ABSTRACT
It is of great significance to establish an effective method for removing Cr(VI) from wastewater. Herein, Fe-doped g-C3N4 (namely Fe-g-C3N4-2) was synthesized and then employed as photocatalyst to conduct the test of Cr(VI) reduction. Notably, the embedding of Fe ion in g-C3N4 can offer the Fe2+/Fe3+ redox couples, so reducing the interfacial resistance of charge transfer and suppressing the recombination of photogenerated electrons and holes. The impurity energy levels will form in g-C3N4 after the introduction of Fe ion, thereby boosting the light absorption capacity of catalyst. Thus, Fe-g-C3N4-2 showed good performance in photocatalytic Cr(VI) reduction, and the reduction efficiency of Cr(VI) can reach 39.9% within 40 min. Different with many previous studies, current work unexpectedly found that the addition of p-benzoquinone (BQ) can promote the Cr(VI) reduction, and the reduction efficiency of Cr(VI) over Fe-g-C3N4-2 was as high as 93.2% in the presence of BQ (1.5 mM). Further analyses showed that BQ can be reduced to hydroquinone (HQ) by photogenerated electrons, and UV light can also directly induce BQ to generate HQ by using H2O as the hydrogen donor. The HQ with reducing ability can accelerate the Cr(VI) reduction. In short, current work shared some novel insights into photocatalytic Cr(VI) reduction in the presence of BQ. Future research should consider possible reactions between photogenerated electrons and BQ. For the UV-induced photocatalysis, the suitability of BQ as the scavenger of O2â¢â must be given carefully consideration.
Subject(s)
Benzoquinones , Chromium , Iron , Oxidation-Reduction , Benzoquinones/chemistry , Chromium/chemistry , Catalysis , Iron/chemistry , Water Pollutants, Chemical/chemistry , Water Pollutants, Chemical/radiation effects , Photochemical Processes , Nitrogen Compounds/chemistry , Nitrogen Compounds/radiation effects , GraphiteABSTRACT
The serious problem of pharmaceutical and personal care product pollution places great pressure on aquatic environments and human health. Herein, a novel coating photocatalyst was synthesized by adhering Ag-AgCl/WO3/g-C3N4 (AWC) nanoparticles on a polydopamine (PDA)-modified melamine sponge (MS) through a facile layer-by-layer assembly method to degrade trimethoprim (TMP). The formed PDA coating was used for the anchoring of nanoparticles, photothermal conversion, and hydrophilic modification. TMP (99.9%; 4 mg/L) was removed in 90 min by the photocatalyst coating (AWC/PDA/MS) under visible light via a synergistic photocatalytic-photothermal performance route. The stability and reusability of the AWC/PDA/MS have been proved by cyclic experiments, in which the removal efficiency of TMP was still more than 90% after five consecutive cycles with a very little mass loss. Quantitative structure-activity relationship analysis revealed that the ecotoxicities of the generated intermediates were lower than those of TMP. Furthermore, the solution matrix effects on the photocatalytic removal efficiency were investigated, and the results revealed that the AWC/PDA/MS still maintained excellent photocatalytic degradation efficiency in several actual water and simulated water matrices. This work develops recyclable photocatalysts for the potential application in the field of water remediation.
Subject(s)
Nanoparticles/chemistry , Trimethoprim/chemistry , Catalysis/drug effects , Graphite/chemistry , Graphite/radiation effects , Indoles/chemistry , Indoles/radiation effects , Light , Nanoparticles/radiation effects , Nitrogen Compounds/chemistry , Nitrogen Compounds/radiation effects , Oxides/chemistry , Oxides/radiation effects , Polymers/chemistry , Polymers/radiation effects , Silver/chemistry , Silver/radiation effects , Silver Compounds/chemistry , Silver Compounds/radiation effects , Temperature , Triazines/chemistry , Triazines/radiation effects , Tungsten/chemistry , Tungsten/radiation effects , Water Purification/methodsABSTRACT
In-depth understanding of interfacial property is the key to guiding the synthesis of biomass composites with desired performance. However, the exploration is of great challenge due to limitations of experimental techniques in locating hydrogen, requiring large/good crystals and detecting a weak interaction like van der Waals (vdW). Herein, we experimentally and computationally investigated the composite cellulose/zinc oxide/g-C3N4. Hydrothermal synthesis afforded cellulose/ZnO, and then fabricated the ternary composite by adding g-C3N4 under ultrasonic condition. Three components are found to co-exist in the composite, and the ZnO nanoparticle is attaching to cellulose and coupling with g-C3N4. These experimental findings were corroborated by relativistic DFT calculations. The interfacial coupling is elaborated as contributions of dative bonds, hydrogen bonds and vdW interaction. The vdW is increased by a factor of 4.23 in the ZnO/g-C3N4 interface. This improves electron-hole separation and offers prospective application of the composite in photocatalysis, antibacteria and gas sensing.
Subject(s)
Cellulose/chemistry , Graphite/chemistry , Nanocomposites/chemistry , Nitrogen Compounds/chemistry , Zinc Oxide/chemistry , Catalysis/radiation effects , Cellulose/radiation effects , Density Functional Theory , Graphite/radiation effects , Light , Models, Chemical , Nanocomposites/radiation effects , Nitrogen Compounds/radiation effects , Static Electricity , Zinc Oxide/radiation effectsABSTRACT
The development of photocatalysts with high catalytic activity that are capable of full utilization of solar energy is a challenge in the field of photocatalysis. Accordingly, in the present study, an efficient Z-scheme cage-structured Co9S8/g-C3N4 (c-CSCN) photocatalyst was constructed for the degradation of tetracycline antibiotics under visible-light irradiation. The Z-scheme charge-transfer mechanism accelerates the separation of photogenerated charge carriers and effectively improves photocatalytic activity. Moreover, c-CSCN has a hollow structure, allowing light to be reflected multiple times inside the cavity, thereby effectively improving the utilisation efficiency of solar energy. As a result, the photocatalytic activity of c-CSCN is 1.5-, 2.5-, and 5.8-times higher than those of sheet-type Co9S8/g-C3N4 (s-CSCN), c-Co9S8, and g-C3N4, respectively, for the degradation of tetracycline. c-CSCN maintains favourable photocatalytic activity over five consecutive degradation cycles, demonstrating its excellent stability. In addition, c-CSCN performs efficient tetracycline removal in different water substrates. Moreover, c-CSCN exhibits excellent ability to remove tetracycline under direct natural sunlight. This work fully demonstrates that c-CSCN has high catalytic activity and the potential for practical application as a wastewater treatment material.
Subject(s)
Anti-Bacterial Agents/chemistry , Cobalt/chemistry , Graphite/chemistry , Nitrogen Compounds/chemistry , Sulfides/chemistry , Tetracycline/chemistry , Water Pollutants, Chemical/chemistry , Catalysis/radiation effects , Cobalt/radiation effects , Graphite/radiation effects , Light , Models, Chemical , Nitrogen Compounds/radiation effects , Sulfides/radiation effectsABSTRACT
Universal access to clean water has been a global ambition over the years. Photocatalytic water disinfection through advanced oxidation processes has been regarded as one of the promising methods for breaking down microbials. The forefront of this research focuses on the application of metal-free photocatalysts for disinfection to prevent secondary pollution. Graphitic carbon nitride (g-C3 N4 ) has achieved instant attention as a metal-free and visible-light-responsive photocatalyst for various energy and environmental applications. However, the photocatalytic efficiency of g-C3 N4 is still affected by its rapid charge recombination and sluggish electron-transfer kinetics. In this contribution, two-dimensionally protonated g-C3 N4 was employed as metal-free photocatalyst for water treatment and demonstrated 100 % of Escherichia coli within 4â h under irradiation with a 23â W light bulb. The introduction of protonation can modulate the surface charge of g-C3 N4 ; this enhances its conductivity and provides a "highway" for the delocalization of electrons. This work highlights the potential of conjugated polymers in antibacterial application.
Subject(s)
Disinfection/methods , Escherichia coli/chemistry , Escherichia coli/radiation effects , Graphite/chemistry , Graphite/radiation effects , Light , Microbial Viability/radiation effects , Nitrogen Compounds/chemistry , Nitrogen Compounds/radiation effects , Protons , Catalysis/radiation effects , Electrons , Graphite/pharmacology , Microbial Viability/drug effects , Nitrogen Compounds/pharmacology , PhotochemistryABSTRACT
Graphitic carbon nitride (g-C3N4) as an outstanding photoresponsive nanomaterial has been widely used in biosensing. Other than the conventional single channel sensing mode, a triple-channel sensing array was developed for high discrimination of proteins based on the photoresponsive g-C3N4. Besides the photoluminescence and Rayleigh light scattering features of g-C3N4, we exploit the new photosensitive colorimetry of g-C3N4 as the third channel optical input. The triple-channel optical behavior of g-C3N4 can be synchronously changed after interaction with the protein, resulting in the distinct response patterns related to each specific protein. Such a triple-channel sensing array is demonstrated for highly discriminative and precise identification of nine proteins (hemoglobin, trypsin, lysozyme, cytochrome c, horseradish peroxidase, transferrin, human serum albumin, pepsin, and myoglobin) at 1 µM concentration levels with 100% accuracy. It also can discriminate proteins being present at different concentration and protein mixtures with different content ratios. The practicability of this sensor array is validated by high accuracy identification of nine proteins in human urine samples. This indicates that the array has a great potential in terms of analyzing biological fluids. Graphic abstract .
Subject(s)
Graphite/chemistry , Nanostructures/chemistry , Nitrogen Compounds/chemistry , Proteins/analysis , Armoracia/enzymology , Colorimetry/methods , Graphite/radiation effects , Humans , Light , Nanostructures/radiation effects , Nitrogen Compounds/radiation effects , Urine/chemistryABSTRACT
As a broad-spectrum tetracycline antibiotic, the overuse of oxytetracycline (OTC) causes antibiotics residues in the environment and seriously threats to human health owing to effective antibacterial properties. Thus, it is particularly important to design a photoelectrochemical (PEC) aptasensor to detect OTC with excellent performance. Herein, we developed a selective and stable PEC aptasensor of OTC on the basis of Co3O4 nanoparticles (Co3O4 NPs)/graphitic carbon nitride (g-CN) heterojunction, used as PEC active materials. The Co3O4 NPs were successfully grown on the g-CN via grinding and calcining mixture of Co3O4 precursors and bulk g-CN. The Co3O4/g-CN heterojunction with improved light utilization and promoted electrons/holes separation capability can exhibit higher PEC signal than that of g-CN. In order to implement the purpose of specific recognition, OTC-aptamer was introduced into modified electrode to construct highly selective PEC aptasensor for OTC determination, which can possess wide linear range (0.01-500 nM) with low detection limit (3.5 pM, S/N = 3). This PEC aptasensor platform with excellent selectivity and high stability can provide a practical application in the field of water monitoring.
Subject(s)
Aptamers, Nucleotide/chemistry , Biosensing Techniques/methods , Electrochemical Techniques/methods , Metal Nanoparticles/chemistry , Oxytetracycline/analysis , Photochemistry/methods , Base Sequence , Cobalt/chemistry , Cobalt/radiation effects , Graphite/chemistry , Graphite/radiation effects , Light , Limit of Detection , Metal Nanoparticles/radiation effects , Nitrogen Compounds/chemistry , Nitrogen Compounds/radiation effects , Oxides/chemistry , Oxides/radiation effects , Oxytetracycline/chemistry , Reproducibility of Results , Rivers/chemistry , Water Pollutants, Chemical/analysis , Water Pollutants, Chemical/chemistryABSTRACT
As a newly emerging treatment strategy for many diseases, hydrogen therapy has attracted a lot of attention because of its excellent biosafety. However, the high diffusivity and low solubility of hydrogen make it difficult to accumulate in local lesions. Herein, we develop a H2 self-generation nanoplatform by in situ water splitting driven by near-infrared (NIR) laser. In this work, core-shell nanoparticles (CSNPs) of NaGdF4:Yb,Tm/g-C3N4/Cu3P (UCC) nanocomposites as core encapsulated with zeolitic imidazolate framework-8 (ZIF-8) modified with folic acid as shell are designed and synthesized. Due to the acid-responsive ZIF-8 shell, enhanced permeability and retention (EPR) effect, and folate receptor-mediated endocytosis, CSNPs are selectively captured by tumor cells. Upon 980 nm laser irradiation, CSNPs exhibit a high production capacity of H2 and active oxygen species (ROS), as well as an appropriate photothermal conversion temperature. Furthermore, rising temperature increases the Fenton reaction rate of Cu(I) with H2O2 and strengthens the curative effect of chemodynamic therapy (CDT). The excess glutathione (GSH) in tumor microenvironment (TME) can deplete positive holes produced in the valence band of g-C3N4 in the g-C3N4/Cu3P Z-scheme heterojunction. GSH also can reduce Cu(II) to Cu(I), ensuring a continuous Fenton reaction. Thus, a NIR-driven H2 production nanoplatform is constructed for H2-mediated cascade-amplifying multimodal synergetic therapy.
Subject(s)
Anti-Inflammatory Agents/therapeutic use , Antineoplastic Agents/therapeutic use , Hydrogen/therapeutic use , Nanoparticles/therapeutic use , Neoplasms/drug therapy , Water/chemistry , Animals , Anti-Inflammatory Agents/chemistry , Antineoplastic Agents/chemistry , Antineoplastic Agents/radiation effects , Cell Line, Tumor , Copper/chemistry , Copper/radiation effects , Fluorides/chemistry , Fluorides/radiation effects , Gadolinium/chemistry , Gadolinium/radiation effects , Graphite/chemistry , Graphite/radiation effects , Humans , Hydrogen/chemistry , Hyperthermia, Induced/methods , Infrared Rays , Lasers , Mice , Nanoparticles/chemistry , Nanoparticles/radiation effects , Nitrogen Compounds/chemistry , Nitrogen Compounds/radiation effects , Photochemotherapy/methods , Reactive Oxygen Species/metabolism , Thulium/chemistry , Thulium/radiation effects , Ytterbium/chemistry , Ytterbium/radiation effectsABSTRACT
Thin 2D/2D WO3/g-C3N4 Step-scheme (S-scheme) heterojunction with carbon doping and bridge (C-W/N) was constructed with anionic polyacrylamide (APAM), in which APAM functioned as an assistant templet and a carbon source. APAM and WO3 were inserted into g-C3N4 nanosheet. The carbon, thin planar structure and WO3 with oxygen vacancies result in fast charge transfer, high quantum efficiency and strong driving force for photocatalytic reaction. Consequently, as-prepared C-W/N ternary composite photocatalyst exhibited significantly enhanced photocatalytic performance for tetracycline (TC) degradation under visible light compared to pure g-C3N4, WO3 and other binary composites. Moreover, the material showed high stability and reusability in cyclic TC degradation. The principal intermediate products over C-W/N photocatalyst were revealed by HPLC-MS analysis. Corresponding degradation pathway of TC was also presented in this work. According to the trapping experiments, analysis of electron spin resource (ESR) and band gap, possible charge transfer pathways of C-W/N are proposed and discussed in detail. Based on the results, carbon derived from APAM works not only as electron mediator but also as acceptor for photocatalytic degradation reaction. It is a promising way to further modulate heterojunction for varies applications.
Subject(s)
Acrylic Resins/chemistry , Graphite/chemistry , Nitrogen Compounds/chemistry , Oxides/chemistry , Tetracycline/chemistry , Tungsten/chemistry , Catalysis/radiation effects , Environmental Pollutants/chemistry , Graphite/radiation effects , Light , Nitrogen Compounds/radiation effects , Oxides/radiation effects , Tungsten/radiation effectsABSTRACT
A novel polymer-based 2D/2D heterojunction photocatalysts of covalent triazine-based frameworks/graphitic carbon nitride nanosheets (CTFNS/CNNS) heterojunction are successfully obtained by an electrostatic self-assembly method using amine-functionalized CNNS and carboxyl-rich CTFNS. Such large contact surface and appropriate interfacial contact between CNNS and CTFNS plays a critical role in transfer and separation of charge-carriers. The resulting CTFNS/CNNS heterojunction showed significantly enhanced photocatalytic activity under the irradiation of simulated solar light, which could decompose 10â¯ppm sulfamethazine (SMT) within 180â¯min with a high degradation efficiency of 95.8 %. Chloride ions can greatly promote the photocatalytic degradation of SMT due to the production of more radical species. O2- is the dominant active species for SMT decomposition over CTFNS/CNNS heterojunction. Moreover, the degradation intermediates of SMT were identified using high performance liquid chromatography-mass spectrometer and the degradation pathway was proposed. This study provides a new insight into the design of 2D/2D heterojunctions using carbon-based nanomaterials, which exhibits great potential in the degradation of sulfonamide antibiotics in wastewaters.
Subject(s)
Anti-Bacterial Agents/chemistry , Graphite/radiation effects , Nitrogen Compounds/radiation effects , Triazines/radiation effects , Water Pollutants, Chemical/chemistry , Water Purification/methods , Catalysis , Graphite/chemistry , Nitrogen Compounds/chemistry , Photochemical Processes , Sunlight , Triazines/chemistry , WastewaterABSTRACT
Silver iodide/graphitic carbon nitride nanocomposites have been successfully fabricated through sonication-assisted deposition-precipitation route at room temperature and hydrothermal method. Varied mass ratios and preparation processes can modify the structure, purity, shape, and scale of specimens. The purity of the product was confirmed by Energy Dispersive X-Ray Spectroscopy (EDS) and X-ray crystallography. The morphology and size of specimens could be observed with transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). The bandgap was evaluated around 2.82â¯eV for pure g-C3N4. The bandgap has reduced to 2.70â¯eV by increasing the quantity of silver iodide in the nanocomposites. The photocatalytic activity of AgI/C3N4 has been studied over the destruction of rhodamine B (RhB) and methyl orange (MO) through visible radiation due to their suitable bandgap. The as-prepared AgI/C3N4 nanocomposites photocatalyst revealed better photocatalytic behavior than the genuine AgI and C3N4 which ascribed to synergic impacts at the interconnection of C3N4 and AgI. Furthermore, these nanocomposites have great potential for being a great antibacterial agent.
Subject(s)
Anti-Bacterial Agents/pharmacology , Graphite/pharmacology , Iodides/pharmacology , Nanocomposites/chemistry , Nitrogen Compounds/pharmacology , Silver Compounds/pharmacology , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/radiation effects , Azo Compounds/chemistry , Bacteria/drug effects , Catalysis/radiation effects , Graphite/chemistry , Graphite/radiation effects , Iodides/chemistry , Iodides/radiation effects , Microbial Sensitivity Tests , Nanocomposites/radiation effects , Nitrogen Compounds/chemistry , Nitrogen Compounds/radiation effects , Oxidation-Reduction/radiation effects , Persistent Organic Pollutants/chemistry , Silver Compounds/chemistry , Silver Compounds/radiation effects , SunlightABSTRACT
A novel tubular graphitic carbon nitride (g-C3N4) modified with carbon quantum dots (CQDs) was fabricated and employed for the elimination of carbamazepine (CBZ) under visible light irradiation. The as-fabricated metal-free catalysts exhibited tubular morphologies due to the preforming of tubular protonated melamine with CQDs surface adsorption as the polymerization precursors. The surface bonded CQDs did not alter the band gap structure of g-C3N4, but greatly inhibited the charge recombination. Therefore, the CBZ degradation kinetics of tubular g-C3N4 were increased by over 5 times by the incorporation of CQDs. The main active species for CBZ degradation were found to be superoxide radical (O2-) and photo-generated holes (h+), which were further confirmed by electron spin resonance (ESR) analysis. In addition, the degradation pathways of CBZ were clarified via intermediates identification and quantum chemical computation using density functional theory (DFT) and wave function analysis. The olefinic double bond with the highest condensed Fukui index (f0 = 0.108) in CBZ molecule was found to be the most preferable sites for radical attack. Moreover, good stability of the as-prepared photocatalysts was observed in the consecutive recycling cycles, while the slight decline of photocatalytic activity was attributed to the minimal surface oxidation.
Subject(s)
Carbamazepine/chemistry , Carbon/chemistry , Graphite/chemistry , Nitrogen Compounds/chemistry , Quantum Dots/chemistry , Water Pollutants, Chemical/chemistry , Water Purification/methods , Carbon/radiation effects , Catalysis , Density Functional Theory , Graphite/radiation effects , Light , Nitrogen Compounds/radiation effects , Photolysis , Quantum Dots/radiation effectsABSTRACT
Photocatalytic degradation is considered as a promising strategy to address the environmental threat caused by antibiotics abuse. Visible light driven g-C3N4 decorated ZrO2-x nanotubes heterostructure photocatalysts for antibiotic degradation were successfully synthesized by anodic oxidation and following a thermal vapor deposition method. Compared with pure g-C3N4 or ZrO2-x nanotubes, the composite photocatalysts exhibited more extended visible light response and higher separation rate of photo-generated electron-holes pairs. The optimized heteroctructure with 7.1â¯wt.% g-C3N4 exhibited 90.6% degradation of tetracycline hydrochloride (TC-H) under 1â¯h visible light irradiation. The mainly active species of TC-H degradation were photo-generated h+ and O2-. The pathway of charge migration in the g-C3N4/ZrO2-x NTs system was also studied and a possible photocatalytic mechanism was proposed for TC-H degradation. Constructing the g-C3N4/ZrO2-x nanotubes heterostructure is anticipated to be an effective strategy for photocatalytic degradation of antibiotics.
Subject(s)
Anti-Bacterial Agents/chemistry , Nanotubes/chemistry , Tetracycline/chemistry , Waste Disposal, Fluid/methods , Water Pollutants, Chemical/chemistry , Catalysis/radiation effects , Graphite/chemistry , Graphite/radiation effects , Light , Nanotubes/radiation effects , Nitrogen Compounds/chemistry , Nitrogen Compounds/radiation effects , Oxidation-Reduction , Zirconium/chemistry , Zirconium/radiation effectsABSTRACT
Photocatalytic disinfection with high performance is thought to be a promising way for water purification. Herein, plasmonic Ag doped urea-derived graphitic carbon nitride (g-C3N4) composites were fabricated via in-situ photo-deposition at room temperature as the visible-light photocatalyst. Scan electron microscopy and transmission electron microscopy images showed the uniform dispersion of Ag nanoparticles on the surface of g-C3N4 sheet, which facilitated the synergistic effect of antibacterial performance from Ag and photocatalytic property from Ag/g-C3N4 composites. Photocatalytic water disinfection against Escherichia coli with visible light was performed to demonstrate the improved photocatalytic property with assistance of Ag. The 3-Ag/g-C3N4 exhibited the best bactericidal performance by inactivating all bacteria within 120â¯min with damaged cell membranes of Escherichia coli observed by scan electron microscopy and transmission electron microscopy images. Photoluminescence spectra, steady-state surface photovoltage spectra, photocurrent response, and electrochemical impedance spectra results revealed that Ag nanoparticles inhibited the recombination of photo-generated e- and h+ pairs and further reinforced the photocatalytic performance of g-C3N4. Scavenger experiments indicated that h+ produced on valence band of g-C3N4 dominated the photocatalytic disinfection process against Escherichia coli. This work further proved Ag/g-C3N4 showed great potential in photocatalytic water disinfection under visible-light irradiation.
Subject(s)
Anti-Bacterial Agents/chemistry , Disinfection/methods , Light , Photochemical Processes , Silver/chemistry , Water Purification/methods , Catalysis , Escherichia coli/drug effects , Escherichia coli/radiation effects , Graphite/chemistry , Graphite/radiation effects , Metal Nanoparticles/chemistry , Nitrogen Compounds/chemistry , Nitrogen Compounds/radiation effects , Photolysis , Silver/radiation effects , Water Pollutants/isolation & purification , Water Pollutants/radiation effectsABSTRACT
A novel graphite-phase carbon nitride (g-C3N4)/bismuth ferrite (BiFeO3)/carbon nanotubes (CNTs) ternary magnetic composite (CNBT) was prepared by a hydrothermal synthesis. Using this material, Cr(VI) and methylene blue (MB) were removed from wastewater through synergistic adsorption and photocatalysis. The effects of pH, time, and pollutant concentration on the photocatalytic performance of CNBT, as well as possible interactions between Cr(VI) and MB species were analyzed. The obtained results showed that CNTs could effectively reduce the recombination rate of electron-hole pairs during the photocatalytic reaction of the g-C3N4/BiFeO3 composite, thereby improving its photocatalytic performance, while the presence of MB increased the reduction rate of Cr(VI). After 5 h of the simultaneous adsorption and photocatalysis by CNBT, the removal rates of Cr(VI) and MB were 93% and 98%, respectively. This study provides a new theoretical basis and technical guidance for the combined application of photocatalysis and adsorption in the treatment of wastewaters containing mixed pollutants.
Subject(s)
Bismuth/chemistry , Chromium/chemistry , Ferric Compounds/chemistry , Graphite/chemistry , Methylene Blue/chemistry , Nanocomposites/chemistry , Nanotubes, Carbon/chemistry , Nitrogen Compounds/chemistry , Ultraviolet Rays , Water Pollutants, Chemical/chemistry , Adsorption , Catalysis , Ferric Compounds/radiation effects , Graphite/radiation effects , Nanocomposites/radiation effects , Nanotubes, Carbon/radiation effects , Nitrogen Compounds/radiation effects , Waste Disposal, Fluid/methods , Wastewater , Water Pollutants, Chemical/radiation effectsABSTRACT
Herein, a novel signal-off photoelectrochemical (PEC) aptasensor was proposed for sensitive detection of thrombin on the basis of C60@C3N4 nanocomposites as quencher and Au nanoparticles (depAu) decorated perylene tetracarboxylic acid (PTCA) as sensing platform. Owing to the excellent membrane-forming of PTCA and superior conductivity of depAu, the PTCA between two depAu layers can simply and effectively produce an extremely high initial photocurrent to afford a precondition for sensitive biodetection. Thereafter, the assembly of C60@C3N4 nanocomposites on electrode via typical sandwich reaction enabled the generation of a significantly decreased photocurrent. Here, the C3N4 with high surface area not only provided massive binding sites for C60 immobilization, but also partly competed with PTCA in light absorption for producing a significantly smaller photocurrent in the presence of electron donor ascorbic acid (AA). Additionally, both the C3N4 and C60 have the poor conductivity, which could inhibit the electron transfer to achieve a further decreased photocurrent, effectively improving the sensitivity of proposed biosensor. As a result, the PEC biosensor in a "signal-off" mode showed an extremely low detection limit down to 1.5â¯fM, providing a sensitive and universal strategy for protein detection.
Subject(s)
Fullerenes/chemistry , Graphite/chemistry , Metal Nanoparticles/chemistry , Nanocomposites/chemistry , Nitrogen Compounds/chemistry , Perylene/analogs & derivatives , Thrombin/analysis , Aptamers, Nucleotide/chemistry , Biosensing Techniques/methods , Electrochemical Techniques/methods , Fullerenes/radiation effects , Gold/chemistry , Graphite/radiation effects , Limit of Detection , Nanocomposites/radiation effects , Nitrogen Compounds/radiation effects , Perylene/chemistry , Reproducibility of Results , Ultraviolet RaysABSTRACT
Herein, a heterostructure based on MnO2 and g-C3N4 was constructed on the surface of metallic Ti implants, in which MnO2 favored the transfer and separation of free charges to enhance the photoconversion efficiency of g-C3N4 by 21.11%. Consequently, the yield of ROS was promoted significantly, which denatured protein and damaged DNA to kill bacteria efficiently. In addition, glutathione (GSH, l-γ-glutamyl-l-cysteinyl-glycine) defending oxidative stress in bacteria, was oxidized by MnO2 in the hybrid coating once the bacterial membrane was disrupted by ROS. Hence, after visible light irradiation for 20â¯min, MnO2/g-C3N4 coating exhibited superior disinfection efficacy of 99.96% and 99.26% against S. aureus and E. coli severally. This work provided a practical sterilization strategy about MnO2/g-C3N4 systems through the synergistic effects of enhanced photodynamic antibacterial therapy and oxidization effect of MnO2 with great biosafety, in which MnO2 enhanced the photocatalyst property of g-C3N4 to generate more ROS and deplete GSH to improve antibacterial efficiency. It will bring more insight into rapid and highly effective disinfection and antibacterial strategy without using traditional high-temperature, ultraviolet ray and antibiotics that cause side-effects.
Subject(s)
Graphite/chemistry , Manganese Compounds/chemistry , Nitrogen Compounds/chemistry , Oxides/chemistry , Photochemical Processes , Sterilization/methods , Bacteria/metabolism , Bacteria/radiation effects , Catalysis , Cell Membrane/metabolism , Cell Membrane/radiation effects , DNA Damage , Escherichia coli/radiation effects , Glutathione/metabolism , Graphite/radiation effects , Light , Manganese Compounds/radiation effects , Microbial Sensitivity Tests , Models, Molecular , Nitrogen Compounds/radiation effects , Oxides/radiation effects , Reactive Oxygen Species , Staphylococcus aureus/metabolism , Staphylococcus aureus/radiation effectsABSTRACT
Novel phosphorus nitride dots mainly consisting of N and P with strong fluorescence, excellent dispersibility and outstanding biocompatibility were prepared via a solvothermal method. The phosphorus nitride dots demonstrated great two-photon imaging capability in living cells under 800 nm excitation.
Subject(s)
Fluorescent Dyes/chemistry , Nitrogen Compounds/chemistry , Phosphorus Compounds/chemistry , Quantum Dots/chemistry , Fluorescence , Fluorescent Dyes/radiation effects , Fluorescent Dyes/toxicity , Humans , Infrared Rays , MCF-7 Cells , Microscopy, Fluorescence/methods , Nitrogen Compounds/radiation effects , Nitrogen Compounds/toxicity , Phosphorus Compounds/radiation effects , Phosphorus Compounds/toxicity , Photons , Quantum Dots/radiation effects , Quantum Dots/toxicityABSTRACT
Sediments exposed to simulated solar radiation can serve as an important source of dissolved organic carbon (DOC) to surrounding waters. However, it is still unclear if dissolved nutrients can be photoproduced from lake sedimentary organic matter. In this study, a series of laboratory-based experiments was conducted to address the photoproduction of dissolved inorganic nutrients and DOC from resuspended Taihu Lake sediments. Dissolved inorganic nutrients and DOC were photoproduced after 8-h irradiation. The released NH4+, NOx-, and DOC levels ranged from 3.57 to 12.14, 1.43 to 6.43, and 24.17 to 69.17 µmol L-1, respectively. The variation in the amount released indicated that sediment source had an effect on DOC and nutrient photorelease. More DOC and nutrients were released from higher concentration suspensions. However, due to the light absorption by suspended sediment, less DOC and nutrients were released from per gram of suspended sediment in high concentration suspensions. The decrease in DOC and increase in dissolved inorganic nitrogen during the last 2-h irradiation indicated that the photoproduction of inorganic nutrients proceeded via direct photodissolution of suspended sediments and subsequent photodegradation of the produced dissolved organic matter. Our results demonstrated that the photoproduction flux of NH4+ and NOx- accounts for 12.3 and 6.5 % of wet deposition, respectively, which suggest that the photodissolution of suspended sediment could be a potential source of DOC and dissolved nutrients in shallow water ecosystems.
Subject(s)
Carbon/analysis , Nitrogen Compounds/analysis , Phosphorus/analysis , Photolysis , Carbon/radiation effects , China , Environmental Monitoring , Geologic Sediments/chemistry , Lakes/chemistry , Nitrogen Compounds/radiation effects , Phosphorus/radiation effectsABSTRACT
Abatement of fluorinated compounds (FCs) used in semiconductor and display industries has received an attention due to the increasingly stricter regulation on their emission. We have developed a 2.45GHz microwave plasma torch with reverse vortex reactor (RVR). In order to design a reverse vortex plasma reactor, we calculated a volume fraction and temperature distribution of discharge gas and waste gas in RVR by ANSYS CFX of computational fluid dynamics (CFD) simulation code. Abatement experiments have been performed with respect to SF6, NF3 by varying plasma power and N2 flow rates, and FCs concentration. Detailed experiments were conducted on the abatement of NF3 and SF6 in terms of destruction and removal efficiency (DRE) using Fourier transform infrared (FTIR). The DRE of 99.9% for NF3 was achieved without an additive gas at the N2 flow rate of 150 liter per minute (L/min) by applying a microwave power of 6kW with RVR. Also, a DRE of SF6 was 99.99% at the N2 flow rate of 60 L/min using an applied microwave power of 6kW. The performance of reverse vortex reactor increased about 43% of NF3 and 29% of SF6 abatements results definition by decomposition energy per liter more than conventional vortex reactor.