This study reports on the synthesis and characterization of an innovative CQDs–decorated porous g-C3N4 (CN) with PANI hybrid nanocomposite for the degradation of a host of toxic pollutants including ...ciprofloxacin in the environment.
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•Novel CQDs–decorated PANI with porous CN synthesized via an in-situ polymerization.•CN-PANI-CQDs has excellent photocatalytic CIP degradation and stability performance.•Effectiveness of photocatalyst and the effect of interfering anions were outlined.•Degradation mechanism and pathways were investigated through LC–MS analysis.•The synthesized photocatalyst can be utilized for the removal of toxic pollutants.
Metal-free photocatalysts are widely used to decontaminate aqueous solutions by eliminating toxic and non-biodegradable compounds. It is desirable to develop a photocatalyst with high charge separation and migration efficiency. The addition of carbon quantum dots (CQDs) to graphitic carbon nitride with polyaniline (PANI) can improve its light absorption abilities and reduce the recombination of holes and electrons. In this study, a novel CQDs decorated on PANI with hollow porous graphitic carbon nitride (CN) was fabricated via an in situ polymerization followed by an ultra-sonication. The optimal CQDs–loaded CN-PANI nanocomposite exhibited the high visible light absorption with a high specific surface area. Furthermore, better photocatalytic degradation of ciprofloxacin (CIP) was achieved under the visible light. The improved photocatalytic activity of CN-PANI-CQDs (5.0%) can be attributed to its higher charge separation, and destruction of recombination rate through the heterojunction of excited electrons among CN, PANI, and CQDs. This effect was further confirmed by high photocurrent intensity, low photoluminescence emission, and electrical resistance. In addition, different parameters including catalyst weight, initial CIP concentration, and interfering effect of anions during CIP removal were investigated. The main active species in the degradation of CIP were identified to h+, •OH, and •O2− through the scavenger test. The high reusability and stability of the photocatalyst composite were also verified. The degradation intermediates and reaction pathways were identified. Furthermore, the effectiveness of the photocatalyst was evaluated using different toxic pollutants including imidacloprid, tetracycline, phenol, and rhodamine B under similar conditions. The CQDs–decorated CN-PANI was proved as a promising material for efficient photodegradation of toxic pollutants in water.
We constructed a novel-binding site for metal ion detection using a fused tetrazole ring conjugated with aminopyrene (
R
). The designed structure of the molecule was successfully synthesized and ...determined the probe's selectivity by testing various metal ions and found that the probe effectively detects Al
3+
ion visually. Checked the sensing ability of the probe with different approaches (fluorimetric and colorimetric), and the effectiveness is double confirmed. The added Al
3+
ion to
R
procured a rapid change in color from yellowish orange to colorless. Under the UV lamp, a turn-on blue fluorescence was observed after adding aluminium ion, whereas the probe was non-fluorescent before detecting aluminium ion. The probable interface of the probe with aluminium ion has also been expected from HRMS spectral analysis results. The probe's utility in real-time monitoring of Al
3+
ion in water is confirmed by a simple test kit prepared using filter paper. The kit showed a possible naked-eye detection with a notable color change, and when checked, the aluminium ion detected test kit under a UV lamp showed blue fluorescence.
A series of four ferrocene based imidazoles (R1–R4), in which the imidazole is attached to different electron acceptor moieties were designed, synthesized and characterized. The anion binding studies ...were carried out using various techniques including electrochemistry, fluorescence and 1H NMR spectroscopy. Fluorescence studies indicated the formation of strong complexes (Binding constant KA in the order of 106 M−1) between the receptors and cyanide ion selectively. 1H NMR titrations demonstrated that R1–R4 bind cyanide ion through imidazole N–H…CN− hydrogen bond formation. Electrochemical studies using cyclic voltammetric technique displayed “two-wave behaviour” with a cathodic shift of the ferrocene/ferrocenium redox couple (ΔE1/2) up to 269 mV with cyanide ion with a high selectivity. The practical applicability of the receptor has also been investigated.
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•The receptors recognize cyanide ion selectively and sensitively.•NMR studies indicated that cyanide ion recognition is by H-bond formation.•The receptor electrochemically recognizes cyanide in deep well water samples.
The topochemical polymerization of diacetylenes (DAs) is closely related to the length of their alkyl chain. DA monomers have two types of alkyl chain side groups: the inner alkyl chain and the outer ...alkyl chain, that is, the peripheral alkyl chain. Herein, we designed and synthesized a series of DA monomers that possess bis-amide linkages with different peripheral alkyl chains (n = 6–9; DA1–DA4). The peripheral alkyl chain length of these DA monomers exhibits an odd/even effect on topochemical polymerization. The polymerization of DAs was achieved only when n is an odd number, whereas no polymerization occurred when n is an even number. The odd/even effect on the topochemical polymerization was also investigated using ab initio density functional theory calculations. The thermochromic reversibility of polydiacetylenes (PDAs) was investigated using UV–vis absorption spectroscopy at temperatures ranging from 20 to 60 °C. Monomer DA2 was used as a single-component ink solution in a fountain pen that can be transformed into thermochromic letters on conventional paper. Furthermore, a PDA-embedded polyethylene oxide film was included to monitor the thermochromic reversibility and was found to exhibit excellent thermochromic reversibility between 20 and 100 °C and stability, enabling storage for a few months without deformation. Finally, a green-colored patterned polymer film is readily obtained by a subtractive color (blue and yellow) mixing method and exhibits high thermochromic reversibility at temperatures between 20 and 100 °C.
We designed the new xanthene dyes by introducing the donor and acceptor group of electrons in the 5' position of the carboxyphenyl ring. These synthesized dye molecules were identified using ...spectroscopy. And the photophysical studies, such as solvent optimization, were further explored before and after photodegradation of all synthesized dye compounds in both states (solution and solid). The resulting dyed modacrylic fabrics and measured their K/S values, reflectance (%), solid UV absorbance, and photoluminescence. All compounds are plotted on a chromaticity map in the pink region. During photodegradation, the stability of the molecule depends on the effect of the functional groups (donor to acceptor). In this case,
lnC/C0 (%)
became the decreasing sequence from an electron donor to acceptor, as the electrons followed from the donation function group to the carboxylic function group. Therefore, the electron-accepting group dyes decompose rapidly during ultraviolet radiation.
Even though literature available on EPDM is abundant, the data on physical, mechanical, thermal, interface properties and ablative performance as specifically required for the design and acceptance ...of internal insulation of large Composite Rocket Motor Casing is scant in the plethora of literature available in the subject of EPDM insulation. This gave the impetus to take up this experimental work wherein most promising formulation of EPDM with Kevlar and silica as reinforcing fillers and with only silica as reinforcing filler were thoroughly characterized for the insulation requirements of large Composite Rocket Motor Casing and compared with the performance of proven Nitrile rubber based insulation. The significant findings which are unique, are discussed in this paper.
Five new chemosensors ( R1–R5 ), possessing benzoquinone as the signaling unit and imidazole as the H-bond donor unit, for cyanide sensing have been rationally designed, synthesized and characterized ...by NMR and mass spectroscopy. The structure of R5 was confirmed by single crystal XRD studies. These receptors exhibited a prominent visual colour change toward the cyanide ion over other common anions in an aqueous HEPES buffer–DMF (9 : 1 v/v) medium. The complexation of receptor–CN − has been addressed by UV-Vis, fluorescence and 1 H NMR spectra and was supported by electrochemical and DFT studies. The mechanism of sensing involves formation of H-bonds between imidazole N–H and CN − ions. The stoichiometry of the receptor–CN − complexes was found to be 1 : 2 (receptor–CN − ) and the detection limit was observed to be in the range of 1.1–3 nM. The test strips based on R5 were fabricated and could act as convenient and efficient CN − test kits. Notably, the novelty of the present investigation is that the receptor R5 selectively senses CN − ions in solid, aqueous and gas phases i.e. ‘ a complete receptor ’.
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•A rhodamine-labelled tripeptide was synthesized and spectroscopically characterized.•It self-assembled to form spherical nanoaggregates in H2O-ACN mixture (fw = 80 %).•It holds a ...fast response time (≤15 s) and low LOD (51 nm) towards Al3+ ions.•Test-strips, thin-films, and Arduino-based optosensing platform were fabricated.
Peptide-fluorophore conjugates (PFCs) have been expeditiously utilized for metal ion recognition owing to their distinctive characteristics. Selective detection and quantification of aluminum is essential to minimize health and environmental risks. Herein, we report the synthesis and characterization of a new chemoprobe with aggregation-induced emission characteristics by chemically conjugating rhodamine-B fluorophore with a tripeptide. The probe revealed β-sheet secondary conformation in both solid and solution states, as confirmed by FT-IR, PXRD, and CD experiments. AIE characteristics of the probe in water-MeCN mixtures revealed the formation of spherically shaped nanoaggregates with an average size of 353 ± 7 nm, as confirmed by SEM, TEM, and DLS studies. The probe exhibited a large stokes shift (175 nm) and displayed selective colorimetric and fluorometric responses towards Al3+ ions with an extremely low detection limit (51 nm) and a fast response time (≤15 s). Comparative NMR studies confirmed the cleavage of spirolactam ring upon aluminum binding. The probe’s practicality was enhanced through integration into test strips and thin films, allowing solid-phase detection of Al3+ ions. Furthermore, an RGB-Arduino enabled optosensing device has been developed to enable instant quantifiable analysis of aluminum concentrations in real-time conditions.
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•An acrylamide-xanthene based hydrogel for sensing Hg2+ ion in 100% water.•The polymeric hybrid probe showed the prompt high-visible color change and turn-on fluorescence ...response.•The synthesized polymeric form of probe is reusable and responds rapidly to changes in the environment.
An acrylamide-xanthene hybrid polymeric probe was synthesized for the selective and sensitive detection of mercury ions (Hg2+) in 100% water. The non-polymeric form of probe displayed extraordinary selectivity above other additional metal cations via both a visual color change and fluorescence change with exceptional reversibility and responds rapidly to changes in the environment. The 1H NMR titration study revealed the binding of an Hg2+ ion on the imine hydrogen of the probe by the opening of the spiro-lactam ring, which instigates an instant color change. Reversible behavior of the polymeric probe using an aqueous solution of EDTA was confirmed by both absorption and fluorescence studies. The prepared polymeric probe detects Hg2+ in 100% water and is a promising material for the mercury recognition in real-time.
