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In order to develop the degradation technology of toxic and refractory pollutants, a new Rhodamine B-sensitized BiOClBr photocatalyst was synthesized by a simple impregnation method. Different from the previous work, this work made good use of the pollutant RhB. The dye RhB acted as a component of the nanocomposite. The sensitization of the dye not only promotes the effective degradation of 2,4,6-TCP, but also RhB itself. The morphology, structure, optical and electrochemical properties of the as-prepared catalyst were systematically characterized. The factors affecting photocatalytic removal 2,4,6-TCP (dosage, initial concentration and pH) were optimized by modeling the 3D surface response. Under visible light irradiation, the removal rate of 2,4,6-TCP can reach 92.3% in 80 min at an optimal initial concentration of 10 mg·L − 1, a pH of 4.2 and a dosage of 16.2 mg. The photocatalytic mechanism of the material was discussed in conjunction with the energy band structure and capture agent experiment. The main active species are h+ and ·OH. This research provides a new idea for the simultaneous treatment of dye and chlorophenol wastewater.

The graphitic carbon nitride (g-C3N4) and the Fe3O4/g-C3N4 magnetic materials were synthesized in this paper. The structures of the materials were confirmed by a series of analysis. The Fe3O4/g-C3N4 was then used as a sorbent to adsorb polychlorinated diphenyl ethers and polychlorinated biphenyls. Different extraction conditions were examined, including adsorbent amount, salinity, pH of the sample matrix, adsorption time, reaction temperature, elution solvent and preconcentration factor. The maximum recoveries were obtained by employing methanol to desorb pollutants on 40.0 mg Fe3O4/g-C3N4 in 120.0 mL environmental water with a salinity of 5% (w/v) at a pH of 7 at 25 °C within 10 min. Using the optimized parameters, the detection limits of the method are between 0.01 and 0.04 μ · L−1 with a satisfying linear relationship. The adsorbent can be recycled at least 10 times with no significant reduction in the extraction efficiency.

The Z-scheme Bi2WO6/NaBiO3 nanocomposites were first fabricated by a facile hydrothermal method, and were then characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive spectrometer, Fourier-transform-infrared spectroscopy, X-ray photoelectron spectroscopy and N2 adsorption–desorption. The as-prepared Bi2WO6/NaBiO3 nanocomposites exhibit outstanding photocatalytic activity and recyclability. A 98.4% photodegradation of 2,3-dichlorophenol (50 mg·L−1) was attained in the presence of Bi2WO6/NaBiO3 (1:10) under the visible-light irradiation in 30 min. In particular, the photocatalytic mechanism has been discussed in detail, based on four aspects: (1) oxidative species, (2) photoelectrochemical performance, (3) conduction band and valence band energy levels and (4) possible transition states and reactions. In conclusion, O−2 is the main active oxidative species in the Bi2WO6/NaBiO3 nanocomposite. The material has higher photocurrent and visible light adsorption but lower electron–hole pairs recombination, which contributes to distinguished photocatalytic efficiency. The Z-scheme photocatalytic path was proposed and the possible degradation process and routes have been summarized.

The aperture of KIT-6 can influence the recoveries of magnetic solid phase extraction. In this context, aperture regulated magnetic KIT-6 was prepared and characterized to improve the performance in the detection of deltamethrin and permethrin diastereomers. The novel Fe3O4@SiO2@KIT-6/130 °C nanocomposite was selected for the extraction of pyrethroid insecticides including deltamethrin, cis-permethrin and trans-permethrin. The variables influencing the extraction process such as the material dosage, adsorption time, pH, salinity of the solution, desorption solvent and enrichment factor were evaluated. The method has the advantages of low LODs, a wide linear range, good reproducibility and acceptable recoveries. Under the optimal conditions, the recoveries are between 88.5% and 95.4%. The adsorption process corresponds well with pseudo-second order kinetics and Langmuir adsorption isotherms. The process is spontaneous and exothermic on the basis of thermodynamic records. Magnetic solid phase extraction coupled with high performance liquid chromatography based on the Fe3O4@SiO2@KIT-6/130 °C nanocomposite offers an easy and sensitive way to detect trace pyrethroid insecticides in environmental water samples.

The high-efficient photocatalytic material Ag3PO4/g-C3N4 was synthesized through calcination and precipitation methods. The physico-chemical properties of the material were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), ultraviolet–visible (UV–Vis) diffuse reflectance spectroscopy (DRS) photoluminescence spectra (PL) and Brunauer-Emmett-Teller (BET) surface area test. The morphology analysis indicated that Ag3PO4 particles were heterogeneously dispersed on the surface of layered g-C3N4. The Ag3PO4/g-C3N4 nanocomposites were applied in the photodegradation of bisphenol A under the visible light irradiation. The effects of the material proportion, the initial concentration of BPA, and the salinity on the degradation were discussed. The results showed that 92.8% bisphenol A (10 mg/L) can be photodegraded under 3 h irradiation by Ag3PO4/g-C3N4 with 25% Ag3PO4 mass ratio. The photodegradation kinetics and possible photocatalytic mechanism were discussed. The active specie ·O2− was found to play a key role during the photocatalytic reaction. The reaction mechanism was described based on valence band, conduction band energy levels and reduction potentials of oxygen and hydroxyl radicals.

In this study, the Z-scheme heterojunction photocatalysts Ag/NH2-MIL-125(Ti)/CdS (AMC-5, AMC-10 and AMC-20) were first successfully obtained by stepwise deposition of Ag and CdS. The morphology, crystallinity and photochemical properties of the materials were investigated. The N2 adsorption–desorption isotherm showed that AMC-10 had a large specific surface area (363.41 m2/g). Cyclic tests proved that the heterojunction exhibited good stability. In comparison, AMC-10 exhibited a significantly higher photocatalytic activity. Results suggested that 94.2% ketoprofen (10 mg/L) can be photocatalytically degraded to intermediates and small molecules after 180 min of simulated sunlight illumination. AMC-10 had a large degradation rate constant 0.0168 min−1, which is 3.15 and 2.50 times higher than that of CdS and NH2-MIL-125(Ti), respectively. The total organic carbon removal percentage of ketoprofen was 57.5%. Free radical trapping experiments indicated that ·O2− and h+ were the main active species, which can also be verified by the detection of electron paramagnetic resonance. Possible degradation pathways and reaction mechanisms were proposed by band potential calculations and liquid chromatography-mass spectrometry. The results of Vibrio qinghaiensis sp.-Q67 culture demonstrated that the biotoxicity of ketoprofen increased first and then decreased with time. It can be concluded that the Z-scheme heterojunction of Ag/NH2-MIL-125(Ti)/CdS was beneficial for the separation of photo-generated electrons and holes and the noble metal Ag nanoparticles play the important role in the photocatalytic degradation with the surface plasmonic resonance effect and Schottky junction.

In this study, chlorella was first used as the carbon source of Carbon dots (CDs) and further modified the BiOCl. Then, a novel photocatalyst Carbon dots/BiOCl (CBOC) was successfully synthesized. The morphology, crystal structure, chemical states and optical properties of the material were characterized by different techniques. Meanwhile, the energy band structure and density of states of CBOC2 composite were calculated based on density functional theory. In order to investigate the photocatalytic performance of the materials, the photodegradation of tetracycline was carried out under the simulated sunlight. The conditions of different materials, materials dosage and sample concentration were compared. About 99.5% tetracycline (10 mg/L) can be photodegraded by 15 mg CBOC2 in 75 min illumination with 52.2% mineralization rate. The material can be reused with high stability. The ·O2− is the main reactive species. The possible degradation pathways and mechanism of photocatalysis was discussed in detail. The CDs originated from chlorella has the large contribution in the photocatalysis. The work creates a new road of the application of chlorella in photocatalysis.

Carbon-encapsulated Ni nanoparticles (the average diameter of the particles is 7–8 nm) in B matrix were successfully in situ synthesized by chemical vapor deposition (CVD) in order to solve the agglomeration of nanoparticles by traditional mixing method. The influences of CVD technique on the carbon yield, morphology and structure were well investigated based on model system, and the (MgB 2 ) 0.96 Ni 0.04 bulks containing 3.8, 8.2 and 8.5 wt% carbon were prepared at 750 °C. The X-ray diffraction patterns showed no substitution of Ni for Mg and less substitution of C for B during the synthesis process, whereas the TEM analysis suggested such decorated insertions with core-shell structure were stable within the MgB 2 matrix and hopefully acted as pinning center due to the small size. In our experiment, although the advantage of nanoparticles was suppressed by the large amount of MgO impurities during the deposition process, a small enhancement of J c was observed in the low field range, which indicated improved grain connectivity because of the refinement of MgB 2 grains by inducing homogeneous nanoparticles. In view of this, a desirable J c performance at high field could be further obtained under the control of MgO content.

The novel, stable, and environment-friendly Fe 3 O 4 /g-C 3 N 4 nanocomposites (10–15 nm) were synthesized with a combination of calcination and co-precipitation methods. The nanocomposites were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), vibrating sample magnetometry (VSM), Fourier transform infrared spectroscopy (FT-IR), ultraviolet–visible (UV–vis) diffuse reflectance spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller analysis (BET). The results indicated that the Fe 3 O 4 nanoparticles were uniformly deposited on the g-C 3 N 4 nanosheets. The photocatalytic activity of the Fe 3 O 4 /g-C 3 N 4 nanocomposites was investigated for the first time in terms of the photodegradation of 2,4,6-trichlorophenol (2,4,6-TCP) under visible light. The nanocomposites with 50% g-C 3 N 4 (mass percent) were found to have good photocatalytic activity for the photodegradation of 2,4,6-TCP. In addition, the nanocomposites could be reused several times by applying an external magnetic field to separate them from the solution. The photodegradation kinetics and a possible reaction mechanism were investigated. Hydroxyl radicals were detected during the photodegradation reactions by using fluorescence spectroscopy.

Novel material wool ball-like F-doped BiOCl0.4Br0.3I0.3 has been successfully fabricated via a facile solvothermal method. In this work, the as-synthesized catalyst was characterized to examine the structure, morphology, optical and electrochemical properties. The catalyst was used in sulfamethazine degradation under visible-light irradiation. The optimized photocatalyst F-BiOCl0.4Br0.3I0.3 (Bi:F = 3:2) exhibits superior activity and the degradation efficiency can reach 99.6 % in pH 6 within 60 min. There are two reasons to explain it: (i) The F-BiOCl0.4Br0.3I0.3 has narrow band gap; (ii) Wool ball-like morphology can cause multiple reflections of the irradiated light, and availably prolong the action time. The primary oxidative species are holes and superoxide radicals. The possible degradation mechanism was discussed based on the experimental results.

In view of the deterioration of the environment and the shortage of resources, it is necessary to develop efficient photocatalysts for the degradation of organic pollutants. Herein, a novel and environmentally friendly ZnNb2O6/g-C3N4 heterojunction nanocomposite was synthesized by calcination-hydrothermal method successfully. The chemical and physical capabilities of the material were characterized by various kinds of analytical instruments. Compared with ZnNb2O6 and g-C3N4, ZnNb2O6/g-C3N4 showed the strongest photocatalytic activity. The nanomaterial was used in the removal of the pollutant 2,4-DCP. The effects of degradation conditions were discussed including component ratio, material dosage, initial analyte concentration, pH and salinity. After 180 min’ simulated sunlight illumination, the removal efficiency of 2,4-DCP (10 mg/L) reached 95.7% under the optimum condition. Furthermore, the possible photocatalytic mechanisms were discussed according to four aspects: (i) The conformation of the active species; (ii) The calculation of valence and conduction band; (iii) The analysis Z-scheme heterojunction mechanism; (iv) The speculation of feasible photocatalytic paths. In conclusion, the ZnNb2O6/g-C3N4 (ZC-7) nanocomposite has the least recombination rate of electron-hole pairs and the highest photocatalytic efficiency.

The novel semiconductor heterojunction of MIL-53(Fe)/BiOCl composite was first prepared through the solvothermal reaction. The prepared materials were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Brunner-Emmet-Teller (BET) and ultraviolet-visible diffuse reflectance spectroscopy (DRS). MIL-53(Fe)/BiOCl heterojunction is a kind of photoexcited materials and it accelerates the photoreactivity of BiOCl under the visible light irradiation. It was used to remove Rhodamine B (RhB) with the existence of persulfate (PS). The UV–vis spectrophotometer and the TOC detector show that the degradation rate and TOC removal efficiency of RhB (20 mg/L) are 99.5% and 69.4%within 30 min visible-light irradiation, respectively. Due to the proper band gap of material and the presence of electron acceptor, PS, the survival time of active radicals are increased. The active species h+, ·SO4− and ·OH are found to play the important roles during the reaction system. The possible mechanism for the RhB degradation of MIL-53(Fe)/BiOCl/PS is also proposed. Furthermore, the results of the material reusability for the degradation of RhB indicate that the MIL-53(Fe)/BiOCl has a good stability and can be used in the environmental water sample treatment.