio molitor larvae and their nutritional profile after supplementing their diets with vegetable wastes. Over a 6-week period, 45-day larvae were fed a diet comprising wheat bran supplemented (1:1) with cucumber or tomato wastes from both conventional and ecological crops. The control diet consisted of wheat bran and an equivalent amount of water to compensate for the waste moisture. Larval weight was measured weekly, and length measures were taken fortnightly. Nutritional composition and fatty acid profile were analyzed at the end of the study in 90-day larvae. Regardless of using vegetable waste from conventional or ecological harvesting, the weight of 6-week supplemented larvae almost doubled that of larvae fed with just wheat bran, and their length was 15% higher. Supplementation also increased larval polyunsaturated fatty acid percentage by 22-37%, with linoleic acid being the most abundant. Likewise, larval protein content reached 50% after supplementation. This study demonstrates that both cucumber and tomato wastes from conventional or ecological crops are excellent supplements for T. molitor's diet, improving their nutritional value and reducing the time necessary for larvae growth.

Extraction of High Value Products from Zingiber officinale Roscoe (Ginger) and Utilization of Residual Biomass

Zingiber officinale Roscoe (ginger) is a plant from the Zingiberaceae family, and its extracts have been found to contain several compounds with beneficial bioactivities. Nowadays, the use of environmentally friendly and sustainable extraction methods has attracted considerable interest. The main objective of this study was to evaluate subcritical propane (scPropane), supercritical CO2 (scCO2), and supercritical CO2 with ethanol (scCO2 + EtOH) as co-solvent methods for the extraction of high value products from ginger. In addition, the reuse/recycling of the secondary biomass in a second extraction as a part of the circular economy was evaluated. Both the primary and the secondary biomass led to high yield percentages, ranging from 1.23% to 6.42%. The highest yield was observed in the scCO2 + EtOH, with biomass prior used to scCO2 extraction. All extracts presented with high similarities as far as their total phenolic contents, antioxidant capacity, and chemical composition. The most abundant compounds, identified by the two different gas chromatography-mass spectrometry (GC-MS) systems present, were a-zingiberene, β- sesquiphellandrene, a-farnesene, β-bisabolene, zingerone, gingerol, a-curcumene, and γ-muurolene. Interestingly, the reuse/recycling of the secondary biomass was found to be promising, as the extracts showed high antioxidant capacity and consisted of significant amounts of compounds with beneficial properties.

Mapping the research landscape of bauxite by-products (red mud): An evolutionary perspective from 1995 to 2022

The global population growth has significantly impacted energy and raw material consumption, unmatched since the Industrial Revolution. Among metals, aluminium ranks second only to steel, with annual production exceeding 69 million tonnes. Due to its high demand, bauxite, the primary ore from which aluminium is extracted, is now classified as a critical material in the EU and the US, given the potential risk of supply shortages for essential applications. Geographical and production challenges surround bauxite, presenting geo-economic and environmental challenges. A critical concern in aluminium production is managing by-products, notably red mud, a bauxite residue, generating over 175 million tonnes annually worldwide. Comprehensive bibliometric research is imperative due to the high amount of bibliographical resources related to this topic, encompassing circular economy, re-valorisation, sustainability, and disposal. This study employs bibliometric methods to assess red mud valorisation, offering insights into research topics, influential authors, and key journals, shedding light on the past, present, and future of red mud research. Such bibliometric analysis not only highlights the current state of the field but also serves as a valuable tool for decision-making, enabling researchers and policymakers to identify trends, gaps, and areas for further exploration, fostering informed and sustainable advancements in the by-products of the aluminium industry.

Salicornia ramosissima Biomass as a Partial Replacement of Wheat Meal in Diets for Juvenile European Seabass (Dicentrarchus labrax)

The green tips of Salicornia ramosissima are used for human consumption, while, in a production scenario, the rest of the plant is considered a residue. This study evaluated the potential of incorporating salicornia by-products in diets for juvenile European seabass, partially replacing wheat meal, aspiring to contribute to their valorization. A standard diet and three experimental diets including salicornia in 2.5%, 5% and 10% inclusion levels were tested in triplicate. After 62 days of feeding, no significant differences between treatments were observed in fish growth performances, feeding efficiency and economic conversation ratio. Nutrient digestibility of the experimental diets was unaffected by the inclusion of salicornia when compared to a standard diet. Additionally, salicornia had significant modulatory effects on the fish muscle biochemical profiles, namely by significantly decreasing lactic acid and increasing succinic acid levels, which can potentially signal health-promoting effects for the fish. Increases in DHA levels in fish fed a diet containing 10% salicornia were also shown. Therefore, the results suggest that salicornia by-products are a viable alternative to partially replace wheat meal in diets for juvenile European seabass, contributing to the valorization of a residue and the implementation of a circular economy paradigm in halophyte farming and aquaculture.

Synthetic biology enables mushrooms to meet emerging sustainable challenges

With the increasing sustainability challenges, synthetic biology is offering new possibilities for addressing the emerging problems through the cultivation and fermentation of mushrooms. In this perspective, we aim to provide an overview on the research and applications mushroom synthetic biology, emphasizing the need for increased attention and inclusion of this rapidly advancing field in future mushroom technology over China and other countries. By leveraging synthetic biology, mushrooms are expected to play a more versatile role in various area, including traditional fields like circular economy, human wellness and pharmaceutics, as well as emerging fields like vegan meat, mushroom-based materials and pollution abatement. We are confident that these efforts using synthetic biology strategies have the potential to strengthen our capacity to effectively address sustainable challenges, leading to the development of a more sustainable social economy and ecology.

Evaluation of Growth Performance and Environmental Impact of Hermetia illucens Larvae Reared on Coffee Silverskins Enriched with Schizochytrium limacinum or Isochrysis galbana Microalgae

Hermetia illucens is a promising insect due to its ability to convert low-value substrates as food chain by-products into highly nutritious feed. Its feeding and nutrition are important issues. The aim of this work was to investigate the effect of different substrates consisting of coffee silverskin, a by-product of the roasting process, enriched with different inclusions of microalgae (5%, 10%, 20%, and 25%), Schizochytrium limacinum, and Isochrysis galbana, combined with the assessment of environmental sustainability by LCA. In general, the addition of microalgae led to an increase in larval growth performance due to the higher content of protein and lipids, although S. limacinum showed the best results with respect to larvae fed with coffee silverskin enriched with I. galbana. A higher prepupal weight was observed in larvae fed with 10%, 20%, and 25% S. limacinum; shorter development times in larvae fed with 25% of both S. limacinum and I. galbana; and a higher growth rate in larvae fed with 25% S. limacinum. The 10% S. limacinum inclusion was only slightly different from the higher inclusions. Furthermore, 10% of S. limacinum achieved the best waste reduction index. The greater the inclusion of microalgae, the greater the environmental impact of larval production. Therefore, the addition of 10% S. limacinum appears to be the best compromise for larval rearing, especially considering that a higher inclusion of microalgae did not yield additional benefits in terms of the nutritional value of H. illucens prepupae.

Component-Level Residential Building Material Stock Characterization Using Computer Vision Techniques

Residential building material stock constitutes a significant part of the built environment, providing crucial shelter and habitat services. The hypothesis concerning stock mass and composition has garnered considerable attention over the past decade. While previous research has mainly focused on the spatial analysis of building masses, it often neglected the component-level stock analysis or where heavy labor cost for onsite survey is required. This paper presents a novel approach for efficient component-level residential building stock accounting in the United Kingdom, utilizing drive-by street view images and building footprint data. We assessed four major construction materials: brick, stone, mortar, and glass. Compared to traditional approaches that utilize surveyed material intensity data, the developed method employs automatically extracted physical dimensions of building components incorporating predicted material types to calculate material mass. This not only improves efficiency but also enhances accuracy in managing the heterogeneity of building structures. The results revealed error rates of 5 and 22% for mortar and glass mass estimations and 8 and 7% for brick and stone mass estimations, with known wall types. These findings represent significant advancements in building material stock characterization and suggest that our approach has considerable potential for further research and practical applications. Especially, our method establishes a basis for evaluating the potential of component-level material reuse, serving the objectives of a circular economy.

Phospholipase D Immobilization on Lignin Nanoparticles for Enzymatic Transformation of Phospholipids

Lignin nanoparticles (LNPs) are promising components for various materials, given their controllable particle size and spherical shape. However, their origin from supramolecular aggregation has limited the applicability of LNPs as recoverable templates for immobilization of enzymes. In this study, we show that stabilized LNPs are highly promising for the immobilization of phospholipase D (PLD), the enzyme involved in the biocatalytic production of high-value polar head modified phospholipids of commercial interest, phosphatidylglycerol, phosphatidylserine and phosphatidylethanolamine. Starting from hydroxymethylated lignin, LNPs were prepared and successively hydrothermally treated to obtain c-HLNPs with high resistance to organic solvents and a wide range of pH values, covering the conditions for enzymatic reactions and enzyme recovery. The immobilization of PLD on c-HLNPs (PLD-c-HLNPs) was achieved through direct adsorption. We then successfully exploited this new enzymatic preparation in the preparation of pure polar head modified phospholipids with high yields (60-90 %). Furthermore, the high stability of PLD-c-HLNPs allows recycling for a number of reactions with appreciable maintenance of its catalytic activity. Thus, PLD-c-HLNPs can be regarded as a new, chemically stable, recyclable and user-friendly biocatalyst, based on a biobased inexpensive scaffold, to be employed in sustainable chemical processes for synthesis of value-added phospholipids.

Repurposing Kraft black Liquor as Reductant for Enhanced Lithium-Ion Battery Leaching

The economic advantages of H2 SO4 make it the acid of choice for the hydrometallurgical treatment of waste lithium-ion batteries (LIBs). However, to facilitate the full dissolution of the higher valency metal oxides present in the cathode black mass, a suitable reducing agent is required. Herein, the application of industrial black liquor (BL) obtained from the Kraft pulping for papermaking is investigated as a renewable reducing agent for the enhanced leaching of transition metals from LIB powder with H2 SO4 . The addition of acidified BL to H2 SO4 significantly improved the leaching efficiency for a range of LIB cathode chemistries, with the strongest effect observed for manganese-rich active material. Focusing on NMC111 (LiMnx Coy Niz O2 ) material, a linear correlation between the BL concentration and the leaching yield of Mn was obtained, with the best overall leaching efficiencies being achieved for 2.0 mol L-1 H2 SO4 and 50 vol % of BL at 353 K. A quasi-total degradation of oxygenated and aromatic groups from the BL during NMC111 dissolution was observed after leaching, suggesting that these chemical groups are essential for LIB reduction. Finally, the leached transition metals could be easily recovered by pH adjustment and oxalic acid addition, closing the resource loop and fostering resource efficiency.

Biochar as Alternative Material for Heavy Metal Adsorption from Groundwaters: Lab-Scale (Column) Experiment Review

The purpose of this manuscript is to present a review of laboratory experiments (including methodology and results) that use biochar, a specific carbon obtained by a pyrolysis process from different feedstocks, as an alternative material for heavy metal adsorption from groundwater. In recent years, many studies have been conducted regarding the application of innovative materials to water decontamination to develop a more sustainable approach to remediation processes. The use of biochar for groundwater remediation has particularly attracted the interest of researchers because it permits the reuse of materials that would be otherwise disposed of, in accordance with circular economy, and reduces the generation of greenhouse gases if compared to the use of virgin materials. A review of the different approaches and results reported in the current literature could be useful because when applying remediation technologies at the field scale, a preliminary phase in which the suitability of the adsorbent is evaluated at the lab scale is often necessary. This paper is therefore organised with a short description of the involved metals and of the biochar production and composition. A comprehensive analysis of the current knowledge related to the use of biochar in groundwater remediation at the laboratory scale to obtain the characteristic parameters of the process that are necessary for the upscaling of the technology at the field scale is also presented. An overview of the results achieved using different experimental conditions, such as the chemical properties and dosage of biochar as well as heavy metal concentrations with their different values of pH, is reported. At the end, numerical studies useful for the interpretation of the experiment results are introduced.

Rubber Compounds from Devulcanized Ground Tire Rubber: Recipe Formulation and Characterization

In this study, our focus was on developing and investigating rubber recipes that are suitable for devulcanized ground tire rubber (dGTR). Devulcanized rubber has a powdery or sticky uncured rubber-like appearance depending on the extent of main-chain degradation that occurs with selective crosslinking scission. Still, it has a significantly shorter scorch time than a new rubber compound. Therefore, our primary goal was to slow down the vulcanization process of dGTR and improve its mechanical properties via recipe development. We formulated several recipes (sulfur-, peroxide-, and phenolic resin-based) and studied the vulcanization process and the main properties of the revulcanized rubber sheets. We observed that the vulcanization process could be altered with different vulcanization methods: using peroxide and vulcanizing resin extended the process significantly. Peroxide vulcanization also provided enhanced elongation compared to sulfuric systems. With a balance of properties in mind, we selected a semi-efficient sulfur-based recipe and studied the characteristics of natural rubber/dGTR mixtures with the help of plasticizer oils. We successfully replaced a notable portion of natural rubber with dGTR, maintaining its properties without much compromise.

Immobilizing white-rot fungi laccase: Toward bio-derived supports as a circular economy approach in organochlorine removal

Despite their high persistence in the environment, organochlorines (OC) are widely used in the pharmaceutical industry, in plastics, and in the manufacture of pesticides, among other applications. These compounds and the byproducts of their decomposition deserve attention and efficient proposals for their treatment. Among sustainable alternatives, the use of ligninolytic enzymes (LEs) from fungi stands out, as these molecules can catalyze the transformation of a wide range of pollutants. Among LEs, laccases (Lac) are known for their efficiency as biocatalysts in the conversion of organic pollutants. Their application in biotechnological processes is possible, but the enzymes are often unstable and difficult to recover after use, driving up costs. Immobilization of enzymes on a matrix (support or solid carrier) allows recovery and stabilization of this catalytic capacity. Agricultural residual biomass is a passive environmental asset. Although underestimated and still treated as an undesirable component, residual biomass can be used as a low-cost adsorbent and as a support for the immobilization of enzymes. In this review, the adsorption capacity and immobilization of fungal Lac on supports made from residual biomass, including compounds such as biochar, for the removal of OC compounds are analyzed and compared with the use of synthetic supports. A qualitative and quantitative comparison of the reported results was made. In this context, the use of peanut shells is highlighted in view of the increasing peanut production worldwide. The linkage of methods with circular economy approaches that can be applied in practice is discussed.

Unveiling the bioactivity and bioaccessibility of phenolic compounds from organic coffee husks using an in vitro digestion model

BACKGROUND

The large quantities of by-products generated in the coffee industry are a problem. Studies related to the biological potential of organic coffee husks are still limited. The aim of this work was to investigate the occurrence of phenolic compounds in organic coffee husks and to evaluate their potential as a source of bioactive dietary components.

RESULTS

To achieve this objective, three extracts were prepared, namely extractable polyphenols (EPs), hydrolyzable non-extractable polyphenols (H-NEPs), and non-extractable polyphenols (NEPs). These extracts were characterized and evaluated for their bioactive properties after simulated gastrointestinal digestion. The results show that the extraction process affected the occurrence of phenols from coffee peels, especially for caffeic acid, gallic acid, and chlorogenic acid. The free and bound polyphenols found in the extracts and digests not only showed antioxidant properties against 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals but were also strongly bioavailable and had good anticoagulant potential.

CONCLUSION

These results highlight the potential health benefits of phytochemicals from coffee husks and open new perspectives for the use of such compounds in dietary supplements. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Evaluation of hydrochar from peach stones for caffeine removal from aqueous medium and treatment of a synthetic mixture

The presence of micropollutants, such as caffeine (CAF), has been detected throughout the world, since conventional treatment plants are not able to properly degrade them. CAF is a widely consumed stimulant, and has been demanding the development of efficient methodologies for its removal. Aiming at the agriculture waste valorization, a new hydrochar was developed based on chemical and thermal modification of peach stones (mod-PS) for CAF removal from water and from a synthetic mixture. The morphology, functional groups and surface electrical charge of the adsorbent were characterized by SEM, FTIR and zeta potential, respectively. Regarding CAF adsorption performance, the equilibrium time was reached at 480 min and the pseudo-second-order model presented the best fit for the experimental data. The maximum adsorption capacity was 68.39 mg g-1 (298 K) and the Langmuir model exhibited a better fit for the isothermal data. The thermodynamic properties confirmed that the process was exothermic, spontaneous and reversible. The main adsorption mechanisms were hydrogen bonds and π-interactions. The global removal efficiency was satisfactory in the synthetic mixture simulating real wastewater (67%). Therefore, the proposed new hydrochar has potential application as a low-cost adsorbent for CAF removal.

Legacy and Emerging Plasticizers and Stabilizers in PVC Floorings and Implications for Recycling

Hazardous chemicals in building and construction plastics can lead to health risks due to indoor exposure and may contaminate recycled materials. We systematically sampled new polyvinyl chloride floorings on the Swiss market (n = 151). We performed elemental analysis by X-ray fluorescence, targeted and suspect gas chromatography-mass spectrometry analysis of ortho-phthalates and alternative plasticizers, and bioassay tests for cytotoxicity and oxidative stress, and endocrine, mutagenic, and genotoxic activities (for selected samples). Surprisingly, 16% of the samples contained regulated chemicals above 0.1 wt %, mainly lead and bis(2-ethylhexyl) phthalate (DEHP). Their presence is likely related to the use of recycled PVC in new flooring, highlighting that uncontrolled recycling can delay the phase-out of hazardous chemicals. Besides DEHP, 29% of the samples contained other ortho-phthalates (mainly diisononyl and diisodecyl phthalates, DiNP and DiDP) above 0.1 wt %, and 17% of the samples indicated a potential to cause biological effects. Considering some overlap between these groups, they together make up an additional 35% of the samples of potential concern. Moreover, both suspect screening and bioassay results indicate the presence of additional potentially hazardous substances. Overall, our study highlights the urgent need to accelerate the phase-out of hazardous substances, increase the transparency of chemical compositions in plastics to protect human and ecosystem health, and enable the transition to a safe and sustainable circular economy.

Waste to energy, indispensable cornerstone for circular economy: A mini-review

This mini-review aims at proving that waste-to-energy (WtE) is an essential cornerstone for circular economy (CE). Based on literature, the history of thermal waste treatment over the last 150 years is investigated, from open burning to WtE with resource recovery and final sink function. The results show that in the past incineration solved the issues it was designed for but often created new and sometimes even worse problems: The introduction of incineration in the 19th century improved urban sanitation, decreased waste volume and prolonged operational life of landfills. But it also polluted the environment, triggering an unprecedented scientific and engineering effort of all stakeholders. Today, WtE is one of the best investigated and optimized technologies in waste management. It enables the recovery of energy as heat and electric power and facilitates the 'cleaning' of cycles by the destruction of hazardous organic substances. Recent developments in resource recovery from WtE residues allow to recycle metals and, in the case of sewage sludge, even phosphorus by thermal recycling. Combined with carbon capture and storage technology, WtE stands for a quantifiable contribution to greenhouse gas reduction. Today, WtE is indispensable to reach the goals of CE, namely recycling of energy and materials, supplying safe final sinks for persistent organic substances and minimizing the need for sinks for hazardous inorganic substances.

Eco-Design and Characterization of Sustainable Lightweight Gypsum Composites for Panel Manufacturing including End-of-Life Tyre Wastes

The incorporation of rubber recycled aggregates from end-of-life tyres (ELT) in the manufacturing process of sustainable building materials has gained great interest in recent decades as a result of the large volume of this waste being generated annually. In this work, the objective is to make a contribution towards the circularity of construction products by carrying out a physico-mechanical characterisation of new gypsum composites made with the incorporation of these recycled rubber aggregates. To this end, up to 30% by volume of the original raw material has been substituted, analysing the mechanical resistance to bending and compression. Although lower than those of traditional gypsum material, both properties exceed the limits set at 1 and 2 MPa, respectively, by the current regulations. In addition, water absorption by capillarity significantly decreases, and thermal conductivity is reduced by more than 35% with respect to the reference material. Finally, in order to provide the research with a practical application, a prefabricated plate design has been proposed that incorporates the gypsum materials studied and an agglomerated rubber band that increases the thermal resistance and improves the efficiency of the designed construction system. In this way, this research reflects the potential of these novel building materials and explores new avenues for their application in building construction.

Formulation of Antioxidant Gummies Based on Gelatin Enriched with Citrus Fruit Peels Extract

In this work, the peels of red and blonde oranges as well as lemons were efficiently (5.75-9.65% yield) extracted by hydroalcoholic solution with ultrasound assistance and employed as active molecule sources in the preparation of functional gummies. Antioxidant performances of the hydroalcoholic extracts were characterized by colorimetric assays, whereas LC-HRMS analyses identified the main bioactive compounds (phenolic acids and flavonoids). The highest scavenging activity was recorded for lemon extract in an aqueous environment (IC50 = 0.081 mg mL-1). An ecofriendly grafting procedure was performed to anchor polyphenols to gelatin chains, providing macromolecular systems characterized by thermal analysis and antioxidant properties. Scavenger abilities (IC50 = 0.201-0.454 mg mL-1) allowed the employment of the conjugates as functional ingredients in the preparation of gummies with remarkable antioxidant and rheological properties over time (14 days). These findings confirmed the possible employment of highly polluting wastes as valuable sources of bioactive compounds for functional gummies preparation.

Blueberry Pruning Wastes: From an Undervalued Agricultural Residue to a Safe and Valuable Source of Antioxidant Compounds for the Food Industry

Blueberry fruits have been widely explored for their rich composition of bioactive compounds with recognized health benefits. In contrast, blueberry pruning waste (BPW), generated during the pruning stages of blueberries, has been typically overlooked, even though it can represent a potential source of natural antioxidants. This study aims to characterize the value-added compounds extracted from BPW using green techniques, namely microwave-assisted and subcritical water extraction. The total phenolic content ranged from 157 ± 5 to 335 ± 12 mg GAE/g dw, while the radical scavenging activity determined by a DPPH assay varied from 223 ± 21 to 453 ± 21 mg Trolox equivalents/g dw. Additionally, to ensure the safe application of BPW and its extracts, a screening of pesticides and several environmental contaminants was conducted. Chlorpyrifos-methyl was quantified at a concentration of 4.27 µg/kg in a Bluecrop variety collected in 2019; however, none of the studied compounds were found in the extracts. Despite the presence of a pesticide, this level was below the maximum residue limits for blueberry crops. The results of this study demonstrated the potential of this agro-industrial residue as a natural source of bioactive compounds with high antioxidant activity for food industry applications.

Raw and Pre-Treated Styrene Butadiene Rubber (SBR) Dust as a Partial Replacement for Natural Sand in Mortars

The circular economy (CE) is widely known for its emphasis on reducing waste and maximizing the use of resources by reusing, recycling, and repurposing materials to create a sustainable and efficient system. The CE is based on 3R-reuse, reduce, and recycle. The aim of this article is to use styrene butadiene rubber dust (SBR) in building material, constituting secondary waste in the production of SBR, which is currently disposed of as landfill. SBR is partly intended to replace the natural raw material sand. The purpose of the final material is to use it for its light weight, insulating properties, or ability to absorb vibrations and sounds. Various shares of SBR dust in mortars were tested. Some of the mortars used SBR thermal pre-treatment at temperatures of 200, 275, and 350 °C. The strength and SEM results are presented. The best pre-treatment for SBR dust is thermal treatment at 275 °C. The maximum usage of rubber dust with thermal treatment is 60% as a sand substitute. The novel finding of this study is the possibility to use more than 30% rubber dust (as a substitute for sand) thanks to pre-treatment, whereby 30% is a common maximum ratio in mortars.

Four-decades evolutionary development of municipal solid waste management in China: Implications for sustainable waste management and circular economy

This study collected data on waste generation and management in China between 1979 and 2020 from government statistics and literature and reviewed the development of municipal solid waste (MSW) management in China. The extended stochastic impact by regression on population, affluence and technology (STIRPAT) model was employed to identify the driving forces of MSW generation, and the cointegration analysis showed that economy (0.35, t = -3.47), industrial structure (3.34, t = -20.77) and urbanization (-1.5, t = 5.678) were the significant socioeconomic driving forces in the long run. By employing the framework of evolutionary economics, this study then investigated the internal rules of long-term interaction between socioeconomic factors and MSW management. The results indicate that, in the long run, MSW management development can be viewed as an evolutionary process that includes a continuous adaptation to external socioeconomic factors and the co-evolution of internal institutions and technologies. Adaptation and diversity of institutions and technologies play an important role in achieving sustainable waste management and circular economy (CE). This study offers a novel evolutionary perspective for explaining dynamic changes of MSW management in China, as well as recommendations for emerging economies to achieve sustainable waste management and CE goals.