Search Results (224)

The treatment of olive mill wastewater (OMW) remains a major environmental challenge due to its high organic load and phenolic content. This study investigates a combined approach using lime pretreatment and limestone (LS)-based adsorption for cost-effective and sustainable OMW remediation. Locally sourced limestone was used in both micro- and nanoscale forms, while lime (CaO) was produced by calcination. The materials were characterized using X-ray Diffraction pattern (XRD), Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller (BET), and Point of Zero Charge (pH_PZC) analyses to evaluate surface properties relevant to adsorption. Lime pretreatment achieved notable reductions in total suspended solids (TSS, 99%), chemical oxygen demand (COD, 43%), and total phenolic content (TPC, 48%). Subsequent adsorption with nano-limestone (particles obtained through high-energy ball milling, followed by sieving, with a size distribution 400–500 nm) further enhanced pollutant removal, achieving up to 72% COD and 89% TPC reduction in batch experiments. Column studies confirmed the synergistic effect of mixed particle sizes, yielding 65% COD and 76% TPC removal. The combined process demonstrates the potential of lime–limestone composites as locally available and eco-friendly materials for OMW treatment. While promising, the results represent laboratory-scale findings; further optimization and long-term assessments are recommended for field applications. Full article

Silver nanoparticles (AgNPs) have drawn great attention, owing to their unique physico-chemical and biological properties and various applications, particularly in the biomedical field. In addition to conventional chemical and physical methods, materials scientists have been exploring the capabilities endowed by several bioresources, such as plants, bacteria, fungi and algae, in the cost-effective and eco-friendly production of AgNPs. This review article provides a comprehensive overview of the current state of research on the bioapplications of biogenic AgNPs (bio-AgNPs). The various bioresources used and methodologies followed to synthesize bio-AgNPs are briefly examined, along with some aspects of the underlying mechanisms. Then, the review surveys the toxicity of AgNPs, in general, and presents the unique biological properties of bio-AgNPs. Furthermore, the review details numerous applications of bio-AgNPs with paramount importance to human health, such as the control of infectious disease vectors, cancer therapy, antibiofilm activity and environmental remediation. Importantly, the review highlights the paradoxical effect of these nano-objects since they specifically seem to exert their action solely on targeted cells and (micro)organisms. By featuring the unique advantages of biogenic methods and their challenges, this article aims at serving as a valuable resource to attract research on bio-AgNPs and elicit further developments towards the scalable and sustainable production of AgNPs for large scale industrial and clinical use. Full article

Heavy metals (HMs) contamination in agricultural soils poses significant risks to crop production and human health through bioaccumulation in the food chain. While traditional remediation techniques exist, they often face limitations including high operational costs, low efficiency, and time-intensive processes. Nano-enabled agrochemicals have emerged as a promising solution for HM remediation in contaminated soils. In this review, we highlight distinct nano-enabled mechanisms involved in HMs remediation in agricultural soils. Further, this review describes HM remediation potential of three different classes of nano-agrochemicals exhibiting unique physicochemical properties, such as surface charge, controlled release capability, and metal chelating ability, etc. Nano-agrochemicals also enhance plant resilience through multiple pathways, such as the regulation of nutrient profiles and photosynthesis, activation of antioxidant defense systems, modulation of protein and osmolyte synthesis, stimulation of phytohormone pathways, and activation of stress-responsive transcription factors. While nano-agrochemicals show tremendous potential for sustainable agriculture, their environmental impact and safety considerations require careful assessment. The review highlights the need for continued research to fully understand nano-agrochemical interactions with plants and soil ecosystems, and to develop improved strategies for their safe and effective implementation in agricultural systems. Future studies should focus on optimizing nano-agrochemical formulations, investigating long-term effects, and establishing comprehensive risk assessment frameworks. Full article

Barium carbonate (BaCO₃) nanoparticles were synthesized by a facile hydrolysis route using BaCl₂ and KOH in aqueous solution, with atmospheric CO₂ as the carbonate source, without external agents. Their structural and morphological properties were investigated by XRD, ATR-FTIR, SEM, and BET, confirming the formation of a pure orthorhombic witherite phase with rod-like morphology and different surface specific areas. The crystallite size increased from 52 to 86 nm with higher precursor concentration and synthesis temperature, as predicted by a regression model correlating synthesis parameter with particle growth. When incorporated into polymer (PVC) and geopolymer (GP) matrices, BaCO₃ enhanced the photocatalytic degradation of methylene blue (MB) under solar light, with GP@Nano-BaCO₃ achieving a higher rate constant compared to PVC@Nano-BaCO₃. The results highlight that the synthesis strategy yields well-defined BaCO₃ nanoparticles with tunable structural features and promising photocatalytic potential when integrated in functional polymer matrices. Future work will address doping strategies and testing in real wastewater conditions. Overall, this synthesis strategy offers a reproducible and environmentally friendly route to BaCO₃ nanoparticles with potential applications in hybrid materials for visible light-driven environmental remediation. Full article

This study presents a comprehensive bibliometric analysis of 217 publications on nanomaterials for soil and groundwater remediation, sourced from the Scopus database, covering the period from 2010 to 2024. The findings highlight significant contributions from various countries, with India identified as the leading contributor, followed by China and the United States. This reflects robust international collaboration in addressing environmental contamination. The analysis also identifies influential journals in this field, particularly “Science of the Total Environment” and “Environmental Science and Technology”, which are recognized for their high citation impact and play a crucial role in disseminating research findings and advancing knowledge in nanomaterials for environmental remediation. A keyword co-occurrence analysis reveals six distinct clusters that emphasize critical research themes. The first cluster focuses on environmental toxicity, underscoring the risks posed by contaminants, particularly heavy metals and emerging pollutants such as PFAS, highlighting the need for advanced monitoring strategies. The second cluster showcases innovative nanoremediation technologies, particularly zero-valent iron (nZVI) and carbon nanotubes (CNTs), which are noted for their effectiveness in pollutant removal despite challenges like surface passivation and high production costs. The third cluster addresses heavy metals and phytoremediation, advocating integrated strategies that enhance crop resilience while managing soil contamination. The fourth cluster explores photocatalysis and advanced oxidation processes, demonstrating how nanomaterials can enhance pollutant degradation through light-activated catalytic methods. The fifth cluster emphasizes adsorption mechanisms for specific contaminants, such as arsenic and pharmaceuticals, suggesting targeted remediation strategies. Finally, the sixth cluster highlights the potential of nanomaterials in agriculture, focusing on their role in improving soil fertility and supporting plant growth. Overall, while nanomaterials demonstrate significant potential for effective environmental remediation, they also pose risks that necessitate careful consideration and further research. Future studies should prioritize optimizing these materials for practical applications, addressing both environmental health and agricultural productivity. Full article

Lead (Pb) in soil poses serious environmental and health risks, and its removal requires complex and costly treatment methods to meet strict regulatory standards. To effectively address this challenge, innovative and efficient techniques are essential. Sepiolite-supported MnFe₂O₄ (MnFe₂O₄/SEP) composites were synthesized via a chemical co-precipitation method. The effects of MnFe₂O₄/SEP on soil pH, cation exchange capacity (CEC), available Pb content, Pb²⁺ uptake, and the activities of antioxidant enzymes in Brassica chinensis (Pak Choi) were examined. MnFe₂O₄/SEP showed superior Pb²⁺ adsorption compared to SEP alone, fitting Langmuir models, Dubinin-Radushkevich (D-R) models, Temkin models and pseudo-second-order kinetics. The maximum adsorption capacities at 298, 308, and 318 K were 459, 500 and 549 mg·g⁻¹, respectively. XPS analysis indicated that chemisorption achieved through ion exchange between Pb²⁺ and H⁺ was the main mechanism. MnFe₂O₄/SEP increased the soil pH by 0.2–1.5 units and CEC by 18–47%, while reducing available Pb by 12–83%. After treatment with MnFe₂O₄/SEP, acid-extractable and reducible Pb in the soil decreased by 14% and 39%, while oxidizable and residual Pb increased by 26% and 21%, respectively. In Brassica chinensis, MnFe₂O₄/SEP reduced Pb²⁺ uptake by 76%, increased chlorophyll content by 36%, and decreased malondialdehyde (MDA) levels by 36%. The activities of antioxidant enzymes—superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)—were decreased by 29%, 38% and 17%, respectively. These findings demonstrate that MnFe₂O₄/SEP is an efficient Pb²⁺ adsorbent that immobilizes Pb in soil mainly through ion exchange, thereby providing a highly effective strategy for remediating Pb-contaminated soils and improving plant health. Full article

With the increasing severity of cadmium (Cd) contamination in soil and its persistent toxicity, developing efficient remediation methods has become a critical necessity. In this study, sodium borohydride (NaBH₄) and tea polyphenols (TP) were employed as reducing agents to synthesize biochar (BC)-supported nanoscale zero-valent iron (nZVI), denoted as BH₄-nZVI/BC and TP-nZVI/BC, respectively. The effects of dosage, pH, and reaction time on Cd immobilization efficiency were systematically investigated. Both composites effectively stabilized Cd, significantly reducing its mobility and toxicity. Toxicity Characteristic Leaching Procedure (TCLP) results showed that Cd leaching concentrations decreased to 8.23 mg/L for BH₄-nZVI/BC and 4.65 mg/L for TP-nZVI/BC, corresponding to performance improvements of 29.9% and 60.5%. The immobilization process was attributed to the reduction of Cd(II) into less toxic species, together with adsorption and complexation with oxygen-containing groups (-OH, -COOH, phenolic) on biochar. TP-nZVI/BC exhibited superior long-term stability, while maintaining slightly lower efficiency than BH₄-nZVI/BC under certain conditions. Microbial community analysis revealed minimal ecological disturbance, and TP-nZVI/BC even promoted microbial diversity recovery. Mechanistic analyses further indicated that tea polyphenols formed a protective layer on nZVI, which inhibited particle agglomeration and oxidation, reduced the formation of iron oxides, preserved Fe⁰ activity, and enhanced microbial compatibility. In addition, the hydroxyl and phenolic groups of tea polyphenols contributed directly to Cd(II) complexation, reinforcing long-term immobilization. Therefore, TP-nZVI/BC is demonstrated to be an efficient, sustainable, and environmentally friendly amendment for Cd-contaminated soil remediation, combining effective immobilization with advantages in stability, ecological compatibility, and long-term effectiveness. Full article

Brazil leads tropical agriculture, yet annual yield losses from insect pests and concerns over water contamination, non-target impacts, and resistance sustain demand for safer, more efficient control tools. This review synthesizes advances in nanopesticides for Brazil’s major crops (soybean, sugarcane, coffee, and citrus) and is organized into five parts, comprising concepts and definitions; formulation families; modes of action; efficacy evidence from laboratory, greenhouse, and field studies; and environmental and human health risk considerations. Evidence indicates that nano-enabled delivery can increase on-target deposition, prolong residual activity, and match or exceed control at reduced active ingredient loads by improving foliar adhesion, transcuticular transport, plant uptake, and spatiotemporal targeting with pheromone-releasing nanofibers and other dispensers. Because nanoformulations can alter exposure pathways and environmental fate, this review emphasizes nano-specific physicochemical characterization under use conditions, fate and transport in Oxisols and Ultisols, and tropical waters, ecotoxicity panels that include pollinators, aquatic invertebrates, soil biota, and vertebrate surrogates, and scenario-based exposure assessment for applicators, residents, and consumers. The review closes with practical guidance for Brazil: head-to-head efficacy benchmarks against commercial standards, the standardized reporting of release and characterization data, and a nano-specific environmental risk assessment checklist to help realize efficacy gains while protecting environmental and human health. Full article

Addressing the urgent need for robust and sustainable catalysts to detoxify nitroaromatic pollutants, this study introduces a novel approach for synthesizing cobalt oxide nanocomposites via pyrolysis of cobalt benzene-1,3,5-tricarboxylate. By integrating porous carbon (PC) and nano silica (NS) supports with Co₃O₄ to form (Co₃O₄/PC) and (Co₃O₄/NS), we achieved precise morphological control, as evidenced by SEM and TEM analysis. SEM revealed 80–500 nm Co₃O₄ microspheres, 300 nm Co₃O₄/PC microfibers, and 2–5 µm Co₃O₄/NS spheres composed of 100 nm nanospheres. TEM further confirmed the presence of ~15 nm nanoparticles. Additionally, FTIR spectra exhibited characteristic Co–O bands at 550 and 650 cm⁻¹, while UV–Vis absorption bands appeared in the range of 450–550 nm, confirming the formation of cobalt oxide structures. Catalytic assays toward p-nitrophenol reduction revealed exceptional kinetics (k = 0.459, 0.405, and 0.384 min⁻¹) and high turnover numbers (TON = 5.1, 6.7, and 6.3 mg 4-NP reduced per mg of catalyst), outperforming most of the recently reported systems. Notably, both supported catalysts retained over 95% activity after two regeneration cycles. These findings not only fill a gap in the development of efficient, regenerable cobalt-based catalysts, but also pave the way for practical applications in environmental remediation. Full article

With the rapid advances of the electronics industry, a large amount of acidic etching waste solutions (AEWS) for etching Printed Circuit Board (PCB) are generated, which require complete remediation and sustainable recycling to avoid environmental pollution and wasting of resources. Herein, the novel purification technology for the acidic copper-containing etching waste solution was exploited via integrated alkali gradient pH control (3.0, 3.2, and 3.5). At pH 3.0, the system demonstrated selective metal removal with 94.02% efficiency for Fe and 82.60% for Mn. Elevating the pH to 3.2 enabled effective elimination of Zn (59.32%), Cr (59.46%), and Al (33.24%), while maintaining minimal copper loss (8.16%). Further pH adjustment to 3.5 achieved enhanced removal efficiencies of 97.86% (Fe), 91.30% (Mn), 59.38% (Zn), 62.10% (Cr), 21.66% (Ca), 34.05% (Al), and 26.66% (Co), with copper retention remaining high at 70.83% (29.17% loss). Furthermore, using the purified AEWS (pH 3.2) as precursor, high-purity nano-CuO was successfully synthesized through a Cu₂(OH)₃Cl conversion-calcination process, exhibiting 99.20% CuO purity with 0.0012% chlorine content and <0.1% metallic impurities. The development and application of the purification technology for AEWS containing copper, along with the production methodology for high-purity CuO, were significant to the fields of electronic information industry, environmental engineering, green industry and sustainable development of the ecological environment. Full article

This study presents a plant-fabricated nanoparticle system of zirconia (ZrO₂) using Sonchus asper plant extract, compared with conventionally synthesized ZrO_2, for their efficacy in Cr(VI) removal from aqueous solutions. The nanoparticles were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS) for elemental composition, Fourier-transform infrared spectroscopy (FTIR), and Brunauer–Emmett–Teller (BET) analysis. The plant-fabricated ZrO₂ exhibited mesoporosity and enhanced surface functionality, attributed to bioactive compounds from Sonchus asper, which improved adsorption performance via increased surface area and residual organic functional groups. Batch adsorption experiments showed that Cr(VI) removal was optimized at 100 mg/L Cr(VI), 300 mg/L adsorbent dosage, pH 5, and 30 min reaction time at 25 °C. Adsorption followed the Langmuir isotherm and pseudo-second-order kinetics models. According to Langmuir model fitting, the maximum adsorption capacity (qmax) reached 142.24 mg/g for PF-ZrO₂ NPs and 133.11 mg/g for conventional ZrO₂ NPs, indicating the superior adsorption performance of the green-synthesized material. This work highlights the sustainable potential of plant-fabricated ZrO₂ nanoparticles as cost-effective and environmentally friendly nano-adsorbents for heavy metal remediation, contributing to the achievement of UN SDG No. 6 by providing clean water solutions. Full article

This study evaluates and compares the sorption performance of natural zeolite (NZ) and Fe(III)-modified zeolite (FeZ) in removing Cu(II) ions from aqueous solutions, with the goal of assessing their potential for environmental remediation. NZ was modified with Fe(NO₃)₃, NaOH and NaNO₃ solutions to improve its sorption properties. The modification led to a slight decrease in crystallinity (XRD), increase in pore volume (BET), functional groups (FTIR) and negative surface charge (zeta potential), thereby improving the affinity of FeZ towards Cu(II). Batch sorption experiments were conducted to optimize key parameters including pH, solid/liquid ratio (S/L), contact time, and initial Cu(II) concentration. The pH_o and S/L ratio were identified as key factors significantly influencing Cu(II) sorption on both zeolites, with a particularly pronounced effect observed for FeZ. The optimal conditions determined were pH_o = 3–5 for NZ, pH_o = 3 for FeZ, S/L = 10 g/L and a contact time of 600 min. Experimental results confirmed that FeZ has almost twice the sorption capacity for Cu(II) compared to NZ (0.271 mmol/g vs. 0.156 mmol/g), as further supported by elemental analysis, SEM-EDS and mapping analysis of saturated samples. The sorption of Cu(II) followed a mechanism of physical nature driven by ion exchange, dominated by intraparticle diffusion as the rate-controlling step. Leaching of copper-saturated zeolites according to the standard leaching method, DIN 38414 S4, demonstrated the ability of both zeolites to fully retain Cu(II) within their structure over a wide pH range, 4.01 ≤ pH_o ≤ 10.06. These findings highlight the superior performance of FeZ and its potential as an effective material for the remediation of copper-contaminated environments. Full article

In this study, we report the development of a novel magnetized coal fly ash-supported nano-silver composite (AgNPs/MCFA) for dual-functional applications in wastewater treatment: the efficient degradation of methyl orange (MO) dye and broad-spectrum antibacterial activity. The composite was synthesized via a facile impregnation–reduction–sintering route, utilizing sodium citrate as both a reducing and stabilizing agent. The AgNPs/MCFA composite was systematically characterized through multiple analytical techniques, including Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and vibrating sample magnetometry (VSM). The results confirmed the uniform dispersion of AgNPs (average size: 13.97 nm) on the MCFA matrix, where the formation of chemical bonds (Ag-O-Si) contributed to the enhanced stability of the material. Under optimized conditions (0.5 g·L⁻¹ AgNO₃, 250 °C sintering temperature, and 2 h sintering time), AgNPs/MCFA exhibited an exceptional catalytic performance, achieving 99.89% MO degradation within 15 min (pseudo-first-order rate constant k_a = 0.3133 min⁻¹) in the presence of NaBH₄. The composite also demonstrated potent antibacterial efficacy against Escherichia coli (MIC = 0.5 mg·mL⁻¹) and Staphylococcus aureus (MIC = 2 mg·mL⁻¹), attributed to membrane disruption, intracellular content leakage, and reactive oxygen species generation. Remarkably, AgNPs/MCFA retained >90% catalytic and antibacterial efficiency after five reuse cycles, enabled by its magnetic recoverability. By repurposing industrial waste (coal fly ash) as a low-cost carrier, this work provides a sustainable strategy to mitigate nanoparticle aggregation and environmental risks while enhancing multifunctional performance in water remediation. Full article

Silver nanoparticles (AgNPs), iron oxide nanoparticles (Fe₂O₄NPs), and multiwalled carbon nanotubes (MWCNTs) are widely used in various applications, such as biomedicine, environmental remediation, and agriculture. In addition, these nanomaterials can affect the production of bioactive compounds in plants that have pharmacological activities. In the current study, the in vitro plant cultures of Chinese lobelia (Lobelia chinensis Lour.) were established in MS medium and treated with 0, 12.5, 25, 37.5, and 50 mg L⁻¹ AgNPs or Fe₂O₄NPs, or MWCNTs. Initially, plants were grown for four weeks without any elicitors, and after that, the cultures were treated with nano-elicitors for one week. After five weeks, the effects of nano-elicitors were estimated on growth, total phenolic, flavonoids, polyacetylenes, and ABTS/DPPH/FRAP antioxidant activity was investigated. The results showed that lower levels of AgNPs (25 mg L⁻¹), Fe₂O₄NPs (25 mg L⁻¹), and MWCNTs (12.5 mg L⁻¹) favored the accumulation of fresh and dry biomass. Whereas, 37.5 mg L⁻¹ AgNPs, 25 mg L⁻¹ Fe₂O₄NPs, and 37.5 mg L⁻¹ MWCNTs enhanced the accumulation of total phenolics, flavonoids, specific phenolic compounds including chlorogenic acid, catechin, phloretic acid, coumaric acid, salicylic acid, naringin, myricetin, linarin, and polyacetylenes viz. lobetylonin and lobetyolin in higher concentrations. The plant extracts elicited by nanomaterials also depicted very good antioxidant activities according to ABTS, DPPH, and FRAP assays. These results suggest that specific nanomaterials, and at specific levels, could be used for the production of bioactive compounds from shoot cultures of Chinese lobelia. Full article

Due to its persistence and potential negative effects on ecosystems and human health, microplastic pollution in aquatic environments has become a major worldwide concern. Photocatalytic degradation is a sustainable manner to degrade microplastics to non-toxic by-products. In this review, comprehensive discussion focuses on the synergistic effects of various photocatalytic materials including TiO₂, ZnO, WO₃, graphene oxide, and metal–organic frameworks for producing heterojunctions and involving multidimensional nanostructures. Such mechanisms can include the generation of reactive oxygen species and polymer chain scission, which can lead to microplastic breakdown and mineralization. The advancements of material modifications in the (nano)structure of photocatalysts, doping, and heterojunction formation methods to promote UV and visible light-driven photocatalytic activity is discussed in this paper. Reactor designs, operational parameters, and scalability for practical applications are also reviewed. Photocatalytic systems have shown a lot of development but are hampered by shortcomings which include a lack of complete mineralization and production of intermediary secondary products; variability in performance due to the fluctuation in the intensity of solar light, limited UV light, and environmental conditions such as weather and the diurnal cycle. Future research involving multifunctional, environmentally benign photocatalytic techniques—e.g., doped composites or composite-based catalysts that involve adsorption, photocatalysis, and magnetic retrieval—are proposed to focus on the mechanism of utilizing light effectively and the environmental safety, which are necessary for successful operational and industrial-scale remediation. Full article