Showing papers in "Journal of Photochemistry and Photobiology A-chemistry in 2022"

Construction of magnetically separable novel arrow down dual S-scheme ZnIn2S4/BiOCl/FeVO4 heterojunction for improved photocatalytic activity

Abstract: • ZnIn 2 S 4 /BiOCl/FeVO 4 ternary heterojunction synthesised by facile co-precipitation method. • The ternary heterojunction was meticulously characterised and studied. • Improved light absorption, redox capability, and easy magnetic separation. • Decolourised 98% of 10ppm solution of RhB in 30 minutes with excellent photostability. • Dual S-Scheme mechanism of charge transfer. The dual S-scheme ZnIn 2 S 4 /BiOCl/FeVO 4 heterojunction was synthesized as it can promote carrier separation while enhancing redox capability. The XRD results indicated the synthesis of pure ZnIn 2 S 4 , BiOCl, and FeVO 4 and the presence of peaks corresponding to these semiconductors in the ternary nanocomposite. The FTIR and XPS investigations confirmed these findings and revealed a change in structural characteristics because of strong heterogeneous contact at the surface. The improved light absorption in the construction of binary and ternary composite was confirmed by UV-Vis spectroscopy. Electrochemical impedance spectroscopy confirmed reduced resistance at the interface and better charge separation. The faster interfacial transport was found, and lower photogenerated charge recombination was found for ternary photocatalysts using the EIS Nyquist plot and the photoluminescence spectrum. The RhB degrading efficiency order was found to be ZnIn 2 S 4 /BiOCl/FeVO 4 > BiOCl/FeVO 4 > FeVO 4 > BiOCl > ZnIn 2 S 4 . The ternary photocatalyst ZnIn 2 S 4 /BiOCl/FeVO 4 decolorized RhB almost completely (98%) in 30 min, and COD studies showed 71.2% of RhB completely degraded under simulated solar radiations. GC-MS spectra for samples drawn from the reaction over time validated the results. The ternary composite has the highest rate constant value (0. 0.12415 min -1 ), which is 13.42, 10.70, 11.04, and 5.30 times more than ZnIn 2 S 4 , FeVO 4 , BiOCl, and BiOCl/FeVO 4 , respectively. Radical scavenging studies confirmed reactive oxidizing species, • OH, • O 2 -, and h + , and validated the proposed dual S-scheme charge transfer mechanism. Moreover, ternary photocatalyst can be reused four times with high photocatalytic stability.

Efficient sonophotocatalytic degradation of acid blue 113 dye using a hybrid nanocomposite of CoFe2O4 nanoparticles loaded on multi-walled carbon nanotubes

Abstract: Complete degradation of acid blue 113 (AB113) dye was successfully achieved by using the sonophotocatalytic process with CoFe2O4 nanoparticles loaded on multi-walled carbon nanotubes (MWCNTs/CoFe2O4), as a novel catalyst. The catalyst used was synthesized using the solvothermal co-precipitation method. First, the characteristic parameters of the synthesized catalyst were evaluated using advanced analyses of Field Emission Scanning Electron Microscopy (FESEM), X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Energy-Dispersive X-Ray Spectroscopy (EDX), Thermogravimetric (TGA), Vibrating Sample Magnetometry (VSM), and Fourier Transform Infrared Spectroscopy (FTIR). The results of the sonophotocatalytic degradation experiments showed that the optimum parameters for 100% AB113 removal were: AB113 concentration = 25 mg/L, pH = 3, MWCNTs/CoFe2O4 dose = 0.4 g/L, reaction time = 40 min, intensity of UV light = 36 W, and intensity of ultrasonic waves = 50 kHz. To identify the utility of using MWCNTs/CoFe2O4 as a catalyst, the degradation efficiencies of AB113, resulting from the sonophotocatalytic process, were compared with those determined from other similar treatment processes, that is, adsorption, photolysis, sonolysis, and sonocatalytic and photocatalytic processes, where the sonophotocatalytic process was found to be the most efficient one. Catalyst recycling was performed in eight degradation–regeneration cycles, whereas, a total reduction of 9% was observed in removal efficiency after the 8th cycle. The results showed that the AB113 dye, which was a non-biodegradable contaminant, became almost a biodegradable compound after subjection to sonophotocatalytic treatment. The results also demonstrated a high mineralization rate of the applied treatment method. In addition, a toxicity test was performed using Daphna Magna, and the results indicated a low toxicity of the AB113 dye effluent. The results of this study clarified that the sonophotocatalytic process system using MWCNTs/CoFe2O4 could be a feasible and cost-effective system for degrading dyes, for example, AB113.

Efficient sonophotocatalytic degradation of acid blue 113 dye using a hybrid nanocomposite of CoFe2O4 nanoparticles loaded on multi-walled carbon nanotubes

Abstract: Complete degradation of acid blue 113 (AB113) dye was successfully achieved by using the sonophotocatalytic process with CoFe2O4 nanoparticles loaded on multi-walled carbon nanotubes (MWCNTs/CoFe2O4), as a novel catalyst. The catalyst used was synthesized using the solvothermal co-precipitation method. First, the characteristic parameters of the synthesized catalyst were evaluated using advanced analyses of Field Emission Scanning Electron Microscopy (FESEM), X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Energy-Dispersive X-Ray Spectroscopy (EDX), Thermogravimetric (TGA), Vibrating Sample Magnetometry (VSM), and Fourier Transform Infrared Spectroscopy (FTIR). The results of the sonophotocatalytic degradation experiments showed that the optimum parameters for 100% AB113 removal were: AB113 concentration = 25 mg/L, pH = 3, MWCNTs/CoFe2O4 dose = 0.4 g/L, reaction time = 40 min, intensity of UV light = 36 W, and intensity of ultrasonic waves = 50 kHz. To identify the utility of using MWCNTs/CoFe2O4 as a catalyst, the degradation efficiencies of AB113, resulting from the sonophotocatalytic process, were compared with those determined from other similar treatment processes, that is, adsorption, photolysis, sonolysis, and sonocatalytic and photocatalytic processes, where the sonophotocatalytic process was found to be the most efficient one. Catalyst recycling was performed in eight degradation–regeneration cycles, whereas, a total reduction of 9% was observed in removal efficiency after the 8th cycle. The results showed that the AB113 dye, which was a non-biodegradable contaminant, became almost a biodegradable compound after subjection to sonophotocatalytic treatment. The results also demonstrated a high mineralization rate of the applied treatment method. In addition, a toxicity test was performed using Daphna Magna, and the results indicated a low toxicity of the AB113 dye effluent. The results of this study clarified that the sonophotocatalytic process system using MWCNTs/CoFe2O4 could be a feasible and cost-effective system for degrading dyes, for example, AB113.

A new reversible aldehyde-appended salamo-like fluorogenic probe for cascade sensing of Ni and HPO42- ions in aqueous medium

Abstract: A reversible salamo-like probe (H2L) and its nickel(II) complex which could be fully characterized by various physicochemical and spectroscopic techniques. Furthermore, the solid-state crystal structure of the nickel(II) complex along with detailed structural analysis using single crystal X-ray crystallography. The developed probe could be used as an efficient fluorogenic probe to detect Ni2+ ion in aqueous medium. Subsequently, the in situ generated complex exhibited a high sensitivity and selectivity to HPO42− ion with detection limit of 3.42 × 10−8 M. The sensing mechanism of H2L towards Ni2+ ion and sequential detection towards HPO42− ion are well studied by UV–Vis and ESI mass methods. The practical applicability values of this probe have been examined by test paper and reversible cycle.

Evaluation of synergistic effect of polyglycine functionalized gold/iron doped silver iodide for colorimetric detection, photocatalysis, drug delivery and bactericidal applications

Abstract: The present study investigated the mercury ion detection by gold/iron doped Silver iodide supported on polyglycine (Au/Fe/AgI/PGA). The characterization of Au/Fe/AgI/PGA nanocomposites was conducted by using TEM, zeta/particle size analyzer, UV–visible absorption spectroscopy, FTIR and TGA. The Au/Fe/AgI/PGA depicted the λmax at 500 nm. The real water sample was investigated for the detection of mercury ion by using the prepared Au/Fe/AgI/PGA. The presence of other metal ions did not influence on interference for mercury ion detection. The photo-degradation of methyl orange in water by Au/Fe/AgI/PGA photocatalyst was evaluated. The degradation efficiency of Au/Fe/AgI/PGA was nearly 100% within 100 min, which was 1.7 and 1.3 times higher than of AgI and Au/Fe/AgI composites, respectively. Moreover, the antibacterial performance of the Au/Fe/AgI/PGA nanocomposites was studied against Legionella pneumophila and Mycobacterium tuberculosis. The Au/Fe/AgI/PGA as a carrier can be load and release doxorubicin (Dox) in a pH-sensitive pattern. The delivery performance of this carrier was investigated in vitro using MCF-7 cells.

Evaluation of synergistic effect of polyglycine functionalized gold/iron doped silver iodide for colorimetric detection, photocatalysis, drug delivery and bactericidal applications

Abstract: The present study investigated the mercury ion detection by gold/iron doped Silver iodide supported on polyglycine (Au/Fe/AgI/PGA). The characterization of Au/Fe/AgI/PGA nanocomposites was conducted by using TEM, zeta/particle size analyzer, UV–visible absorption spectroscopy, FTIR and TGA. The Au/Fe/AgI/PGA depicted the λmax at 500 nm. The real water sample was investigated for the detection of mercury ion by using the prepared Au/Fe/AgI/PGA. The presence of other metal ions did not influence on interference for mercury ion detection. The photo-degradation of methyl orange in water by Au/Fe/AgI/PGA photocatalyst was evaluated. The degradation efficiency of Au/Fe/AgI/PGA was nearly 100% within 100 min, which was 1.7 and 1.3 times higher than of AgI and Au/Fe/AgI composites, respectively. Moreover, the antibacterial performance of the Au/Fe/AgI/PGA nanocomposites was studied against Legionella pneumophila and Mycobacterium tuberculosis. The Au/Fe/AgI/PGA as a carrier can be load and release doxorubicin (Dox) in a pH-sensitive pattern. The delivery performance of this carrier was investigated in vitro using MCF-7 cells.

A strategy of silver Ferrite/Bismuth ferrite nano-hybrids synthesis for synergetic white-light photocatalysis, antibacterial systems and peroxidase-like activity

Abstract: • The AgFe 2 O 4 /BiFeO 3 nanocomposites were fabricated via hydrothermal method. • The photocatalytic activity was evaluated by degradation of MB under visible light irradiation. • The antibacterial properties was studied against H. pylori and B. cereus . • The E. coli detection from real samples was conducted by the aptamer-AgFe 2 O 4 /BiFeO 3. In this paper, the Silver Ferrite/Bismuth ferrite (AgFe 2 O 4 /BiFeO 3 ) nanocomposites were fabricated via hydrothermal method. Scanning electron analysis, X-ray diffraction, UV–vis/Kubelka-Munk instrument, specific surface area analysis, and X-ray photoelectron method were utilized to characterize the structural of the prepared nanomaterials. X-ray diffraction shows the cubic and rhombohedral crystal status for composites. The surface area of AgFe 2 O 4 /BiFeO 3 was 52.41 m 2 /g. White-light activity of composites was observed due to the bandgap about 1.93 eV. The photocatalytic activity of composites was experimented by using methylene blue dye under visible light irradiation. The dye was completely degraded in 120 min. After fifth cycles, the photocatalysis response was almost constant. The antibacterial study shows that the AgFe 2 O 4 /BiFeO 3 exposure to Helicobacter pylori and Bacillus cereus with great growth inhibition. The AgFe 2 O 4 /BiFeO 3 with aptamers was used to detection of Escherichia coli by using the peroxidase activity. The detection limit of Escherichia coli by using Aptamer/AgFe 2 O 4 /BiFeO 3 as biosensor was about 59 CFU/mL.

Synthesis of Fe3O4@activated carbon to treat metronidazole effluents by adsorption and heterogeneous Fenton with effluent bioassay

Abstract: Metronidazole (MNZ), widely used to treat human bacterial infections, enters surface water and groundwater through sewage effluent that endangers the aqueous environment. In this study, MNZ is removed from real and synthetic wastewater through adsorption and heterogeneous Fenton processes. The Fe3O4 magnetic-activated carbon (AC) nanocomposite (Fe3O4@AC) was synthesized by coprecipitation and characterized by Fourier transform infrared spectroscopy, Field emission scanning electron microscope, Energy dispersive spectroscopy, Brunauer–Emmett–Teller, X-ray powder diffraction and Vibrating sample magnetometer analyzes. MNZ removal efficiency was studied under the influence of several parameters such as pH (3–11), Fe3O4@AC dose (0.1–1 g/L), H2O2 concentration (5–30 mmol/L), initial MNZ concentration (5–30 mg/L), contact time (5–60 min) and temperature (20–60 °C). Bioassay of treated effluents was evaluated by the germination index. Fe3O4@AC was synthesized with high magnetic strength (43.48 emu/g) and large surface area (210.95 m2/g) at nanoscale with a pseudo spherical structure. The maximum MNZ removal efficiency from real and synthetic wastewater by adsorption was 73.77% and 97.6% at pH 7, respectively; whereas, 74.75% and 98.03% at pH 5, respectively, was obtained by the heterogeneous Fenton process. MNZ adsorption is an exothermic process, it follows pseudo-second order kinetics, Langmuir and Freundlich isotherms. Whilst, MNZ oxidation follows pseudo-first order kinetics. Finally, the MNZ removal efficiency during the recovery and regeneration of Fe3O4@AC nanocomposite in the adsorption and heterogeneous Fenton processes was 86.88% and 78.34%, respectively. Bioassay results showed significant reductions in effluent toxicity after treatment with both processes. Clearly, the Fe3O4@AC nanocomposite produced a high efficiency in the treatment of wastewater containing antibiotics.

Multipurpose properties the Z-scheme dimanganese copper oxide/cadmium sulfide nanocomposites for photo- or photoelectro-catalytic, antibacterial applications, and Thiamine detection process

Abstract: Cadmium sulfide improved with dimanganese copper oxide (Mn2CuO4/CdO) was prepared and applied this semiconductor nanocomposites in advanced oxidative processes via the photoelectrocatalytic efficiency for cephalexin degradation. The Z-scheme Mn2CuO4/CdO nanocomposites was characterized by FESEM, XPS, UV–vis, EIS, and XRD. The photocurrent response were conducted in to evaluate the photo generated in the degradation reaction. Mn2CuO4/CdO was obtained to displays better photoelectrocatalytic response compared to bare CdO; this result shows the role of other semiconductor oxide material as photoanode construction. The degradation of cephalexin in photoelectrocatalytic response is higher than the photocatalytic process. A possible catalysis mechanism was depicted using free radicals scavengers. It was observed that hydroxyl radical and holes contribute as the main role in antibiotic degradation. The Mn2CuO4/CdO was used as great antibacterial agent versus Gram+/−. The Mn2CuO4/CdO probe was used to determine of vitamin B1 in peroxidase activity. The limit of detection was 41.21 nM.

Engineering titanium-organic framework decorated silver molybdate and silver vanadate as antimicrobial, anticancer agents, and photo-induced hydroxylation reactions

Abstract: Hydroxylation is a chemical process that presents a hydroxyl group (–OH) into a natural compound. It is greatly vital in detoxification of unsafe compounds to clean the environment and giving new functionality to organic compounds. Therefore, investigation multi-properties of metal organic frameworks (MOFs) are most critical field. Here, titanium based MOFs (MIL-125-NH2) was enhanced with silver molybdate (Ag2MoO4) and silver vanadate (AgVO3) nanocrystals. The component of joining Ag2MoO4 and AgVO3 into MIL-125-NH2 network has been examined. The novel arranged composites were tried to change aromatic-Cl into aromatic-OH, the chemical response continues through the addition–elimination reactions. The expansion of our work focuses on examining the effect of MOFs on both of antimicrobial and anticancer agents. Surprising data comes over when using Ag2MoO4@MIL-125-NH2 nanocomposite as anti-bacterial material; the inhibition zone was minimized (seven times less) when treated with a parent Ti-MOFs (MIL-125-NH2) match with its Ti-MOFs composite (Ag2MoO4@MIL-125-NH2). As well as, the potential of anticancer activity for Ti-MOFs composite (Ag2MoO4@MIL-125-NH2) display 1.58 times more than a parent Ti-MOFs.

Facile green synthesis, characterization and visible light photocatalytic activity of MgFe2O4@CoCr2O4 magnetic nanocomposite

Abstract: A new, facile, low-cost, and green sol–gel route for the synthesis of the MgFe2O4@CoCr2O4 magnetic nanocomposite is reported. The photocatalytic performances of the prepared magnetic nanocomposite was investigated for the degradation of organic dye under visible light irradiation. The synthesized magnetic photocatalyst depicted high degradation performance for Reactive Blue 222 dye under the optimized conditions. The nanocomposite dosage, initial dye concentration, dark and visible light, irradiation time, and reusability of photocatalysis had a notable influence on dye degradation performance. Fourier transforms infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), dispersive X-ray analysis (EDX), Brunauer-Emmett-Teller (BET), vibrating sample magnetometer (VSM), UV–Vis diffuse reflectance spectroscopy (DRS), and elemental mapping (MAP) analysis were considered to thoroughly characterize the synthesized magnetic nanocomposite. The analysis confirmed that the MgFe2O4@CoCr2O4 had a spinel cubic structure, with a crystallite size of 11 nm, ferromagnetic activity, uniform spherical morphology, narrow bandgap, and spatial distribution of all elements that can be noticed as a merit of this method over other methods developed techniques. The fast and high-efficiency degradation for RB222 dye with 40 mg/L concentration under ambient conditions was 93% in only 10 min. Photodegradation mechanism of RB222 dye was specified in presence of radical scavenger agents and degradation pathway was verified by Gas chromatography–mass spectrometry (GC–MS) analysis. Furthermore, the as synthesized magnetic nanocomposite could be easily separated from the solution by an external magnet, structural integrity and stability of reused photocatalyst attested by FTIR, XRD, SEM, and EDX analysis and their photocatalysis performance was maintained even after four continuous runs in the same optimized condition.

Facile green synthesis, characterization and visible light photocatalytic activity of MgFe2O4@CoCr2O4 magnetic nanocomposite

Abstract: A new, facile, low-cost, and green sol–gel route for the synthesis of the MgFe2O4@CoCr2O4 magnetic nanocomposite is reported. The photocatalytic performances of the prepared magnetic nanocomposite was investigated for the degradation of organic dye under visible light irradiation. The synthesized magnetic photocatalyst depicted high degradation performance for Reactive Blue 222 dye under the optimized conditions. The nanocomposite dosage, initial dye concentration, dark and visible light, irradiation time, and reusability of photocatalysis had a notable influence on dye degradation performance. Fourier transforms infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), dispersive X-ray analysis (EDX), Brunauer-Emmett-Teller (BET), vibrating sample magnetometer (VSM), UV–Vis diffuse reflectance spectroscopy (DRS), and elemental mapping (MAP) analysis were considered to thoroughly characterize the synthesized magnetic nanocomposite. The analysis confirmed that the MgFe2O4@CoCr2O4 had a spinel cubic structure, with a crystallite size of 11 nm, ferromagnetic activity, uniform spherical morphology, narrow bandgap, and spatial distribution of all elements that can be noticed as a merit of this method over other methods developed techniques. The fast and high-efficiency degradation for RB222 dye with 40 mg/L concentration under ambient conditions was 93% in only 10 min. Photodegradation mechanism of RB222 dye was specified in presence of radical scavenger agents and degradation pathway was verified by Gas chromatography–mass spectrometry (GC–MS) analysis. Furthermore, the as synthesized magnetic nanocomposite could be easily separated from the solution by an external magnet, structural integrity and stability of reused photocatalyst attested by FTIR, XRD, SEM, and EDX analysis and their photocatalysis performance was maintained even after four continuous runs in the same optimized condition.

g-C3N4/TiO2 S-scheme heterojunction photocatalyst with enhanced photocatalytic Carbamazepine degradation and mineralization

Abstract: In the present work, UVA light-driven g-C3N4/TiO2 photocatalyst was synthesized for the photodegradation of Carbamazepine (CBZ) in aqueous medium. The morphological, the optical properties and the structure of the TiO2, g-C3N4 and the prepared composites were analyzed using X-ray diffraction (XRD), Nitrogen adsorption–desorption isotherm based on BET, Raman Spectroscopy, Scanning Electron Microscopy (SEM) with EDX, UV–vis Diffuse Reflectance Spectroscopy (UV–vis DRS). Optical absorption studies revealed a 2.97 and 2.78 eV of band gap for the developed composites for 10%g-C3N4/TiO2 (A10) and 30%g-C3N4/TiO2 (A30), respectively. The N2 adsorption–desorption isotherm showed an 80.64 and 59.67 m2/g of specific surface area for A10 and A30, respectively. Photodegradation studies show that A10 a composite photo-catalyst can eliminate 71.41% of CBZ with 30.38 % of mineralization yield within 360 min of UVA irradiation at optimum conditions (10 ppm of initial CBZ concentration and 0.1 g of 10%g-C3N4/TiO2 loading). The kinetic results showed that the removal of this pollutant nearly followed a First-order kinetic model with a regression coefficient (R2) values more than 0.98 and a high reaction rate constant recorded of 0.0034 min−1 for A10.

Selectivity, stability and reproducibility effect of Uric acid integrated carbon nitride for photocatalytic application

Abstract: An ideal solution to water or pollutant contamination and energy problem is to advance photocatalysts that are highly effective for both reducing contaminants and cleaning water. In this regard, carbon nitride (CN) has strong stability with prominent band structure and can be used to produce hydrogen through water splitting due to an easier fabrication process. Uric acid (UA) was integrated as a conjugated monomer in the urea based CN system using the molecular doping (copolymerization) process. The photocatalysis of water reduction (HER) by using a new growth technique of minimally priced effective monomer UA inside CN, which also optimized the photodegradation of Rhodamine B dye (RhB) under light illumination (λ = 420 nm). By increasing light transmittance, speeding up photogenerated electrons and holes, and changing the physicochemical properties of CN, modified samples dramatically improve photocatalytic efficiency. The ideal samples CNU-UA10.0 showed a substantial increase in photocatalytic activity, with an HER 690.01 μmol/h higher than CNU (82.89 μmol/h), based on the implications of different configurations on the reaction mechanism. Moreover, an extraordinary apparent quantum yield (AQY) of about 57.43% at 420 nm has been observed for CNU-UA10.0. Under the same conditions and illuminations, H2 performance versus RhB dye degradation was compared. CNU-UA, on the other hand, had a three-fold higher pseudo-order kinetic constant for photodegradation of RhB than CN. The results demonstrate a major step toward in the direction of custom-designed photocatalysts with efficient water reduction and pollutants degradation capability for future demand.

Theoretical investigation of the influence of π-spacer on photovoltaic performances in carbazole-based dyes for dye-sensitized solar cells applications

Abstract: • Optoelectronic properties of carbazole dyes with different π-spacers are studied. • The designed dyes show small HOMO-LUMO energy gap. • The variation of π-spacer group could increase the performance of dyes used in DSSCs. • Dye adsorption on TiO 2 surface is analyzed. A series of D-A-π-A metal-free organic dyes (D i , i = 1–8) have been taken into account to study the influence of different π-spacer groups on their efficiency in dye-sensitized solar cells (DSSCs). Density functional theory (DFT) and time-dependent DFT (TD-DFT) methods have been used to investigate the geometrical structures, absorption properties, molecular electrostatic potential, and some important parameters in relation with the short-circuit current density (J SC ) and the open-circuit photovoltage (V OC ), such as nonlinear optical properties (NLO), light-harvesting efficiency (LHE), electron injection driving force (ΔG inject ), total reorganization energy (λ total ), and chemical reactivity. The results of theoretical calculations of these dyes showed that the variation of π-spacer group could increase the open-circuit photovoltage, enhance light absorption ability and intramolecular charge transfer properties, reduce energy gap, thus leading to improved photovoltaic performance. In addition, the effects of the dyes adsorption on TiO 2 surface, absorption spectra and energy levels were evaluated. Accordingly, we can assume that this theoretical investigation is predictable to provide guidance for experimental synthesis of greatly efficient metal-free organic dyes based on carbazole for DSSC applications.

Selectivity, stability and reproducibility effect of Uric acid integrated carbon nitride for photocatalytic application

Abstract: An ideal solution to water or pollutant contamination and energy problem is to advance photocatalysts that are highly effective for both reducing contaminants and cleaning water. In this regard, carbon nitride (CN) has strong stability with prominent band structure and can be used to produce hydrogen through water splitting due to an easier fabrication process. Uric acid (UA) was integrated as a conjugated monomer in the urea based CN system using the molecular doping (copolymerization) process. The photocatalysis of water reduction (HER) by using a new growth technique of minimally priced effective monomer UA inside CN, which also optimized the photodegradation of Rhodamine B dye (RhB) under light illumination (λ = 420 nm). By increasing light transmittance, speeding up photogenerated electrons and holes, and changing the physicochemical properties of CN, modified samples dramatically improve photocatalytic efficiency. The ideal samples CNU-UA10.0 showed a substantial increase in photocatalytic activity, with an HER 690.01 μmol/h higher than CNU (82.89 μmol/h), based on the implications of different configurations on the reaction mechanism. Moreover, an extraordinary apparent quantum yield (AQY) of about 57.43% at 420 nm has been observed for CNU-UA10.0. Under the same conditions and illuminations, H2 performance versus RhB dye degradation was compared. CNU-UA, on the other hand, had a three-fold higher pseudo-order kinetic constant for photodegradation of RhB than CN. The results demonstrate a major step toward in the direction of custom-designed photocatalysts with efficient water reduction and pollutants degradation capability for future demand.

Influence of coordinating environment on photophysical properties of UV excited sharp red emitting material: Judd Ofelt analysis

Abstract: • Structural and photophysical investigation of luminescent red color emissive ternary europium complexes have been carried out experimentally and theoretically. • The foremost purpose of investigation is to study the impact of substituted neutral ligands on optoelectronic properties of complexes. • Photoluminescence emission spectra specify that fluorinated β-diketone ligand have efficiently sensitized Eu(III) ion via antenna effect. • Red color emanating synthesized materials could found good significance in solid state electronics and OLEDs. The photophysical and optoelectronic characteristics of a series of ternary europium complexes having general formula [Eu(TFNB) 3 L] were estimated in detail. The synthesized octa coordinated complexes have different heteroaromatic ancillary ligand (L) i.e., 1,10-phenanthroline (Phen) derivatives. The synthesized heteroleptic europium complexes were thoroughly characterized by various techniques. Photoluminescence emission spectra specify that β-diketone ligand has efficiently sensitized Eu (III) ion through antenna effect which results in excellent luminescent intensity and long decay time. Most intense peak accredited to 5 D 0 → 7 F 2 is accountable for red luminescence of complexes. By investigating the PL emission data, CIE color coordinates were calculated which indicates that subsequent complexes give emission in red region. The Judd-Ofelt parameters of trivalent europium complexes were calculated and also derived theoretically via computational methods. The higher value of hypersensitive electric dipole Ω 2 intensity parameter displays the existence of highly polarizable chemical environment around central metal ion. Red light emanating materials might have found good significance in solid state electronics, flat panel devices and OLEDs.

Biological matrix-derived carbon quantum dots: Highly selective detection of tetracyclines

Abstract: As a kind of abundant resource, the development of biomass has been drawn quite more curiosity to the present research community. In this study, a facile, environment friendly, and repeatable one-step hydrothermal synthesis approach of CDs (carbon dots) by using carp roe as raw material was established. The CDs prepared from carp roe did not require any surface modification, besides, it has the properties such as low toxicity, fantastic water solubility and environmental friendliness. The average particle size of the prepared CDs was about 7.60 nm, and the maximum excitation/emission wavelength was 365/443 nm. In order to verify the low toxicity of CDs, two kinds of cells HCT-116 (human colon cancer cell) and MC (mouse cardiomyocytes) were used to investigate the cytotoxicity of CDs. Owing to the inner filter effect (IFE), the fluorescence of CDs can be quenched in the presence of tetracycline antibiotics (TCs), realizing the detection of tetracycline, chlortetracycline, oxytetracycline and other tetracyclines, which has high accuracy and selectivity, providing the foundation of TCs quantification. The value of fluorescence intensity has a linear relationship with the concentration of TCs in the range of 0.1–50 µM, and the detection limit was 41.7 nM. It was suitable to be applied in the detection of tetracycline in river water, serum and milk with good recovery rate (98.6∼104.5%), demonstrating its potential and broad application prospects in detecting TCs in complex matrix.

Biological matrix-derived carbon quantum dots: Highly selective detection of tetracyclines

Abstract: As a kind of abundant resource, the development of biomass has been drawn quite more curiosity to the present research community. In this study, a facile, environment friendly, and repeatable one-step hydrothermal synthesis approach of CDs (carbon dots) by using carp roe as raw material was established. The CDs prepared from carp roe did not require any surface modification, besides, it has the properties such as low toxicity, fantastic water solubility and environmental friendliness. The average particle size of the prepared CDs was about 7.60 nm, and the maximum excitation/emission wavelength was 365/443 nm. In order to verify the low toxicity of CDs, two kinds of cells HCT-116 (human colon cancer cell) and MC (mouse cardiomyocytes) were used to investigate the cytotoxicity of CDs. Owing to the inner filter effect (IFE), the fluorescence of CDs can be quenched in the presence of tetracycline antibiotics (TCs), realizing the detection of tetracycline, chlortetracycline, oxytetracycline and other tetracyclines, which has high accuracy and selectivity, providing the foundation of TCs quantification. The value of fluorescence intensity has a linear relationship with the concentration of TCs in the range of 0.1-50 µM, and the detection limit was 41.7 nM. It was suitable to be applied in the detection of tetracycline in river water, serum and milk with good recovery rate (98.6∼104.5%), demonstrating its potential and broad application prospects in detecting TCs in complex matrix.

Synthesis of chitosan/SnO2 nanocomposites by chemical precipitation for enhanced visible light photocatalytic degradation efficiency of congo red and rhodamine-B dye molecules

Abstract: • SnO 2 NPs and CS/SnO 2 NCs were synthesized by a chemical precipitation method. • TEM revealed that the nanosized SnO 2 NPs were homogeneously distributed within the CS matrix. • CS/SnO 2 NCs demonstrated enhanced photodegradation efficiency against CR and Rh-B. Tin oxide (SnO 2 ) nanoparticles (NPs) as well as SnO 2 /chitosan(CS) nanocomposites (NCs) were successfully synthesized by a simple chemical precipitation technique and their photocatalytic degradation ability against congo red (CR) and Rhodamine-B (Rh-B) were subsequently evaluated. The crystallinity and surface morphology of the materials were evaluated using X-ray diffraction analysis and transmission electron microscopy (TEM), respectively. The TEM images revealed that nanosized SnO 2 NPs were successfully obtained and were homogeneously distributed within the CS matrix. The CS/SnO 2 NCs were exposed to Rh-B dye molecules, resulting in 95% degradation within 60 min, which was significantly higher than for SnO 2 NPs. On the other hand, CS/SnO 2 NCs were found to degrade 98% of CR dye molecules within 40 min of visible light irradiation, which was also significantly shorter than for SnO 2 NPs. The CR dye molecules experienced significantly better levels of photodegradation parameters than Rh-B. The present study demonstrates the potential of CS/SnO 2 NCs in the area of environmental remediation of organic dye-based water pollutants.

Low cost carbazole-based organic dye bearing the acrylamides and 2-pyridone moieties for efficient dye-sensitized solar cells

Abstract: The design and synthesis of eight novel carbazole-based acrylamide derivatives (M1-4) and 2-pyridone-based dyes (M5-8) for dye-sensitized solar cell (DSSC) purposes are discussed in this article. Due to superior delocalization of electrons over the π-conjugated molecules when a cyanoacrylamide moiety is incorporated in the chemical structure, M1-4 with an acrylamide moiety outperformed other dyes M5-8 in photovoltaic performance, leading to better light harvesting ability and higher JSC values. The best efficiency was 4.51% (JSC = 10.45 mA/cm2, VOC = 0.677 V, FF = 63.58) for M2 and 4.56% (JSC = 10.93 mA/cm2, VOC = 0.683 V, FF = 64.12) for M4. Furthermore, structure M4 was utilized as a co-sensitizer alongside the conventional ruthenium-based sensitizer N-719 to expand the spectrum of responses of the co-sensitized DSSC. The photovoltaic investigations indicated that M4 considerably improved the device's light harvesting capabilities. The device achieved a maximum efficiency of 8.13% (JSC = 18.85 mA/cm2, VOC = 0.703 V, FF = 62.70) when co-sensitized with 0.2 mM M4 and ruthenium-based chromophore N-719. Our findings suggest that M1-8 dyes are suitable for use in DSSC.

Colorimetric Detection of Hg2+ Ion using Fluorescein/Thiourea Sensor as a Receptor in Aqueous Medium

Abstract: A simple and selective colorimetric method was used for detection of mercury ions (Hg2+) in the aqueous medium and environmental water sample. Fluorescein-thiourea (FLTU) conjugate complex as receptor was prepared by 1:1 molar ratio of 10µmol L-1 fluorescein dye and thiourea in phosphate buffer solution at pH 7.00. The IR spectra of FLTU receptor have illustrated the formation of H-bond between thiourea and fluorescein dye. The receptor fluorescein-thiourea (FLTU) was used as a chemo-sensor highly selectively to detect the Hg2+ ion by changing the receptor color from a yellow color to red through the quenching of fluorescence intensity of the receptor. The lower detection limit (LOD) and quantitation limit (LOQ) of Hg2+ ions with the receptor FLTU are 0.24 and 0.73 nmol L–1 (correlation coefficient R2 = 0.985) as determined through the absorption spectroscopic method, respectively. The mercury ions are promising and could be achieved via the formation of the complex in a 1:1 stoichiometric ratio of receptor to Hg2+ ions.

Mechanochemical Synthesis of Ferrite/MOF nanocomposite: Efficient photocatalyst for the removal of Meropenem and hexavalent Chromium from water

Abstract: Photocatalysts have been recognized as a promising solution to environmental water pollution, and research is underway to find suitable photocatalysts to remove various drugs and heavy metals. Herein, we prepared novel nanocomposites of metal–organic framework-808 (MOF-808) and NiFe2O4 with different mass ratios to employ them in the visible-light photocatalytic Meropenem degradation and Cr(VI) reduction. The as-fabricated magnetic NiFe2O4/MOF-808 nanocomposites were characterized by FESEM, DRS, TEM, EDX, XRD, IR, VSM, PL, EIS, and BET. In the following, the NiFe2O4/MOF-808 nanocomposites are compared to illustrate the effect of the bandgap on photocatalytic results. Generally, among different mass ratios of NiFe2O4/MOF-808 nanocomposites, which have a lower bandgap, exhibited a more efficient transfer of photo-excited electrons to the catalytic site and performed the best photocatalytic activity. By changing conditions such as the amount of catalyst, pH, type of scavenger, drug dose, etc., the maximum and best efficiency has been optimized, which results in using a 1:2 ferrite: MOF mass ratio of nanocomposite and under optimal conditions for each contaminant, degradation occurs in 60 min. The outcomes presented the removal efficiency of chromium and meropenem in optimal conditions of pH = 2 and pH = 6, respectively. Also, catalyst recovery tests show that the degradation rate has not decreased even after eight consecutive cycles of using this catalyst.

Ag/AgCl@Tubular g-C3N4 nanostructure as an enhanced visible light photocatalyst for the removal of organic dye compounds and biomedical waste under visible light

Abstract: Water contamination is a drastic worldwide issue menacing the whole biosphere and disturbing people lives as long as human health is strongly depended on the drinkable form of this liquid. It becomes a growing concern when we know the major cause of many diseases around the world is dirty water. Ag/AgCl decorated tube-like g-C3N4 (T-C3N4) nanostructures were successfully fabricated by thermal pyrolysis and coprecipitation methods. The photocatalysts were comprehensively characterized through a multi-technique approach including XRD, DRS, SEM, EDX, TEM, FTIR, BET-BJH, PL, and DLS physicochemical techniques. The photoactivity of the structures was evaluated for Acid Blue 92 (AB92), a dye compound, removal and GBM (U87) cancer cells treatment under visible light. MTT viability assay, ROS assay, fluorescent images, flocytometry (Cell Cycle assay) and mitochondria membrane potential (ΔΨm) techniques were also served to illustrate the mechanism of tumor cells removal. From our results, ionic liquid-mediated growth of Ag/AgCl nanoparticles on the surface improved the photoactivity and anticancer properties of tubular g-C3N4 significantly.

Concentration effect on optical properties and optical limiting of PVA doped with nigrosin films

Abstract: Polyvinyl alcohol doped nigrosin films are fabricated on glass substrates with four concentrations. The surface images and optical transmission and absorption spectra of the four films are investigated via microscope and softwares. The linear and nonlinear susceptibilities of the four films are determined. The open aperture and closed aperture Z-scan measurements are adopted to measure the optical nonlinearities viz., the nonlinear index of refraction (NIR) and the nonlinear coefficient of absorption (NCA), where as high as 10-8 cm2/W and 10-3 cm/W of both are determined respectively with 532 nm continuous wave (CW) laser beam. The optical limiting property of the four films at 532 nm are tested where it is proved that nigrosin doped PVA films are potential candidates for the use as optical limiters.

Photosensitization in highly luminescent nonmacrocyclic Samarium(III) complexes for application in light-emitting systems

Abstract: • Samarium(III) complexes were synthesized and characterized using various methods. • The complexes show strong orange luminescence in solution and red luminescence in powder state under 370 nm optical excitation. • The complexes exhibited crystalline character with average crystal size falling in nanometer range. • The [Sm(L) 3 .Bathophen] complex deliver highest luminescence quantum yield of 6.62% and the longest average lifetime of 0.55 ms. The synthesis of highly luminescent Samarium(III) complexes based on 6,8-Dichlorochromone-3-carboxaldehyde (L) and other heterocyclic ligands is described. The complexation was confirmed by elemental analysis, electrospray ionization mass spectrometry, thermal gravimetric analysis, UV–visible, and FTIR spectroscopy. The surface topology and crystalline nature were evaluated by FESEM and powder XRD. The sharp peaks in X-ray Diffractograms suggest crystallinity in the complexes. The results of elemental analysis and electrospray ionization mass spectrometry were in accordance with the proposed formula weight of the complexes. The complexes exhibit good thermal stability up to 170 °C under an inert atmosphere of dinitrogen (N 2 ) gas. The luminescence properties were discussed in solution and powder state which depicts representative emission peaks of Samarium(III) ion at ∼563, 600, and 647 nm. The ternary complex featuring bathophenanthroline revealed the highest luminescence lifetime of 0.55 ms and quantum yield of 6.62% among other synthesized complexes.

Efficacy of 2-nitrobenzylidene-hydrazine-based selective and rapid sensor for Cu2+ ions, histidine, and tyrosine: Spectral and computational study

Abstract: Spectroscopic detection of metal ions and amino acids has gained significant attention owing to the public health domain. In this study, we design and synthesize a rapid UV–visible and fluorescence sensor 1,3-bis(2-methoxy-4-((E)-(((E)-2-nitrobenzylidene)hydrazineylidene)methyl)phenoxy)propane (BMNHMPP) for the selective detection of Cu2+ ions (limit of detection (LOD) ≈ 14–18 × 10−7 M, linear range = 0–130 μM, and the binding constant KCu = 3.30 × 1010 M−2) through turn-off response. The reversibility and snatching of BMNHMPP-Cu2+ complex with EDTA, cysteine (Cys), proline (Pro), and threonine (Thr) in a solvent systemis demonstrated with the restoring of emission intensity. Moreover, the BMNHMPP shows the blue shift in ultraviolet UV–visible and turn-off selective response for the detection of Histidine (His) (LOD ≈ 6–11 × 10−7 M, KHis = 6.53 × 104 M−1 and range of 0–80 μM) and Tyrosine (Tyr) (LOD ≈ 8–13 × 10−7 M, and KTyr = 2.13 × 1010 M−2, range of 0–112 μM). Also, the binding behavior of BMNHMPP with Cu2+, His and Tyr, quantum yields, binding stoichiometry and pH effects are determined using spectroscopic techniques. The mechanistic insights of metal acceptor bonds (BMNHMPP-Cu2+), H-bonding (BMNHMPP-His), H-bonding, and π–π edge to face bondings (BMNHMPP-Tyr-Tyr) were studied. The in-silico study provides a better understanding of the structural behavior and binding mode with the binding and docking energy values. Moreover, the time-dependent density functional theory calculation provides a proper highlight of the frontier molecular orbitals (FMOs).

Efficacy of 2-nitrobenzylidene-hydrazine-based selective and rapid sensor for Cu2+ ions, histidine, and tyrosine: Spectral and computational study

Abstract: • Synthesis of 2-nitrobenzylidene-hydrazine-based ligand ( BMNHMPP ). • BMNHMPP acted as a sensor for the selective detection of Cu 2+ ions. • BMNHMPP-Cu 2 + complexes show unique snatching of cysteine (Cys), proline (Pro), and threonine (Thr) in a solvent system. • Spectroscopic studies were performed to determine the binding behavior of BMNHMPP with Cu 2+ ions and amino acids. • Computational studies were performed to validate the experimental results. Spectroscopic detection of metal ions and amino acids has gained significant attention owing to the public health domain. In this study, we design and synthesize a rapid UV–visible and fluorescence sensor 1,3-bis(2-methoxy-4-((E)-(((E)-2-nitrobenzylidene)hydrazineylidene)methyl)phenoxy)propane ( BMNHMPP ) for the selective detection of Cu 2+ ions (limit of detection (LOD) ≈ 14–18 × 10 −7 M, linear range = 0–130 μM, and the binding constant K Cu = 3.30 × 10 10 M −2 ) through turn-off response. The reversibility and snatching of BMNHMPP-Cu 2 + complex with EDTA, cysteine (Cys), proline (Pro), and threonine (Thr) in a solvent systemis demonstrated with the restoring of emission intensity. Moreover, the BMNHMPP shows the blue shift in ultraviolet UV–visible and turn-off selective response for the detection of Histidine (His) (LOD ≈ 6–11 × 10 −7 M, K His = 6.53 × 10 4 M −1 and range of 0–80 μM) and Tyrosine (Tyr) (LOD ≈ 8–13 × 10 −7 M, and K Tyr = 2.13 × 10 10 M −2 , range of 0–112 μM). Also, the binding behavior of BMNHMPP with Cu 2+ , His and Tyr, quantum yields, binding stoichiometry and pH effects are determined using spectroscopic techniques. The mechanistic insights of metal acceptor bonds ( BMNHMPP -Cu 2+ ), H-bonding ( BMNHMPP -His), H-bonding, and π–π edge to face bondings ( BMNHMPP -Tyr-Tyr) were studied. The in-silico study provides a better understanding of the structural behavior and binding mode with the binding and docking energy values. Moreover, the time-dependent density functional theory calculation provides a proper highlight of the frontier molecular orbitals (FMOs).

Photosensitization in highly luminescent nonmacrocyclic Samarium(III) complexes for application in light-emitting systems

Abstract: The synthesis of highly luminescent Samarium(III) complexes based on 6,8-Dichlorochromone-3-carboxaldehyde (L) and other heterocyclic ligands is described. The complexation was confirmed by elemental analysis, electrospray ionization mass spectrometry, thermal gravimetric analysis, UV–visible, and FTIR spectroscopy. The surface topology and crystalline nature were evaluated by FESEM and powder XRD. The sharp peaks in X-ray Diffractograms suggest crystallinity in the complexes. The results of elemental analysis and electrospray ionization mass spectrometry were in accordance with the proposed formula weight of the complexes. The complexes exhibit good thermal stability up to 170 °C under an inert atmosphere of dinitrogen (N2) gas. The luminescence properties were discussed in solution and powder state which depicts representative emission peaks of Samarium(III) ion at ∼563, 600, and 647 nm. The ternary complex featuring bathophenanthroline revealed the highest luminescence lifetime of 0.55 ms and quantum yield of 6.62% among other synthesized complexes.

Enhanced Photocatalytic Activity of TiO2/WO3 Nanocomposite from Sonochemical-Microwave Assisted Synthesis for the Photodegradation of Ciprofloxacin and Oxytetracycline Antibiotics under UV and Sunlight

Abstract: • TiO 2 /WO 3 nanocomposite was successfully prepared by a simple assisted sonochemical – microwave approach. • TiO 2 /WO 3 was tested for the photodegradation of Ciprofloxacin and Oxyteracycline antibiotics under UV and Sunlight. • This nanocomposite results in high photodegradation rates under UV and sunlight comparing to pure TiO 2 . • TiO 2 /WO 3 maintained high performances in the presence of high concentrations of pollutants as well as good stability after several uses. The TiO 2 /WO 3 photocatalysts were prepared by a simple assisted sonochemical − microwave combination. The wide surface and structural characterization of synthesized material confirmed that the adopted preparation method resulted in nanoparticulated crystallite anatase phase of TiO 2 with a large surface area (>200 m 2 /g), and the dispersion of WO 3 on the surface of TiO 2 . The photoactivity was assessed for the photodegradation of ciprofloxacin (CIP) and oxytetracycline (OTC) antibiotics under UV and sunlight irradiation. The mineralization rate, toxicity assessment, pollutant concentration effect on photodegradation efficiency, and reusability potential under sunlight were all investigated. Results showed that TiO 2 doped with 5 wt% of WO 3 exhibited the best photocatalytic activity under UV (100% degradation) and solar light. Rate constants for CIP and OTC degradation showed that TiO 2 /WO 3 significantly improved with respect to bare TiO 2 . The antibacterial study revealed that the photodegraded solutions became less toxic than the initial CIP and OTC solutions showing a significant decrease in the inhibition zone diameter and mineralization rates. The prepared TiO 2 /WO 3 maintained high performances in the presence of high concentrations of pollutants as well as good stability after four consecutive uses. The increased photocatalytic activity is attributed to the incorporation of WO 3 , which extends the light absorption range and decreases the rate of electron − hole recombination.