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Bi2O3/BiFeO3 composite was successfully fabricated by a conventional sol-gel method and structural properties were characterized based on X-ray diffractometer, scanning electron microscope, transmission electron microscope, energy-dispersive X-ray analyzer, nitrogen adsorption-desorption measurement, and UV-visible diffuse reflectance spectroscopy. Bi2O3/BiFeO3 had a good absorption for visible light, which was benefit to photocatalytic activity. The highest degradation efficiency was obtained when the content of Bi2O3 in Bi2O3/BiFeO3 was 63.9%. Effect of experimental conditions was investigated, and the highest photocatalytic activity of Bi2O3/BiFeO3 was observed at photocatalyst dosage of 0.5 g/L, initial BPA concentration of 10 mg/L, and solution pH of 6.3. Bi2O3/BiFeO3 photocatalyst exhibited enhanced photocatalytic activity for BPA, and the reaction rate constant over Bi2O3/BiFeO3 composite was 2.23, 3.65, and 8.71 times higher than that of BiFeO3, Bi2O3 and commercial TiO2 (P25), respectively. Bi2O3/BiFeO3 showed high photocatalytic activity after three cycles, suggesting that it was a stable photocatalyst. The possible photocatalytic mechanism has been discussed on the basis of the theoretical calculation and the experimental results. The hydroxyl and superoxide radicals together with photogenerated holes played significant roles in the photocatalytic reaction. [ABSTRACT FROM AUTHOR]

The α/β-Bi 2 O 3 photocatalyst was successfully synthesized by a novel solvothermal-calcination method. The physical and chemical properties of as-prepared samples were characterized based on XRD, XPS, SEM, TEM, EDS, BET, UV–vis DRS and PL techniques. The synthesized α/β-Bi 2 O 3 photocatalyst exhibited enhanced photocatalytic activity for 17α-ethinylestradiol (EE2), and 96.9% of EE2 was degraded after only 24 min of visible-light irradiation using α/β-Bi 2 O 3 as photocatalyst. The reaction rate constant over α/β-Bi 2 O 3 photocatalyst was 1.42, 2.23, 9.22 and 54.1 times higher than pure β-Bi 2 O 3 , α-Bi 2 O 3 +β-Bi 2 O 3 , α-Bi 2 O 3 and P25 respectively. Effect of catalyst dosage and pH value was investigated. The possible photocatalytic mechanism has been discussed on the basis of the theoretical calculation and the experimental results. α/β-Bi 2 O 3 was a fairly stable and efficient photocatalyst under the studied experimental conditions, proving that the α/β-Bi 2 O 3 photocatalyst was a promising photocatalyst for the practical application. [ABSTRACT FROM AUTHOR]

A novel magnetically separable photocatalyst comprising hollow TiO 2 -SiO 2 -CoFe 2 O 4 (TSC) was prepared. In the TSC photocatalyst, an SiO 2 interlayer between CoFe 2 O 4 core and TiO 2 shell is used to both weaken adverse influence of the magnetic core on photocatalysis and increase the temperature of the transition from anatase to rutile phase TiO 2 , thus increasing the anatase TiO 2 crystallinity. Such an interlayer promotes photocatalytic activity by changing the competition between the injecting process and reacting process of the photogenerated carriers. The photocatalytic activity of TSC was determined for degradation of dye molecules in water under either UV or visible light. The photocatalytic reaction of cationic dyes was governed by OH radicals, while O 2 − was the main active species in the initial photoreaction of anionic dyes. [ABSTRACT FROM AUTHOR]

A novel bismuth vanadate-palygorskite (BiVO 4 -Pal) photocatalyst was successfully prepared by a hydrothermal method. The morphology, structure and chemical composition of the composite was characterized. The adsorption capacity and photocatalytic activity under visible light of this composite to tetracycline hydrochloride were also investigated. The results indicated that BiVO 4 was successfully loaded on the Pal. Pal, as a low cost support, improved the adsorption capacity of the photocatalyst, thus increased the contact possibility with the active radicals, hence, the degradation activity of BiVO 4 was improved. The maximum adsorption capacity of BiVO 4 -Pal for tetracycline (TC), calculated by the Langmuir model at 20 °C, was 33.11 mg·g − 1 . The pseudo-first-order degradation rate constant for BiVO 4 -Pal composites was approximately 2.1 times higher than that of pure BiVO 4 , and the photodegradation ratio on the BiVO 4 -Pal composite was 1.4 times greater than that of pure BiVO 4 . In addition, the recovery of the BiVO 4 -Pal composite was carried out after the reaction by calcination at 400 °C for 4 h. The test showed that the prepared BiVO 4 -Pal catalyst was stable during the photodegradation of TC. There was no obvious reduction in the degradation rate of TC over the four successive runs and might be useful for practical applications. [ABSTRACT FROM AUTHOR]

A palygorskite (Pal)-supported Cu 2 O–TiO 2 heterojunction composite (Cu 2 O–TiO 2 –Pal) was successfully prepared. The morphology, structure and chemical composition of the composite was characterized, and the adsorption and photocatalytic degradation of tetracycline hydrochloride using this composite was also investigated. The results showed that a layer of TiO 2 − Cu 2 O was successfully loaded on the surface of Pal. The Cu 2 O–TiO 2 –Pal composite had a specific surface area of 93 m 2 ·g − 1 , mesoporous features, and a uniform slit channel. The composite possessed twofold removal ability to TC, including adsorptive capability for the separation and solar-light illuminate photocatalytic in degradation. The maximum adsorption capacity of Cu 2 O–TiO 2 –Pal for TC was 113.6 mg·g − 1 at 20 °C as calculated by the Langmuir model. The pseudo-first-order degradation rate constant of 50 mL of TC with an initial concentration of 30 mg·L − 1 reached 0.0129 min − 1 when the Cu 2 O–TiO 2 –Pal concentration was 1.0 g·L − 1 . The total removal rate of TC reached 88.81% in the presence of Cu 2 O–TiO 2 –Pal. In addition, the composite could be regenerated by calcination at 400 °C and recycled more than three times, which is useful for practical applications. [ABSTRACT FROM AUTHOR]

Tetracycline hydrochloride (TC) wastewater has complex components, high concentration of organic matter and certain biological toxicity. Photocatalytic degradation is of great application prospect due to its green, thorough and efficient removal of TC. In this study, heterojunction photocatalyst supported on Palygorskite (Pal) AgBr–TiO 2 -Pal with visible light response was successfully prepared via sol-gel and liquid deposition method successfully. Taking TC as the target pollutant, the photocatalytic performance of AgBr–TiO 2 -Pal photocatalys excited by visible light was studied. The spreading/grafting of AgBr–TiO 2 on the surface of Pal was improved by a series of structural characterization and composition analysis. The results also demonstrated that the specific surface area of AgBr–TiO 2 -Pal was about 48.06 m2⋅g−1 with uniform mesoporous slit. The AgBr–TiO 2 -Pal catalyst was very effective for the degradation of TC, and it still retained its high stability and reusability after five cycles. The results showed that under the best reaction conditions (initial concentration of tetracycline 10 mg⋅L−1, catalyst dosage 0.5 g⋅L−1, pH value 9), with the excitation of visible light, the maximum removal ratio of TC was 90%, and the mineralization ratio was 67%. The removal efficiency and degradation rate of TC by AgBr–TiO 2 -Pal catalyst were 2.17 and 4.75 times as much as those of TiO 2 respectively. The outstanding photocatalytic performance of heterogeneous AgBr–TiO 2 -Pal catalyst was obtained by fully participate in the reaction by photoinduced charge. This study could be expected to be used in photocatalytic degradation of antibiotic pollutants in wastewater treatment. • A novel AgBr–TiO 2 -Pal photocatalyst is prepared for tetracycline degradation. • The catalyst support, Palygorskite, has a porous structure and large surface area. • The AgBr–TiO 2 heterostructure has enhanced visible light photocatalytic activity. • The catalyst can be recycled more than five times by a simply filtered. [ABSTRACT FROM AUTHOR]

A novel CdS/BiOI composite has been prepared via a chemical bath deposition method. The physical and chemical properties of as-prepared composites were characterized by XRD, SEM, TEM, EDS, XPS, UV–vis DRS, and PL. The synthesized CdS/BiOI composites exhibited superior photocatalytic activity in photodegrading of 17α-ethinyl estradiol (EE2) compared to pure CdS and pure BiOI, and the removal rate of EE2 could approach 100% after only 12 min of visible light irradiation using 3:1 CdS/BiOI composite as photocatalyst. The reaction rate constant over 3:1 CdS/BiOI composite was 6.3, 7.1 and 70.9 times higher than that of pure CdS, pure BiOI and P25 respectively. In addition, a Z-scheme charge separation mechanism was proposed on the basis of the experimental results and the theoretical calculation. Moreover, the prepared composite showed good stability and recyclability which are beneficial for its practical application. [ABSTRACT FROM AUTHOR]

The C/N-doped β-Bi 2 O 3 nanosheets photocatalyst was successfully synthesized via a novel solvothermal-calcination method and applied for removing 17α-ethynylestradiol (EE2). Poly (aniline-co-pyrrole) (PACP) was not only used as C and N resources, but also as template to enlarge specific surface area during the preparation process. The PACP templated precursor calcined at 300 °C and 350 °C for 2 h were denoted as DBO-300 and DBO-350, respectively. The physical and chemical properties of as-prepared samples were characterized by element analysis, XRD, TEM, BET, XPS and UV–vis DRS techniques. The N element mass ratios in DBO-300 and DBO-350 were 1.883 wt% and 0.913 wt%, respectively. While the C element mass ratio in DBO-300 and DBO-350 were 2.579 wt% and 0.512 wt%, respectively. The total removal ratio of EE2 over DBO-300 was 95.30% after only 2 min of visible-light irradiation. While the total removal ratio of EE2 over DBO-350 reached 98.86% after 20 min of visible-light irradiation. The reaction rate constant over DBO-300 and DBO-350 were 13.93, 5.68 times higher than BO-350 (pure β-Bi 2 O 3 without PACP template calcined at 350 °C) respectively. The adsorption ability for EE2 over DBO-300 and DBO-350 was attributed to the high specific surface area and the hydrophobic nature of carbon, and the good photocatalytic performance was attributed to the narrower band gap induced by C and N doping. The hydrophobic EE2 in water could be rapidly removed by adsorption and photocatalytic degradation on C/N-doped β-Bi 2 O 3 nanosheets synergistically. [ABSTRACT FROM AUTHOR]

Our previous study reported that a more dispersed palygorskite (Pal) with a multiparous structure can be fabricated from rigid nano-rods by ion beam bombardment. In this study, the new multiparous structure of Pal (MPal) was used to carry a nanocomposite prepared from graphitic carbon nitride (CN) and nano zero-valent iron (NZVI) following a simple thermopolymerisation method for the first time. The as-prepared sample (MPal/NZVI/CN) achieved broader light absorption in the visible light region and low recombination, according to the characterisation results of the UV–vis diffuse reflectance and photoluminescence (PL) spectra of the photocatalysts. The photocatalysis of CrVI and methylene blue (MB) in an aqueous solution by MPal/NZVI/CN revealed that the MPal/NZVI/CN-1:5:6 composites exhibited superior catalytic activity, with CrVI and MB removal efficiencies of 98.48% and 99.2% in 120 min, respectively. Additionally, the reaction rate constants (k Cr and k MB) of MPal/NZVI/CN were much higher than those of CN, NZVI/CN, and MPal/CN because the formation of MPal and NZVI composites with CN promoted the separation of photo-generated electron-hole pairs. After four cycles, MPal/NZVI/CN exhibited great photoactivity, which could not only be attributed to the improved dispersion of MPal, but also to the ability of the photo-generated electrons of CN to reduce the FeIII/FeII to Fe0. This study opens new opportunities for modifying photocatalysts using the inorganic nanomaterials readily formed by physical irradiation. • A new dispersed structure of palygorskite was used to modify a complex. • The complex was based on nano zero valent iron and carbon nitride. • The ternary composite demonstrates improved photocatalytic degradation ability. • Cycle effect in the ternary composite can be improved by the new palygorskite. • The dispersed structure and negative charges of palygorskite play the key roles. [ABSTRACT FROM AUTHOR]