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Antimicrobial films are widely used in food and other fields. The present work established a method of preparing antimicrobial films made of calcium alginate and lysozyme. For the sake of the optimization of antimicrobial effect, sonication was applied to increase the immobilization efficiency. Different ultrasonic power and treatment duration were studied. With the assistant of sonication, lysozyme immobilization rate was speeded up and the amount of lysozyme immobilized on the supporters was increased. The catalytic activity of the antimicrobial film was measured using the turbidimetric assay and reached the maximum at 147.8 W. The antimicrobial activity determined by the inhibition zone test was also promoted by sonication. To explore the mechanism of the ultrasonic effect on the lysozyme immobilization, lysozyme structures alteration before and after ultrasonic treatment was considered. The circular dichroism and fluorescence spectra illustrated that sonication affected the secondary and tertiary structures of lysozyme. The changes in the enzyme structures may lead to the improvement of the enzymatic activity. The impact of sonication on the microstructure of the films was investigated by the scanning electron microscope. The film surface showed some cracks after sonication that increased the superficial area accordingly.

Mo-N-co-doped mesoporous TiO 2 microspheres were synthesized via a solvothermal method, followed by nitriding treatment under ammonia gas flow. The efficiency of the samples was investigated by monitoring the degradation of Rhodamine-B under visible light irradiation. The experimental results revealed that Mo-N-co-doped mesoporous TiO 2 microspheres showed better performances than Mo-TiO 2 microspheres. It was observed that; 0.1% molar quantity of Mo doped on TiO 2 at 500 °C for 2 h under nitriding conditions gave highest photocatalytic activities. The nitridation under ammonia gas of Mo-TiO 2 samples created oxygen vacant sites and led to incorporation of substitutional and interstitial Nitrogen. The enhanced visible light photocatalytic activities of Mo-N-co-doped TiO 2 photocatalyst was attributed to the large surface areas, narrow band gap and intense light absorbance in visible region. This study may create a promising and eco-friendly method towards synthesis of metal and non-metals co-doped on semiconductor materials to improve their photocatalytic activities and applications.

Iron (III) and nitrogen co-doped mesoporous TiO 2 microspheres (Fe-N-TiO 2 ) are prepared using a self-assembly based solvothermal process followed by an ammonothermal method. Among all samples, 1 mol.% of Fe dopants and 500 °C nitridation (for 2 h) gives the highest visible light photoactivity. Results imply that the Fe 3+ /Fe 2+ dopant trap energy level introduced within the band gap in mildly Fe (∼1 at%) doped TiO 2 and the mesoporous nature of the material, both aid in the observed catalytic performance. Subjecting Fe-TiO 2 samples to ammonothermal process induces oxygen vancancies, and substitutional and interstitial N. This reduces optical band gap, and introduces local states. The lower band gap and local states together aid in the absorption of visible light and separation of charge carriers. Co-dopants are distributed uniformly in the best photocatalysts. The active species generated in the photocatalytic system is shown to be singlet molecular oxygen ( 1 O 2 ) using selective radical quenchers.

Edge- and corner-truncated octahedral Cu2O is successfully synthesized using an aqueous mixture of CuCl2, sodium dodecyl sulfate, NaOH, and NH2OH3·HCl. Cu2O1-xNx(150 °C, 30 min) samples are synthesized by nitridation of Cu2O using an ammonothermal process. Cu retains a formal valence state through and beyond the nitridation process. N concentration in this sample is 1.73 at%, out of which 1.08 at% is substitutional in nature. Photocatalytic activity of Cu2O1-xNx(150 °C, 30 min) sample is investigated and compared to that of pristine edge- and corner-truncated octahedral Cu2O. Results show that Cu2O1-xNx(150 °C, 30 min) sample with dominant {110} facets has a higher photocatalytic activity than the pristine Cu2O material. Higher surface energy and a greater density of the “Cu” dangling bonds on {110} facets of edge- and corner-truncated octahedral Cu2O1-xNx is the plausible reason for the observed optimum catalytic activity. Furthermore defect states induced by nitridation results in improved visible light adsorption. And also the band edge states changes which brought about by N doping. This is an interesting result since it bypasses the usual challenge faced by pristine Cu2O which have band edge states between which transitions are normally forbidden. Selective radical quenching experiments suggest that photocatalytic activity of Cu2O1-xNx is due to formation of hydroxyl radicals in water, subsequent to photogeneration of charge carriers in the photocatalyst.

A simple solvothermal approach with post-calcination is used to obtain (Ag, Ag2O) co-loaded TiO2 microspheres with high specific surface area (43.8 m2g-1) and desirable visible light photocatalytic degradation (64% after 2 h visible light irradiation). Generally, N-doping of TiO2 via nitridation using NH3 improves the visible light absorption property of material. However, nitridation of (Ag, Ag2O) co-loaded TiO2 results in a deleterious impact on the photocatalytic performance (around 20% after 2 h visible light irradiation). This is because nitridation of Ag-Ag2O-TiO2 results in (a) reduction of Ag2O to Ag and (b) Ag agglomeration and grain growth on TiO2 particles. These results in fact imply that in as-synthesized (Ag, Ag2O) co-loaded TiO2 systems, local surface plasmonic resonance (associated with of 5–12 nm Ag particles) aids in enhanced broad band visible light absorption; furthermore the heterojunction between TiO2 and Ag2O improves efficiency with which photogenerated carriers become available for photocatalysis. In all cases we show through selective radical quenching experiments that singlet oxygen is the primary reason for the dye degradation observed.

A dual-site fluorescent probe with double bond and aldehyde as reactive sites, was designed for the selective detection of sulfite and biothiols. Sulfite reacts with conjugate bond selectively, while Cys responses with aldehyde and GSH occurs substitution reaction. Different interactions cause different absorption and fluorescence responses. Moreover, it could be further applied in imaging in living cells.

Nickel, nitrogen-codoped mesoporous TiO2 microspheres (Ni–N–TiO2) with high surface area, and an effective direct band gap energy of ∼2.58 eV. Nickel sulfate used as the Ni source and ammonia gas as the N source here. The efficiency of the as-prepared samples was investigated by monitoring the degradation of Rhodamine B under visible light irradiation. The experimental results indicate that Ni-doped mesoporous TiO2 microspheres show higher photocatalytic activity than mesoporous TiO2 microspheres under visible light irradiation. It mainly due to that the electron trap level (Ni2+/Ni+) promoting the separation of charge carriers and the oxygen vacancies inducing the visible light absorption. In addition, Ni–N–TiO2 shows enhanced activity compared with Ni–TiO2. Codopants and dopants are found to be uniformly distributed in TiO2 matrix. Among the all samples the 0.5% molar quantity of Ni dopant and 500 °C 2 h nitriding condition gives the highest photocatalytic activity. The treatment of ammonia gas on Ni–TiO2 sample induced oxygen vancancies, substitutional and interstitial N. A suitable treatment by ammonia gas also promote separation of charge carriers and the absorption of visible light. The active species generated in the photocatalytic system were also investigated. The strategy presented here gives a promising route towards the development of a metal and non-metal codoped semiconductor materials for applied photocatalysis and related applications.

Mesoporous anatase TiO 2 microspheres were prepared via solvothermal method. Ammonium tungstate was used as the W source, and ammonia gas flowing in an ammonothermal reactor as the N source for codoping. TiO 2 :(W,N) mesoporous microspheres, which were prepared from solvothermal treatment at 160 °C for 16 h and thermal ammonolysis at 500 °C for 2 h after calcination, have high specific surface area of 106 m 2 g −1 . XPS results indicate the presence of N O , N i and W 6+ in the codoped mesoporous TiO 2 microspheres. Monodoping with N shifts the absorption band edge of anatase TiO 2 from ultraviolet region to visible region. Although codoping with W makes the visible light absorbance decrease a little, the photocatalytic degradation of a cationic dye rhodamine B (RhB) on mesoporous TiO 2 :(W,N) microspheres is increased to 1.7 times of that on mesoporous TiO 2 :N microspheres. This may due to decreasing recombination centers by W-doping charge compensation.

Because of the hydrophobicity and formation of biofilm, Bacillus cereus spores are highly resistant and widespread in food industry. The outermost layer: exosporium of Bacillus cereus spore plays an important role in its surface property. Previous work indicated that ultrasound detached the exosporium of spores, thus the surface properties were further investigated in this study. The detachment of exosporium was observed without damage to inner layers through TEM micrographs. Besides, the size of spores dropped rapidly from 2017.67 to 960.53 nm after 1 min ultrasound treatment. At the same time, the absolute zeta potential value also decreased rapidly. The ratio of hydrophobic spores (RHS) was defined as hydrophobicity, and it dropped-off with the detachment of exosporium. The SDS-PAGE results showed that the intensity of protein bands dropped especially that with higher molecular weight after ultrasound treatment. What's more, a lot of bands disappeared because of the separation of exosporium. In a word, these results indicated that ultrasound could detach exosporium and decrease the hydrophobicity of spores, which had lower adhesion to hydrophobic surface and easier to be cleaned.

With the extensive application of enzyme-catalyzed reactions in numerous fields, improving enzymatic efficiency has attracted wide attention for reducing operating costs and increasing output. There are three targets throughout enzymatic reactions: the enzyme, substrate, and mixed reaction system. Ultrasound has been known to accelerate enzymatic reactions by acting on different targets. It can modify both enzyme and substrate macromolecules, which is helpful for enhancing enzyme activity and product yields. The synergistic effect of ultrasound and enzymes is widely reported to increase catalytic rates. The present review discusses the positive effect induced by ultrasound throughout the enzymatic process, including ultrasonic modification of enzymes, ultrasound assisted immobilization, ultrasonic pretreatment of substrates, and ultrasound assisted enzymatic reactions.

Manganese- and nitrogen-co-doped mesoporous TiO2 microsphere photocatalysts are prepared by a simple sol–gel method with controllable sizes in the range of 400–500 nm and high surface area of 112 m2 g−1. Manganous acetate is the Mn source, and ammonia gas is the nitrogen source used. The dopants are found to be uniformly distributed in the TiO2 matrix. Interestingly, in (Mn,N)-co-doped TiO2, we observe an effective indirect band gap of ~2.58 eV. (Mn,N)-co-doped mesoporous TiO2 microspheres show higher photocatalytic activity than Mn–TiO2 microspheres under visible light irradiation. Among the samples reported in this work, 0.2 at.% Mn doping and 500 °C 2-h nitriding condition give the highest photocatalytic activity. The observed photocatalytic activity in the (Mn,N)-co-doped TiO2 is attributed to the contribution from improved absorption due to trap levels of Mn, oxygen vacancies and N doping. Manganese- and nitrogen-co-doped mesoporous TiO2 microspheres containing substitutional N, interstitial N and O vacancies show high visible light photocatalytic activity.

Highly crystalline mesoporous anatase TiO2 nanospheres with high surface area (higher than P25 and anatase TiO2) are prepared by a soft-template method. Despite the high specific surface area, these samples have three times lower equilibrium adsorption (