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The class of insecticides known as neonicotinoid insecticides has gained extensive application worldwide. Two characteristics of neonicotinoid pesticides are excellent insecticidal activity and a wide insecticidal spectrum for problematic insects. Neonicotinoid pesticides can also successfully manage pest insects that have developed resistance to other insecticide classes. Due to its powerful insecticidal properties and rapid plant absorption and translocation, dinotefuran, the most recent generation of neonicotinoid insecticides, has been widely used against biting and sucking insects. Dinotefuran has a wide range of potential applications and is often used globally. However, there is growing evidence that they negatively impact the biodiversity of organisms in agricultural settings as well as non-target organisms. The objective of this review is to present an updated summary of current understanding regarding the non-target effects of dinotefuran; we also enumerated nano- and bio-based mitigation and management strategies to reduce the impact of dinotefuran on non-target organisms and to pinpoint knowledge gaps. Finally, future study directions are suggested based on the limitations of the existing studies, with the goal of providing a scientific basis for risk assessment and the prudent use of these insecticides.
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Guanidinas , Inseticidas , Animais , Inseticidas/toxicidade , Ecossistema , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , InsetosRESUMO
Malachite green (MG) dye and cadmium metal ion are toxic pollutants that should be removed from aqueous environment. The recent study aimed to examine the adsorption behavior of MG dye and Cd (II) from wastewater onto low-cost adsorbent prepared by activating corn silk with nitric acid (ACS) and characterized by SEM, FTIR, XRD, BET and TGA. The optimum MG and Cd (II) adsorption was observed at pH 7 and pH 9 and maximum uptake of both pollutants was at 0.5 g dosage, 60 mins contact time and 20 mg/L initial concentration. The retention of dye and metal ion by the studied adsorbent was best fit to Langmuir isotherm and Pseudo-second order kinetics. The maximum monolayer coverage capacity of ACS for MG dye and Cd (II) ion was 18.38 mg/g and 25.53 mg/g, respectively. Thermodynamic studies predicted a spontaneous reaction with exothermic process for MG dye whereas an endothermic and spontaneous process was confirmed for Cd ion based on estimated parameters. The adsorption mechanism of MG dye and Cd (II) uptake was by combination of electrostatic interaction, pore diffusion, ion exchange, pie-pie attraction, hydrogen bonding, and complexation. The adsorbed pollutants were effectively desorbed with significant regeneration efficiency after successive five cycles that proved the potential of low-cost biosorbent for selective sequestration of cationic dye and divalent metal ion from effluents.
The use of nitric acid-modified corn silk has been reported to enhance its adsorption performance over the unmodified cob for pollutants such as cadmium ions and malachite green. Although there may be no recorded data on the adsorption efficiency of acid-treated corn silk for selected pollutants, it can be considered as a prospective bio-sorbent owing to its chemical composition and functional groups for exchange of hydrogen ions for other cations.
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Cádmio , Corantes de Rosanilina , Termodinâmica , Águas Residuárias , Poluentes Químicos da Água , Zea mays , Cádmio/metabolismo , Poluentes Químicos da Água/metabolismo , Zea mays/metabolismo , Adsorção , Cinética , Águas Residuárias/química , Corantes de Rosanilina/química , Biodegradação Ambiental , Eliminação de Resíduos Líquidos/métodos , Corantes/químicaRESUMO
NOVELTY STATEMENT: nsufficient innovative research on the sequestration of Cr(VI) from the aquatic ecosystem has made Cr(VI) a recalcitrant water contaminant that often affects water sources. In this work, a novel plant anchor-nanocomposite was fabricated from the spent molecular sieve, multi-walled carbon nanotubes, and the extract from the stem bark of Pentaclethra macrophylla. It was envisaged that due to the phytochemical constituent of the modifier, this nanocomposite could also act as potent adsorbents for the treatment of Cr(VI) polluted water. To the best of our knowledge, the application of Pentaclethra macrophylla stem bark extract as a modifier for the green fabrication of nanocomposite has not been reported. The resulting composites showed good uptake capacity for Cr(VI) as well as efficient reusability.
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Fabaceae/química , Nanocompostos , Nanotubos de Carbono , Extratos Vegetais/química , Poluentes Químicos da Água , Purificação da Água , Adsorção , Biodegradação Ambiental , Cromo , Ecossistema , Concentração de Íons de Hidrogênio , Cinética , Casca de Planta/química , Poluentes Químicos da Água/análiseRESUMO
The high efficiency of metal-organic-frameworks (MOFs) such as the ZIF, MIL and UiO type species in dye adsorption is well established. Recently, an emerging class of photoresponsive azobenzene-based MOFs has found suitable application in gas adsorption. However, there is a dearth of research on their use in the adsorption of dyes and other water pollutants. In this research, two microporous photoresponsive azobenzene dicarboxylate MOFs of Al3+ (Al-AZB) and Zr4+ (Zr-AZB) were synthesized for the adsorption of congo red (CR) dye. The surface and textural properties of the synthesized MOFs were characterized by FTIR, PXRD, SEM, TGA, BET and pore analysis. Both MOFs were crystalline, thermally stable up to 300 °C and stable in aqueous medium at room temperature. The Al-AZB displayed a higher surface area (2718 m2/g) than the Zr-AZB (1098 m2/g), which significantly impacted the higher adsorption of CR. Besides, pore volumes of 0.86 cm3/g and 0.35 cm3/g were obtained for Al-AZB and Zr-AZB, respectively. The maximum adsorption capacity of Al-AZB and Zr-AZB was 456.6 mg/g and 128.9 mg/g, respectively, with the former superior to other potent adsorbents. The pseudo-second-order and Langmuir models were well correlated with the dye uptake on the MOFs. Thermodynamics revealed random and endothermic sorption of CR dominated by chemisorption, while efficient regeneration and reuse of both MOFs were achieved using dimethylformamide as eluent. The results proved the potency of the synthesized photoresponsive MOFs, as highly efficient and reusable materials for dye adsorption.
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Estruturas Metalorgânicas , Adsorção , Alumínio , Compostos Azo , Corantes , ZircônioRESUMO
The aim of the study was to investigate biogenic amine production in different types of cooked protein foods. The food samples were incubated at varying temperatures (4, 37 and 55 °C) on different microbiological media for 48, 72 and 180 h. Resulting bacteria were isolated and characterized using cultural, biochemical and molecular methods, further screened for production of biogenic amines in decarboxylase broth media supplemented with 0.4% of histidine, tyrosine, lysine and ornithine. The samples were incubated at 25 °C for 48 h and the biogenic amine concentration in each food sample determined by means of HPLC. There was a high prevalence of the isolates among the food samples. All the isolates except Klebsiella sp. and Pseudomonas sp. were positive for decarboxylase activity indicating 84.6% of the isolates capable of biogenic amine production. The amine concentration varied among the types of food and methods of cooking. Histamine was detected in 41.67% of the inoculated food samples (9.2 ± 1.2-100.95 ± 0.1 µg/g) while putrescine was the least detected (41.67%) in the inoculated food sample (7.7 ± 0.1-8.8 ± 0.2 µg/g). Cadaverine and histamine were detected in 16.4% (2.6 ± 0.2-49.9 ± 0.9 µg/g) and 7.5% (1.4 ± 0.1-20.4 ± 0.3 µg/g) of the foods, respectively. Microbial contamination of the cooked protein foods led to high levels of biogenic amines irrespective of the cooking methodology adopted and type of foods investigated. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-022-05576-0.
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The current study aimed on isolating thermotolerant, cellulolytic fungi from different tropical soil/waste materials samples such as wood waste, sawmill, decomposing straw and compost pit sites in Abraka, Southern Nigeria and assessing their applications in diverse cellulolytic processes. Fungal isolates were identified based on cultural, morphological, ITS-5.8S barcoding, reproductive structures and thereafter screened for thermotolerance and cellulolytic activities [carboxy methyl cellulase (CMC-ase) and filter paperase (FP-ase)] by cultivating at 45, 50, 60, 70, 80° and 45 °C, respectively. The highest fungal abundance (44.4%) was observed in the compost pit while the lowest (11.1%) was recorded for sawmill. Nine thermotolerant fungal isolates were identified: Aspergillus flavus (4), Blakeslea sp. (3), and Trichoderma asperellum (2). Among them only five, including three A. flavus, one Blakeslea sp. and one T. asperellum, exhibited cellulolytic activity ranging from 12.11 ± 0.01 to 18.42 ± 5.39 µg/mL and 0.36 ± 0.01-9.21 ± 2.52 µg/mL for CMC-ase and filter paperase FP-ase assay, respectively. The low Michaelis-Menten constants of 1.137 for CMC-ase and 1.195 for FP-ase were obtained, indicated a strong affinity for the substrate. The thermotolerance coupled with cellulolytic activity of these isolates make them attractive for potential application in industries where they can be of economic and environmental benefits as against the use of chemicals.
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Celulase , Termotolerância , Fungos/genética , Hypocreales , Nigéria , Solo , Microbiologia do SoloRESUMO
This research evaluated the adsorption of celestine blue (CB) onto a novel Solanum tuberosum waste-magnetite nanocomposite (Mt@STB), prepared by an ecofriendly impregnation of magnetite (Mt) nanoparticles onto Solanum tuberosum waste (STB). The adsorbents characterization revealed that Mt@STB had a surface area (18.92 m2/g), pHpzc (7.55), porous morphology as well as suitable functional groups for efficient sequestration of CB onto the composite. The SEM, XRD, and EDX showed successful incorporation of 31.21 nm average size Mt nanoparticles on Mt@STB. Faster kinetics of CB sequestration from the wastewater was obtained for Mt@STB (100 min) compared to STB (140 min). Among four isotherm models, the Langmuir exhibited the best fit with R2 > 0.9971 and sum square errors (SSE) < 0.0151. The pristine STB and Mt@STB composite showed maximum monolayer CEB uptake of 7.61 and 9.02 mg/g, as well as optimum removal of 73.8 and 84.7%, respectively. The pseudo-second-order model was more suitable in the kinetic description, while thermodynamics revealed a physical, spontaneous, and endothermic CB uptake. Besides, the efficacy of the composite for CB was confirmed from efficient regeneration over three adsorption/desorption cycles, which specified the viability of Mt@STB as a sustainable material for the decontamination of CB polluted water. NOVELTY STATEMENT The adsorption of dyes from wastewaters has been widely studied due to the harmful effects on the ecosystem. However, research on the removal of celestine blue (CB) dye is rare despite its wide use in the nuclear and textile industries. Until date, there is no report on the adsorption of CB on biomaterial via biosorption. Therefore, the biosorption behavior of CB is presently unknown. Hence, this study reports the biosorption of CB onto a biosorbent (Solanum tuberosum peel [STB]) in an attempt to understand its biosorption behavior. Besides, the impregnation of magnetite (Mt) nanoparticles has been reported to enhance the uptake of most adsorbents for dye. To the best of our knowledge, such magnetic nanoparticle impregnation of STB has not been reported. We, therefore, synthesized a novel biowaste-magnetite composite (Mt@STB) and evaluated its potentials for the uptake as well as its reuse for CB biosorption.
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Nanopartículas de Magnetita , Solanum tuberosum , Poluentes Químicos da Água , Purificação da Água , Adsorção , Biodegradação Ambiental , Corantes , Ecossistema , Concentração de Íons de Hidrogênio , Cinética , Oxazinas , Termodinâmica , Poluentes Químicos da Água/análiseRESUMO
A low-cost adsorbent (Detarium senegalense stem bark extract coated shale (DSMS)) comprising pristine shale (PSH) coated with D. senegalense stem bark extract was prepared and utilized for the adsorption of Cr(VI). The DSMS and PSH were characterized by the SEM, XRD, FTIR, EDX, TGA, and BET. The batch adsorption experiment results showed that DSMS exhibited an excellent ability to adsorb chromium with a maximum removal occurring at pH 2, dosage of 0.05 g and 180 min contact time. The adsorption process was best described by the pseudo-second-order for DSMS and Elovich model for PSH which depicts chemisorption as the major mechanism responsible for the uptake of Cr(VI) onto the adsorbents. Langmuir model provided the best fit to the isotherm analysis on both materials. The maximum adsorption capacity of DSMS and PSH were 64.98 mg g-1 and 29.97 mg g-1 respectively. The thermodynamics revealed that the adsorption of Cr(VI) was feasible, endothermic and entropy driven. Furthermore, after five cycles of reuse, both DSMS and PSH demonstrated effective regeneration and reusability for Cr(VI) uptake. The structural properties, reusability, and high adsorption capabilities of DSMS indicate that they could be used as low-cost adsorbents in large-scale Cr(VI) wastewater treatment. Novelty statement Plant extracts are packed with a variety of polyphenolic compounds, such as aldehydes, alcohols, carboxylics, ethers, ketones, and phenols which contains several functionalities useful in the adsorption of toxic metals. Despite this, research on the use of plant extracts in the modification of adsorbent materials for enhanced adsorption is rare. This study reports for the first time the use of Detarium senegalense stem bark extract coated shale adsorbent for the efficient uptake of Cr(VI) ion.
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Cromo/metabolismo , Fabaceae/química , Extratos Vegetais/química , Poluentes Químicos da Água , Purificação da Água , Adsorção , Biodegradação Ambiental , Concentração de Íons de Hidrogênio , Cinética , Casca de Planta/química , Termodinâmica , Poluentes Químicos da Água/análiseRESUMO
Cotton-based adsorbents (CBAs) are promising materials for combating the problem of heavy metal pollution of environmental waters. This is ascribed to the low cost, abundance, biodegradability and efficiency of CBAs. Herein we review the adsorption of heavy metals (HMs) onto CBAs. We found that several surface modifications were employed to improve the efficiency of the CBAs. These modifications were effected via thermal, physical and chemical means to obtain activated carbons, biochars, ionic liquids, aerogels, hydrogels, chitosans and nanoparticle-derived CBAs. The CBAs exhibited maximum HMs uptake as low as 0.002 mg/g to as high as 505.6 mg/g. Although, the cotton-derived activated carbons and biochars exhibited enhanced HM uptake from that of the unmodified CBAs, they were less efficient than CBAs modified by other methods. Recent chemical, ionic liquid, chitosan and nano-derived CBAs were the most efficient, with high uptake and fast kinetic removal. However, the nanoparticle-based adsorbents are preferred to the chemically modified forms, due to the possibility of secondary pollution and the noxious effect of the latter to the environment. Findings showed that chemical treatment produced CBAs most efficient for As(V), Pb(II) and Fe(III), while ionic liquid CBA was more efficient for Cu(II) and Ni(II). Nano-based treatment was suitable for the uptake of Co(II), Zn(II), Pb(II) and Cd(II), while the chitosan based adsorbent was viable for Hg(II). Isotherm and kinetic evaluation of CBAs mostly conformed to the Langmuir and pseudo-second order models, respectively. Spontaneous adsorption of HMs onto CBAs was deduced from thermodynamic analysis, with endothermic and exothermic characteristics. Over 88% desorption of HMs was obtained from the CBAs studied with good average reusability from 3 to 20 cycles. We also discussed the directions for future research.
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Gossypium/química , Metais Pesados/análise , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Biodegradação Ambiental , Carvão Vegetal/química , Quitosana/química , Íons , Cinética , TermodinâmicaRESUMO
This work evaluated the use of Dialium guineense seed waste (DGS) and its sodium hydroxide modified form (NH-DGS) as biosorbent for ciprofloxacin (CPF) from synthetic solution as well as the desorption potentials. Central composite design (CCD) was applied for optimization of the alkaline treated biosorbent by response surface methodology using design expert. Both biosorbents were characterized by FTIR, SEM, EDX, and BET analysis. The CCD showed NaOH concentration of 0.46 M and temperature of 96 °C to be effective for optimized modification of NH-DGS. Optimum removal of CPF was obtained at pH 6.0, contact time 120 min, temperature 300 K, and dosage of 0.1 g. The Freundlich model gave the best fit compared to the other isotherms tested with R2 values >0.97951. NH-DGS exhibited a maximum uptake capacity of 120.34 mg/g higher than some reported adsorbents for CPF. The pseudo-second-order model was suitable in the fitting of the kinetic data. A non-spontaneous process was obtained for CPF biosorption on DGS which became spontaneous after alkaline treatment. Over 84% desorption of CPF was achieved on both biosorbents using 0.3 M HCl which envisaged the use of NH-DGS as an efficient material for treatment of waters contaminated with CPF.
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Ciprofloxacina , Poluentes Químicos da Água/análise , Adsorção , Biodegradação Ambiental , Concentração de Íons de Hidrogênio , Cinética , Pós , Sementes , TermodinâmicaRESUMO
Polychlorinated naphthalenes (PCNs) were included in the banned list of the Stockholm Convention due to their potential to provoke a wide range of adverse effects on living organisms and the environment. Many reviews have been written to clarify the state of knowledge and identify the research needs of this pollutant class. However, studies have yet to analyse the scientometric complexities of PCN literature. In this study, we used bibliometric R and vosviewer programs as a scientometric tool to fill this gap by focusing on articles indexed on Web of Science and Scopus databases and those published between 1973 and 2022. A total of 707 articles were published within this period with a publication/author, author/publication, and co-authors/publication ratios of 0.45, 2.19, and 4.86, respectively. Developed countries dominated most scientometric indices (number of publications, citations, and collaboration networks) in the survey period. Lotka's inverse square rule of author productivity showed that Lotka's laws do not fit PCN literature. An annual percentage growth rate of 7.46% and a Kolmogorov-Smirnoff goodness-of-fit of 0.88 suggests that more output on PCNs is likely in years to come. More research is needed from scholars from developing countries to measure the supremacy of the developed nations and to effectively comply with the Stockholm Convention agreement.
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Bibliometria , Naftalenos , Poluentes AmbientaisRESUMO
Copper oxide nanoparticles (CuONPs) have received tremendous attention as efficient adsorbents owing to their low cost, desirable surface area, abundant active sites, potent textural characteristics and high adsorption capacities. However, CuONPs have not been employed to decontaminate water laden with increasing environmental contaminants such as thiazolyl blue and paracetamol. Herein, the adsorption of thiazolyl blue and paracetamol onto green synthesized CuONPs prepared from the aqueous leaf extract of Platanus occidentalis was studied. The BET, SEM, FTIR, XRD, EDX and pH point of zero charge showed the successful synthesis of CuONPs having desirable surface properties with a surface area of 58.76 m2/g and an average size of 82.13 nm. The maximum monolayer adsorption capacities of 72.46 mg/g and 64.52 mg/g were obtained for thiazolyl blue and paracetamol, respectively. The Freundlich, pseudo-second-order and intraparticle diffusion models were well fitted to the adsorption of both pollutants. The pH studies suggested the predominance of electrostatic and weaker intermolecular interactions in the adsorption of the thiazolyl blue and paracetamol, respectively. Spontaneous, physical, endothermic and random adsorption of the pollutants on CuONPs was obtained from the thermodynamic consideration. The biosynthesized CuONPs were found to be highly reusable and efficient for the adsorption of thiazolyl blue and paracetamol from water.
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Nanopartículas , Poluentes Químicos da Água , Acetaminofen , Adsorção , Cobre , Nanopartículas/química , Água/química , Poluentes Químicos da Água/análise , Cinética , Concentração de Íons de Hidrogênio , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
Persistent organic pollutants (POPs) are toxic chemicals that stay in the environment for a long time. To address the toxicity issues, global nations, including 53 African countries, ratified the Stockholm Convention to minimize or eliminate the production of 12 POPs known as the "Dirty Dozen". However, these Dirty Dozen Chemicals (DDCs) still exist in significant concentration in the African environment, prompting numerous research to investigate the level of their occurrences. Here, we conducted a bibliometric analysis to examine the publication trends in DDCs-related research in Africa using articles published between 1949 and 2021 from the Web of Science and Scopus databases. A total of 884 articles were published within the survey period, with a publication/author and author/publication ratio of 0.36 and 2.76, respectively. South Africa ranked first in terms of number of publications (n = 133, 15.05%), and total citations (n = 3115), followed by Egypt (n = 117), Nigeria (n = 77), USA (n = 40), and Ghana (n = 38). Research collaboration was relatively high (collaboration index = 2.88). The insignificant difference between the theoretical and observed Lotka's distribution indicates Lotka's law does not fit the DDC literature. An annual growth rate of 0.57% implies that a substantial increase of articles in years to come is not expected. More research programs should be established in other African countries to measure up to South Africa's supremacy. This is critical in order to provide a basis for effective compliance to the Stockholm Convention on POPs in Africa.
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Poluentes Ambientais , Poluentes Orgânicos Persistentes , Bibliometria , Egito , Poluentes Ambientais/análise , GanaRESUMO
There has been an increase in the use of antidepressant drugs owing to significant economic challenges across the globe. Consequently, the increase in production of such drugs has impacted pharmaceutical pollution of industrial wastewaters discharged into the environment. Hence, there is a need to develop efficient adsorbents for antidepressant wastewater treatment. The impregnation of silver nanoparticles on biowaste was found to be highly effective in the treatment of oil-polluted water but has not been utilized in the adsorption of drugs. Herein, the dataset associated with the adsorption of antidepressants onto Ananas Comosus Peel (AP) and Silver nanoparticle-loaded Ananas Comosus peel (AgAP) was reported. Batch adsorption methodology was used to study the effect of antidepressant concentration (10-50 mg/L), sonication time (10-120 min), temperature (300-320 K) and adsorbent dosage (0.10-0.18 g). The concentration of antidepressant (Nortriptyline) in solution before and after adsorption was determined by the UV-Spectrophotometer at a maximum wavelength of 239 nm. The isotherm dataset was obtained from the Langmuir, Freundlich, Temkin and Dubinin-Raduskevich models, while kinetic data was evaluated by the pseudo-first order-pseudo-second-order, film diffusion and intraparticle diffusion rate equations. The data on the thermodynamics and adsorbent reusability were also provided. The dataset showed an adsorption capacity of 3.27 mg/g and 4.74 mg/g for AP and AgAP, respectively. The dataset is important to material and environmental scientists and revealed the efficiency of AP and AgAP in the treatment of antidepressant wastewater.
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Metallic nanoparticles (NPs) have gained significant attention in recent years due to their efficiency in the adsorption of water pollutants. Except for magnetic NPs, metallic NPs are rarely used in oil sorption studies, due to the difficulty in recovering the NPs from the treated water. This study reports for the first time the application of ZnONPs for oil spill treatment. The ZnONPs were impregnated onto Musa acuminata peel (MP) support to form a novel material (ZnOMP), which was utilized for the sorption of oil from synthetic oil spills. The as-prepared sorbents were characterized by the SEM, EDS, BET, FTIR, FE-SEM, TGA, and XRD techniques. The presence of 31.32-nm average-sized ZnONPs enhanced the oil uptake characteristics, with clear affinity for the oil phase in comparison to the pristine MP. A maximum sorption capacity of 4.146 g/g and 5.236 g/g was obtained for biosorbents MP and ZnOMP, respectively, which was higher than most reported sorbents. The Freundlich model presented the best fit for the isotherm data, while the pseudo-second-order model was most suited for the kinetics. The presence of competing heavy metal ions in solution did not have any significant effect on the oil sorption capacity onto ZnOMP. The sorption mechanism was attributed to absorption and hydrophobic interactions. ZnONPs impregnated onto the biomass enhanced the spontaneity of oil uptake at higher temperatures. Over 82% desorption of the oil contaminant from the biosorbents was achieved during recovery, using petroleum ether and n-pentane as eluents. Concisely, ZnONPs enhanced the uptake and hydrophobic characteristic of MP biomass and showed good recovery and reusability. Thus, the application of ZnONPs impregnated onto biosorbents in oil spill treatment is highly recommended.
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Poluição por Petróleo , Poluentes Químicos da Água , Óxido de Zinco , Adsorção , Biomassa , Interações Hidrofóbicas e Hidrofílicas , Cinética , Propriedades de Superfície , Poluentes Químicos da Água/análiseRESUMO
In this research, zinc oxide nanoparticles (ZnONPs) were prepared via a facile one-pot chemical precipitation approach and applied in the adsorption of bromophenol blue (BRB) and as antifungal agents against the filamentous fungi and plant pathogens; Alternaria alternata CGJM3078, Alternaria alternata CGJM3006 and Fusarium verticilliodes CGJM3823. The ZnONPs were characterized by the UV-Vis, FTIR, XRD, TGA, BET, SEM, TEM, and EDX techniques, which showed efficient synthesis. The characteristics ZnO UV-Vis absorption band was observed at 375 nm, while the XRD showed an average ZnONPs crystalline size of 47.2 nm. The SEM and TEM images showed an irregular shaped and aggregated porous structure of 65.3 nm average-sized ZnONPs. The TGA showed 22.9% weight loss at 800 °C indicating the high thermal stability of ZnONPs, while BET analysis revealed a surface area, pore volume and pore diameter of 9.259 m2/g, 0.03745 cm3/g and 9.87 nm respectively. The Freundlich, pseudo-second-order, and intra-particle diffusion models showed R2 > 0.9494 and SSE < 0.7412, thus, exhibited the best fit to the isotherm and kinetics models. Thermodynamics revealed feasible, endothermic, random, and spontaneous adsorption of BRB onto the synthesized ZnONPs. The antifungal assay conducted depicts strong antifungal activities against all three tested fungi. Noticeably, ZnONPs (0.002-5 mg/mL) showed maximum activities with the largest zone of inhibition against A. alternata CGJM 3006 from 25.09 to 36.28 mm. This was followed by the strain F. verticilliodes CGJM 3823 (range from 23.77 to 34.77 mm) > A. alternata CGJM3078 (range from 22.73 to 30.63 mm) in comparison to Bleach 5% (positive control). Additionally a model was proposed based on the possible underlying mechanisms for the antifungal effect. This research demonstrated the potent use of ZnONPs for the adsorption of BRB and as effective antifungal agents.
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Azul de Bromofenol/química , Precipitação Química , Fungos/efeitos dos fármacos , Nanopartículas , Óxido de Zinco/síntese química , Óxido de Zinco/farmacologia , Adsorção , Farmacorresistência FúngicaRESUMO
Aluminium oxide (ALU) and carbon-coated aluminium oxide modified with Kigelia africana leaf extract (KECA) were employed for the removal of toxic hexavalent chromium (Cr(VI)) from the aqueous phase. The adsorbents (ALU and KECA) were characterized by TGA, BET, FESEM, FTIR, Raman and XRD spectroscopic techniques. The potential of KECA and ALU to remove Cr(VI) from simulated wastewater was optimum at pH 2, sorbent dose of 0.025 g and a contact time of 200 min. Meanwhile, the uptake capacity of KECA and ALU was enhanced with an increase in sorbent dose, contact time and initial Cr(VI) concentration. The uptake of Cr(VI) onto the adsorbents ALU and KECA was kinetically best described by the pseudo-second-order and Elovich models, respectively. Besides, the equilibrium data acquired for ALU and KECA obeyed Freundlich and Langmuir isotherm models, respectively. ALU and KECA were observed to have optimum adsorption capacity of 56.45 mg g-1 and 258.2 mg g-1, respectively. The adsorption of Cr(VI) onto the adsorbents was thermodynamically feasible, endothermic in nature and entropy-driven. A decrease in efficiency was observed on regeneration of the absorbents, thus limiting their reusability. However, the presence of functional groups with reducing property in the extract of Kigelia africana leaves was noticed to enhance the capacity of the adsorbent to abstract Cr(VI) from the solution. Hence, this study demonstrates the potential of KECA to sequestrate Cr(VI) from an aqueous solution and provides a reference for its application to the treatment of Cr(VI)-laden industrial wastewater.
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Carbono , Poluentes Químicos da Água , Adsorção , Óxido de Alumínio , Cromo/análise , Concentração de Íons de Hidrogênio , Cinética , Extratos Vegetais , Poluentes Químicos da Água/análiseRESUMO
Multiwalled carbon nanotubes/quartzite nanocomposite modified with the extract of Dacryodes edulis leaves was synthesized and designated as Q, which was applied for the removal of Cr(VI) from water. The adsorbents (PQ and Q) were characterized using the SEM, EDX, FTIR, TGA, XRD, and BET analyses. The XRD revealed the crystalline composition of the nanocomposite while the TGA indicated the incorporated extract as the primary component that degraded with an increase in temperature. The implication of the modifier was noticed to enhance the adsorption capacity of Q for Cr(VI) by the introduction of chemical functional groups. Optimum Cr(VI) removal was noticed at a pH of 2.0, adsorbent dose (50 mg), initial concentration (100 mg dm-3), and contact time (180 min). The kinetic adsorption data for both adsorbents was noticed to fit well to the pseudo-second-order model. The adsorption equilibrium data were best described by the Langmuir model. The uptake of Cr(VI) onto PQ and Q was feasible, endothermic (ΔH: PQ = 1.194 kJ mol-1 and Q = 34.64 kJ mol-1) and entropy-driven (ΔS : PQ = 64.89 J K-1 mol-1 and q = 189.7 J K-1 mol-1). Hence, the nanocomposite demonstrated potential for robust capacity to trap Cr(VI) from aqueous solution.
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This work was aimed at the synthesis of a hybrid (STpe-AgNP), obtained by impregnation of silver nanoparticles (AgNP) onto Solanum tuberosum peel (STpe), for the ultrasonic assisted adsorption of bromophenol blue (BB) dye. SEM, FTIR, XRD, EDX, TGA and BET techniques were used to characterize the adsorbents. The XRD, SEM and EDX confirmed successful impregnation of AgNPs onto STpe to form the hybrid. The AgNPs impregnated onto the hybrid were found to be water stable at various pH values of 2.0-9.0. Chi-square (χ2 < 0.024) and linear regression (R2 > 0.996) showed that the Freundlich model was best fitted among the isotherm models, corroborated by the oriented site model. Kinetic analysis conformed to the intraparticle diffusion and pseudo-first-order rate equations, while thermodynamics displayed a physical, spontaneous and endothermic adsorption process. The presence of competing Pb(II), Ni(II), Cd(II) and Zn(II) metal ions in solution interfered with the adsorption of BB onto the biosorbents. In terms of reusability, STpe and STpe-AgNP showed BB desorption of 91.3% and 88.5% respectively, using NaOH as eluent. Ultra-sonication significantly enhanced the adsorption of BB by both adsorbents, but the impregnation of AgNPs only slightly improved adsorption of the dye from the simulated wastewater. This study also illustrated that pristine STpe biomass waste is a cheap viable option for the decontamination of BB from water.
Assuntos
Azul de Bromofenol/farmacocinética , Corantes/farmacocinética , Nanopartículas Metálicas , Tubérculos/metabolismo , Solanum tuberosum/metabolismo , Poluentes Químicos da Água/farmacocinética , Purificação da Água/métodos , Adsorção , Azul de Bromofenol/análise , Corantes/análise , Nanopartículas Metálicas/ultraestrutura , Microscopia Eletrônica de Varredura , Prata , Espectroscopia de Infravermelho com Transformada de Fourier , Ultrassom , Poluentes Químicos da Água/análise , Difração de Raios XRESUMO
Despite the efficiency of ZnO nanoparticle (NPs) composite adsorbents in the adsorption of various pollutants, there is presently no report on the combo of ZnONPs with biomass for adsorption. Besides, there is a dearth of information on the biosorption of celestine blue (CEB), a dye used in the nuclear and textile industry. In this study, biogenic-chemically mediated synthesis of a composite (ZnO@ACP) was prepared by the impregnation of ZnONPs onto Ananas comosus waste (ACP) for the adsorption of CEB. The SEM, EDX, FTIR, XRD, BET, and TGA characterizations showed the successful presence of ZnONPs on the biomass to form a nanocomposite. The uptake of CEB was enhanced by the incorporation of ZnONPs on ACP. A faster CEB adsorption onto ZnO@ACP (120 min) compared to ACP (160 min) was observed. The Langmuir (R2 > 0.9898) and pseudo-second-order (R2 > 0.9518) models were most appropriate in the description of the adsorption process. The impregnation of ZnONPs onto the biomass enhanced the spontaneity of the process and displayed endothermic characteristics. High CEB desorption of 81.3% from the dye loaded ZnO@ACP as well as efficient reusability showed the efficacy of the prepared nanocomposite for CEB adsorption.