Search Results (48)

The production of essential oils generates substantial quantities of solid post-distillation residues, a largely unutilized waste stream rich in bioactive compounds (e.g., phenolics, flavonoids) as well as polysaccharides. Managing this organic waste presents both environmental and economic challenges. This review critically examines environmentally friendly green innovations and resource-efficient technologies within circular bio-economy strategies for valorizing these residues, focusing on four primary conversion pathways: physico-mechanical, thermochemical, biological, and chemical methods. We highlight their potential for practical applications, including the extraction of active compounds for food, cosmetic, and pharmaceutical industries, utilization in agriculture, incorporation into construction materials and wastewater treatment. Despite these opportunities, wider industrial adoption remains limited by high processing costs and the lack of scalable, cost-effective technologies. Key research gaps included the need for methods applicable at the farm level, optimization of the residue-specific conversion process, and life-cycle assessments to evaluate environmental and economic impacts. Addressing these gaps is crucial to fully exploit the economic and ecological potential of post-distillation solid residues and integrate them into sustainable circular bio-economy practices through various processes. Full article

Cross-linked polyethylene (PEX) is very stable, both chemically and mechanically. This makes its waste difficult to process. A very promising approach is slow pyrolysis catalyzed by hematite (α-Fe₂O₃). Such pyrolysis was carried out on a large scale (feedstock of 38 kg, catalyst amount of 2 wt.%, heating rate of 4 K min⁻¹, end temperature of 435 °C, delay at the end temperature several hours) and provided an oil containing both liquid (up to C₁₇) and solid hydrocarbons (>C₁₇). Thus, the oil obtained can be a source of valuable chemicals, solvents, and paraffin, and/or used as a clean liquid fuel and/or as a source of lubricants. Pyrolysis of PEX also yielded energy gas (12 wt.%) and solid carbonaceous residue (15 wt.%) for further use. The process mass balance and parameters (temperature, heating rate, dwell time, catalyst amount), composition, and chemical (elemental analysis, XRF, GC-MS, GC, distillation curve) and physical (viscosity, density, higher and lower heating value) properties of the oil, gas, and solid carbonaceous residue obtained are presented and discussed. The main product of the proposed technology is oil with a yield of almost 73 wt.%. The by-products are energy gas (12 wt.%) and solid carbonaceous residue (15 wt.%). The results obtained showed that the proposed technology successfully recycles difficult-to-process PEX with a process efficiency of 70%. Full article

Baijiu, China’s traditional distilled spirit, is produced through solid-state fermentation and distillation of grains, resulting in a highly complex chemical and sensory profile. However, exogenous impurities introduced via raw materials, water, equipment, packaging, or the surrounding environment pose significant challenges to both safety and quality. These impurities, including heavy metals, plasticizers, pesticide residues, mycotoxins, environmental pollutants, and un-authorized food additives, are associated with neurotoxicity, carcinogenicity, endocrine disruption, and sensory defects. This narrative review synthesizes current knowledge on their sources, reported concentration ranges in Baijiu (generally at trace µg/kg–mg/kg levels), analytical detection methods with sub-mg/kg sensitivity, and control strategies for these substances. Regulatory frameworks, including China’s standards, are critically assessed, with emphasis on gaps such as the lack of explicit limits for certain classes of impurities. Case studies of contamination incidents are discussed to illustrate practical risks and monitoring gaps. Emerging trends, including low- and zero-alcohol Baijiu, are also considered in relation to changing impurity profiles and detection requirements. Recommendations include tightening regulatory limits, adopting portable and real-time detection technologies, and promoting the development of “pure Baijiu” that meets international safety and quality expectations. Future research priorities center on high-resolution mass spectrometry, advanced real-time monitoring, and eco-friendly analytical solutions, ensuring that Baijiu maintains both cultural heritage and global competitiveness. Full article

Traditional sample preparation for terpene analysis includes distillation, solvent extraction, and solid phase extraction and is followed by using gas chromatography with a mass spectrometer (GC-MS) to complete identification and quantification. The preparations rely on the volatility and low polarity of terpenes which exist in free form. However, terpenes in bound form are still largely retained in the extracted residues because, by binding with sugar moiety, they have high polarity and water solubility and low volatility. In this study, distributions and profiles of free and bound form terpenes in different fruit and crop byproducts were evaluated by using different extraction media followed by acid hydrolysis. The acid hydrolysis significantly broke down the binding between terpene and sugar moiety and freed the bound terpene. The concentration of bound terpenes in fruit peel or corn silk was much higher than that of originally existing free terpenes. For example, the terpene concentration in watermelon peel increased from 47.0 to 101 μg/g after hydrolysis. The profile of bound terpenes was also more diverse than that of free terpenes. Among the three extraction media, water, ethanol, and acetone, acetone was the best media to extract bound terpenes with over one and a half times higher total bound terpene extraction yield than ethanol or water extract. The findings of this study explored the bound form terpenes in agricultural products which are usually underexplored in current terpene research. It also demonstrated an effective sample preparation and approach for determining bound terpenes in plants. This study could be an initiating effort and work to assist in exploring rarely mindful bound terpenes in foods and plants. The odorless nature and high stability and water solubility of bound terpenes could provide them a great advantage over free terpenes in various applications requiring neutral scent. Full article

The current study focuses on a preliminary evaluation of the use of solid residues produced from the distillation of selected medicinal and aromatic plants (MAP) as fertilizers for alkaline soils. Specifically, the residues of hemp (Cannabis sativa L.), helichrysum (Helichrysum Italicum (Roth) G. Don), lavender (Lavandula angustifolia Mill.), oregano (Origanum vulgare L.), rosemary (Rosmarinus officinalis L.) and sage (Salvia officinalis L.) were added in an alkaline and calcareous soil at the rates of 0 (control), 1, 2, 4 and 8%, in three replications (treatments), and the treated soils were analyzed. The results showed that upon application of the residues, soil electrical conductivity (EC), organic C, total N and the C/N ratio significantly increased, especially at the 4 and 8% rates. The same was found for soil available P, K, B, Cu and Mn. The effects of the residues on soil pH, cation exchange capacity (CEC) and available Zn and Fe were rather inconclusive, whereas soil available N significantly decreased, which was somewhat unexpected. From the different application rates tested, it seems that all residues could improve soil fertility (except N?) when they were applied to soil at rates of 2% and above, without exceeding the 8% rate. The reasons for the latter statement are soil EC and available Mn: the doubling of EC upon application of the residues and the excessive increase in soil available Mn in treatments with 8% residues raise concerns of soil salinization and Mn phytotoxicity risks, respectively. This work provides the first step towards the potential agronomic use of solid residues from MAP distillation in alkaline soils. However, for the establishment of such a perspective, further research is needed in respect to the effect of residues on plant growth and soil properties, by means of at least pot experiments. Based on the results of the current study, the undesirable effect of residues on soil available N should be investigated in depth, since N is the most important essential element for plant growth, and possible risks of micronutrient phytotoxicities should also be studied. In addition, application rates between 2 and 4% should be studied extensively in order to recommend optimum application rates of residues to producers. Full article

This study evaluated and compared two encapsulation techniques—co-crystallization and ionic gelation—for stabilizing bioactive components derived from lavender distillation residues. Utilizing aqueous ethanol extraction (solid residues) and concentration (liquid residues), phenolic-rich extracts were incorporated into encapsulation matrices and processed under controlled conditions. Comprehensive characterization included encapsulation efficiency (Ef), antioxidant activity (AA), moisture content, hygroscopicity, dissolution time, bulk density, and color parameters (L*, a*, b*). Co-crystallization outperformed ionic gelation across most criteria, achieving significantly higher Ef (>150%) and superior functional properties such as lower moisture content (<0.5%), negative hygroscopicity (−6%), and faster dissolution (<60 s). These features suggested enhanced physicochemical stability and suitability for applications requiring long shelf life and rapid solubility. In contrast, extruded beads exhibited high moisture levels (94.0–95.4%) but allowed better control over morphological features. The work introduced a mild-processing approach applied innovatively to the valorization of lavender distillation waste through structurally stable phenolic delivery systems. By systematically benchmarking two distinct encapsulation strategies under equivalent formulation conditions, this study advanced current understanding in bioactive microencapsulation and offers new tools for developing functional ingredients from aromatic plant by-products. Full article

The aim of this work was to extract phenolic compounds (PCs) from Cistus ladanifer L. post-distillation residues using two different methods (solid–liquid extraction (SLE) and subcritical water extraction (SWE)) and to compare the extracts’ total phenolic content (TPC) and antioxidant activity (AA) by 1,1-diphenyl-2-picrylhydrazyl radical (DPPH^•) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS^•+) scavenging activities, as well as by the ferric-reducing antioxidant power (FRAP) assay. SWE extraction displayed a higher TPC value (increased from 146.53 ± 11.68 to 276.37 ± 20.59 mg gallic acid equivalents (GAEs)/g extract dry weight (dw)) and higher AA in the DPPH^• (increased from 334.27 ± 36.06 to 532.17 ± 66.38 mg Trolox equivalents (TEs)/g extract dw), ABTS^•+ (increased from 438.07 ± 77.22 to 594.08 ± 33.57 mg TEs/g extract dw), and FRAP (increased from 10.91 ± 2.03 to 170.26 ± 25.36 mg ascorbic acid equivalents (AAEs)/g extract dw) assays. These results demonstrate the importance of the extraction method in PC extraction and the antioxidant power of the extracts produced. These results provide critical insights into the potential application of C. ladanifer post-distillation residues and the production of polyphenol rich extracts that might be useful in the food, cosmetic, and pharmaceutical sectors. Full article

The textile industry consumes large volumes of freshwater, producing enormous wastewater containing chemicals from dyeing and bathing, but also microplastics concentrations that have not been deeply studied. Liquid wastes from the synthetic and natural textile manufacturers were treated with a new disruptive technology (Adiabatic Sonic Evaporation and Crystallization, ASEC), which completely removed contaminants from water, providing distilled water and crystallized solids. The current study presents the characterization of the industrial residues and the obtained by-products: microplastics and organic matter contained in the solid residue were analyzed and characterized through chromatography. The results of the analyses displayed that compounds such as benzene, benzoic acid and 2,4-dymethyl-1-heptene were found in the synthetic industry water samples as degraded compounds of polyester and polypropylene. Meanwhile, the natural industry water also contained polyester, nylon and PMM polymer. After the depuration of samples, microplastics were completely retained in the solid phase, together with the organic matter (sulfate and surfactants) resulting on clean water. This is the first study focused on the study of microplastics generated by the textile industry and their prevention by removing them as solid waste. 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

This study investigates the potential of sequential solid-state and submerged fermentation (SeqF) to enhance lipase production by Yarrowia lipolytica using by-products from the palm oil production chain. Palm fiber and palm oil deodorizer distillate (PODD) were utilized as substrates in both fermentation stages. Solid-state fermentation (SSF) yielded significant lipase activity when palm fiber was used alone (1.55 U/g in 48 h), while submerged fermentation (SmF) showed improved enzymatic production with the combination of fiber and PODD (1171 U/L in 72 h). The integration of SSF and SmF in SeqF achieved superior lipase activities, reaching 4464.5 U/L, an 8.3-fold increase compared to SmF alone, in Erlenmeyer flasks. SeqF-lyophilized biocatalysts from Erlenmeyer experiments showed better hydrolytic activity (131 U/g) when the best conditions were reproduced in a 4 L bioreactor (33 U/g). The SeqF-lyophilized biocatalyst was employed in esterification reactions to synthesize mono- and diacylglycerols, achieving a 24.3% conversion rate. The study highlights SeqF as a promising and sustainable approach for valorizing agro-industrial residues, contributing to biocatalyst production and advancing circular bioeconomy initiatives. Full article

Dredged material is a common environmental and economic issue worldwide. Tons of highly contaminated material, derived from cleaning the bottoms of bays and harbours, are stored until depuration. These volumes occupy huge extensions and require costly treatments. The Ria of Huelva (southwest Spain) receives additionally high metal contamination inputs from the Odiel and Tinto Rivers which are strongly affected by acid mine drainage (acid lixiviates with high metal content and sulphates). These two circumstances convert the port of Huelva into an acceptor/accumulator of contamination. The current study proposes an alternative active treatment of dredged material and mining residues using ASEC (Adiabatic Sonic Evaporation and Crystallization) technology to obtain distilled water and valuable solid conglomerates. Different samples were depurated and the efficiency of the technology was tested. The results show a complete recovery of the treated volumes with high-quality water (pH~7, EC < 56 µS/cm, complete removal of dissolved elements). Also, the characterization of the dried solids enable the calculation of approximate revenues from the valorization of some potentially exploitable elements (Rio Tinto: 4 M, Tharsis: 3.7 M, dredged material: 2.5 M USD/yr). The avoidance of residue discharge plus the aggregated value would promote a circular economy in sectors such as mining and dredging activities. Full article

Rosemary is a versatile Mediterranean shrub valued for its culinary and medicinal uses, also finding applications as a food additive (E-392). This study explores the potential of rosemary for large-scale cultivation as well as the valorization of its distillation residue, which constitutes more than 95% of the total biomass. Rich in bioactive compounds, this solid waste represents a valuable opportunity to develop renewable plant-based products. This study monitored the agronomic adaptations of cultivated clones of rosemary and evaluated the essential oil and phenolic content. This study also evaluated the biological potential of the ethanolic extracts from the distilled residue as an antifungal, antioxidant, chelator, and biostimulant in model tests. Interestingly, the extracts showed substantial phenolic content, exhibiting strong antifungal activity, antioxidant capacity, and efficient metal chelation. Furthermore, all extracts also demonstrated promising biostimulant effects on rooting. Among the clones evaluated, Pina de Ebro stood out especially for its balanced adaptability, high essential oil yield, and outstanding phenolic content, along with uniform biological capacities among individual plants and plots. Therefore, this study highlights the potential of utilizing the entire rosemary plant, enhancing the overall profitability of the crop and meeting the growing demand for eco-friendly and renewable resources in the market. Full article

Lavender distillation produces huge quantities of solid waste yearly. This waste is usually discarded, resulting in serious environmental issues. However, it still contains residual essential oil and other bioactive compounds. This research reports on the development and comparison of optimized solid–liquid separation methods, i.e., microwave- (MAE) and ultrasound-assisted extraction (UAE) of phenolic compounds from lavender distillation waste. The optimal pretreatment conditions, such as waste moisture content and particle size, were also determined. The extracts were spray- or freeze-dried and the resulting powders were characterized for their physicochemical properties. The majority of the original phenolic compounds in lavender were found in the leachate fraction after distillation (61%), whereas 43% was found in the solid waste. Drying of the solid waste before extraction affected the process efficiency. UAE led to a higher phenolic content and greater antioxidant properties compared to MAE. Drying (spray or freeze) the extracts did not significantly affect their phenolic content, whereas the use of maltodextrin as a drying agent improved the drying process yield, especially when using the freeze-drying method. It is concluded that valorization of lavender distillation wastes can be achieved via an integrated process consisting of a green extraction method and a consequent drying process that results in a stable bioactive powder. Full article

The impact of dumping plastic waste is realized in different ecosystems of the planet. Several methods have been adopted to dispose of these wastes for energy recovery. This study, for the first time, proposed the Box–Behnken design technique to optimize the pyrolysis process parameters for fuel oil production from waste polypropylene (PP) grocery bags using a semibatch-type pyrolytic reactor. The semibatch-type pyrolytic reactor was developed and employed to produce fuel oil from waste PP grocery bags. The effect of different process parameters on fuel oil production was comprehensively analyzed using the response surface methodology (RSM) with the conjunction of the Box–Behnken design (BBD). The BBD facilitates the prediction of the response variables with respect to changes in the input variables by developing a response model. The BBD was used to optimize the process parameters, such as the reaction temperature (400–550 °C), nitrogen flow rate (5–20 mL min⁻¹), and substrate feed rate (0.25–1.5 kg h⁻¹), and their effect on the responses were observed. The optimum response yields of the fuel oil (89.34 %), solid residue (2.74%), and gas yield (7.92%) were obtained with an optimized temperature (481 °C), a nitrogen flow rate (13 mL min⁻¹), and a feed rate (0.61 kg h⁻¹). The quadratic model obtained for the fuel oil response denotes the greater R² value (0.99). The specific gravity and calorific value of the fuel oil were found to be 0.787 and 45.42 MJ kg⁻¹, respectively. The fuel oil had higher research octane number (RON) (100.0 min) and motor octane number (MON) (85.1 min) values. These characteristics of the fuel oil were matched with conventional petroleum fuels. Further, Fourier transform infrared spectroscopy (FT-IR) and gas chromatography–mass spectroscopy (GC-MS) were used to analyze the fuel oil, and the results revealed that the fuel oil was enriched with different hydrocarbons, namely, alkane (paraffins) and alkene (olefins), in the carbon range of C₄–C₂₀. These results, and also the fractional distillation of the fuel oil, show the presence of petroleum-range hydrocarbons in the waste PP fuel oil. Full article

The use of selective herbicides is one of the best methods for weed management. However, the extensive use of herbicides can have adverse impacts on non-target organisms. The goals of this study were to assess the dissipation kinetics, leaching, and ecological risk assessment of S-metolachlor and benfluralin residues in silty loam soil planted with chickpea (Cicer arietinum L.). The experimental setup included four different layers with four replications corresponding to an experimental randomized complete block design consisting of 16 plots. The application doses of S-metolachlor and benfluralin were 1350 and 1920 g a.i./ha, respectively, according to manufacturer recommendations. Soil samples were split into four depths, 0 to 20 cm (Layer A), 20 to 40 cm (Layer B), 40 to 60 cm (Layer C), and 60 to 80 cm (Layer D), to determine the dissipation kinetics and the leaching behavior of the herbicides. Gas chromatography coupled with the electron capture detector (GC-ECD) method was developed and validated for the determination of S-metolachlor and benfluralin residues in soil. The analytes were extracted from the soil with distilled water and ethyl acetate followed by solid-phase extraction (SPE). The limit of quantification (LOQ) of the method was 0.1 μg/g, and the recoveries of S-metolachlor and benfluralin were in the ranges 81% to 97% and 88% to 101%, respectively, with relative standard deviations (RSD) of less than 9.7%. The dissipation kinetics of S-metolachlor and benfluralin in soil (0–20 cm) followed first-order kinetics with half-lives of 21.66 and 30.13 days, respectively. The results for samples obtained from the 20–80 cm soil profile showed that both benfluralin and S-metolachlor presented high leaching, following preferential flow. Also, a soil ecological risk assessment was conducted in the top 0–20 cm soil profile, estimating the toxicity–exposure ratio (TER) for four soil organisms and the risk quotient (RQ). The mean herbicide levels found at the studied soil profile at 0 days (2 h) and 60 days of the experiment were used for risk assessment. In the first case, the mean pesticide concentration (MPC) gives a worst-case scenario (ws); in the second case, a dissipation scenario (ds) is given using the respective MPC. In all cases, both TER and RQ values showed that benfluralin corresponds to a higher risk than S-metolachlor for soil organisms. Full article