Rapid sequential detection of Al3+ and glyphosate using an "Off-On-Off" fluorescent probe based on salicylate modified layered double hydroxides.

A fluorescent probe based on salicylate modified layered double hydroxide (LDH-SA) is presented, enabling the swift sequential detection of Al3+, fosetyl-Al and glyphosate in aqueous environment. The probe was synthesized using a simple co-precipitation procedure, and its properties and synthesis conditions were thoroughly characterized and optimized. A unique "off-on-off" fluorescent response was observed when the probe sequentially interacted with Al3+ and glyphosate, and the detection method based on this phenomenon was established. The limits of detection for Al3+ and glyphosate were determined as 0.03 µmol/L and 0.03 mg/L, respectively, with rapid detection periods of one minute and four minutes. The LDH-SA/Al3+ complex requires Al3+ to generate a chelation-gathered fluorescence effect, which is the mechanism by which it quenches LDH-SA. This is possible due to the inhibition of excited-state intramolecular proton transfer and photoinduced electron transfer processes within LDH-SA after incorporating Al3+. Upon interaction with glyphosate, competitive complexation between glyphosate and Al3+ is initiated, which leads to a recovery of the fluorescence spectrum of LDH-SA and demonstrating the "off-on-off" behavior. An "INHIBIT" logic gate system was devised utilizing the response, indicating potential applications in fluorescence-based devices. Such a rapid, sequential detection capacity is impressive. It attests to the utility of LDH-SA as a probe for Al3+ or glyphosate, and suggests promise for applications in pollutant analysis or environmental monitoring applications.

An 'on-off-on' fluorescent switch based on a luminous covalent organic framework for the rapid and selective detection of glyphosate.

Glyphosate, the most used herbicide in the world, has a residue problem that cannot be ignored. However, glyphosate itself does not have fluorescence emission and lacks the conditions for fluorescence detection. In this work, a rapid and selective fluorescence detection method of glyphosate was designed by an 'on-off-on' fluorescent switch based on a luminous covalent organic framework (L-COF). Only the fixed concentration of Fe3+ as an intermediate could trigger the fluorescent switch and no incubation step was required. The proposed method showed good accuracy with a correlation coefficient of 0.9978. The method's limits of detection and quantitation were 0.88 and 2.93 µmol/L, which were lower than the maximum allowable residue limits in some regulations. Environmental water samples and tomatoes were selected as actual samples to verify the application in a complex matrix. A satisfactory mean recovery from 87% to 106% was gained. Furthermore, Fe3+ could induce fluorescence quenching of L-COF through the photo-induced electron transfer (PET) effect, while the addition of glyphosate could block the PET effect to achieve detection. These results demonstrated the proposed method had abilities to detect glyphosate and broaden the application of L-COF.

Preparation of aromatic ß-cyclodextrin nano/microcapsules and corresponding aromatic textiles: A review.

Fragrance finishing of textiles is receiving substantial interest, with aromatherapy being one of the most popular aspects of personal health care. However, the longevity of aroma on textiles and presence after subsequent launderings are major concerns for aromatic textiles directly loaded with essential oils. These drawbacks can be weakened by incorporating essential oil-complexed ß-cyclodextrins (ß-CDs) onto various textiles. This article reviews various preparation methods of aromatic ß-cyclodextrin nano/microcapsules, as well as a wide variety of methods for the preparation of aromatic textiles based on them before and after forming, proposing future trends in preparation processes. The review also covers the complexation of ß-CDs with essential oils, and the application of aromatic textiles based on ß-CD nano/microcapsules. Systematic research on the preparation of aromatic textiles facilitates the realization of green and simple industrialized large-scale production, providing needed application potential in the fields of various functional materials.

A Carbon-Negative Hydrogen Production Strategy: CO2 Selective Capture with H2 Production.

We reported a strategy of carbon-negative H2 production in which CO2 capture was coupled with H2 evolution at ambient temperature and pressure. For this purpose, carbonate-type Cux Mgy Fez layered double hydroxide (LDH) was preciously constructed, and then a photocatalysis reaction of interlayer CO3 2- reduction with glycerol oxidation was performed as driving force to induce the electron storage on LDH layers. With the participation of pre-stored electrons, CO2 was captured to recover interlayer CO3 2- in presence of H2 O, accompanied with equivalent H2 production. During photocatalysis reaction, Cu0.6 Mg1.4 Fe1 exhibited a decent CO evolution amount of 1.63 mmol g-1 and dihydroxyacetone yield of 3.81 mmol g-1 . In carbon-negative H2 production process, it showed an exciting CO2 capture quantity of 1.61 mmol g-1 and H2 yield of 1.44 mmol g-1 . Besides, this system possessed stable operation capability under simulated flu gas condition with negligible performance loss, exhibiting application prospect.

Light-Induced Structural Dynamic Evolution of Pt Single Atoms for Highly Efficient Photocatalytic CO2 Reduction.

Revealing the structural evolution of the real active site during photocatalysis is very important for understanding the catalytic mechanism, but it remains a great challenge. By employing single atoms (SAs) as the mechanism research platform, we investigated the variation of the SA structure under light and the corresponding reaction pathway controlment mechanism. In particular, taking the defect anchoring strategy, Pt SAs are anchored on the metal ion vacancy-rich ZnNiTi layered double hydroxide-etched (ZnNiTi-LDHs-E) support. It is proved by CO-Fourier transform infrared and X-ray absorption fine structure characterization methods that the Pt SAs could gain photoelectrons to form cationic Pt(IV), electron-rich Pt(II), and near-neutral Ptδ+ species at different light intensities. By in situ inducing the above different Pt SAs in photocatalytic CO2 reduction, a dramatic product distribution is observed: (1) under weak light, Pt(IV) SAs cannot activate CO, so CO cannot be further transformed into hydrocarbons; (2) under the moderate light, electron-rich Pt(II) SAs could cooperate with adjacent LDH surface sites (Ni2+/Ti4+) to open up the C-C coupling route for C2H6 generation; and (3) Pt SAs in the state of near-neutral Ptδ+ could directly hydrogenate CO into CH4. This work reveals the structural evolution of Pt SAs in photocatalysis and the corresponding effect on catalytic performance, which provides a new idea for the construction of highly efficient photocatalysts.

Perfluoro octanoic acid-modified magnetic hyperbranched polyamideamine as a sorbent for the extraction of fluorine-containing pesticides from water samples.

Perfluoro octanoic acid was modified on the surface of magnetic hyperbranched polyamideamine by acid amine condensation. The morphology and chemical composition of perfluoro octanoic acid-modified magnetic hyperbranched polyamideamine was characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, zeta potential, particle size analysis, Brunauer-Emmett-Teller measurement, and X-ray photoelectron spectroscopy. Perfluoro octanoic acid-modified magnetic hyperbranched polyamideamine was applied in magnetic solid phase extraction for the separation and enrichment of four fluorine-containing pesticides (indoxacarb, metaflumizone, cyflumetofen, and cyhalothrin). The magnetic solid phase extraction method based on perfluoro octanoic acid-modified magnetic hyperbranched polyamideamine has low method detection limits (0.30-0.49 µg/L), a satisfactory coefficient of determination (0.9995-0.9999), wide linear ranges (2.5-250 µg/L), and good repeatability (intraday: 2.6-4.7%; interday: 1.1-7.9%). The enrichment factors and extraction efficiences varied from 55 to 76 and 69 to 96%, respectively. The sorbent-to-sorbent reproducibility was in the range of 3.2-7.6%, indicating that the synthesis of the sorbent was reliable. For the detection of actual water samples, the relative recoveries were in the range from 80.1 to 114.4% with relative standard deviations less than 9.6%. The calculation results of quantum chemistry calculations showed that after the modification of perfluoro octanoic acid, the interaction between the sorbent and four fluorine-containing pesticides was stronger.

Use of 1-octyl-3-methylimidazole hexafluorophosphate modified magnetic hyperbranched polyamideamine as sorbent for the extraction of pyrethroid insecticides from tea infusion.

Magnetic hyperbranched polyamideamine was carboxylated using succinic anhydride and modified further with 1-octyl-3-methylimidazole hexafluorophosphate successively. The morphology and chemical composition of the prepared material was characterized by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller measurement, X-ray photoelectron spectroscopy, etc. 1-Octyl-3-methylimidazole hexafluorophosphate modified magnetic hyperbranched polyamideamine was used as sorbent in the magnetic solid-phase extraction for the separation and enrichment of five pyrethroid insecticides from tea infusion. The magnetic solid-phase extraction method proposed in this article has low method detection limits (0.53-0.71 ng/mL), acceptable coefficient of determination (0.9992-0.9998), wide linear ranges (2.5-500.0 ng/mL), and good repeatability (intraday: 1.2-6.3%; interday: 1.6-5.4%). In the detection of five pyrethroid insecticides in tea infusion, relative recoveries were in the range from 87.7 to 114.7% with satisfactory relative standard deviations (0.2-7.4%). With the aid of quantum chemistry calculations, the interaction energy between the sorbent and five pyrethroid insecticides was calculated, which proved the necessity of the modification of 1-octyl-3-methylimidazole hexafluorophosphate.

PEG-modified magnetic Schiff base network-1 materials for the magnetic solid phase extraction of benzoylurea pesticides from environmental water samples.

It is necessary to establish a rapid, simple and environmentally friendly detection method for benzoylurea pesticides (BUs) in environmental water samples because of their toxicity in environmental circulation. Herein, a novel polyethylene glycol (PEG) modified magnetic covalent organic framework material based on the Schiff base reaction was prepared (PEG/Fe3O4@SNW-1). This material was used as a sorbent for enriching five BUs by magnetic solid phase extraction prior to detection via high-performance liquid chromatography. After the optimization of several parameters (such as the salinity, extraction time, amount of sorbent, desorption time, etc.) that influenced the recovery of the magnetic solid phase extraction process, the limits of detection (S/N = 3) were defined as less than 1.0 µg L-1, and the limits of quantitation (S/N = 10) were calculated as being lower than 3.4 µg L-1. A satisfactory linear range of 5-1000 µg L-1 was achieved. Finally, the proposed method was applied to analyze benzoylurea pesticides in three environmental water samples. These results indicated that the proposed method was feasible and demonstrated the potential application of the PEG/Fe3O4@SNW-1 material for detecting similar pesticide residues in environmental water samples.