International Journal of Environmental Science and Technology最新文献

{"title":"Design, synthesis and characterization of g-C3N4/GO/CoFe2O4 nanocomposite for efficient photocatalytic degradation of pollutants using sunlight","authors":"S. Tahir,&nbsp;Z. A. Rehan,&nbsp;M. S. Khan,&nbsp;G. Mustafa,&nbsp;S. Noreen,&nbsp;M. Zahid,&nbsp;N. Al-Zaqri","doi":"10.1007/s13762-026-07252-8","DOIUrl":"10.1007/s13762-026-07252-8","url":null,"abstract":"<div><p>Methyl orange (MO), an azo dye broadly employed in textile industry, adversely affects water reservoirs and human health, prompting the need for efficient methods for its elimination. Photodegradation of organic pollutants is an auspicious, eco-friendly technology for wastewater treatment. Herein, an efficient and novel ternary composite comprising g-C₃N₄/Graphene oxide/CoFe₂O₄ (CGCo) was synthesized using simple in situ hydrothermal approach for degradation of MO dye. Various characterization tools, including XRD, FTIR, XPS, SEM–EDX, and UV–Vis spectroscopic analyses were utilized to validate effective synthesis of the ternary CGCo composite. The influencing operational parameters, like pH, oxidant dose, photocatalyst dosage, irradiation time, and initial dye concentration (IDC), on photocatalytic degradation were comprehensively examined and elucidated. Novel ternary CGCo composite displays improved photocatalytic performance for MO dye degradation than binary g-C₃N₄/CoFe₂O₄ (CCo, 89%) and GO/CoFe₂O₄ (GCo, 91%) composites under sunlight. At optimum photocatalytic conditions of pH (5), photocatalyst amount (0.3 g/L), oxidant dosage (10 mM), and initial pollutant concentration (25 ppm), MO dye was successfully degraded (~ 98%) using CGCo within 60 min. No obvious loss of photoactivity was observed after 3rd subsequent recycling run. The enhanced photocatalytic performance was ascribed to synergistic impact among graphene oxide, g-C₃N_4, and CoFe₂O₄, which promotes efficient charge separation, light harvesting, and delays the life span of photoinduced carriers. This study presents an effective approach, offering insight into role of g-C₃N₄/GO/CoFe₂O₄ as a promising photocatalyst for degradation of contaminants in wastewater treatment.</p></div>","PeriodicalId":589,"journal":{"name":"International Journal of Environmental Science and Technology","volume":"23 6","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance evaluation of a plastic bottle separation system using MobileNetV2 CNN and a simple sweep arm mechanism","authors":"M. Qibthiyah,&nbsp;R. Dhelika","doi":"10.1007/s13762-026-07240-y","DOIUrl":"10.1007/s13762-026-07240-y","url":null,"abstract":"<div><p>Plastic waste management remains a critical environmental challenge, particularly in developing countries where low-cost and scalable sorting technologies are required. This study presents the development and evaluation of an automated plastic bottle separation system integrating a convolutional neural network (CNN) with a mechanically simple sweep-arm mechanism. The system is designed to classify and separate high-density polyethylene (HDPE) and polyethylene terephthalate (PET) bottles conveyed on a belt using RGB imaging and a MobileNetV2-based object detection model. A custom dataset of HDPE and PET bottles was developed and used to train the CNN, achieving mean Average Precision (mAP) values exceeding 80% for both HDPE and PET classes at standard Intersection over Union (IoU) thresholds. The trained model was deployed in a prototype consisting of a conveyor belt and a single-actuator sweep arm, enabling material-based diversion at the end of the conveyor. Beyond algorithmic evaluation, this work presents an analytical and experimentally validated model for determining the minimum inter-bottle spacing required for reliable separation, which is critical for ensuring stable operation and preventing mis-separation. The obtained waste-handling capacity of the system was analytically estimated to range from 32.4 to 103.6 kg/h, depending on the bottle material composition. The results demonstrate that a mechanically simple, CNN-assisted separation system can achieve reliable plastic bottle sorting with competitive throughput, offering a cost-effective alternative to more complex robotic or spectroscopic sorting systems. This work highlights the importance of integrating mechanical design considerations with machine vision performance for practical waste separation applications.</p></div>","PeriodicalId":589,"journal":{"name":"International Journal of Environmental Science and Technology","volume":"23 6","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147797163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-scale evaluation of Alternanthera reineckii (var. Lilacina) under nickel stress: a molecular, physiological and phytoremediation perspective","authors":"B. N. Erkencioglu,&nbsp;A. Hocaoglu-Ozyigit,&nbsp;I. E. Yalcin,&nbsp;Z. Memis,&nbsp;H. Yazicioglu,&nbsp;I. I. Ozyigit","doi":"10.1007/s13762-026-07163-8","DOIUrl":"10.1007/s13762-026-07163-8","url":null,"abstract":"<div><p>Heavy metal contamination in aquatic ecosystems poses a major threat to the environment. While nickel (Ni) plays a vital role in plant growth at low concentrations, excessive concentrations can induce toxicity, leading to genotoxicity and disrupting fundamental biological processes and cellular homeostasis in aquatic plants. This study focuses on evaluating the capacity of <i>Alternanthera reineckii</i> Briq (var. Lilacina), a hardy submerged aquatic plant, to remove Ni from freshwater and examines the subsequent physiological and genotoxic effects caused by Ni exposure. Samples were subjected to NiCl₂.6H₂O in a 0.2% Hoagland nutrient solution at concentrations of 0, 10, 25, 50, and 100 µM for 10 days. The results indicated a concentration-dependent increase in Ni accumulation. Although Ni concentrations did not meet the classical hyperaccumulation threshold, the calculated BCFs (ranging from 3 to 9) and TF values consistently &gt; 1 suggest that <i>A. reineckii</i> possesses effective internal Ni translocation and moderate accumulation potential. The alterations in essential mineral nutrients, including Ca, Cu, B, and Zn, are indicative of physiological adjustments in response to exposure. ISSR marker analysis revealed noticeable changes in band intensity under various treatments. A high GTS value of 100% and low polymorphic changes suggest that the plant’s genetic integrity was largely preserved. The findings indicate that <i>A. reineckii</i> exhibits notable accumulation capabilities for Ni and has potential for the remediation of Ni-contaminated freshwater. Moreover, the efficacy of remediation may be further enhanced when used in combination with other plant species.</p></div>","PeriodicalId":589,"journal":{"name":"International Journal of Environmental Science and Technology","volume":"23 6","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13762-026-07163-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147797123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Soil mapping, development and classification in Kurdistan, Northern Iraq: a geospatial and analytical study","authors":"J. A. H. Doski,&nbsp;M. A. Fayyadh,&nbsp;H. D. Abdulrahman","doi":"10.1007/s13762-026-07222-0","DOIUrl":"10.1007/s13762-026-07222-0","url":null,"abstract":"<div><p>This geospatial and analytical study integrates GIS techniques with survey data and laboratory analysis results to investigate soil mapping units, classify soils, and evaluate its development and capability for agriculture at the Sulaivani plain, north-west of Duhok city, Kurdistan, Northern Iraq. The analysis of 43 soil samples indicates that clay (156–551 g kg⁻¹), total organic matter (15.24–47.03 g kg⁻¹), total carbonate (168.34–319.84 g kg⁻¹), and active carbonate (70–280 g kg⁻¹) contents varied across the study area, with CEC values falling between 14.34 and 36.24 Cmolc kg⁻¹. The application of the USDA-NRCS Soil Taxonomy (USDA-NRCS (2006) Keys to Soil taxonomy by soil survey staff. USDA. Natural Resources Conserv. Serv., Washington, DC) revealed that the soils within the study area, derived from limestone parent material, were predominantly Vertisols order, only pedon 5 was classified as Inceptisols order due to its underdeveloped state and contains only Ap and Ch horizons. The soils are generally well-developed with organic matter in an advanced state of decomposition, as evidenced by the ratios of carbon to nitrogen (C/N) (4.51–26.99), active carbonate to total carbonate (0.31–0.92), and total clay in the B horizon to that in the A horizon (0.55–1.45). Their classification falls within the Xererts suborder, Haploxererts and Calcixerets great-groups, with Typic, Chromic, Entic and Vertic subgroups. The analysis of 14 pedons revealed the presence of 5 distinct soil mapping units, with a significant promise for agriculture due to a combination of suitable topographic features, soil properties and prevailing climate. The findings of this study provide critical support for policy-makers aiming to improve sustainable agricultural productivity and monitoring land cover and its management of ecosystems.</p><h3>Graphical abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture><span>The alternative text for this image may have been generated using AI.</span></div></div></figure></div></div>","PeriodicalId":589,"journal":{"name":"International Journal of Environmental Science and Technology","volume":"23 6","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ephedra alata aqueous extract mediated green synthesis of CuO nanoparticles and their antioxidant, antidiabetic, and antibacterial properties","authors":"C. Ben Cheikh,&nbsp;M. S. Nedjimi,&nbsp;M. R. Ouahrani,&nbsp;H. Belkhelfa,&nbsp;N. Dizge","doi":"10.1007/s13762-026-07229-7","DOIUrl":"10.1007/s13762-026-07229-7","url":null,"abstract":"<div><p>The rising prevalence of oxidative stress–related disorders, diabetes, and bacterial infections has driven the search for sustainable biomedical solutions. Developments in green technology have prompted researchers to explore low-cost, eco-friendly approaches for nanoparticle synthesis. This research presents a green strategy for synthesizing copper oxide nanoparticles (CuO NPs) using aqueous extracts of desert <i>Ephedra alata</i> and investigates their antioxidant, antidiabetic, and antibacterial properties. CuO NPs prepared from <i>Ephedra alata</i> extract were studied by UV–Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDX) procedures, identifying an absorption peak at 340 nm, an average size of 28.81 nm, and a semi-spherical to irregular morphology. The DPPH and ABTS examinations assessed the antioxidant activity of copper oxide nanoparticles, revealing inhibition rates of 76.89 ± 0.11% and 92.04 ± 0.47%, respectively. The α-amylase and α-glucosidase inhibition rates for antidiabetic effectiveness were 67.17 ± 3.79% and 61.55 ± 0.26%, respectively. The investigation of the antibacterial efficacy of the biosynthesized CuO NPs revealed the most significant inhibitory effect against <i>S.aureus</i> (17 ± 0.06 mm), then against <i>B.subtilis</i> (16 ± 0.25 mm), <i>K.pneumoniae</i> (15 ± 0.05 mm), <i>E.coli</i> (14 ± 0.18 mm), and <i>P.aeruginosa</i> (8 ± 0.02 mm). This study provides the first comprehensive assessment of these activities of CuO NPs derived from <i>Ephedra alata</i>, highlighting their potential in the field of nanotechnology for medicine.</p></div>","PeriodicalId":589,"journal":{"name":"International Journal of Environmental Science and Technology","volume":"23 6","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13762-026-07229-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147797031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimized design of a sequencing batch reactor (SBR) for efficient municipal wastewater treatment","authors":"M. A. Abdel-Fatah,&nbsp;M. M. Abou-Krisha,&nbsp;E. A. Abdelrahman","doi":"10.1007/s13762-026-07179-0","DOIUrl":"10.1007/s13762-026-07179-0","url":null,"abstract":"<div><p>This study presents a comprehensive and optimized design for a Sequencing Batch Reactor (SBR) system tailored for municipal wastewater treatment in resort areas characterized by significant hydraulic and organic load variability. The design explicitly addresses peak and off-peak seasonal fluctuations through strategic tank sizing, flexible cycle control, and an integrated automation strategy. Key process parameters include a Hydraulic Retention Time (HRT) of 1.92 days, a Sludge Retention Time (SRT) of 16 days, and a Mixed Liquor Suspended Solids (MLSS) concentration of 3,617 mg/L, achieving target effluent qualities of BOD₅ ≤ 20 mg/L and TSS ≤ 20 mg/L. Energy optimization is a central focus, achieved using shared fine-bubble aeration blowers operating at less than 50% of the cycle time, resulting in a specific energy consumption of 0.939 kWh/m³, which is competitive with modern wastewater treatment plants. A robust PLC-based control system manages sequencing, aeration, and sludge wasting, enhancing resilience to shock loads. The sludge management strategy yields 1,125 kg of dry solids per day, which are aerobically stabilized and dewatered to 16–25% solids concentration, producing biosolids suitable for agricultural reuse. This work provides a validated, sustainable design framework that bridges the gap between conventional systems and advanced, cost-intensive technologies, offering a practical and efficient solution for wastewater treatment under highly variable conditions.</p></div>","PeriodicalId":589,"journal":{"name":"International Journal of Environmental Science and Technology","volume":"23 6","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147797118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phosphorus recovery from sewage sludge ash via ultrasound-assisted leaching with lemon juice for struvite production","authors":"T. Nazari,&nbsp;M. B. Motlagh,&nbsp;S. O. Rastegar,&nbsp;M. H. Sedri","doi":"10.1007/s13762-026-07165-6","DOIUrl":"10.1007/s13762-026-07165-6","url":null,"abstract":"<div><p>Phosphorus (P) recovery is critical for mitigating environmental pollution and promoting sustainable development, particularly in light of the progressive depletion of phosphate rock resources. Sewage sludge ash (SSA) represents a reliable secondary source of P. In this study, an integrated ultrasound-assisted bioleaching strategy using lemon juice (sonoleaching) was developed to enhance P extraction from SSA, followed by struvite crystallization for P recovery. Response Surface Methodology (RSM) was employed to optimize the key leaching parameters, including SSA concentration, lemon juice concentration, ultrasonic power, and leaching time, as well as three crystallization parameters: Mg/P molar ratio, N/P molar ratio, and pH. A reduced cubic model developed using Central Composite Design showed strong agreement with the experimental data, with R² and adjusted R² values of 0.95 and 0.92. Under the optimized extraction conditions of 1.34% w/v SSA, 55% v/v lemon juice, an ultrasonic power of 137 W, and a leaching time of 70 min, the P extraction efficiency reached 98.4%. The leachate was then purified using a cation-exchange resin, AG 50W-X8, applied at 0.08 g ml⁻¹, which effectively removed co-extracted metals while retaining dissolved P. The recovered struvite contained 11.55% P, 5.3% N, and 10.3% Mg. These values corresponded to a P: N: Mg molar ratio of 0.86:1.3:1.1 and a struvite purity of 77.4%. XRD and SEM-EDX analyses confirmed the formation of orthorhombic struvite crystals with a well-defined morphology. Overall, the combined bio-acid and ultrasound-assisted process provides an efficient, low-chemical route for producing a slow-release phosphorus fertilizer with reduced metal impurities.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture><span>The alternative text for this image may have been generated using AI.</span></div></div></figure></div></div>","PeriodicalId":589,"journal":{"name":"International Journal of Environmental Science and Technology","volume":"23 6","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147797198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated tree and soil-based monitoring of vehicular pollution in a megacity","authors":"O. Zorluer,&nbsp;I. Ertugrul Yalcin,&nbsp;B. Gjergjizi Nallbani,&nbsp;I. Ilker Ozyigit","doi":"10.1007/s13762-026-07232-y","DOIUrl":"10.1007/s13762-026-07232-y","url":null,"abstract":"<div><p>Traffic-related environmental pollution is increasing in developing countries due to deficient pollution prevention methods and a lack of use of sophisticated technology. Increasing urbanization, vehicle use, and inadequate environmental regulations cause health and environmental problems. This study assessed the suitability of <i>Robinia pseudoacacia</i> var. <i>umbraculifera</i> DC. as a biomonitor of urban metal contamination in Istanbul by quantifying Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, and Zn in washed and unwashed leaves, branches, and bark, together with paired soils collected from ten localities representing contrasting traffic and background conditions. Spatial patterns across independent matrices revealed a clear contaminated-to-background gradient. The control locality (Buyukada) showed the lowest elemental burdens overall, whereas traffic-impacted districts, particularly Besiktas and Bakirkoy, exhibited the highest loads for several traffic-associated elements in plant tissues and co-located soils. Pronounced washed versus unwashed leaf contrasts, strongest at the most impacted sites, indicated a substantial contribution from surface-deposited particulates, consistent with non-exhaust traffic sources (brake and tire wear), road-surface abrasion, and resuspended road dust. Pb emerged as the most diagnostically informative element for localized contamination, with exceedances of commonly used benchmark ranges at selected localities, while Cd, Cr, Cu, Fe, and Zn in washed leaves were broadly consistent with commonly accepted background ranges reported for comparable contexts. Overall, the coherent site-dependent enrichment in plant compartments, combined with paired-soil correspondence and strong leaf-deposition signals, supports <i>R. pseudoacacia</i> var. <i>umbraculifera</i> DC. as an effective biomonitor for traffic-influenced urban metal pollution and a practical tool for hotspot screening and spatial risk mapping in megacity environments.</p></div>","PeriodicalId":589,"journal":{"name":"International Journal of Environmental Science and Technology","volume":"23 6","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13762-026-07232-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147797119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of citizen perception of air quality in Bogotá: a natural language processing approach","authors":"J. D. Baron,&nbsp;O. A. Fajardo","doi":"10.1007/s13762-026-07245-7","DOIUrl":"10.1007/s13762-026-07245-7","url":null,"abstract":"<div><p>Prolonged exposure to fine airborne particles has a significant impact on health, natural ecosystems, climate, and the economy. This study examines how citizens perceive air quality in a Latin American megacity, such as Bogotá, through natural language processing techniques and correlates their perceptions with data recorded by the Bogotá Air Quality Monitoring Network, focusing on three air quality categories: good, moderate, and low. Initially, a thorough preprocessing of Instagram posts and online news was executed. Next, Bidirectional Encoder Representations from Transformers models were fine-tuned using synthetic data from Claude 3.5 Sonnet for sentiment classification. Latent topics within the texts were identified using Latent Dirichlet Allocation, and the correlation between PM_2.5 levels and social media posts and news articles was calculated. The findings reveal that (1) public sentiment on Instagram and in online news does not consistently reflect particulate matter _2.5 pollution levels. (2) The Pearson correlation between air quality and social media mentions was 0.20 for low quality, 0.68 for moderate quality, and 0.10 for good quality. For news articles, the correlations were 0.27, 0.25, and 0.13, respectively. This research demonstrates the capabilities of natural language processing in enhancing our understanding of online environmental discussions, providing insight into how citizens perceive specific issues. Such insights can help government entities make more informed decisions.</p></div>","PeriodicalId":589,"journal":{"name":"International Journal of Environmental Science and Technology","volume":"23 6","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147797196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrochars from waste biomass of açaí and curauá as adsorbents for methylene blue using factorial experimental design","authors":"R. I. L. dos Santos,&nbsp;L. F. L. Souto,&nbsp;A. C. S. Mendes,&nbsp;N. A. de Moraes,&nbsp;N. N. A. Araújo,&nbsp;F. A. de Freitas","doi":"10.1007/s13762-026-07223-z","DOIUrl":"10.1007/s13762-026-07223-z","url":null,"abstract":"<div><p>This study investigated the performance of four hydrochars derived from açaí seeds and curauá mucilage for methylene blue (MB) removal from aqueous solutions. Untreated (AWR, CWR) and phosphoric acid-treated (AAR, CAR) hydrochars were produced via hydrothermal carbonization and comprehensively characterized by Boehm titration, pH_pzc, FTIR, SEM, TG/DTG, surface area, and elemental analyses. A 2³- factorial experimental design was employed to optimize adsorption conditions (pH, adsorbent dosage, and initial MB concentration). The statistical models explained more than 90% of the experimental variability, identifying pH as the most influential parameter and enabling MB removal efficiencies above 94% under alkaline conditions. Optimal adsorption was achieved at pH 10, with dosages of 0.05 g for açaí-derived hydrochars and 0.150 g for curauá-derived hydrochars at an initial MB concentration of 50 mg L⁻¹. Equilibrium data were well described by the Langmuir model, with maximum adsorption capacities of 22.65 (AWR), 27.95 (CWR), 27.10 (AAR), and 48.04 mg g⁻¹ (CAR), demonstrating the positive effect of acid treatment on adsorption performance. Kinetic analysis followed the pseudo-second-order model, and thermodynamic results indicated a spontaneous and endothermic adsorption process. Reusability tests confirmed satisfactory stability over successive cycles. Overall, the results demonstrate that Amazonian agricultural residues can be effectively transformed into functional hydrochars for dye removal, combining sustainable waste valorization with statistically optimized adsorption performance.</p></div>","PeriodicalId":589,"journal":{"name":"International Journal of Environmental Science and Technology","volume":"23 6","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13762-026-07223-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147797117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}