Search Results (459)

Halogenated flame retardants have been amongst the most widely used and effective solutions for enhancing fire resistance. However, their use is currently strictly regulated due to serious health and environmental concerns. In this context, phosphorus-based and mineral flame retardants have emerged as promising alternatives. Despite this, their combined use is neither straightforward nor guaranteed to be effective. This study scrutinizes the interactions between these two classes of flame retardants (FR) through a systematic analysis aimed at elucidating the antagonistic pathways that arise from their coexistence. Specifically, this study focuses on two inorganic fillers, mineral huntite and chemically precipitated magnesium hydroxide, both of which produce basic oxides upon thermal decomposition. These fillers were incorporated into a poly(butylene terephthalate) (PBT) matrix to be utilized as advanced-mattress FR coating fabric and were subjected to a series of flammability tests. The pyrolysis products of the prepared polymeric composite compounds were isolated and thoroughly characterized using a combination of analytical techniques. Thermogravimetric analysis (TGA) and differential thermogravimetric analysis (dTGA) were employed to monitor decomposition behavior, while the char residues collected at different pyrolysis stages were examined spectroscopically, using FTIR-ATR and Raman spectroscopy, to identify their structure and the chemical reactions that led to their formation. X-ray diffraction (XRD) experiments were also conducted to complement the spectroscopic findings in the chemical composition of the resulting char residues and to pinpoint the different species that constitute them. The morphological changes of the char’s structure were monitored by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). Finally, the Limited Oxygen Index (LOI) and UL94 (vertical sample mode) methods were used to assess the relative flammability of the samples, revealing a significant drop in flame retardancy when both types of flame retardants are present. This reduction is attributed to the neutralization of acidic phosphorus species by the basic oxides generated during the decomposition of the basic inorganic fillers, as confirmed by the characterization techniques employed. These findings underscore the challenge of combining organophosphorus with popular flame-retardant classes such as mineral or basic metal flame retardants, offering insight into a key difficulty in formulating next-generation halogen-free flame-retardant composite coatings. Full article

Luminescent metal–organic frameworks (MOFs) are used for the detection of organophosphorus pesticides (OPs) due to their large surface area and pore volume as well as their special optical properties. However, most self-luminescent MOFs are not only complex to synthesize and unstable in water but also feature a “turn-off” sensing system, which has highly restricted their practical applications in OP detection. Herein, a “turn-on” fluorescence sensor based on the guest-induced luminescence MOF Ru(bpy)₃²⁺@UiO-66 was constructed, which realized the sensitive detection of OPs through a dual-enzyme system for the first time. Compared with self-luminescent MOFs, Ru(bpy)₃²⁺@UiO-66 was not only more easily synthesized but also had higher chemical and photostability in water. In this strategy, by means of the hydrolysis of AChE and ChOx, H₂O₂ will be produced, which can oxidize Fe²⁺ to Fe³⁺, thereby quenching the fluorescence of Ru(bpy)₃²⁺@UiO-66. In the presence of OPs, the activity of AChE can be inhibited, resulting in the inability to generate H₂O₂ and Fe³⁺, which will turn on the fluorescence signal of Ru(bpy)₃²⁺@UiO-66. As a result, the Ru(bpy)₃²⁺@UiO-66 sensing system not only had high sensitivity for OPs detection but also possessed a satisfactory detection recovery rate for parathion-methyl in real samples, which provides a new approach for OP detection in food safety as well as environmental monitoring. Full article

Tomatoes are among the most widely consumed and economically significant fruits in the world. However, the extensive use of pesticides in their cultivation has led to the contamination of the peels, posing potential health risks to consumers. As one of the top global producers, consumers, and exporters of tomatoes, Mexico requires rapid, non-destructive, and real-time methods for pesticide monitoring. In this study, a detailed characterization of six pesticides using Raman and Fourier Transform Infrared (FT-IR) spectroscopies was carried out to identify their characteristic vibrational modes. The pesticides examined included different chemical classes commonly used in tomato cultivation: organophosphorus (dichlorvos and methamidophos), pyrethroids (lambda-cyhalothrin and cypermethrin), and carbamates (methomyl and benomyl). Tomato peel samples were examined both before and after pesticide application. Prior to treatment, the peel exhibited a well-organized polygonal structure and showed the presence of carotenoid compounds. After pesticide application, no visible structural damage was observed; however, distinct vibrational bands enabled the detection of each pesticide. Organophosphorus pesticides could be identified through vibrational bands associated with P-O and C-S bonds. Pyrethroid detection was facilitated by benzene ring breathing modes and C=C stretching vibrations, while carbamates were identified through C-N stretching contributions. Phytotoxicity testing in the presence of pesticides indicates no significant damage during the germination of tomatoes. Full article

Bemisia tabaci (Aleyrodidae family) is one of the most damaging pests of numerous crops worldwide. Insecticides, namely pyrethroids and organophosphates, have long been the primary control tools against this pest, resulting in several resistance cases. In Tunisia, the two most damaging biotypes of B. tabaci, MEAM1-B and MED-Q, are sympatric, and more concerns about developing resistance keep rising due to the extensive use of insecticides. Here, we aimed to elucidate the molecular mechanism of resistance to pyrethroids and organophosphorus insecticides in two Tunisian populations of B. tabaci, collected respectively on Capsicum annuum and Lantana camara, and then determine the bacterial community associated with insecticide resistance and susceptible biotypes based on 16S rRNA Illumina sequencing. The results showed that the population collected on Capsicum annuum belonged to the MEAM1-B biotype with an insecticide resistance profile. In contrast, the population collected on the Lantana camara belonged to the MED-Q biotype with a sensitive profile. The bacterial communities of the two biotypes were predominantly structured by the Proteobacteria phylum and three genera, including Candidatus Portiera, the secondary facultative symbiont, and Hamiltonella, which were unevenly distributed between the two biotopes. Our results provide the first evidence for insecticide resistance alleles in Tunisian MEAM1-B populations and suggest an association between bacterial community composition within susceptible biotypes and insecticide resistance. Full article

Organophosphorus (OP) pesticides are a class of chemicals that are extensively used worldwide. The exposure to and use of organophosphates can be assessed by analyzing their metabolites and degradation products, such as dialkyl phosphate (DAP), dialkyl thiophosphate (DATP), and dialkyl dithiophosphate (DADTP). However, since these metabolites/hydrolysis products can result from the metabolism or breakdown of several organophosphorus pesticide families, they serve as nonspecific biomarkers and do not indicate the specific pesticide involved in exposure. In an earlier study, chemical derivatization using N-(2-(bromomethyl)benzyl)-N,N-diethylethanaminium bromide (CAX-B) was described to improve the signal intensity of numerous organophosphorus (OP) acids in liquid chromatography tandem mass spectrometry (LC-ESI-MS/MS) analysis. In the present study, CAX-B was employed to derivatize a set of seven phenolic compounds corresponding to the complementary portion of OP pesticides. The derivatization process using CAX-B was performed in acetonitrile with potassium carbonate at 50 °C for 30 min. LC-Orbitrap-ESI-MS/MS was used to analyze the resulting phenol derivatives and their fragmentation patterns were studied. Notably, the derivatized phenols were markedly more sensitive than the underivatized phenols when LC-ESI-MS/MS was used in MRM technique, without being affected by the sample matrix (soil or plant extracts). This derivatization technique aids in identifying OP pesticides, offers insights into their subfamily, and pinpoints a specific compound through the analysis of corresponding phenol derivative. Full article

The design of efficient and stable visible-light-driven photocatalysts is paramount for sustainable hydrogen (H₂) evolution and the degradation of organophosphorus pesticides, exemplified by dichlorvos (DDVP). In this work, we synthesized a co-catalyst-free nanocomposite photocatalyst composed of Al₆Si₂O₁₃ (ASO) and Cd_8.05Zn_1.95S₁₀ (ZCS). By constructing a Type-I heterojunction, the optimized ASO/ZCS-1 nanocomposite (ASO loading ratio: 30%) enhanced visible-light-driven H₂ evolution activity (5.1 mmol g⁻¹ h⁻¹), nearly doubling that of pristine ZCS (2.7 mmol g⁻¹ h⁻¹). Stability assessments revealed catalytic durability for ASO/ZCS-1 over five successive cycles, whereas the activity of pure ZCS precipitously declined to 59.7% of its initial level. Additionally, ASO, ZCS, and ASO/ZCS-2 (ASO loading ratio: 50%) demonstrated notable photocatalytic efficiency toward DDVP degradation without any co-catalyst, reducing DDVP concentration to 56.2% (ASO), 18.9% (ASO/ZCS-2), and 38.4% (ZCS), with corresponding degradation stability of 93.8%, 95.1%, and 93.8%, respectively. These results underscore the superior photocatalytic activity and stability of ASO, ZCS, and ASO/ZCS in the remediation of organophosphorus pesticides, with the Type-I heterojunction structure of ASO/ZCS enhancing both degradation activity and stability. Comprehensive characterizations by X-ray photoelectron spectroscopy (XPS), ultraviolet–visible diffuse reflectance spectroscopy (UV–vis DRS), and differential charge density analyses verified the Type-I heterojunction charge-transfer mechanism, effectively suppressing charge recombination and thus improving photocatalytic performance. Consequently, ASO/ZCS nanocomposites exhibit significant promise for broad applications in sustainable H₂ production, pollutant degradation, and ensuring food and agricultural product safety. Full article

The thermodynamic properties of di-2-ethylhexylphosphoric acid (D2EHPA) in organic solvents are critical for optimizing metal extraction processes in hydrometallurgy, necessitating precise determination of activity coefficients in binary systems such as D2EHPA–n-hexane. This study was devoted to the determination of n-hexane’s concentrations in the vapor phase over D2EHPA solutions at 293.0 K using gas chromatography (GC) and isopiestic (IP) methods. Comparison with literature data confirmed the superior reliability of GC measurements at low n-hexane concentrations. The experimentally determined activity coefficients of hexane, obtained via GC, served as the initial input parameters for UNIFAC modeling. The optimized interaction parameters were 1144 ± 25 (CH₂-HPO₄) and 228 ± 50 (HPO₄-CH₂), with the infinite dilution activity coefficient for D2EHPA ${\gamma }_{\infty }=22.1$. These results experimentally clarify the non-ideal behavior of D2EHPA–n-hexane mixtures, establishing a validated thermodynamic modeling framework for organophosphorus extractant systems. This work establishes a fundamental basis for investigating ternary systems, such as D2EHPA–aliphatic solvent–aromatic solvent and D2EHPA–metal complex–solvent systems, paving the way for enhanced liquid–liquid extraction efficiency. Full article

Glyphosate (N-phosphonomethylglycine) is a widely used organophosphorus herbicide that inhibits the shikimate pathway, a crucial metabolic route responsible for the synthesis of aromatic amino acids in plants and certain microorganisms. Due to its broad-spectrum activity, glyphosate serves as the main active ingredient in various commercial herbicide formulations, including Roundup and Kalach 360 SL (KL). It poses a health hazard to animals and humans due to its persistence in soil, water erosion, and crops. The aim of our study was to continue the previous research to explore the impact of KL on bone using physico-chemical parameters and in silico studies after exposing female wistar rats for 60 days. The in silico study concerned the assessment of binding affinity and molecular interactions using computational modeling approach. The rats were allocated into three experimental groups: group 1 (n = 6) served as controls, while groups 2 and 3 received low and high doses (Dose 1: 126 mg/Kg and Dose 2: 315 mg/Kg) of KL dissolved in water, respectively. All rats were sacrificed after 60 days of exposure. XRD and FTIR spectrum analysis of bone tissues in female rats showed significant histoarchitectural changes associated with bone mineralization disruption. Our results have demonstrated that sub-chronic exposure of adult female rats to KL causes bone rarefaction, as confirmed by a previous histological study. This physico-chemical study has further confirmed the harmful impact of KL on the crystalline fraction of bone tissue, composed of hydroxyapatite crystals. In addition, the computational analyses showed that glyphosate binds to 3 Glu form of osteocalcin (3 Glu-OCN) (4MZZ) and decarboxylated osteocalcin (8I75) with good affinities and strong molecular interactions, which justified and supported the in vivo findings. In conclusion, KL may interfere with hydroxyapatite and osteocalcin and, therefore, impair bone remodeling and metabolism. Full article

In Romania, groundwater is an important source of drinking water, especially in rural areas. This study investigated the concentrations of organophosphorus, carbamate, and triazine pesticides (OPs) along with organochlorine pesticides (OCPs) in groundwater samples collected from the Titu-Sarata Plain. Sensitive analytical techniques were employed, including Ultrahigh-Performance Liquid Chromatography coupled with Q Exactive™ HF Hybrid Quadrupole-Orbitrap™ Mass Spectrometry (UHPLC-Orbitrap-MS/MS) and Gas Chromatography coupled with an electron capture detector (GC-ECD). Environmental and human health risks were assessed in the case of pesticides that exceeded the maximum allowed concentration. The environmental risk assessment (ERA) revealed significant risks associated with Phosdrin, Phorate, and pp’DDE. Additionally, particular concerns arose from the presence of Aldrin and Dieldrin, which pose a high carcinogenic risk, especially through groundwater consumption in agricultural areas. The results of this research highlight the need for the implementation of a continuous quality monitoring program for groundwater in the agricultural regions that were studied. Full article

Organophosphorus compounds (OPC) are a large class of organic compounds that provide a wide range of applications, and their importance has grown steadily in recent years. In each category and family, these compounds have similarities and differences. Due to their immense variety, these chemicals have various properties and, therefore, various applications. In fact, various works have been published recently that present the main applications of OPC, especially in metal extraction. Despite their extemsive range of use, optimizing their performance as extractant agents remains a challenge due to their structural variability and sensitivity to process parameters. This review provides a critical analysis of pentavalent OPCs, focusing on how their chemical nature influences heavy metal extraction efficiency. For the first time, we present a novel classification system for OPCs based on phosphorus valency and heteroatom coordination, offering a framework to guide future research. Our findings reveal that the direct coordination of the phosphorus to heteroatoms such as oxygen, sulfur, and nitrogen has a great influence on the physicochemical characteristics of the extractant and the metal extraction efficiency. This observation is in line with Pearson’s Hard and Soft Acids and Bases (HSAB) theory in the sense that it demonstrates that altering the heteroatom alters the metal affinity of the ligand. As a result, these structural modifications can improve the extraction performance by up to 40% for some heavy metals, highlighting the potential for optimized molecular designs to maximize industrial applications. In the future, this work offers a solid foundation for future studies on the rational design of organophosphorus-based extractants. Using HSAB theory and our novel classification system, researchers can rationally design OPCs for their target metal with unparalleled precision. These results have transformative impacts on metal recovery efficiency-intensive sectors like mining, waste recycling, and clean energy technologies. Full article

Organophosphorus pesticides (OPs), while pivotal for agricultural productivity, pose severe environmental and health risks due to their persistence and bioaccumulation. Existing detection methods, such as chromatography and spectroscopy, face limitations in field adaptability, cost, and operational complexity. To address these challenges, this study introduces a novel dual-mode photoelectrochemical–electrochemical (PEC-EC) sensor based on a Co,N-TiO₂@ZrO₂/3DGH nanocomposite. The sensor synergistically integrates zirconium oxide (ZrO₂) for selective OP capture via phosphate-Zr coordination, cobalt-nitrogen co-doped titanium dioxide (Co,N-TiO₂) for visible-light responsiveness, and a three-dimensional graphene hydrogel (3DGH) for enhanced conductivity. In the PEC mode under light irradiation, OP adsorption induces charge recombination, yielding a logarithmic photocurrent attenuation with a detection limit of 0.058 ng mL⁻¹. Subsequently, the EC mode via square wave voltammetry (SWV) self-validates the results, achieving a detection limit of 0.716 ng mL⁻¹. The dual-mode system demonstrates exceptional reproducibility, long-term stability, and selectivity against common interferents. Parallel measurements revealed <5% inter-mode discrepancy, validating the intrinsic self-checking capability. This portable platform bridges the gap between laboratory-grade accuracy and field-deployable simplicity, offering transformative potential for environmental monitoring and food safety management. Full article

To understand the effect of the hydroxyl group and processing temperatures on dielectric losses of flame retardants and flame-retardant polymers, the performance difference between 6-methyldibenzo[c,e][1,2]oxaphosphinine 6-oxide (DOPO-Me) and 6-(hydroxymethyl)dibenzo[c,e][1,2]oxaphosphinine 6-oxide (DOPO-HM) has been investigated, respectively, in non-polar and polar polymers at 7–20 GHz. DOPO-HM and DOPO-Me differ by only one OH group. The former demonstrates a lower dissipation factor (Df) than the latter, owing to hydrogen bonds. In polystyrene and crosslinked polyphenylene oxide, both flame retardants increase a dielectric loss of flame-retardant polymers, with DOPO-HM being less detrimental because of its higher crystallizability and lower plasticization. In polar poly(methyl methacrylate) (PMMA), conformational changes in PMMA main chains caused by flame retardants and high processing temperatures lead to an early Df drop of PMMA at low loadings of the flame retardants. At high loadings, a change in the physical form of flame retardants from a primitive crystalline state to an amorphous state increases a dielectric loss of flame retardant PMMA, with DOPO-HM resulting in a slightly higher dielectric loss than DOPO-Me. These results prove that the effect of a hydroxyl group in organophosphorus structures on the dielectric loss of flame-retardant polymers is crucially dependent on its interaction with the polymer matrix. Full article

This work focuses on developing a Zn₂SnO₄-based electrochemical sensor for detecting parathion-ethyl (EP), a toxic organophosphorus pesticide. Monitoring such hazardous compounds is essential to ensure environmental and food safety. Zn₂SnO₄, known for its excellent electrical conductivity, catalytic activity, simple synthesis process, and eco-friendly nature, was utilized as an electrode material to enhance the detection of EP. Zn₂SnO₄ was synthesized via a hydrothermal method and characterized using XRD to confirm its crystalline structure. Zn₂SnO₄ was subsequently modified onto a glassy carbon electrode (GCE), enabling the study of its electrochemical properties and interaction with EP. River water and carrot samples were collected, pretreated, and analyzed for EP detection to evaluate real-world applicability. Electrochemical detection of EP using differential pulse voltammetry (DPV) showed a linear response in the concentration range of 0.01–78.4 μM, with a detection limit of 0.0059 µM. The sensor demonstrated excellent repeatability and selectivity in the presence of potential interferents. Real sample analysis confirmed the sensor’s effectiveness, achieving satisfactory recovery rates in river water and carrot samples. The high surface area and conductivity of Zn₂SnO₄ significantly enhanced the electrochemical response, validating its potential for reliable EP detection in environmental and agricultural samples. Full article

This is a broad look at the history of phosphorus—from the element through its inorganic and organic compounds to the applications of organophosphates. In addition to commercial and peaceful applications, they were used as chemical warfare agents (CWA), both in military operations and for terrorist purposes. This article attempts to provide a concise history of their development and application in this shameful role. The origin of the chemistry of phosphorus compounds to obtain precursors for the production of CWA is presented. Rapid progress in organophosphorus chemistry in the second half of the 20th century is also described. A broad overview of chemical structures is presented, including lesser-known representatives. The mode of action and the associated toxicity of organophosphorus compounds are briefly mentioned. The Chemical Weapons Convention (CWC) schedules and their changes during their validity are indicated. They are also demonstrated to be used in proficiency tests organised by the Organization for the Prohibition of Chemical Weapons (OPCW). Organophosphates called “Novichok agents”, classified as fourth-generation chemical warfare agents, are also briefly discussed. Full article

Widespread use of pesticides in agriculture causes adverse impacts on non-target organisms and environmental pollution. Efficient and sustainable pesticide removal alternatives must be developed to reduce pesticide environmental impacts. Recently, bioremediation based on immobilized microorganisms has been proposed as an environmentally friendly and cost-effective approach for pesticide degradation in water. Agro-industrial wastes are produced in large quantities in crop fields; their high availability, low cost, and potential for reuse make them ideal support materials for microbial immobilization. This systematic review, conducted through the PRISM 2020 methodology, compiles recent research on using agro-industrial waste to immobilize microorganisms for pesticide degradation. The identified studies highlight corn straw as the most studied agro-industrial waste, while the organophosphorus insecticides, chlorpyrifos, and methyl parathion were the most representative pesticides; in the identified studies, pesticide degradation was conducted mainly by bacteria of the Acinetobacter, Bacillus, and Pseudomonas genera. Overall, microbial immobilization significantly enhanced pesticide degradation, rendering it a viable bioremediation strategy for pesticide-contaminated water. Full article