Search Results (72)

Spent coffee grounds (SCGs) are one of the most abundant agro-industrial by-products worldwide, with 650 kg generated per ton of green coffee processed, corresponding to an estimated global production of 6.7 million tons in 2022/2023. Improper disposal of SCG raises environmental concerns, while their reuse offers opportunities for sustainable resource management and circular economy strategies. This review examines SCG valorization by addressing their chemical composition, functional properties, and key applications in sectors such as food, agriculture, environmental remediation, bioenergy, and selected industrial fields, including pharmaceuticals, cosmetics, construction materials, and functional devices. In this context, it discusses technological approaches, performance outcomes, and implementation considerations, emphasizing the multifunctional potential of SCGs as a renewable feedstock capable of reducing waste, improving resource efficiency, and generating economic value. By consolidating the current state of knowledge and exploring diverse valorization pathways, this work frames SCG utilization within a circular bioeconomy framework and highlights how innovative applications can transform this widely available waste into sustainable and economically valuable products. Full article

The large-scale generation of industrial waste salts (IWSs) across sectors such as coal chemical, pesticide, pharmaceutical, and dye manufacturing has raised increasing environmental and regulatory concerns. These IWSs often exhibit complex physicochemical profiles—featuring high concentrations of inorganic salts, persistent organic pollutants, and trace heavy metals—that pose significant challenges for both safe disposal and resource recovery. This review provides a comprehensive and pollutant-oriented overview of industrial waste salts, focusing on their sector-specific characteristics, dominant contaminant types, and tailored treatment strategies. Removal pathways for organic matter (e.g., thermal decomposition, advanced oxidation) and inorganic impurities (e.g., precipitation, ion exchange) are systematically analyzed, followed by technical pathways for salt separation based on crystallization and membrane processes. Resource utilization routes for major salt components, particularly NaCl and Na₂SO₄, are critically assessed in terms of technical feasibility, impurity tolerance, and end-use compatibility. The emergence of reclaimed salt quality standards and sector-specific impurity thresholds reflects a paradigm shift from purity-based to performance-based reuse evaluation. Finally, the review highlights future priorities including adaptive impurity control, downstream-specific salt grading, and enforceable regulatory frameworks to ensure the safe, scalable, and circular deployment of reclaimed salts in industrial systems. This study supports the coordinated advancement of control technologies and reuse standards, enabling the transformation of waste salts from environmental liabilities to secondary resources. Full article

One of the major current societal challenges concerns the reuse of waste materials and valuable substances to mitigate the environmental impact of human activities, which has led to the increasing release of pollutants, from plastics to pharmaceuticals. In this study, we report a simple recycling strategy for surgical masks to obtain an activated carbon-like material, suitable for the solid-phase extraction (SPE) of Phthalic acid esters (PAEss) from plastic bottled water. The sorbent was produced by high-temperature calcination after sulfuric acid treatment to enhance the thermal stability of polypropylene. The sorbent was characterized by thermal analysis, Raman spectroscopy, FTIR and scanning electron microscopy. SPE was used to preconcentrate the analytes, and the main parameters affecting the extraction, such as pH, sorbent amount, organic modifier percentage, ionic strength and elution volume, were optimized. PAEs were determined by UHPLC-PDA under gradient elution. The developed method was linear in the range 0.25–1000 ng/mL, with LOQs between 0.25 and 0.10 ng/mL and LODs between 0.008 and 0.003 ng/mL. Recovery ranged from 95.9 to 104.7%, the precision expressed as RSD% was below 7.32, and the accuracy expressed as BIAS% ranged from −5.75 to 5.93. The proposed approach provides a simple and low-cost valorization route for PPE waste, while enabling reliable PAEs analysis in drinking water. Full article

Coffee is the second most widely traded commodity worldwide. This makes the management and valorization of waste generated during its production and brewing of considerable importance. Spent coffee grounds (SCG), the residue remaining after coffee brewing, account for approximately seven million tons of waste produced annually. Due to their nutrient-rich composition, SCG have significant potential for reuse in various sectors. This review briefly examines SCG’s applications as nutritional additives and flavoring agents in the food industry; as sorbent materials for removing chemical contaminants from water and air; as UV-protective and hydrating ingredients in cosmetics; and as a source of bioactive compounds with health-promoting properties in the pharmaceutical industry. Full article

Circular economy emphasizes sustainability and resource efficiency by extending product life cycles and minimizing waste. This study explores the reuse of polyamide press felts from the paper industry for removing endocrine disruptors (EDCs) from water, aligning with circular economy principles. EDCs, as defined by the WHO, are external substances that disrupt endocrine functions and can cause adverse health effects even at very low concentrations. Common EDCs include industrial chemicals, pesticides, pharmaceuticals, and natural hormones, with bisphenol A (BPA) and 17β-estradiol (E2) being particularly problematic in water due to their health risks. Polyamide, valued for its strength and durability, is widely used in press felts but becomes waste after its industrial use. Reusing these felts is both environmentally and economically beneficial, as the production of polyamide involves high costs and significant impacts. This study investigates the adsorption capacity of polyamide felts for BPA and E2, a process favored for its simplicity, cost-effectiveness, and efficiency in water treatment. Results show that polyamide felts achieve a 75% initial deposition efficiency, adsorbing up to 135 μg BPA and 130 μg E2 per gram of felt. Thus, reusing polyamide felts effectively reduces EDCs in water, supporting water security and advancing the circular economy. Full article

Wastewater treatment plants (WWTPs) have been identified as the major sources of contaminants of emerging concern (CECs) in water bodies, as they are not designed to remove organic micropollutants efficiently. Consequently, many technologies have been explored for WWTP upgrading, including activated carbon adsorption. However, the high production cost and environmental challenges associated with activated carbon production limit its application in industrial settings. Therefore, a wide range of alternative materials has been investigated as potential replacements. In this study, biochar produced from waste raspberry biomass was evaluated as an adsorbent for the removal of pharmaceuticals and pesticides quantified in the secondary effluent of municipal WWTP. The results showed that the biochar efficiently removed almost all detected compounds, except for three compounds (clarithromycin, propranolol, and linuron). The wastewater pH (6–8) did not significantly affect removal efficiency significantly, and kinetic tests demonstrated rapid adsorption. The potential for biochar reuse was confirmed through three consecutive batch adsorption cycles. A comparative study between biochar and powdered activated carbon (PAC) revealed some differences in efficiency, primarily attributed to the larger surface area of PAC. π-π interactions, hydrogen bonding, and pore-filling were proposed as possible adsorption mechanisms based on the adsorption efficiency and biochar characterization. Full article

The agro-industrial sector is a key pillar of the global economy, playing a central role in the supply of food, energy, and industrial inputs. However, its production chain generates significant amounts of residues and by-products, which, if not properly managed, may cause considerable environmental impacts. In this context, the search for alternatives to reuse these materials is essential, particularly when they can be converted into high-value products. One promising application is their use as a nutrient source for microorganisms in high-value biotechnological processes, such as the production of L-Asparaginase, an important enzyme used both in mitigating acrylamide formation in foods and as a biopharmaceutical in Acute Lymphoblastic Leukemia therapy. This approach offers a sustainable and competitive pathway, combining robust, scalable, and economical enzyme production with waste valorization and circular economy benefits. Although interest in developing more sustainable processes is growing, supported by international agreements and strategies for the valorization of agricultural residues, important challenges remain. The variability and impurity of residues pose significant challenges for producing biological products for the pharmaceutical and food industries. In addition, meeting regulatory requirements is essential to ensure product safety and traceability, while achieving high yields is crucial to maintain production viability compared to conventional media. Overcoming these barriers is critical to enable industrial-scale application of this approach. This review provides a residue-centered revision of the most relevant agro-industrial by-products used as substrates for L-asparaginase production, systematically comparing their compositional characteristics, fermentation strategies, and reported yields. Additionally, we present a novel SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis that critically examines the technical, regulatory, and economic challenges of implementing residue-based processes on an industrial scale. Full article

Regenerative combustion represents an efficient and energy-saving combustion technology that significantly enhances thermal efficiency, reduces energy consumption, and minimizes pollutant emissions by recovering and reusing heat energy. This technology has found extensive applications in traditional industries, such as chemical engineering, coating, and printing, as well as in contemporary fields, including food processing and pharmaceuticals. In recent years, advancements in the optimization of combustion devices and the development of efficient catalysts have successfully reduced the combustion temperature for treating organic waste gases while simultaneously improving pollutant removal efficiency. This paper reviews the current status of regenerative combustion technology, summarizes key achievements, analyzes the challenges faced in industrial applications, and anticipates future research directions. Full article

The current paper examines the sustainable possibility for recycling unused or expired Metoprolol (MET), a benzodiazepine derivative, as an effective corrosion inhibitor for carbon steel in saline solutions. Repurposing expired medicinal drugs aligns with green chemistry concepts and supports circular economy initiatives by reducing pharmaceutical waste and averting the production of new synthetic inhibitors. The technical benefit of recycling expired MET drugs pertains to the elimination of costs associated with organic inhibitor manufacturing and the decrease in disposal expenses for the expired medication. A combination of electrochemical techniques (potentiodynamic polarization and electrochemical impedance spectroscopy) and quantum chemical calculations was employed to evaluate the inhibitory mechanism and efficacy of MET. At a concentration of 10⁻³ M, MET reduced the corrosion current density from 19.38 to 5.97 μA cm⁻², achieving a maximum IE of 69.1%. Adsorption Gibbs free energy, determined using different adsorption isotherms, revealed that interactions between metal atoms and MET adsorbed molecules have a chemical character with a ∆G^o_ads value of −50.7 kJ·mol⁻¹. Furthermore, quantum chemistry calculations indicate that the investigated drug, owing to its molecular structure (E_HOMO = −9.12 eV, E_LUMO = 0.21 eV, µ = 3.95 D), possesses the capacity to establish an adsorption layer on the metal surface, thereby impeding the diffusion of molecules and ions involved in the overall corrosion process. The results obtained using the different techniques were in good agreement and highlighted the effectiveness of MET in the corrosion inhibition of carbon steel. Full article

The ever-increasing importance of sustainable environmental remediation calls for academics’ contribution to satisfy such a need. The 3R’s criteria of recover, recycle and reuse is designed to sustain the waste stream to produce a valuable product. In this regard, the circular economy looks to deliver banana peel waste as a photocatalyst for pharmaceutical effluent oxidation, which we investigated in this study. Banana peel waste is treated thermally and chemically then augmented with magnetite nanoparticles and labeled as ACBP-Fe₃O₄. The mixture is characterized through Scanning Electron Microscopy (SEM) and the composition of the composite material is attained by energy dispersive X-ray spectroscopy (EDX), and then introduced as a Fenton catalyst. The notable oxidation of tetracycline (TC), evaluated by TC removal and chemical Oxygen Demand (COD) oxidation tenancy, is achieved. The effectiveness of the operational parameters is also assessed and the most influenced parameters are optimized through numerical optimization based on a Response Surface Methodology (RSM) tool. The effects of initial pH value, ACBP-Fe₃O₄ and H₂O₂ concentrations on the oxidation efficiency of the Tetracycline were optimized at pH 6.6 and 350 mg/L and 43 g/L for H₂O₂ and ACBP-Fe₃O₄, respectively. Thermodynamics and kinetics were also studied and the experimental and model data revealed the reaction is spontaneous and exothermic in nature and follows the first-order reaction kinetics. Also, the thermodynamic results the reaction proceeds at a low energy barrier of 34.33 kJ mol⁻¹. Such a system introduces the role of engineers and academics for a sustainable world without a waste stream. Full article

Tepals of the Crocus sativus flower constitute the most abundant floral residue during saffron production (350 kg tepals/kg stigmas). Being a natural source of polyphenols with antioxidant properties, they can be reused to create potentially valuable products for pharmaceutical applications, generating a new income source while reducing agricultural bio-waste. In this work, composite hydrogels based on blends of pectin and gellan gum containing Crocus sativus tepal extract (CSE) have been proposed for the regeneration and healing of cutaneous wounds, exploiting the antioxidant properties of CSE. Various physico-chemical and mechanical characterizations were performed. The skin permeation of CSE was investigated using Franz cell diffusion system. The composite films were cytocompatible and able to counteract the increase in ROS, restore the production of matrix proteins, and favor wound closure. To conclude, CSE-loaded composite films represent a promising strategy to promote the body’s natural healing process. In addition, by reusing saffron tepals, not only can we develop new, sustainable treatments for skin diseases, but we can also reduce agricultural waste. Full article

Reducing agricultural waste through reuse has become one of the most important strategies to minimise impact on the environment—an emerging global issue. Sunflower ranks fourth in the world in the production of vegetable oilseeds and therefore generates large amounts of agricultural waste. The aim of this study was to investigate the phytochemical composition and bioactivity of sunflower crop residues in order to open up new opportunities for waste management. TPC and TFC were determined spectrophotometrically, while the dominant compounds were identified by LC-DAD-ESI-MS as ent-kaur-16-en-19-oic acid (KA) and 6Ac-7OH-dimethylchromone (DMC). Both compounds were present in higher concentrations in the ethyl acetate fraction (245.5 and 16.8 mg/g, respectively) than in the ethanol extract. None of the tested samples showed antimicrobial effects in the microdilution test. DMC showed remarkable antioxidant activity by DPPH, ABTS, FRAP and TRC in vitro assays, while both compounds proved to be promising enzyme inhibitory agents, being particularly efficient in inhibiting anti-neurodegenerative enzymes (IC₅₀ values of DMC and KA were 1.20/1.37 mg/mL and 1.44/1.63 mg/mL for AChE/BChE, respectively) and tyrosinase. The results presented indicate that sunflower crop residues are a good candidate for the extraction of bioactive compounds with potential application in the food, pharmaceutical and cosmetic industries. Full article

Contaminants of emerging concern (CECs) in water, including pharmaceuticals and personal care products, represent a significant threat to environmental and human health. In this context, the electro-Fenton (EF) process has emerged as a highly effective technique for the removal of such pollutants. This study investigates the innovative use of tea waste material (TWM) in combination with copper-iron nanoparticles (FeCuNPs) to degrade a mixture of CECs. A central aspect of this research is the sustainable reuse of organic waste material, such as TWM, to support catalytic nanoparticles. This approach not only utilizes a resource that would otherwise be discarded but also promotes sustainability in the treatment of contaminated water, aligning with the principles of the circular economy. The as-prepared FeCuNPs@TWM catalyst was fully characterized, and critical parameters influencing the pollutant removal were assessed, including adsorption capacity, catalyst load, and applied current. Under optimized conditions, the EF process, enhanced by FeCuNPs@TWM, achieved complete degradation of the contaminants within 15 min of the electrochemical process, and the activity remained after five catalytic cycles. Results demonstrate that using tea waste functionalized with FeCu nanoparticles as a catalyst not only improves the efficiency of the EF process but also offers an eco-friendly and cost-effective alternative. Full article

The growth of the human population worldwide has increased food demand, generating the massive production of foods and consequently causing enormous production of waste every year. The indiscriminate exploitation of the already limited natural resources has also generated serious environmental and economic crises. The use, or reuse, of waste or by-products represents a viable solution to constrain the problem by promoting alternative routes of exploitation with multiple food and biotechnological applications. This review focuses on the most recent advances in the valorization of food by-products, with specific reference to legume-derived by-products. The main technological solutions for reintroducing and/or valorizing food waste are reported together with a critical discussion of the main pros and cons of each alternative, supported by practical case studies whenever available. First, the possibility to exploit the by-products as valuable sources of functional compounds is presented by reviewing both conventional and innovative extraction techniques tailored to provide functional extracts with multiple food, pharmaceutical, and biotechnological applications. Second, the possibility to valorize the by-products as novel food ingredients by inclusion in different formulations, either as a whole or as hydrolyzed/fermented derivatives, is also presented and discussed. To the best of our knowledge, several of the technological solutions discussed have found only limited applications for waste or by-products derived from the legume production chain; therefore, great efforts are still required to gain the full advantages of the intrinsic potential of pulse by-products. Full article

Solvents are particularly hazardous among the mixture of pollutants found in the air, as their low vapor pressure allows them to reach the atmosphere, causing damage to ecosystems, and producing secondary deleterious effects on living organisms through a wide variety of possible reactions. In response, innovative, sustainable, and ecological methods are being developed to recover solvents from industrial wastewater, which is typically contaminated with other organic compounds. This study describes the procedure for recovering acetone from a residue from the pharmaceutical industry. This compound contains a high amount of solid organic compounds, which are generated during the manufacture of medicines. The treatment consisted of performing a simple solar distillation using a single-slope glass solar still, which separated the acetone from the mother solution. Under ideal circumstances, the use of solar radiation allowed an efficiency rate of 80% using solar concentration by means of mirrors to increase the temperature and 85% without the use of mirrors in the production of distilled acetone, which was characterized to evaluate its quality using instrumental analytical techniques: NMR, IR, and GC. The results obtained indicate that the acetone recovered by this procedure has a good quality of 84%; however, due to this percentage obtained, its reuse is limited for certain applications where a high degree of purity is required, such as its reuse for pharmaceutical use; for this reason, it was proposed to use said compound to eliminate the organic impurities contained in the catalyst waste granules used in a Mexican oil refinery. The resulting material was examined by SEM and EDS, revealing a high initial carbon content that decreased by 29% after treatment. Likewise, as an additional study, a study was carried out to evaluate the characteristics of the residues obtained at the end of the distillation where rubidium, silicon, carbon, nitrogen, oxygen, and chlorine contents were observed. Full article