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Graphical abstract Highlights • Synthesis of Sup-Bi 2 O 3 /Bi 2 MoO 6 under optimized reaction conditions i.e. time, pH and concentration. • The photocatalytic activity of the synthesized Sup-Bi 2 O 3 /Bi 2 MoO 6 is better in polar solutions. • Sup-Bi 2 O 3 /Bi 2 MoO 6 composite presents zero gap heterojunction. • Tetracycline (TC), ciprofloxacin (CPFX), Rhodamine B (RhB), and Methylene blue (MB) degraded successfully. Abstract In this article, Bi 2 O 3 /Bi 2 MoO 6 composites were synthesized hydrothermally under optimized conditions, by adjusting pH, the concentration of polyvinylpyrrolidone (PVP (K30)) and reaction time. During the synthesis process, flower-root shaped zero-gap Bi 2 O 3 /Bi 2 MoO 6 heterojunctions were successfully synthesized. The adopted samples were characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), Diffuse reflectance spectra (DRS), Photoluminescence (PL), and Fourier transform infrared spectroscopy (FT-IR). The photocatalytic activity was measured under visible-light-irradiation (λ > 420 nm) by degrading tetracycline (TC), ciprofloxacin (CPFX) (antibiotics) and rhodamine B (RhB), methylene blue (MB) (dangerous dyes). The degradation results indicated that photocatalyst sample synthesized at pH 9.0, PVP (K30) 0.05 mol/L and 80 min reaction time (Sup-Bi 2 O 3 /Bi 2 MoO 6) demonstrated highly efficient performance. The Sup-Bi 2 O 3 /Bi 2 MoO 6 showed the highest apparent rate constant (K app) that's 50% more than the samples prepared at ordinary conditions. Photocatalytic degradation order was i.e. RhB > TC > CPFX > MB, which depends on the polarity of the degrading medium. [ABSTRACT FROM AUTHOR]

A novel metal free, graphitic carbon nitride self-type heterojunction was successfully created. A self-type heterojunction between two different kind of graphitic carbon nitride with a promote charge separation ability, one was prepared by solvothermal using the dicyandiamide as precursor and other was prepared by direct heating from melamine precursor. This synthesis process is facile, economical and environment friendly. The confirmation of synthesis and heterojunction formation was based on the X-ray-Diffraction, Transmission electron microscopy, Scanning electron microscopy, Fourier transform infrared spectra, X-ray photoelectron spectroscopy and photocurrent. The potential difference in heterojunction between different types of g-C 3 N 4 is the main acting power for the proficient separation and transformation of photo generated charges. Degradation results indicated that, the removal of antibiotic from effluents, graphitic carbon nitride heterojunction (GCN-DM) pointedly enhanced the visible light catalytic activity over solo graphitic carbon nitride (GCN-D, GCN-M). The improved photocatalytic behaviour of heterojunction may be due to charge separation and transfer ability with prolong lifetime of photo-generated charge carrier. The results also indicated that the optical and surface area properties also play a significance role in enhancement of photo-catalytical ability of target photo-catalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] • Designed a fluorescent probe to detect 1-hydroxyethane-1,1-diphosphonic acid. • Explored the optimum conditions for detection. • Researched the fluorescence quenching mechanism in detail. Organic phosphonates are widely used as scale inhibitors and metal ion chelators in industrial water treatment. 1-hydroxyethane-1,1-diphosphonic acid (HEDP) is one of the application of extensive organic phosphonates. However, due to physical and chemical properties, the detection process is extremely complicated. In this work, a fluorescent probe was prepared to detect HEDP which used salicylic acid (SA) and ferric ion (Fe3+) as sources for the first time. As far as optical properties were concerned, Fe3+-salicylic acid complex (Fe-SA) designed as fluorescent probe was significantly different from SA. The detection limit of HEDP was 2.7 μM (0.56 mg/L) under the optimal experimental conditions. The fluorescence quenching of SA can be attributed to static quenching.. [ABSTRACT FROM AUTHOR]

3-D composite materials containing nanorods of copper–biphenylamines framework at the exterior of Ag doped g-C 3 N 4 , to reduce colorless/refractory and colored organic contaminants, with prominent improvement in catalytic action was witnessed for 3-D composite 5% Ag/g-C 3 N 4 /Cu(BA), in contrast to original g-C 3 N 4 . The improved samples forced electrons colonizing in upper CB and holes colonizing in lower VB, hence improving redox reaction supremacy of the charge carriers. 5% Ag/g-C 3 N 4 /Cu(BA) can easily degrade 100% to 99.5% of MO & RhB solutions in 60 min and 73% of phenol and 57% of TCP were degraded. Whereas the degradation efficacies of 5% Ag/g-C 3 N 4 /Cu(BN), 5% Ag/g-C 3 N 4 /Cu(PD), 5% Ag/g-C 3 N 4 and g-C 3 N 4 are inferior related to 5% Ag/g-C 3 N 4 /Cu(BA). The resilient dynamic reactive species (O 2 − , h + , 1 O 2 , OH), directly caused mineralization of MO, RhB, phenol and TCP. The k app for 5% Ag/g-C 3 N 4 /Cu(BA) also showed superiority over other modified samples. The above results are advantageous for the expansion of a modified catalyst in a wholesale amount and its use. TEM, SEM, EDS elemental mapping, XRD, UV–vis, XPS, and VBXPS studies confirmed that Cu(BA) and 5% Ag/g-C 3 N 4 display close communication with each other. This investigation delivers an innovative approach for extremely worthwhile composite photocatalyst enterprises for environmental remediation. [ABSTRACT FROM AUTHOR]

A novel and highly efficient ternary mpg-C 3 N 4 /BiVO 4 /TiO 2 composite was successfully synthesized and characterized with regard to structure, chemical composition, optical properties and degradation application. The photocatalytic activities of as-prepared samples were evaluated by the photocatalytic decomposition of methylene blue (MB), practical effluent from alkylation and amination steps in 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) production. Compared with TiO 2 , BiVO 4, and mpg-C 3 N 4 , the binary composites TiO 2 /BiVO 4 and the ternary mpg-C 3 N 4 /BiVO 4 /TiO 2 composites exhibited the higher photocatalytic activity under visible light irradiation. Compared to solo mpg-C 3 N 4 and BiVO 4 , the photocatalytic efficiency of g-C 3 N 4 /TiO 2 /BiVO 4 raised up to 94%. The catalytic activity of g-C 3 N 4 /TiO 2 /BiVO 4 against TATB (alkylation and amination) also confirms its efficiency by creating intermediate which were detected by Q-TOF-MS. The thermal stability and photo-stability of the produced composites were investigated. From the view of practical application, mpg-C 3 N 4 /BiVO 4 /TiO 2 displayed superior photostability after five times recycle. The mechanism research showed the fitting of band structure among BiVO 4 , g-C 3 N 4, and TiO 2 . The presence of mpg-C 3 N 4 and BiVO 4 can notably adjust the band gap energy and the synergy effects of them can prolong the lifetime of the charge carrier. [ABSTRACT FROM AUTHOR]