Pesticides In Aqueous Solutions Research Articles

A novel potato peels waste β-cyclodextrin biocomposite for the efficient uptake of diuron and glyphosate herbicides.

A novel biocomposite (FPPW-β-CD) was prepared by a simple and sustainable method involving fine potato peel waste, β-cyclodextrin (β-CD), and green citric acid through the crosslinking reaction. The polymer was characterized using SEM, FTIR, XRD, TGA, and DSC analyses. The adsorbent performance was evaluated about the glyphosate and diuron adsorption from the aqueous solution. Pesticide removal was investigated regarding the influence of solution pH, temperature, and initial concentration of contaminants. Also, it highlights the main interactions involved in the adsorption phenomenon based on the pH effect and characteristics of adsorbent and adsorbate molecules. The maximum adsorption capacity values according to the Sips model were higher than 2000µgg-1. The pseudo-second-order and general-order models described the kinetic data well. Thermodynamic parameters indicated that pesticide removal was spontaneous and favorable. The magnitude of enthalpy variation values (27.37kJmol-1 and - 100.79kJmol-1) revealed that the glyphosate and diuron adsorption occurred through the physisorption and chemisorption, respectively. The novel biocomposite is a promising green adsorbent for the uptake of micropollutant pesticides in aqueous solutions at concentrations of µg L-1.

Adsorptive removal of organophosphate pesticides from aqueous solution using electrospun carbon nanofibers.

Organophosphate pesticides (OPPs) are widely prevalent in the environment primarily due to their low cost and extensive use in agricultural lands. However, it is estimated that only about 5% of these applied pesticides reach their intended target organisms. The remaining 95% residue linger in the environment as contaminants, posing significant ecological and health risks. This underscores the need for materials capable of effectively removing, recovering, and recycling these contaminants through adsorption processes. In this research, adsorbent materials composed of electro-spun carbon nanofibers (ECNFs) derived from polyacrylonitrile was developed. The materials were characterized through several techniques, including scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) analysis, and contact angle measurements. SEM analysis revealed details of the structural properties and inter-fiber spacing variations of the carbon nanofibers. The results revealed that ECNFs possess remarkable uniformity, active surface areas, and high efficiency for adsorption processes. The adsorption studies were conducted using batch experiments with ethion pesticide in aqueous solution. High-Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD) was utilized to quantify the concentrations of the OPP. Various parameters, including adsorbent dosage, pH, contact time, and initial ethion concentration, were investigated to understand their impact on the adsorption process. The adsorption isotherm was best described by the Freundlich model, while the kinetics of adsorption followed a non-integer-order kinetics model. The adsorption capacity of the ECNFs for OPP removal highlights a significant advancement in materials designed for environmental remediation applications. This study demonstrates the potential of ECNFs to serve as effective adsorbents, contributing to the mitigation of pesticide contamination in agricultural environments.

Photocatalytic degradation of four organophosphorus pesticides in aqueous solution using D-cys/Au NPs modified TiO2 by natural sunlight

The widespread use of organophosphorus pesticides (OPPs) in foods, poses a serious threat to human and environmental health, it is crucial to develop methods that can efficiently degrade residual OPPs. Herein, a chiral TiO2 photocatalyst was developed by modification TiO2 with D-cys/Au NPs (DAT) for the simultaneous degradation of four OPPs (chlorpyrifos, chlorpyrifos-methyl, malathion, and parathion) by natural light. The influence of D-Au NPs concentration on the degradation process was optimized, along with the initial pesticide concentration. Under optimal conditions, the photocatalytic degradation efficiencies of DAT for four OPPs were 96.7 %, 56.9 %, 42.6 %, and 49.2 %, respectively, after 12 h of natural light exposure. 12 degradation products of OPPs were identified, among which three products were identified for the first time. The degradation pathway revealed that the degradation of OPPs by DAT involves the oxidation of the P═S bond and the cleavage of the P-O bond and C-O bond. This study establishes a theoretical foundation for applying chiral TiO2 nanomaterials for the photocatalytic degradation of OPPs in foods.

Photocatalytic degradation of chlorpyrifos pesticide in aqueous solution using Cu-doped TiO2/GO photocatalysis vicinity of UV and visible light

In this study, the sol-gel method was used to synthesize Cu-doped TiO2/GO composite nanoparticles. The prepared samples were identified utilizing XRD, EDX-SEM, TEM, BET, FT-IR and Raman methods. Photocatalytic absorber prepared vicinity of UV light and visible light was used to remove chlorpyrifos pesticide. The effect of factors, such as pH, amount of adsorbent, and irradiation time, on the amount of pesticide removal, was investigated. The maximum efficiency of chlorpyrifos removal was obtained at pH = 2, irradiation time of 80 min, and photocatalyst amount of 0.2 g for UV light and visible light, equal to 91.4 % and 78.25 %, respectively. The Pseudo-first order kinetics as best choice efficiency described the chlorpyrifos degradation process according to Langmuir-Hinshelwood kinetic with rate constants equal to 0.0301 and 0.0177 min−1 vicinity of UV light and visible light respectively.

Determination of the efficiency of electrolyzed water devices for the removal of pesticides in aqueous solutions and the characteristics of the pesticide residues and their transformation products

The effect of electrolyzed water treatment on the degradation of pesticide residues (malathion, fenitrothion, p,p′-DDT, and 2-hydroxybiphenyl) in tap water was investigated. Electrolyzed water was generated by electrolysis in commercially available kitchen devices. Three devices with different parameters were tested. The transformation products of pesticides, which are formed after the electrolysis process, were also investigated. Results show that the reduction percentage for electrolyzed water was from 6.2 to 99.7 % for 2-hydroxyphenyl, from 75.5 to approx. 100 % for fenitrothion, from 79.7 to approx. 100 % for malathion, and from 52.1 to 78 % for p,p′-DDT. It was also shown that the obtained transformation products of selected pesticides are more toxic than the parent compounds. Extending the electrolysis time in water electrolysis devices results in more effective degradation of pesticides and transformation products. Our research has shown that electrolyzed water devices can effectively remove pesticide residues, but they can also be a source of other toxic transformation products that may have a synergistic effect.

Design and Construction of a Mixed-Ligand Coordinated Fluorescent Complex and Its Application for Sensing Ions, Antibiotics, and Pesticides in Aqueous Solution

In this work, a fluorescent complex [Zn(NTD)2(DTP)2(H2O)2]·(H2O)0.8 (Complex Zn), (H2NTD = 1,4-naphthalenedicarboxylic acid and DTP = 3,5-di(1,2,4-triazol-1-yl)pyridine) was synthesized. The fluorescent complex was characterized by single-crystal X-ray diffraction, powder X-ray diffraction, and thermogravimetric, elemental, infrared spectroscopy, and fluorescence analyses. In the fluorescence sensing tests, Complex Zn exhibited excellent fluorescence quenching efficiency towards Fe3+, MnO4−, Cr2O72−, nitrofurantoin, and imidacloprid in aqueous media. A mechanism investigation suggested that the fluorescence quenching caused by the quenchers toward the sensor was due to the inner filter effect and the fluorescence resonance energy transfer effect in the fluorescent sensing process.

Water-stable mixed-ligand Cd(II) metal-organic frameworks as bis-color excited fluorescent sensors for the detection of vitamins and pesticides in aqueous solutions

The synthesis and characterization of three 2D to 3D metal-organic frameworks (MOFs) with mixed ligands, namely {[Cd(DINT)(TPA)(H2O)]ACN}n (BAO24) (H2TPA = terephthalic acid, DINT = 1,4-di(imidazol-1-yl)naphthalene, and ACN = acetonitrile), {[Cd(DINT)(IPA)]DMF}n (BAO25) (H2IPA = isophthalic acid and DMF = N,N-dimethylformamide), and [Cd(DINT)(PA)]n (BAO26) (H2PA = phthalic acid), were reported herein. The structures and purities of the MOFs were revealed and confirmed by single-crystal X-Ray diffraction, Fourier transform infrared spectroscopy, powder X-Ray diffraction, thermogravimetric analysis, and elemental analysis. The MOFs exhibited a fluorescence emission peak around λem = 340 nm with relative excitation wavelengths at both 230 and 290 nm. Since the MOFs showed similar fluorescence properties, BAO24 was selected as a representative MOF in the fluorescent sensing processes. The result showed that BAO24 exhibited a high sensitivity for vitamin B2. However, when sensing pesticides, the sensor performed differently at each excitation wavelength. At λex = 230 nm, the sensor was quenched the most significantly with the nitenpyram analyte, while at λex = 290 nm, the highest fluorescence quenching was achieved by the imidacloprid analyte.

Titanium-based metal-organic framework capsulated with magnetic nanoparticles: Antimicrobial and photocatalytic degradation of pesticides

Pesticide residues create an ecological ecosystem that is incredibly dangerous and presents major risks to human health. To solve this issue, scientists are concentrating on creating extremely effective composites with superior photocatalytic performance. Even if several efforts have been made to remove pesticides and dangerous compounds using adsorption, the development of novel adsorbents with large adsorption capabilities is still very desirable. Here, the photocatalytic of carbamate pesticides in aqueous solution under simulated sunlight irradiation in the existence of Fe3O4, CuO/Cu2O, MIL-125-NH2, Fe3O4@MIL-125-NH2 and CuO/Cu2O@MIL-125-NH2 were investigated. The photocatalytic process may be credited with the effective electron-hole separation and wider area of light response. Moreover, the mechanism of pesticide photocatalytic process was discovered as mineralization of pesticides to carbon dioxide, water, sulphate, and ammonia. Total organic carbon (TOC) analysis was used to quantify the mineralization of pesticides while UV spectroscopy was used to measure the rates of pesticides photocatalytic activity. CuO/Cu2O@MIL-125-NH2 and Fe3O4@MIL-125-NH2 composite demonstrated the maximum pesticide photocatalytic efficiency and outstanding cycle stability. The antimicrobial potency was increased and the inhibition zone was minimised when treated by a parent MIL-125-NH2 and its composites, which is surprising data when employing CuO/Cu2O@MIL-125-NH2 and Fe3O4@MIL-125-NH2 nanocomposite as an anti-bacterial material.

Silver-Loaded Carbon and Phosphorous Co-Doped Boron Nitride Quantum Dots (Ag@CP-BNQDs) for Efficient Organic Waste Removal: Theoretical and Experimental Investigations.

In this paper, silver-loaded phosphorous and carbon co-doped boron nitride quantum dot (Ag@CP-BNQD) nanocomposites were synthesized using a co-precipitation method followed by a hydrothermal approach. The nanocomposites of Ag@CP-BNQDs were characterized by scanning electron microscopy, energy-dispersive spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and ultraviolet–visible spectrophotometry. The as-prepared Ag@CP-BNQDs were used for photocatalytic degradation of 10 common organic pollutants, including dyes, pharmaceuticals, and pesticides in aqueous solution under visible light irradiation. The high-performance photocatalysis of Ag@CP-BNQDs proved that Ag@CP-BNQDs is plasmonic and the n–p junction photocatalyst. Theoretical calculations were done to measure the crystals and electronic structures of Ag@CP-BNQDs. Theoretical results showed that loading of Ag behaves as plasmonic sensitizers and co-catalysts and provides extra bands, which make electron movement easier between valance and conduction bands. The mechanism of the charge separation enhancement was postulated. Our findings might deepen our understanding of how sensitizer surface modification works in photodegradation applications.

Two bis-color excited luminescent sensors of two-dimensional Cd(II)-MOFs bearing mixed ligands for detection of ions and pesticides in aqueous solutions

Two metal organic framework were constructed from mix-ligands and Cd(II) ions: [Cd(NIP)2(DTP)(H2O)2]·H2O (Cd-1) (H2NIP = 5-nitroisophthalic acid and DTP = 3,5-di(1,2,4-triazol-1-yl)pyridine) and [Cd(NTP)2(DTP)(Et)(H2O)2]·(H2O)0.5 (Cd-2) (H2NTP = nitroterephthalic acid and Et = ethanol). The MOFs were determined and confirmed by single-crystal X-ray diffraction (XRD), elemental analysis, infrared spectroscopy (IR), powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA) and fluorescence analysis. The fluorescence sensing application of the sensors demonstrated the two sensors were extra sensitive and selective towards Fe3+ and Cr2O72- during the sensing of the ions under both 250 and 290 nm excitation wavelength; were extra effective and sensitive towards NTP (EX 250 nm) and MMT (EX 290 nm) in sensing of the pesticides for the two sensors. Mechanism investigation revealed both inner filter effect (IFE) and fluorescence resonance energy transfer (FRET) mechanisms played major roles during the sensing process of Fe3+, Cr2O72−, NTP and MMT.

Research trends and emerging physical processing technologies in mitigation of pesticide residues on various food products.

The application of pesticides enhances food production vastly, and it cannot be prevented; longer fresh produce is contaminated with health-threatening pesticides even though traditional processing methods can remove these pesticides from food surfaces to a certain extent; novel emerging technologies such as cold plasma, ultrasound, electrolyzed water, and pulsed electric field could more effectively dissipate the pesticide content in food without the release of toxic residual on the food surface. The present review focuses on applying emerging technologies to degrade pesticide residues in great utility in the food processing industries. This review also discusses the pesticide removal efficacy and its mechanism involved in these technologies. The oxidation principle in cold plasma is recently gaining more importance for the degradation of pesticide residue in the food processing industries. Analysis of the emerging physical processing methods indicated greater efficacy in eradicating pesticide residues during agriculture processing. Even though the technologies such as EO (99% reduction in dimethoate), ultrasound (98.96% for chlorpyrifos), and irradiation (99.8% for pesticide in aqueous solution) can achieve promising results in pesticide degradation level, the rate and inactivation highly depend on the type of equipment and processing parameters involved in different techniques, surface characteristics of produce, treatment conditions, and nature of the pesticide. Therefore, to effectively remove these health-threatening pesticides from food surfaces, it is necessary to know the process parameters and efficacy of the applied technology on various pesticides.

Facile synthesis disposable MOF membrane filter: Growth of NH2-MIL-125 (Ti) on filter paper for fast removal of organophosphorus pesticides in aqueous solution and vegetables

Metal-organic frameworks (MOFs) have great potential to remove pesticide residues. However, the lack of affinity between the materials and target and the process of trivial sample preparation resulted in limited removal efficiency. Here, we report a one-pot method for the fast preparation of NH2-MIL-125 (Ti)-based filter paper to synthesise NH2-MIL-125 (Ti)-based filter paper membranes. The NH2-MIL-125 (Ti)-based filter paper membrane takes advantage of π-π interactions between the organophosphorus pesticides (OPPs) and the benzene ring of MOFs. The affinity of amino groups and metal Ti for phosphorus atoms in the OPPs exhibits rapid removal efficiency for three OPPs, imidan, fenthion, and fenitrothion. The isothermal adsorption results for imidan, fenthion, and fenitrothion were consistent with the Langmuir, Freundlich, and Langmuir models, respectively. The kinetic results for imidan, fenthion, and fenitrothion agreed with the pseudo-second-order kinetic model, and the removal efficiency reached equilibrium within 1 min. There was no significant change in the adsorption capacity of OPPs in different pH solutions (pH = 2–10). Compared with that of MOFs, the NH2-MIL-125 (Ti)-based filter paper membrane removal efficiency of OPPs is the same, and it also has better removal efficiency in actual spinach samples. As a result, the sample pretreatment procedure was simplified using a low-cost and simple-to-synthesize disposable NH2-MIL-125 (Ti)-based filter paper membrane, samples’ quick separation and the simultaneous fast removal of OPPs.

Bisligand-coordinated cadmium organic frameworks as fluorescent sensors to detect Ions, antibiotics and pesticides in aqueous solutions

Three bisligand-coordinated two-dimensional or one-dimensional cadmium-based luminescent coordinated polymers, namely, [Cd3(BTC)2(DTP)(H2O)6]·(H2O)2.5 (1) (BTC = benzene-1,3,5-tricarboxylic acid and DTP = 3,5-di(1,2,4-triazol-1-yl)pyridine); [Cd2(IPA)2(DTP)(H2O)4]·(H2O)3(DMF)2 (2) (IPA = isophthalic acid and DMF = dimethylformamide); and [Cd4(DFDA)4(DTP)2(H2O)8]·(H2O)17 (3) (DFDA = 2,5-dihydrofuran-2,5-dicarboxylic acid), were constructed by solvothermal synthesis. The obtained MOFs were characterized by employment of single crystal X-ray diffraction, powder XRD analysis, elemental analysis, IR, TGA and luminescence analysis. Fluorescence sensing experiments show that complexes 1–3 are effective and selective in sensing MnO4−, Fe3+ and Cr2O72−. For the analysis of antibiotics and pesticides, complex 1 exhibited the highest quenching rates for norfloxacin (NOR) and nitenpyram (NTP). For complexes 2–3, cefixime (CFX) and metamitron (MMT) caused the most obvious fluorescence quenching of all of the tested antibiotics and pesticides, respectively. During the sensing processes, both the inner filter effect (IFE) and fluorescence resonance energy transfer (FRET) play a key role in fluorescence quenching for all three complexes.

Solar assisted green photocatalysis for deducing carbamate insecticide from agriculture stream into water reclaiming opportunity

ABSTRACT ‘Ultraviolet’ and ‘Solar’ wastewater treatment units are used augmented with nanocrystals of magnetite, Fe2O3, which were previously synthesised via a cost-efficient co-perception route. The nanocrystals produced were used as a Fenton reagent source for the oxidising carbamate pesticide in aqueous solution through a combination of natural abundant solar radiation as well as artificial UV source. System parameters were examined and the optimal operating conditions were investigated to maximise the system yield. The objective optimisation was attained using a Box-Behnken factoring design (BBD) based on Response Surface Methodology, RSM. A mathematical model was developed and the maximal removal efficiency reached to 84.1% within 15 min of reaction time. Furthermore, the chemical oxygen demand was then investigated and it was oxidised and deduced to 57%. Analysis of the experimental data revealed that a second-order reaction model is best described the reaction kinetics. The calculated thermodynamic parameters suggested that the non-spontaneous nature of oxidation at high temperature was corroborated by positive Gibbs free energy change ∆G• and negative entropy, ∆S• values. Also, the negative values of enthalpy, ∆H•, indicated that the reaction was exothermic. The low activation energy barrier (−35.85 kJ/mol) indicated that the reaction proceeds at a low energy level.

Two bis-ligand-coordinated Zn(ii)-MOFs for luminescent sensing of ions, antibiotics and pesticides in aqueous solutions.

Two organometallic complexes with two and three-dimensional architectures were constructed by using multiple ligands and Zn(ii) ions: [Zn3(BTC)2(DTP)4(H2O)2]·(H2O)4 (Zn-1) (BTC = benzene-1,3,5-tricarboxylic acid and DTP = 3,5-di(1,2,4-triazol-1-yl)pyridine) and [Zn2(NTD)2(DTP)] (Zn-2) (NTD = 1,4-naphthalenedicarboxylic acid). The as-prepared complexes were characterized by single-crystal X-ray diffraction (SCXRD), elemental analysis, powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and fluorescence analysis. Fluorescence sensing tests revealed that the two complexes are effective, sensitive and selective toward cationic Fe3+ and anionic MnO4− and Cr2O72−. During the antibiotic sensing process, cefixime (CFX) for Zn-1 and nitrofurantoin (NFT) for Zn-2 exhibited the highest quenching efficiencies. For sensing pesticides, the highest quenching efficiencies were exhibited by imidacloprid (IMI) toward Zn-1 and Zn-2. The fluorescence quenching of the complexes that was induced by antibiotics, pesticides and MnO4− was attributed to both the inner filter effect (IFE) and the fluorescence resonance energy transfer (FRET) effect.

Complexation effect between Pb2+ and carbendazim in natural waters: An electroanalytical study

• The interaction between the metal ion Pb 2+ and the pesticide CBZ affects the analysis of the pesticide in aqueous solution. • Natural compounds in water decrease the sensitivity of the method in the pesticide analysis. • Pb 2+ contributes to the increase in the intensity of the oxidation peak current of CBZ. • IES study confirms the formation of the complex in solution. The use of pesticides has been increased to obtain higher agricultural yields, prevent the proliferation of harmful organisms and ensure durability in food storage. The inappropriate use of these substances present risks to the environment and human health, and in the presence of metal ions can interact, forming complexes with different properties. Thus, in this work, the interaction between the metal ion Pb 2+ and carbendazim was evaluated by electrochemical techniques using a glassy carbon electrode. The metal ion Pb 2+ showed a reduction peak at −0.570 V, and, in systematic studies in the presence of CBZ, this peak shifted to a more negative potential, indicating the complex formation. The K f value founded for the complex formed was 4.5 × 10 16 , and the estimated proportion metal:pesticide was 1:3.7, using the data collected from these experiments. On the other hand, CBZ showed an oxidation peak at 0.989 V and a reduction peak at 0.919 V, with the characteristic of a quasi -reversible process. A shift of the oxidation peak to less positive potentials was observed when in the presence of the metallic ion. Furthermore, experiments on the analysis of carbendazim in the presence of Pb 2+ were performed in aqueous solutions and natural water, indicating that the metal ion affects the electrochemical signal of the pesticide. The electrochemical impedance spectroscopy results showed that Pb 2+ ions do not interfere in the electrochemical double layer during oxidation of carbendazim, indicating that the interaction between the metallic ion and the pesticide occurs in solution. The analyses performed using samples of natural water showed an increase in charge transfer resistance without alteration of the electrical double layer or significant changes in the oxidation potential of the pesticide. The results showed that the electroanalytical method is feasible for the analysis of CBZ in the presence of Pb 2+ and analysis of the influence of the metal on the electrochemical response of the pesticide, with low sample preparation.

Water-stable europium(III) and terbium(III)-metal organic frameworks as fluorescent sensors to detect ions, antibiotics and pesticides in aqueous solutions

The reliable, convenient and rapid detection methods for various environmental pollutants using fluorescent sensors had attracted great attention. Herein, we reported the assembly and characterizations of two new fluorescent 3D lanthanide metal-organic frameworks (Ln-MOFs), namely [Eu(PMBB)1.5(H2O)2] (Eu-MOF) and [Tb(PMBB)1.5(H2O)2] (Tb-MOF) (H2PMBB = 4,4′-((1,4-phenylenebis(methylene))bis(oxy))dibenzoic acid). The fluorescent sensing results reveal that the two MOFs exhibit effective sensitivity toward Fe3+, Cr2O72−, cefixime (CFX), nitrofurazone (NFZ), imidacloprid (IMI) and nitenpyram (NTP) in aqueous medium. Notably, the Tb-MOF is more sensitive toward MnO4− than Eu-MOF due to the enhanced fluorescence resonance energy transfer (FRET) effect. This work provides the example for more effective designs to employ Ln-MOFs as fluorescent sensors for detection of environmental pollutants in aqueous solution.

Kinetics and equilibrium of the adsorption process of dimethoate with corn stalk

The corn stalk (CS) is a waste material generated from the corn crop, with important cellulose and hemicellulose content within its structure. This study has been focused on evaluating the possibility of using CS as an adsorbent for the removal of organophosphate dimethoate pesticides in aqueous solutions. The adsorption study was conducted to determine the effect of adsorbent dose, initial pH, and contact time to dimethoate solution at the initial concentration of 50 mg.L−1. The process conditions were established at initial pH of 11, adsorbent dose of 1.5 g/100 ml, and equilibrium time of 140 minutes. It was verified that dimethoate removal is favored in an alkaline medium. The process kinetic was adjusted to the pseudo-n order model and pseudo-second order model to a lower extent, with several limiting stages, as it was demonstrated through the Weber-Morris model. The equilibrium isotherms were analyzed by employing, the Langmuir, Freundlich, Toth, Sips, and Redlich-Peterson models, where the Sips, Redlich-Peterson, and Toth models proved to be the best adjustment for experimental data, representing better the dimethoate adsorption process in CS.

Water-Stable Europium(III) and Terbium(III)–Metal Organic Frameworks as Fluorescent Sensors to Detect Inorganic Ions, Antibiotics and Pesticides in Aqueous Solutions

Development of reliable, convenient and rapid detection methods for environmental pollutants using fluorescent sensors has attracted great attention. Herein, we reported the assembly and characterizations of two new fluorescent 3D lanthanide metal-organic frameworks (Ln-MOFs), namely [Eu(PMBB)1.5(H2O)2] (Eu-MOF) and [Tb(PMBB)1.5(H2O)2] (Tb-MOF) (H2PMBB = 4,4'-((1,4-phenylenebis(methylene))bis(oxy))dibenzoic acid). The structural data veal that both of the structures constructed in 3D network, in view of topology, Eu-MOF is in a bnn net and Tb-MOF is in an mab net. The fluorescent sensing results revealed that the two MOFs exhibit effective sensitivity toward Fe3+, Cr2O72-, cefixime (CFX), nitrofurazone (NFZ), imidacloprid (IMI) and nitenpyram (NTP) in aqueous medium. Notably, the Tb-MOF is more sensitive toward MnO4- in fluorescent quenching tests than Eu-MOF due to the Forstert resonance energy transfer (FRET) effect. This work provides the first example to employ MOFs as fluorescent sensors for detection of IMI in aqueous solution.

Micellar enhanced photo-induced fluorescence and absorbance for the development of an on-site early warning water quality monitoring system for pesticides.

This paper describes two prototypes of an on-site Early Warning Water Quality Monitoring System (EWWQMS) for pesticide quantification in natural waters. As many pesticides are non-fluorescent, the EWWQMS setup uses UV photoconversion to form highly fluorescent photoproducts. To enhance sensitivity, the two prototypes use micellar-enhanced fluorescence with surfactant (cetyl trimethyl ammonium chloride) in aqueous solution. To improve specificity, four UV LEDs at different wavelengths then excite the fluorescent photoproducts. The EWWQMS prototypes also employ UV absorption for quantification of non-photosensitive pesticides. The first prototype detects the pesticides via a diode array spectrometer. The second system is developed with higher resolution spectrometer and an intensified CCD camera detection to improve the sensitivity of the method. These experimental set-ups are described, explained and tested. Analytical applications were carried out online in CTAC aqueous solution, for the determination of isoproturon, flufenoxuron and profenofos. The calibration curves obtained are linear over one order of magnitude, and the detection limits are in the ng mL-1 range. The analytical performances of these new methods are good compared with other published classical micellar enhanced photo-induced fluorescence methods for the determination of pesticides in aqueous solutions. Our results show that these EWWQMS prototypes can be used as a warning system to protect against pesticide contamination exceeding the threshold of treatment capabilities at industrial facilities using natural waters.