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1.
Chemosphere ; 286(Pt 1): 131607, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34311398

RESUMO

MXene, comprised of two-dimensional transition metal carbides/nitride, has emerged as a novel material suitable for environmental remediation of toxic compounds. Due to their inherent and superior physical and chemical properties, MXene is employed in separation techniques like photocatalysis, adsorption, and membrane separation. MXene is equipped with a highly hydrophilic surface, ion exchange property, and robust surface functional groups. In this review paper, a comprehensive discussion on the structural patterns, preparation, properties of MXene and its application for the removal of toxic pollutants like Radionuclide, Uranium, Thorium, and dyes is presented. The mechanism of removal of the pollutants by MXene is extensively reviewed. Synthesis of MXene based membranes, their properties, and application for water purification and properties were also discussed. This review will be highly helpful to understand critically the methods of synthesis and use of MXene material for priority environmental pollutants removal. In addition, the challenges behind the synthesis and use of MXene for decontamination of pollutants were reviewed and reported.


Assuntos
Recuperação e Remediação Ambiental , Elementos de Transição , Purificação da Água , Adsorção , Corantes
2.
Chemosphere ; 286(Pt 1): 131479, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34315081

RESUMO

The present work investigates for the first time the presence and isolation of the thermophilic fungi from hydrothermal spring situated at the locality of Guelma, in the Northeast of Algeria. The production of the thermostable proteases and the optimization of culture conditions under agro-wastes solid-state fermentation to achieve optimal production capacity were explored. A statistical experimental approach consisting of two designs was used to determine the optimum culture conditions and to attain the greatest enzyme production. Besides, different agricultural wastes were initially evaluated as a substrate, whereby wheat bran was selected for enzyme production by the isolate under solid-state conditions. The isolate thermophilic fungi were identified as Mycothermus thermophilus by sequencing the ITS region of the rDNA (NCBI Accession No: MK770356.1). Among the various screened variables: the temperature, the inoculum size, and the moisture were proved to have the most significant effects on protease activity. Employing two-level fractional Plackett-Burman and a Box-Behnken designs statistical approach helped in identifying optimum values of screened factors and their interactions. The analysis showed up 6.17-fold improvement in the production of proteases (~1187.03 U/mL) was achieved under the optimal conditions of moisture content 47%, inoculum 5 × 105 spores/g, and temperature at 42 °C. These significant findings highlight the importance of the statistical design in isolation of Mycothermus thermophilus species from a specific location as well as identifying the optimal culture conditions for maximum yield.


Assuntos
Peptídeo Hidrolases , Argélia , Fermentação , Peptídeo Hidrolases/genética , Sordariales , Temperatura
4.
Chemosphere ; 286(Pt 2): 131727, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34352554

RESUMO

Due to its cytotoxic effect, metronidazole (MNZ) is a drug commonly used to treat bacterial, protozoal, and microaerophilic bacterial infections. After consumption, it undergoes a series of metamorphic reactions that lead to the degradation of oxidized, acetylated, and hydrolyzed metabolites in the environment. To eliminate such pollutants, due to their high potential, adsorption and photocatalysis extensive processes are used in which graphene can be used to improve efficiency. This review analyses the use of graphene as an absorbent and catalyst with a focus on absorption and photocatalytic degradation of MNZ by graphene-based materials (GBMs). The parameters affecting the adsorption, and photocatalytic degradation of MNZ are investigated and discussed. Besides, the basic mechanisms occurring in these processes are summarized and analyzed. This work provides a theoretical framework that can direct future research in the field of MNZ removal from aqueous solutions.


Assuntos
Grafite , Poluentes Químicos da Água , Adsorção , Catálise , Metronidazol/análise , Poluentes Químicos da Água/análise
5.
J Hazard Mater ; 421: 126719, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34364215

RESUMO

The photocatalytic degradation of pharmaceutical micropollutants of Penicillin G (PG) was investigated in a photoreactor at a laboratory scale. The impact of type of catalyst, pH, and initial concentration of PG were studied. Maximum removal efficiency was obtained at pH = 6.8, [ZnO]0 = 0.8 g L-1, and [PG]0 = 5 mg L-1 and reaction time of 150 min. The addition of persulfate sodium (PPS) enhanced the efficiency of the photocatalytic reaction. The efficiency of photolysis process in the presence of PPS was significantly improved to 72.72% compared to the classical photocatalysis system (56.71%). Optimum concentration of PPS to completely degraded PG was found to be 500 mg L-1. The QuEChERS extraction, GC-MS/MS method, and concentration technique showed favorable performance identification of the possible mechanism of PG degradation pathway. Toxicity of PG and its by-products were evaluated using microbioassays assessment based on nine selected bacterial strains. Results confirmed the effectiveness of the implemented system and its safe use via the bacteria Bacillus subtilis, which has illustrated significant activity. Due to the high efficiency, facility benefits, and low-cost of the suggested process, the process can be considered for the degradation of various pharmaceutical contaminants in pharmaceutical industry treatment under the optimal conditions.


Assuntos
Espectrometria de Massas em Tandem , Poluentes Químicos da Água , Catálise , Cinética , Penicilina G , Fotólise
6.
Chemosphere ; 286(Pt 2): 131821, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34388869

RESUMO

Acute exposure to trace metals (TMs) in water is hazardous to human health. The average concentrations (Cavg.) and carcinogenic (CAR) and non-carcinogenic (non-CAR) risks of eight TMs to World Health Organization's (WHO) guidelines and national standard limits (NSLs)were determined. The Cavg. and (the range) of As, Hg, Cd, Pb, Co, Cr, Ni, and Zn were measured as 4.29 ± 0.57 µg L-1 (1.12-10.27 µg L-1), 0.22 ± 0.10 µg L-1 (ND-1.05 µg L-1), 0.31 ± 0.18 µg L-1 (ND-1.80 µg L-1), 4.66 ± 0.32 µg L-1 (0.10-14.22 µg L-1), 24.61 ± 4.65 µg L-1 (3.11-67.25 µg L-1), 16.86 ± 5.54 µg L-1 (5.12-34.61 µg L-1), 14.07 ± 4.37 µg L-1 (3.79-31.39 µg L-1), and 268.42 ± 75.82 (87.29-561.22 µg L-1), respectively. The Cavg. of Co and Hg exceeded the WHO and NSLs. The non-CAR risk assessment was used to order the TMs according to the total target hazard quotient (TTHQ) As > Pb > Cr > Co > Zn > Hg > Ni > Cd. None of the investigated age groups are at risk As there is a low Cavg of all trace metals (i.e., the THQ is > 1). The age groups were ranked based on THQ and incremental lifetime cancer risk (ILCR) As < 1 year, >1-10 years, > 11-19 years, and > + 20 years. The ILCR of As for all the age groups was >10-4, whereas for Pb it was <10-6. Cumulative carcinogenic risk (CCR) for As and Pb was at a safe threshold risk (>10-4) for all the age groups.


Assuntos
Água Potável , Mercúrio , Metais Pesados , Oligoelementos , Monitoramento Ambiental , Intoxicação por Metais Pesados , Humanos , Lactente , Metais Pesados/análise , Metais Pesados/toxicidade , Medição de Risco , Oligoelementos/análise , Oligoelementos/toxicidade
7.
Chemosphere ; 286(Pt 3): 131894, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34416589

RESUMO

In this study, a simple and environment-friendly method has been successfully applied for the production of silver nanoparticles (AgNPs) using Poria cocos extract. The reaction time of 60 min, the temperature of 90 °C, and silver ion concentration of 2.0 mM were identified as the best condition for the PC-AgNPs fabrication. The XRD analysis confirmed a highly crystalline face-centered cubic structure of the biosynthesized material. The PC-AgNPs were presented separately in a spherical shape with an average crystal size of 20 nm, as endorsed by the TEM and FE-SEM measurements. The presence and crucial role of biomolecules in stabilizing the nanoparticles were elucidated by FTIR, EDX, and DLS techniques. The prepared biogenic nanoparticles were further applied for the reduction of 4-nitrophenol (4-NP) and colorimetric detection of Fe3+ ions. The study results proved that PC-AgNPs exhibited superior catalytic activity and reusability in the conversion of 4-NP by NaBH4. The complete reduction of 4-NP could be achieved in 10 min with the pseudo-first-order rate constant of 0.466 min-1, and no significant performance loss was found when the material was reused five times. The colorimetric probe based on PC-AgNPs displayed outstanding sensitivity and selectivity towards Fe3+ ions with a detection limit of 1.5 µM in a linear range of 0-250 µM. Additionally, the applicability of the developed assay was explored for testing Fe3+ ions in tap water. PC-AgNPs have a great potential for further applications as a promising catalyst for reducing nitrophenols and biosensors for the routine monitoring of Fe3+ in water.


Assuntos
Nanopartículas Metálicas , Wolfiporia , Compostos Férricos , Íons , Nitrofenóis , Extratos Vegetais , Prata
8.
Chemosphere ; 286(Pt 3): 131892, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34418663

RESUMO

The research and technological advancements observed in the latest years in the nanotechnology field translated into significant application developments in various areas. This is particularly true for the renewable polymers area, where the nano-reinforcement of biobased materials leads to an increase in their technique and economic competitiveness. The efforts were predominantly focused on materials development and energy consumption minimization. However, attention must also be given to the widespread commercialization and the full characterization of any particular potential toxicological and environmental impact. Some of the most important nanomaterials used in recent years as fillers in the bioplastic industry are graphene-based materials (GBMs). GBMs have high surface area and biocompatibility and have interesting characterizations such as strangeness and flexibility. In this paper, the current state of the art for these GBMs in the bioplastics area, their challenges, and the strategies to overcome them are analyzed.


Assuntos
Grafite , Nanoestruturas , Nanotecnologia , Polímeros
9.
J Hazard Mater ; 423(Pt A): 126986, 2022 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-34461534

RESUMO

Conductive crystalline polypyrrole (Cryst-PPy), Nickel-polypyrrole (Ni-PPy), and copper- polypyrole (Cu-PPy) hybrid materials were prepared using a chemical polymerization method in an aqueous solution. Part I was focused on the Chemical synthesis of Cryst-PPy powder from an organic medium. Cryst-PPy powder was successfully synthesized by chemical route from an organic medium of acetonitrile with polyethylene oxide as a stabilizing agent and oxidizing agent like potassium peroxydisulfate. The morphological study was showed the presence of spherical nanoparticles and cubic microparticles giving rise to a denser structure of PPy. In the second part, the based electrodes composites were examined in the oxidation of phenol by an electrochemical process in an alkaline medium. To follow the yield of phenol degradation at the alkaline solution, UV-visible analysis was performed at the following operating conditions: current density of 0.58 mA cm-2, phenol initial concentration of 0.150 M and for 3 h processing; the rate of phenol elimination was 56%, 38% and 28% for Cu-PPy, Ni-PPy, and pure PPy electrodes respectively. Thus, can be found that the doped Cu-PPy electrodes electrode is a new material with high electrochemical oxidation ability for phenol degradation in aqueous solutions.

10.
Environ Res ; 203: 111845, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34384753

RESUMO

The best exceptional Physico-chemical attributes of MXenes including high conductivity, high surface area, high functionalization, hydroxide site, and other interesting properties have attracted recently the attention of scientists in the applications of MXene (Mn+1XnTx)-based nanomaterials for water treatment. To provide a full and comprehensive vision of the current state of the art, and improve the treatment performance, and motivate new researches in this area, this review focused on the uses of these novel 2D transition metal carbides for desalination of water and the general methods of fabrication of MXenes; thus, MXene-based nanomaterials are very efficient candidates in water desalination processes, in this review, the main properties of previous and current works about MXenes applications in this area were properly investigated. Moreover, a particular overview about the different properties of MXenes in desalination such as etching method, hydrophobicity, structural modification, and chemical modification has been performed; meanwhile, the investigation of MXenes and MXenes-based composites would be an excellent candidate in the future of water purification and environmental remediation fields, since they have several good properties compared to the other 2D materials.


Assuntos
Recuperação e Remediação Ambiental , Nanoestruturas , Elementos de Transição , Purificação da Água
11.
J Hazard Mater ; 423(Pt A): 127016, 2022 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-34474364

RESUMO

This study evaluates the degradation efficiency of Malathion using Fenton (Fe2+/H2O2: F), photo-Fenton (UV/Fe2+/H2O2: PF), and sono-photo Fenton (US/UV/Fe2+/H2O2: SPF) processes as well as determines the toxicity of the byproducts of degradation. The effect of various operational parameters on the Malathion degradation rate, including pH, Fe2+ concentration, Malathion concentration, and H2O2 were studied. The removal efficiency was determined to be 98.79% for the SPF, > 70.92% for the PF, and > 55.94% for the F processes under the following optimal conditions: pH = 3, [H2O2]0 = 700 mg/L, [Fe2+]0 = 20 mg/L, and [Malathion]0 = 20 mg/L. The operating costs (USD/kgMalathion-removed) were acquired as SPF > PF > F. Moreover, Malaoxon, diethyl maleate, diethyl malate, ethyl 2-hydroxysuccinate, and D-malate were among the detected byproducts from the Malathion degradation in the SPF process. Both the non-carcinogenic risk and the carcinogenic risk were assessed to establish the quality of the effluent from all three processes. The toxicity of the treated effluents, determined by Vibrio fischeri luminescence, indicated that the toxicity depends on the selected treatment process. The high degradation efficiency of the Fenton-based processes is not equivalent to achieving detoxification of the effluents. As such, the SPF process was determined to be the most effective for the Malathion degradation, total organic carbon (TOC) removal, and health risk assessment.


Assuntos
Praguicidas , Poluentes Químicos da Água , Descontaminação , Peróxido de Hidrogênio/toxicidade , Ferro , Malation/toxicidade , Oxirredução , Praguicidas/toxicidade , Medição de Risco , Raios Ultravioleta , Poluentes Químicos da Água/toxicidade
12.
Chemosphere ; 288(Pt 1): 132405, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34597639

RESUMO

In this study, Kaolin clay, a mining material, was used as an abundant and available mineral as zero-valent iron-kaolinite composites for As2O3 removal from the water samples. The composites were made by the sodium borohydrate reduction method. The existence of Fe0 in the produced composites was confirmed by X-ray diffraction (XRD) and Fourier-Transform Infrared Spectroscopy (FTIR) analysis. The membranes are prepared with zerovalent nano Iron-Kaolin and PES. The synthesized composites were then mixed with polyethersulfone to prepare the membranes S1, S2, and S3 with varying compositions. Field Emission Scanning Electron Microscopy (FESEM) analysis of the produced membranes showed the porous structure and the contact angle of membranes increased the hydrophilicity. The membranes were explored for the removal of As2O3 (AsIII) in potable water samples. The filtration studies were carried out using the syringe filtration setup. Analysis of the arsenic (III) solution was carried out, before and after the filtration process using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), which showed a maximum of 50% reduction in its original concentration. The filtered membrane is analyzed for arsenic by Energy Dispersive X-ray (EDX) technique. Thus, the synthesized membrane effectively sieves the arsenic in water samples.


Assuntos
Água Potável , Poluentes Químicos da Água , Purificação da Água , Adsorção , Argila , Ferro , Caulim , Cinética , Polímeros , Sulfonas , Poluentes Químicos da Água/análise
13.
Chemosphere ; 287(Pt 3): 132271, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34547560

RESUMO

In this study, novel biogenic silver (AgNPs) and gold nanoparticles (AuNPs) were developed using a green approach with Ganoderma lucidum (GL) extract. The optimization of synthesis conditions for the best outcomes was conducted. The prepared materials were characterized and their applicability in catalysis, antibacterial and chemical sensing was comprehensively evaluated. The GL-AgNPs crystals were formed in a spherical shape with an average diameter of 50 nm, while GL-AuNPs exhibited multi-shaped structures with sizes ranging from 15 to 40 nm. As a catalyst, the synthesized nanoparticles showed excellent catalytic activity (>98% in 9 min) and reusability (>95% after five recycles) in converting 4-nitrophenol to 4-aminophenol. As an antimicrobial agent, GL-AuNPs were low effective in inhibiting the growth of bacteria, while GL-AgNPs expressed strong antibacterial activity against all the tested strains. The highest growth inhibition activity of GL-AgNPs was observed against B. subtilis (14.58 ± 0.35 mm), followed by B. cereus (13.8 ± 0.52 mm), P. aeruginosa (12.38 ± 0.64 mm), E. coli (11.3 ± 0.72 mm), and S. aureus (10.41 ± 0.31 mm). Besides, GL-AgNPs also demonstrated high selectivity and sensitivity in the colorimetric detection of Fe3+ in aqueous solution with a detection limit of 1.85 nM. Due to the suitable thickness of the protective organic layer and the appropriate particle size, GL-AgNPs validated the triple role as a high-performance catalyst, antimicrobial agent, and nanosensor for environmental monitoring and remediation.


Assuntos
Anti-Infecciosos , Nanopartículas Metálicas , Antibacterianos/farmacologia , Catálise , Colorimetria , Escherichia coli , Compostos Férricos , Ouro , Química Verde , Íons , Testes de Sensibilidade Microbiana , Extratos Vegetais , Prata , Staphylococcus aureus
14.
Chemosphere ; 287(Pt 4): 132387, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34600004

RESUMO

MXene-based nanomaterials (MBNs) are two-dimensional materials that exhibit a series of sought after properties, including rich surface chemistry, adjustable bandgap structures, high electrical conductivity, hydrophobicity, thermal stability, and large specific surface area. MBNs have an exemplar performance when applied for the degradation of hazardous pollutants with various advanced oxidation processes such as heterogeneous sonocatalysis. As such, this work focuses on the sonocatalytic degradation of various hazardous pollutants using MXene-based catalysts. First, the general principles of sonocatalysis are examined, followed by an analysis of the main components of the MXene-based sonocatalysts and their application for pollutant degradation. Lastly, ongoing challenges are highlighted with recommendations to address the issues.


Assuntos
Poluentes Ambientais , Nanoestruturas , Catálise , Condutividade Elétrica
15.
Environ Res ; 204(Pt C): 112298, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34717947

RESUMO

Pharmaceuticals, personal care items, steroid hormones, and agrochemicals are among the synthetic and indigenous products that make up micropollutants, also known as emerging contaminants. Pharmaceutical and personal care products (PPPs) are a class of developing micropollutants that can harm living organisms even at low concentrations. Many are detected in surface water and wastewater from the treatment process, with quantities ranging from ng L-1 to gL-1; however, residual PPPs at dangerously high levels have indeed recently been recognized in the ecosystem. Residential sewage treatment plant (STP) dump the largest majority of these pollutants into the environment on a regular basis. As a result of its robust structure, it has a longer lifespan in the environment. This review article discusses how surface water pollutants such pesticides, petroleum hydrocarbons, and perfluorinated compounds affect water quality, as well as the most cost-effective adsorbents for removing these PPPs. The goal of this study is to provide information about the origins of PPP, as well as diagnostic procedures and treatment options. Research on developing contaminants is also aimed at evaluating the efficacy and affordability of adsorption.

16.
Environ Res ; 204(Pt D): 112364, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34767819

RESUMO

ZIF-8 is a highly porous, stable, and abundant surface area material that can be used as an environmentally friendly catalyst for Knoevenagel condensations. The effects of the ratio of the reactants (benzaldehyde (BA):ethyl cyanoacetate (ECA)), reaction temperature, and catalyst concentration were systematically investigated using a ZIF-8 catalyst and water as the solvent. ZIF-8 (3-5 wt%) showed excellent catalytic performance with an almost complete conversion of BA in less than 6 h with a BA:ECA molar ratio of 1:2 at different temperatures. At 60 °C, the BA conversion rate and product selectivity of the reaction reached their highest values after 4 h with a BA:ECA molar ratio of 1:1. When employing 5.0 wt% ZIF-8, almost complete BA conversion was achieved after 3 h at room temperature. ZIF-8 also demonstrated good recyclability with almost no change in its catalytic activity over five cycles. The proposed reaction mechanism is based on the catalytic activity of the basic N sites on the surface of ZIF-8, and is supported by density functional theory calculations. The present approach provides a promising strategy for the construction of simple and environmentally friendly ZIF-8 catalysts.

17.
Environ Res ; 204(Pt D): 112360, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34767823

RESUMO

Silver nanoparticles (AgNPs) are a promising technology for the design of antimicrobial agents against drug-resistant pathogens. It could also be used for the photocatalytic degradation of dyes used in industries such as methylene blue (MB). In this study, 17 different actinomycetal strains isolated from hydrocarbon-contaminated soils collected from an oil distribution company in Algeria were evaluated for their ability to produce NPs. After a selection process, S16 was the main strain capable of synthesizing AgNPs extracellularly. The strain S16 was determined using molecular identification based on the sequencing of the 16S rDNA gene. Among various techniques used for the synthesis of AgNPS, a technique using a temperature of 30 °C, pH of 7, a metal salt concentration of 1 mM, and a period of 72 h in the dark were found to be more effective in the biosynthesis of the AgNPs. The biosynthesized AgNPs that were analyzed by UV-visible spectroscopy resulted in a specific peak at a wavelength of (λ = 400 nm). The DRX analyses showed characteristic peaks of the AgNPs at (1 1 1), (2 0 0), (2 2 2), and (3 1 1), which validated the presence and crystalline nature of the biosynthesized NPs. Zetasizer analysis showed an average size and zeta potential of 64 nm (-32.3 mV), while the SEM-EDS analysis confirmed the spherical shape of AgNPs and the presence of Ag atoms in the elemental composition. The biosynthesized AgNPs indicated adequate antibacterial activity against 5 out of the 6 strains tested in this study, using minimum inhibitory concentration (MIC) that ranged from 217.18 µg/mL to 1137.5 µg/mL. The AgNPs were combined with commercial antibiotics and the synergistic effect of the combination was also assessed against MRSA which resulted in increased antibacterial activity of AgNPs in the presence of the strain S16. Furthermore, the photocatalytic degradation of the methylene blue (MB) was evaluated under sunlight and UV irradiations using biosynthesized AgNPs. The AgNPs showed photocatalytic decolorization potential of 71.3% for MB dye (20 ppm) under sunlight irradiation within 6 h of incubation, while only 11.25% of the MB dye degraded using UV irradiation.

18.
Chemosphere ; : 133025, 2021 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-34848226

RESUMO

It is vital to have high sensitivity in gas sensors to allow the exact detection of dangerous gases in the air and at room temperature. In this study, we used 2D MXenes and MoS2 materials to create a Ti3C2-MoS2 composite with high metallic conductivity and a wholly functionalized surface for a significant signal. At room temperature, the Ti3C2-MoS2 composite demonstrated clear signals, cyclic response curves to NO2 gas, and gas concentration-dependent. The sensitivities of the standard Ti3C2-MoS2 (TM_2) composite (20 wt% MoS2) rose dramatically to 35.8%, 63.4%, and 72.5% when increasing NO2 concentrations to 10 ppm, 50 ppm, and 100 ppm, respectively. In addition, the composite showed reaction signals to additional hazardous gases, such as ammonia and methane. Our findings suggest that highly functionalized metallic sensing channels could be used to construct multigas-detecting sensors that are very sensitive in air and at room temperature.

19.
Chemosphere ; 289: 133171, 2021 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-34875292

RESUMO

In this research, reduced graphene oxide (RGO) which is a form of graphene oxide (GO) was formed through a reduction process using a "green agent" called Ascorbic acid (AA). RGO was then modified on the surface of the glassy carbon electrode (GCE) to generate RGO/GCE (an advanced electrode). The RGO/GCE was then used to detect Terbutaline (TB) in urine samples of volunteer athletes (n = 5) using well-known spectrophotometric analyses including X-ray diffraction analysis (XRD), Fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible Spectroscopy (UV-Vis), and Raman and electrochemical methods using voltammetric analyses such as differential pulse anodic stripping voltammetry (DP-ASV) and cyclic voltammetry (CV). Comparing various analysis methods using RGO/GCE to detect TB in human urine samples, voltammetric analysis specifically DP-ASV demonstrated higher sensitivity and selectivity in detecting TB than spectrophotometric analyses. Thus, in this study, several factors that would affect the voltammetric signals such as pH and interferents were evaluated and the electroactive surface area was also calculated. Our findings indicated that the RGO/GCE showed excellent repeatability, reproducibility, and long-term stability suggesting that TB could be detected more effectively using RGO/GCE than bare GCE. The detection limit of 0.0052 µM achieved in this study indicated that RGO/GCE can effectively detect TB in human urine while demonstrating reasonable selectivity and sensitivity.

20.
Chemosphere ; : 133120, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34863724

RESUMO

The SnO2/g-C3N4 composites were fabricated via an annealing mixture of g-C3N4 and SnO2, which were obtained from calcinating melamine and hydrothermal treatment of SnCl4 solution, respectively. The photocatalytic properties of g-C3N4/SnO2 were studied over the degradation of Rhodamine B (RhB) under visible light, which exhibits a significantly improved photocatalytic activity compared to the single components, g-C3N4 and SnO2. The enhancement in photocatalytic activity of SnO2/g-C3N4 could be described by the S-scheme pathway, in which the effective charge transfer between components is demonstrated toward the suppression in recombination of the photogenerated electron-hole pairs within redox potential conservation. Besides, a new criterion, photochemical space-time yield, was applied to evaluate the photocatalytic performance of our samples.

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