Search Results (9,580)

Halogenated ketones (HKs) and aldehydes (HAs) are prevalent emerging disinfection by-products (DBPs) threatening drinking water safety. Although pre-oxidation and coagulation are widely applied in drinking water treatment, critical knowledge gaps remain regarding the precursor-specific effects of KMnO₄ and O₃ pre-oxidation on chlorinated ketone/aldehyde formation potential, as well as the interaction between coagulation optimization and DBP yields. This study systematically investigates the effects of KMnO₄/O₃ pre-oxidation and optimized coagulation on the formation potential (FP) of 1,1-dichloroacetone (1,1-DCP), 1,1,1-trichloroacetone (1,1,1-TCP), and chloral hydrate (CH) from four typical precursors (fulvic acid, citric acid, L-threonine, L-asparagine). Batch pre-oxidation and chlorination experiments were performed; three-dimensional excitation–emission matrix (3D-EEM) fluorescence spectroscopy was used to characterize organic-precursor structural changes, while gas chromatography–mass spectrometry (GC-MS) was adopted to quantify target DBPs. Results show that KMnO₄ and O₃ pre-oxidation significantly promote (p < 0.05) DBP formation from fulvic acid but exert precursor-specific effects on small-molecule precursors: KMnO₄ enhances CKs while inhibiting CH from amino acids, and O₃ suppresses all three DBPs from small-molecule precursors. Coagulation pretreatment weakly inhibits DBP formation (reduction rate < 20%) by removing partial precursors. This study clarifies the mechanism of process-driven DBP modulation and provides a theoretical basis for optimizing water treatment processes to control chlorinated ketone/aldehyde DBPs. Full article

Wildfire impact assessment requires information on both burned areas and the biomass exposed within burned landscapes. We developed a field-calibrated, multi-source remote-sensing framework to estimate above-ground biomass (AGB) and quantify annual wildfire-related potential AGB exposure across the boreal forests of Quebec and Ontario, Canada, during 2018–2024. The dataset comprised 3725 plot-year AGB observations linked to optical, Sentinel-1 C-band, ALOS L-band synthetic aperture radar, environmental, and geographic predictors. Product-wise screening reduced the 91 candidate predictors to 28. An optimized extreme gradient boosting (XGBoost) model was evaluated using five-fold grouped cross-validation, with repeated observations from each plot assigned to a single fold. The model achieved an RMSE of 25.08 ± 0.36 t ha⁻¹, an MAE of 20.89 ± 0.39 t ha⁻¹, and an R² of 0.53 ± 0.02. The full multi-source configuration outperformed all reduced-source and source-only configurations, while removing ALOS L-band SAR or environmental/geographic predictors produced among the largest performance declines. The model was applied to 9937 land-cover-stratified points within wildfire polygons using predictors from the year preceding each fire. Under the complete-loss assumption, cumulative potential AGB exposure was 269.20 Mt across 6.66 Mha of effective burned area, with a 95% bootstrap interval of 254.19–284.06 Mt reflecting finite-point sampling uncertainty and an area-weighted mean exposure intensity of 40.43 t ha⁻¹. The 2023 fire season accounted for 206.44 Mt, representing 76.7% of cumulative exposure and 73.2% of effective burned area. Effective burned area and total potential exposure were strongly correlated (r = 0.99), whereas exposure intensity followed a distinct pattern and peaked in 2022 at 46.86 t ha⁻¹. Thus, burned area was the primary correlate of regional potential biomass exposure, whereas exposure intensity reflected variation in pre-fire biomass among burned landscapes. These estimates represent potential exposure rather than measured combustion, mortality, or carbon emissions and demonstrate the value of integrating spatially explicit pre-fire AGB with wildfire perimeters. Full article

To satisfy the industrial standards for phosphate products, phosphate ore must undergo beneficiation for the removal of gangue minerals such as carbonate minerals, silicate minerals, and clay minerals. Reverse flotation is commonly used to remove carbonate minerals from apatite. However, reverse flotation removes carbonate gangue minerals but fails to eliminate silicate and clay minerals. The use of pre-concentration (such as dense-medium cyclones and photoelectric sorting) in phosphate ore beneficiation enables the early rejection of gangue before the ore enters the fine-grinding and complex flotation circuits, thereby providing a range of technical and economic benefits. In addition, pre-concentration holds the potential to reject silicate and clay minerals in the beneficiation of phosphate ore. The phosphate ore investigated in this study was obtained from Hubei, China. It is characterized by well-defined gangue banding, which facilitates the liberation of some gangue minerals at relatively coarse comminution sizes (−15 + 0.5 mm). Based on these characteristics, photoelectric separation and dense-medium cyclone separation were employed as pre-concentration methods prior to reverse flotation, with the aim of achieving economically viable recoveries and marketable product grades. The results indicate that the combined dense-medium cyclone separation–reverse flotation process was the most effective for this phosphate ore, producing a final concentrate with a P₂O₅ grade of 31.08% and a recovery of 81.91%. Comparative evaluation reveals notable differences in gangue removal efficiency among the tested processes. While both reverse flotation and the combined photoelectric separation–reverse flotation process effectively removed dolomite, the dense-medium cyclone separation–reverse flotation process demonstrated superior overall performance by enabling the simultaneous removal of both silicate and dolomite impurities. Full article

Rice husk, an abundant agro-industrial by-product rich in SiO₂, represents a promising precursor for the sustainable synthesis of zeolites. In this study, rice husk ash was used to synthesize faujasite-type X and faujasite-type Y, and their performance for Hg²⁺ removal from aqueous solutions was comparatively evaluated. X-ray diffraction confirmed the successful formation of the faujasite structures, while physicochemical characterization revealed differences in pore structure and surface chemistry. FAU-type X exhibited higher Hg²⁺ removal than FAU-type Y, consistent with the combined influence of its lower Si/Al ratio, higher framework charge density and ion-exchange capacity, as well as its larger pore volume and average pore diameter. Based on its higher Hg²⁺ removal, FAU-type X was selected for a comprehensive evaluation of its adsorption performance and applicability under environmentally relevant conditions. The pseudo-second-order model best described adsorption kinetics for both zeolites, whereas thermodynamic analyses indicated that the adsorption process was spontaneous and endothermic. Optimal adsorption conditions for FAU-type X were achieved at pH 6.8, using an adsorbent dosage of 0.75 g L⁻¹, a contact time of 24 h, and an initial Hg²⁺ concentration of 1 mg L⁻¹. Equilibrium data were best fitted by the Sips isotherm model, indicating adsorption on a heterogeneous surface with a maximum adsorption capacity of 83.14 mg g⁻¹. FAU-type X retained appreciable adsorption performance after four regeneration cycles, although Hg²⁺ removal efficiency decreased in Caquetá River water because of competition from coexisting metal ions. To assess the environmental implications of the treated water beyond Hg²⁺ removal efficiency, ecotoxicological assays demonstrated the sensitivity of Daphnia magna to residual Hg²⁺ concentrations, whereas reductions in Escherichia coliforms were mainly attributed to the adsorption process. In addition, Lactuca sativa seedlings exhibited approximately 50% inhibition of elongation after treatment. Overall, these findings demonstrate the potential of rice husk-derived faujasite-type X as a sustainable adsorbent for Hg²⁺ removal, while highlighting the need for complementary treatment strategies to ensure the environmentally safe discharge of water and its agricultural reuse. Full article

Rapeseed oil is an important edible oil with a favorable fatty acid composition and contains endogenous phospholipids (PLs) and lipid-soluble minor components that are relevant to refining, oxidative stability, and product quality. In this study, water degumming (WDG), citric acid degumming (ADG), and ethanol degumming (EDG) were systematically evaluated for their effects on oil quality, phospholipid recovery, and bioactive lipid concentrations. A modified Folch extraction was included solely as a laboratory solvent-extraction benchmark for the compositional characterization of phospholipid-rich fractions. WDG and ADG showed the highest phosphorus removal efficiency, reducing phosphorus to undetectable levels, whereas EDG also achieved substantial dephosphorization. ADG produced the highest PL yield (83.22%), while WDG gave the highest oil recovery (98.42%) and PL purity (95.49%). Although the bulk FA composition of the oil remained largely unchanged after treatment, the recovered PL fractions showed clear differences in FA distribution and PL subclass composition. EDG yielded the highest phosphatidylcholine (PC) and lysophosphatidylcholine (LPC) contents, indicating selective enrichment of choline-containing PLs. The concentrations of carotenoids, tocopherols, and phytosterols were also process-dependent. Untargeted metabolomic and lipidomic analyses further showed that EDG induced distinct compositional remodeling relative to crude rapeseed oil. Overall, WDG was preferable for oil retention, ADG for maximum PL recovery, and EDG provided a distinct balance between oil recovery, PL recovery, and enrichment of PC- and LPC-containing fractions. Full article

In this study, the application of the boron-doped diamond (BDD) electrode for electrochemical removal of clavulanic acid was investigated. The studied pharmaceutical is one of the most commonly prescribed β-lactamase inhibitors, which raises concerns about its impact on the spread of antibiotic resistance, as well as environmental toxicity. Preliminary experiments conducted in buffered solutions showed that neutral pH ensures substantially higher degradation rates than basic and acidic conditions. Further studies featuring standardized humic substances revealed that the presence of dissolved organic matter can even improve the process’s performance, resulting in over 99% degradation achieved within 30 min of the electrooxidation experiment. Two detected intermediates were identified as the products of a β-lactam ring cleavage, which supposedly led to the loss of enzyme inhibiting properties. Total organic carbon (TOC) analysis (namely the non-purgeable carbon—NPOC—assay) showed that the time necessary to fully mineralize clavulanic acid is significantly longer than to degrade it. Nevertheless, BDD electrodes can be successfully applied for the removal of the studied compound from aquatic environments, which confirms their suitability as a part of water treatment systems. Full article

The cultivation of Chondracanthus chamissoi has advanced in Chile and Peru, but seedstock production still depends on thalli collected from natural beds. This dependence may limit commercial scale-up and increase pressure on natural beds. This study evaluated a land-based system for successive seedstock production using secondary attachment discs (SADs) as reusable vegetative units. Donor thalli were attached to polycarbonate plates in outdoor tanks to induce SAD formation. After SAD establishment, two harvesting strategies were compared: partial harvesting, in which only newly formed thalli were removed while SADs were retained on the plates, and total scraping, in which all biomass, including SADs, was completely removed. Experiments were conducted in independent cultivation tanks (n = 3), and temporal responses were analyzed using repeated-measures analysis of variance (ANOVA). Across the study, the highest values recorded were 131 ± 22 SADs 100 cm⁻², 15 thalli SAD⁻¹, a growth rate of 9.93 ± 1.21% d⁻¹, and 44 ± 6.2% plate coverage. The partial harvest strategy maintained production between cycles, yielding 58 ± 20 and 51 ± 23 g plate⁻¹ in the first and second harvests, respectively. Under this strategy, thallus production reached 106 ± 12 and 152 ± 17 thalli g⁻¹ in the first and second cycles. The harvested biomass consisted of numerous small vegetative units suitable for use as seedstock. Based on a conservative production scenario, a projected estimate indicates that this technology could yield approximately 1,200,000 thalli per harvest. Overall, these results support the use of SAD as a practical strategy for the successive production of C. chamissoi seedstock. Full article

Considering the limited information available on the use of elephant grass juice (EGJ) as a liquid co-substrate, this study aimed to evaluate its feasibility and biogas production potential for anaerobic co-digestion with dairy cattle wastewater (DCW), focusing on substrate ratios and reactor operating conditions. Initially, batch tests were conducted at different temperatures to evaluate the effects of varying substrate mixture ratios (EGJ/DCW). In the reactor with 20% EGJ/80% DCW at 39 °C, a biogas volume of 414.35 mL was generated, which was considerably higher than that in the test at 25 °C, where 258.7 mL was generated over the 30-day experimental period. Greater efficiency in organic matter removal and other analyzed parameters was also observed under these conditions. The best configuration was selected for the semi-continuous tests. To this end, an Upflow Anaerobic Sludge Blanket (UASB) reactor was operated with hydraulic retention times of 10, 6, 2, and 1 d and volumetric organic loading rates of 2.06, 3.39, 10.40, and 20.70 kg VS m⁻³ d⁻¹, respectively. Volatile solids were removed by 29–58%, with biogas yields ranging from 0.78 to 2.28 m³ m⁻³ d⁻¹ and a maximum CH₄ concentration of 72% (v/v). The co-digestion of the analyzed agricultural waste substrates proved to be a promising approach for bioenergy recovery. These results provide useful guidelines for optimizing co-digestion systems, improving reactor performance, and waste treatment processes. Full article

Two-stage anaerobic digestion (TSAD) is an alternative to single-stage anaerobic digestion, separating hydrolytic–acidogenic and methanogenic phases to improve stability, organic matter degradation, and methane production. This review examines TSAD for co-digestion of sewage sludge (SS) and the organic fraction of municipal solid waste (OFMSW), emphasizing performance, scale-up challenges, digestate intensification, and nutrient recovery. TSAD can increase methane production by 25–50% compared with single-stage systems, while volatile solids removal can reach 87–93% depending on substrate type, temperature regime, hydraulic retention time, and organic loading rate. However, improvement remains variable and depends on substrate biodegradability, reactor configuration, and process control. Beyond methane recovery, the review highlights valorizing digestate as a secondary resource. Digestate post-treatment technologies, including thermal hydrolysis and steam explosion, report methane improvements from 26% to more than 300%, although energy demand and economic feasibility remain constraints. Nitrogen recovery technologies, including ammonia stripping and membrane contactors, can achieve efficiencies above 80–95% under optimized conditions, while phosphorus may be recovered through struvite precipitation, calcium phosphate recovery, or biochar-based pathways. Future TSAD development should integrate biological conversion, digestate recirculation, nutrient recovery, techno-economic assessment, and life-cycle evaluation to support circular, resource-efficient organic waste treatment systems. Full article

Pharmaceutical compounds, emerging medicinal residues, and personal care products (PPCPs) are ubiquitous in aquatic environments and are causing a serious global environmental problem because of their persistence, bioaccumulation, and harmful effects on the environment and human health. Conventional wastewater treatment technologies are sometimes not capable of removing them completely, causing persistent releases of biologically active micropollutants to surface water, groundwater, and drinking water systems. In this context, biomass-derived catalysts are a promising class of advanced materials for environmental remediation because of their sustainable and cost-efficient nature. The catalysts are composed of bio-residues, such as agricultural residues, forestry wastes, and other bioresources, that have tunable surface chemistry, high porosity, and can be activated and functionalized to increase their catalytic activity. This review summarizes recent advances in biomass-derived catalysts for the removal of pharmaceuticals and PPCPs from water. Special attention is given to synthesis methods, such as pyrolysis, hydrothermal carbonization, chemical activation, heteroatom doping, and metal or metal-oxide hybridization. The catalytic mechanisms of pollutant degradation, including adsorption, radical-based advanced oxidation processes, and non-radical electron-transfer mechanisms, are critically discussed. Moreover, the effect of key operating parameters, catalyst stability, and real wastewater test performance are studied. Sustainability aspects such as green synthesis routes, integration of circular bioeconomy, and life-cycle aspects are also emphasized. Finally, current issues like catalyst deactivation, scaling-up, and the lack of a full mechanistic understanding are identified, and future research avenues are suggested to enable the implementation of efficient, durable, and environmentally friendly catalytic systems for large-scale wastewater treatment applications. Full article

Next-generation waste degradation and valorization technologies are increasingly developed as integrated platforms for pollutant removal, resource recovery, and circular manufacturing. This review critically evaluates degradation and valorization routes for liquid, organic solid, and inorganic/electronic waste streams from an engineering perspective. For liquid waste, advanced oxidation processes, photocatalysis, electrochemical oxidation, plasma treatment, and hybrid systems are assessed with emphasis on radical utilization, photon and electron efficiency, catalyst stability, byproduct formation, and reactor hydrodynamics. For organic solid waste, biological, thermochemical, catalytic, enzymatic, and mechanical pathways are compared for agricultural residues, textile waste, and industrial polymers, including fermentation, pyrolysis, hydrogenolysis, solvolysis, enzymatic depolymerization, and mechanical recycling. Their practical viability depends strongly on feed purity, product selectivity, monomer or fuel recovery, and the energy and separation requirements of downstream processing. For inorganic and electronic waste, hydrometallurgical, pyrometallurgical, biohydrometallurgical, and physical separation routes are examined for the recovery of critical metals, mineral phases, and non-metallic fractions. Industrially mature integrated flowsheets generally offer greater feed tolerance, whereas emerging selective routes provide improved recovery potential but remain constrained by reagent consumption, reaction rate, and scale. Across all waste classes, the review identifies reactor design, process intensification, reaction–separation integration, techno-economic analysis, and life-cycle assessment as essential tools for translating laboratory performance into scalable, economically competitive, and environmentally sustainable processes. Full article

Microplastics and heavy metals are widely present in the soil, and their combined contamination affects plant growth and physiological characteristics. Currently, research on the growth, physiology, and quality of Panax notoginseng under combined microplastic-heavy metal contamination with biochar amendment is limited. Pine needle biochar was used as the experimental material, and the adsorption mechanism of pine needle biochar for microplastics and cadmium (Cd) was explored through adsorption experiments. Pot experiments were conducted under the combined stress of 0.1% (w/w) microplastics and 6 mg·kg⁻¹ Cd (MP–Cd), with exogenous application of 0.5%, 1%, and 3% biochar. The biomass, Cd content, photosynthetic characteristics, antioxidant system (superoxide anion, O₂⁻; hydrogen peroxide, H₂O₂; malondialdehyde, MDA; superoxide dismutase, SOD; peroxidase, POD; and catalase, CAT), saponin synthase activities (dammarenediol-II synthase, DS; squalene epoxidase, SE; glycosyltransferase, GT; and squalene synthase, SQS), and saponin content (notoginsenoside R₁, ginsenoside Rg₁, and ginsenoside Rb₁) of P. notoginseng were analyzed. The results showed that under the 1% biochar application, the Cd²⁺ adsorption capacity was 1.31 mg·g⁻¹, with a removal rate of 99.91%. Under biochar application, Cd content in all parts of P. notoginseng was significantly decreased, and the magnitude of the decrease increased with increases in the biochar application rate. Under the 3% biochar application, the plant height and biomass were increased by 18.92% and 29.72%, and the net photosynthetic rate (P_n) and stomatal conductance (G_s) were increased by 1.18-fold and 1.5-fold, respectively. Under the 1% biochar application, chlorophyll a and b contents were highest at 0.077 mg·g⁻¹ and 0.052 mg·g⁻¹, respectively, the activity of SE in rhizomes was increased by 20.24%, and the content of notoginsenoside R₁ was significantly increased by 1.01-fold. Under the 3% biochar application, the activity of SQS in rhizomes was significantly increased by 10.38%, and the activities of GT and DS in fibrous roots were increased by 20.29% and 14.82%, respectively. The content of ginsenoside Rb₁ in rhizomes was significantly increased by 69.64%, while the contents of ginsenoside Rg₁ and total saponin in the main root were increased by 1.41-fold and 0.72-fold, respectively. The activities of saponin synthase in various parts of P. notoginseng were GT (717.167 U·L⁻¹) > DS (472.752 IU·L⁻¹) > SE (378.949 U·L⁻¹) > SQS (144.918 U·L⁻¹). In summary, the growth of P. notoginseng and saponin content were increased under combined MP–Cd contamination, with the 3% pine needle biochar application, with Cd content decreased to ensure the safe production of P. notoginseng. Full article

Soybean hulls, an abundant agro-industrial by-product, were valorized as a renewable cellulose source for nanocellulose production. Cellulose isolates were obtained by alkaline treatment followed by bleaching with sodium chlorite (NaClO₂) or hydrogen peroxide (H₂O₂) and subsequently used to produce cellulose nanocrystals (CNC) and TEMPO-oxidized cellulose nanofibrils (CNF). Process efficiency and the structural and rheological properties of the resulting nanocelluloses were systematically compared. Sodium chlorite bleaching removed lignin and hemicellulose more effectively than hydrogen peroxide treatment, yielding isolates with higher cellulose content. Consequently, CNC_NaClO2 exhibited greater aspect ratio, higher crystallinity, and improved network-forming ability. Their suspensions showed pronounced viscoelastic and thixotropic behavior (G′ > G″), whereas CNC_H2O2 displayed lower moduli and nearly Newtonian flow. CNF suspensions exhibited dominant elastic behavior and gel-like consistency regardless of bleaching method, although this effect was stronger for CNF_NaClO2 due to the formation of longer, more entangled fibrils. FTIR confirmed the high purity of all nanocelluloses, while negative surface charge ensured colloidal stability. Overall, bleaching chemistry governed nanocellulose morphology and rheological performance, enabling tailored functional properties. By maintaining a constant biomass source and identical nanostructure production conditions while varying exclusively the bleaching agent, this study implements a controlled-variable design that rigorously isolates the effect of bleaching treatment. This systematic comparative framework provides methodological robustness rarely achieved in previous studies, where differences in raw materials or processing conditions often confound interpretation. Full article

Brown Rot (Monilinia spp.) and Leaf Curl (Taphrina deformans) are principal fungal diseases affecting peach (Prunus persica L. Batsch) production, lacking validated AI-based diagnostic tools in tropical highland orchards. This study presents a compact Convolutional Neural Network (3658 trainable parameters), applied identically to fruit and leaf classification, integrated with a background-removal preprocessing pipeline and evaluated through stratified 5-fold cross-validation on 800 in-situ images from four orchards in Cómbita and Choachí, Colombia. The proposed architecture achieved mean accuracies of 82.8% (fruit) and 95.3% (leaf), with AUC values of 0.87 and 0.98, and a trained model footprint of approximately 100 KB, supporting storage- and bandwidth-efficient deployment. Benchmarked against ImageNet-pretrained MobileNetV3-Small and MobileNetV2 under an identical protocol, the proposed architecture matched or exceeded MobileNetV3-Small on leaf classification despite a 257-fold smaller parameter count, and achieved comparable or lower inference latency than both larger backbones. To our knowledge, this is the first validated system for simultaneous detection of both pathogens in Prunus persica under real field conditions, combining a compact, deployment-ready architecture with an ablation-verified preprocessing pipeline. The proposed model was deployed in the DurAPP web platform, giving peach growers in tropical highland regions a practical, low-footprint diagnostic tool suited to smallholder farming conditions. Full article

Green and white hop shoots are routinely removed during hop production and represent an underutilized biomass stream with potential for valorization. This study evaluated the biomass yield and polyphenolic composition of shoots from three cultivated hop varieties, Aurora, Celeia, and Styrian Wolf. White and green shoots were sampled in 2021, while green shoots were additionally sampled in 2023. Total phenolics were determined by the Folin–Ciocalteu method, and individual polyphenols were quantified by HPLC. Green-shoot biomass removed during training differed significantly among varieties, ranging from 76 kg/ha in Aurora to 188 kg/ha in Styrian Wolf. Total phenolic content of green shoots ranged from 2.22 to 3.47 mg CAE/g dry matter, with Styrian Wolf showing the highest value. Polyphenolic profiles differed markedly between shoot types: white shoots contained higher concentrations of catechin, epicatechin, and naringin, whereas green shoots contained quercetin, higher ferulic acid levels, and the hop-specific prenylflavonoid xanthohumol. Interannual variation was compound-specific at green shoots: the wetter February–April period in 2021 coincided with higher epicatechin and ferulic acid concentrations, whereas naringin and 4-hydroxybenzoic acid were higher in the drier 2023 February–April period. Compared with commonly consumed polyphenol-rich foods, hop shoots contained relatively low concentrations of individual polyphenols; however, their routine generation as an agricultural side stream may make them an attractive raw material for selective recovery of specific compounds, particularly hop-specific xanthohumol. Full article