Constructing B─N─P Bonds in Ultrathin Holey g-C3N4 for Regulating the Local Chemical Environment in Photocatalytic CO2 Reduction to CO.

The lack of intrinsic active sites for photocatalytic CO2 reduction reaction (CO2RR) and fast recombination rate of charge carriers are the main obstacles to achieving high photocatalytic activity. In this work, a novel phosphorus and boron binary-doped graphitic carbon nitride, highly porous material that exhibits powerful photocatalytic CO2 reduction activity, specifically toward selective CO generation, is disclosed. The coexistence of Lewis-acidic and Lewis-basic sites plays a key role in tuning the electronic structure, promoting charge distribution, extending light-harvesting ability, and promoting dissociation of excitons into active carriers. Porosity and dual dopants create local chemical environments that activate the pyridinic nitrogen atom between the phosphorus and boron atoms on the exposed surface, enabling it to function as an active site for CO2RR. The P-N-B triad is found to lower the activation barrier for reduction of CO2 by stabilizing the COOH reaction intermediate and altering the rate-determining step. As a result, CO yield increased to 22.45 µmol g-1 h-1 under visible light irradiation, which is ≈12 times larger than that of pristine graphitic carbon nitride. This study provides insights into the mechanism of charge carrier dynamics and active site determination, contributing to the understanding of the photocatalytic CO2RR mechanism.

Determination of Methanol, Acetaldehyde, and Ethyl Acetate in Thousand Folds of Ethanol Sample by Headspace Gas Chromatography with Mass Spectrometry.

Alcohol beverages have been widely consumed in several parts of the world. In this study, volatile organic compounds in alcoholic beverages including acetaldehyde, ethyl acetate, methanol, and higher ethanol were investigated and evaluated using a headspace gas chromatograph equipped with a mass spectrometer. This study evaluated the suitability of the chromatographic system, linearity, limit of detection, and limit of quantification, accuracy, and precision of the single and simultaneous determination of acetaldehyde, ethyl acetate, and methanol in thousand folds of ethanol. Results showed that the acetaldehyde concentration in local beer samples and local manual product liqueur samples ranged from 4.65 to 13.22 mg/L and from 5.55 to 75.96 mg/L, respectively, but in local industrial product liqueur samples, acetaldehyde was not detected. Methanol was only detected in a few local beer samples and locally manually produced liqueur samples within low concentrations. Ethyl acetate was only detected in all local beer samples, but it was not present in local industrial product liqueur samples.

A novel n-p heterojunction Bi2S3/ZnCo2O4 photocatalyst for boosting visible-light-driven photocatalytic performance toward indigo carmine.

An innovative p-n heterojunction Bi2S3/ZnCo2O4 composite was first fabricated via a two-step co-precipitation and hydrothermal method. By controlling the weight amount of Na2S and Bi(NO3)3 precursor, different heterogeneous xBi2S3/ZnCo2O4 were synthesized (x = 0, 2, 6, 12, and 20). The p-n heterojunction Bi2S3/ZnCo2O4 was characterized by structural, optical, and photochemical properties and the photocatalyst decoloration of indigo carmine. Mott-Schottky plots proved a heterojunction formed between n-Bi2S3 and p-ZnCo2O4. Furthermore, the investigation of the photocurrent response indicated that the Bi2S3/ZnCo2O4 composite displayed an enhanced response, which was respectively 4.6 and 7.3 times (4.76 µA cm-2) greater than that of the pure Bi2S3 (1.02 µA cm-2) and ZnCo2O4 (0.65 µA cm-2). Especially the optimized p-n Bi2S3/ZnCo2O4 heterojunction with 12 wt% Bi2S3 showed the highest photocatalyst efficacy of 92.1% at 40 mg L-1 solutions, a loading of 1.0 g L-1, and a pH of 6 within 90 min of visible light illumination. These studies prove that p-n Bi2S3/ZnCo2O4 heterojunction photocatalysts can greatly boost their photocatalytic performance because the inner electric field enhances the process of separating photogenerated electron-hole pairs. Furthermore, this composite catalyst showed good stability and recyclability for environmental remediation.

Design of novel p-n heterojunction ZnBi2O4-ZnS photocatalysts with impressive photocatalytic and antibacterial activities under visible light.

Heterojunction structures have attracted considerable attention for enhancing electron migration across interfaces. In this report, ZnBi2O4-ZnS(12%) heterojunction photocatalysts was found to be capable of degrading over 94% of indigo carmine in a 15 mg/L solution within 90 min of visible light irradiation at a catalytic dose of 1.0 g/L and pH 4. Furthermore, more than 82% of the total organic carbon (TOC) was removed, confirming the almost complete mineralization of the indigo carmine by ZnBi2O4-ZnS(12%). Moreover, the photocatalyst exhibited high stability and retained its photocatalytic activity up to the 5th cycle of operation without photocorrosion. The dramatic enhancement in the visible-light photocatalytic performance of the ZnBi2O4-ZnS heterojunctions over pristine ZnBi2O4 and ZnS was due to the formation of a superior heterojunction between the n-type semiconductor, ZnS, and the p-type semiconductor, ZnBi2O4. This heterojunction facilitated the separation and transfer of the photoinduced electron at the interfaces of the two semiconductors. Furthermore, the ZnBi2O4-ZnS(12%) exhibited an inhibition zone of 15 mm against fecal Escherichia coli (ATCC 8739), with a minimum inhibitory concentration (MIC) of 150 µg/mL. These results demonstrated that the novel ZnBi2O4-ZnS p-n-type heterojunction is a promising visible-light active photo-catalyst for the degradation of organic pollutants and inhibition of fecal E. coli.

Effects of Cadmium and Lead on Muscle and Liver Glycogen Levels of Climbing Perch (Anabas testudineus).

The aim of this study was to assess the glycogen content in the muscle and liver tissues of the climbing perch (Anabas testudineus) exposed to sublethal concentrations of Cd and Pb over 28 days of exposure and 14 days of depuration. Muscle and liver glycogen levels in A. testudineus after Pb or Cd treatment were significantly lower (p < 0.05) than that of A. testudineus in the control group during the exposure phase. In the recovery phase, muscle, and liver glycogen levels in A. testudineus increased in all Pb treatment groups, whereas they continuously decreased in all Cd treatment groups. Fish affected by Cd had obvious difficulties recovering from the stress response. It was concluded that exposure to the tested concentrations of Pb and Cd could be a potent endocrine activity disruptor, which may lead to adverse impacts on the health of A. testudineus.

High-efficient photocatalytic degradation of commercial drugs for pharmaceutical wastewater treatment prospects: A case study of Ag/g-C3N4/ZnO nanocomposite materials.

Pharmaceutical drugs' removal from wastewater by photocatalytic oxidation process is considered as an attractive approach and environmentally friendly solution. This report aims to appraise the practical application potential of Ag/g-C3N4/ZnO nanorods toward the wastewater treatment of the pharmaceutical industry. The catalysts are synthesized by straightforward and environmentally-friendly strategies. Specifically, g-C3N4/ZnO nanorods heterostructure is constructed by a simple self-assembly method, and then Ag nanoparticles are decorated on g-C3N4/ZnO nanorods by a photoreduction route. The results show that three commercial drugs (paracetamol, amoxicillin, and cefalexin) with high concentration (40 mg L-1) are significantly degraded in the existence of a small dosage of Ag/g-C3N4/ZnO nanorods (0.08 g L-1). The Ag/g-C3N4/ZnO nanorods photocatalyst exhibits degradation performance of paracetamol higher 3.8, 1.8, 1.3 times than pristine g-C3N4, ZnO nanorods, and g-C3N4/ZnO nanorods. Furthermore, Ag/g-C3N4/ZnO nanorods have an excellent reusability and a chemical stability that achieved paracetamol degradation efficiency of 78% and remained chemical structure of the photocatalyst after five cycles. In addition, the photocatalytic mechanism explanation and comparison of photocatalytic drugs' degradation ability have also been discussed in this study.

Potential health risks of toxic heavy metals and nitrate via commonly consumed bivalve and vegetable species in Ho Chi Minh City, Vietnam.

This study aimed to evaluate the health risks of cadmium (Cd), lead (Pb), inorganic arsenic (As), and nitrate exposure through the consumption of bivalves and vegetables collected from local markets in Ho Chi Minh City. The present study analyzed four favorite bivalve species (Meretrix lyrate; Perna viridis; Anadara subcrenata; Anadara granosa) for concentrations of Cd, Pb, and inorganic As and 9 vegetable species (Brassica juncea; Brassica integrifolia; Brassica rapa chinensis; Nasturtium officinale; Lactuca sativa; Ipomoea aquatica; Amaranthus gangeticus; Ipomoea batatas; Spinacia oleracea) for concentrations of Pb and nitrate. The target hazard quotient (THQ) and target cancer risk (TR) were calculated to estimate non-carcinogenic and carcinogenic health risks, respectively. For bivalves, Cd and inorganic As were present at relatively lower concentrations, whereas a relatively higher accumulation of Pb was recorded. The THQ for Cd, Pb, or inorganic As was below the threshold of 1, suggesting no potential health risks. In the case of vegetables, Pb was present at relatively low concentrations, while nitrate accumulation was at relatively high concentrations. The THQ for nitrate was higher than the threshold of 1, suggesting a potential health risk. The combined effects are estimated according to the hazard index (HI), which shows the health risks associated with the consumption of these bivalves and vegetable species. Therefore, continuous and excess consumption for a lifetime of more than 70 years has a probability of target cancer risk.

Novel reduced graphene oxide/ZnBi2O4 hybrid photocatalyst for visible light degradation of 2,4-dichlorophenoxyacetic acid.

A new highly efficient rGO/ZnBi2O4 hybrid catalyst has been successfully synthesized through oxidation-reduction and co-precipitation methods, followed by heating at 450 °C. The obtained rGO/ZnBi2O4 catalyst was characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The catalytic activity of rGO/ZnBi2O4 under visible light irradiation was tested using 2,4-dichlorophenoxyacetic acid (2,4-D) in aqueous solution. The rGO/ZnBi2O4 hybrid catalyst containing 2% rGO (2.0rGO/ZnBi2O4) showed the best catalytic performance. More than 90% of 2,4-D in a 30 mg/L solution was degraded after 120 min of visible light irradiation using 2.0rGO/ZnBi2O4 at 1.0 g/L concentration. Moreover, the 2.0rGO/ZnBi2O4 catalyst showed excellent stability over four consecutive cycles, with no significant changes in the photocatalytic degradation rate. This study demonstrated that rGO/ZnBi2O4 may be a promising, low-cost, and green photocatalyst for environmental remediation applications.

Lead and Arsenic Accumulation and Its Effects on Plasma Cortisol Levels in Oreochromis sp.

The accumulation, elimination and effect of heavy metals on plasma cortisol levels in Oreochromis sp. were studied in the exposure and recovery phases. In the exposure phase, the mean rate of accumulation in the tissues was in the order gill > liver > muscle for Pb exposure and muscle > liver > gill for As exposure. In the recovery phase, the order of elimination in the tissues was gill > liver > muscle for Pb and liver > gill > muscle for As. The amount of cortisol secreted by the Oreochromis sp. after Pb or As treatment was lower compared to Oreochromis sp. in the control group during the exposure phase. In the recovery phase, plasma cortisol levels in Oreochromis sp. increased in all Pb treatment groups while it continuously decreased in all As treatment groups. A fish affected by As has obvious difficulty recovering from the stress response. It was concluded that exposure to the tested concentrations of Pb and As over 20 days could be a potent endocrine disruptor, which may lead to adverse impacts on the health of the Oreochromis sp.

Identification of purebred Crocodylus siamensis for reintroduction in Vietnam.

Crocodylus siamensis, the Siamese crocodile, is a critically endangered species of freshwater crocodile previously distributed throughout much of SE Asia. Recovery plans call for reintroductions to the wild using founder individuals currently in captivity, mostly in commercial crocodile farms. On many farms C. siamensis has been intentionally hybridised with either Cuban crocodiles, C. rhombifer, or the estuarine crocodile, C. porosus, and hybrids may be difficult to distinguish morphologically. We report on the combined use of microsatellite and mtDNA genetic markers to determine the species status of potential founder individuals for reintroduction of C. siamensis. Genetic markers were used to characterise 103 captive and wild-caught individuals of C. siamensis, C. rhombifer and C. porosus in Vietnam and to distinguish purebred versus hybrid individuals. Although the microsatellite loci used had some overlap of allele sizes among species, assignment tests allowed differentiation. Four hybrids were identified, two of which had not been recognised morphologically as hybrids, and one of these was thought to be a C. siamensis suitable for reintroduction. Ten of the identified purebred C. siamensis were subsequently released into Cat Tien National Park in southern Vietnam.