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• We used theoretical methods to discuss reactions of 4-chloroguaiacol with OH onto catalyst. • Carbon-doped BN nanosheet has outstanding adsorption and catalytic performance. • Carbon-doped BN nanosheet may be a promising photocatalyst for organic removal. • The transformation products of 4-chloroguaiacol are still harmful to aquatic environment. Although carbon-doped BN nanosheet (BCN) has been successfully synthesized and used, it has not been reported as a photocatalyst for the degradation of organic pollutants. In this study, 4-chloroguaiacol (4-CG) was selected as a representative substance to investigate the potential of utilizing BCN as photocatalyst for organic removal by use of computational simulation. The adsorption mechanisms, degradation mechanisms, and kinetics of 4-CG with the presence of different catalysts were determined. The adsorption energy of 4-CG on BCN was 10.71 kcal mol−1, and the Δ G ≠s of initial reactions of 4-CG with OH were also reduced onto the BCN substrate. The band gap of BCN was 1.54 eV. Our computations depicted that the doping of aromatic carbon into BN narrows bandgap, and retains well catalytic performance and adsorption properties. Therefore, BCN nanosheet is a promising photocatalyst for organic pollutants removal. Possible degradation pathways of 4-CG and aquatic toxicity assessment during degradation were also carried out. More toxic products would be formed and the transformation products were still harmful to three trophic levels of aquatic organisms (fish, green algae, and daphnia). [ABSTRACT FROM AUTHOR]

Abstract: The tridimensional morphology and etching kinetics of the etch pit on the C-{0001} plane of sapphire crystal (α-Al2O3) in molten KOH were studied experimentally. It was shown that the etch pit takes on tridimensional morphologies with triangular symmetry same as the symmetric property of the sapphire crystal. Pits like centric and eccentric triangular pyramid as well as hexagonal pyramid were observed, but the latter is less in density. In-depth analyses show the side walls of the etch pits belong to the {1 0 } family, and the triangular pit contains edges full composed by Al3+ ions on the etching surface so it is more stable than the hexagonal pit since its edges on the etching surface contains Al2+ ions. The etch pits developed in a manner of kinematic wave by the step moving with constant speed, which is controlled by the chemical reaction with activation energy of 96.6kJ/mol between Al2O3 and KOH. [Copyright &y& Elsevier]

Canine bufavirus (CBuV) was first discovered in puppies in Italy in 2016, and subsequent studies have reported its possible relationship with acute enteritis. Currently, there is no specific and quantitative detection method for CBuV. This study examined the conserved NS1 gene and used a pair of specific primers to establish a direct SYBR Green I-based real-time quantitative polymerase chain reaction (qPCR) method for the detection and quantification of CBuV. In the sensitivity experiment, the detection limit of SYBR Green I-based real-time qPCR was 4.676 × 101 copies/μL and that of conventional PCR (cPCR) was 4.676 × 103 copies/μL. Furthermore, the qPCR method did not detect other viruses in dogs, indicating good specificity. The intra-assay coefficient of variation was 0.07–0.55% and the inter-assay coefficient of variation was 0.03–0.11%, indicating good repeatability. In clinical sample testing, the detection rate of qPCR was 5.0% (6/120), higher than that of cPCR (2.5%, 3/120). In addition, the samples that tested CBuV-positive in this experiment were all from dogs with acute enteritis. In summary, the SYBR Green I-based qPCR method established in this study has good sensitivity, specificity, and reproducibility for clinical sample detection and can also assist in future research on CBuV. • The study established a SYBR Green I-based real-time RT-PCR assay for Canine Bufavirus detection. • The assay is highly sensitive, specific, and reproducible. • It provides a tool for clinical diagnostics of Canine Bufavirus infection. [ABSTRACT FROM AUTHOR]

Indirect oxidation induced by reactive free radicals, such as hydroxyl radical (HO), sulfate radical (SO 4 -) and carbonate radical (CO 3 -), plays an important or even crucial role in the degradation of micropollutants. Thus, the coadjutant degradation of phenacetin (PNT) by HO , SO 4 - and CO 3 -, as well as the synergistic effect of O 2 on HO and HO 2 were studied through mechanism, kinetics and toxicity evaluation. The results showed that the degradation of PNT was mainly caused by radical adduct formation (RAF) reaction (69% for Г , the same as below) and H atom transfer (HAT) reaction (31%) of HO. For the two inorganic anionic radicals, SO 4 - initiated PNT degradation by sequential radical addition-elimination (SRAE; 55%), HAT (28%) and single electron transfer (SET; 17%) reactions, while only by HAT reaction for CO 3 -. The total initial reaction rate constants of PNT by three radicals were in the order: SO 4 - > HO > CO 3 -. The kinetics of PNT degradation simulated by Kintecus program showed that UV/persulfate could degrade target compound more effectively than UV/H 2 O 2 in ultrapure water. In the subsequent reaction of PNT with O 2 , HO and HO 2 , the formation of mono/di/tri-hydroxyl substitutions and unsaturated aldehydes/ketones/alcohols were confirmed. The results of toxicity assessment showed that the acute and chronic toxicity of most products to fish increased and to daphnia decreased, and acute toxicity to green algae decreased while chronic toxicity increased. Image 1 • The contribution of HO. , SO 4 - and CO 3 −to the degradation of PNT was investigated. • The kinetics of PNT degradation by UV/persulfate and UV/H 2 O 2 were simulated. • Toxicity of PNT degradation products to fish, daphnid and green algae was assessed. [ABSTRACT FROM AUTHOR]

The pharmaceutical and personal care products (PPCPs) in aquatic environment have aroused more interest recently. Many of them are hard to degrade by the typical biological treatments. Diclofenac (DCF), as a significant anti-inflammatory drug, is a typical PPCP and widely existed in water environment. It is reported that DCF has adverse effects on aquatic organisms. This work aims to investigate the mechanism, kinetics and ecotoxicity assessment of DCF transformation initiated by O 3 in aqueous solution, and provide a solution to the degradation of DCF. The O 3 -initiated oxidative degradations of DCF were performed by quantum chemical calculations, including thirteen primary reaction pathways and subsequent reactions of the Criegee intermediates with H 2 O, NO and O 3. Based on the thermodynamic data, the kinetic parameters were calculated by the transition state theory (TST). The total reaction rate constant of DCF initiated by O 3 is 2.57 × 103 M−1 s−1 at 298 K and 1 atm. The results show that the reaction rate constants have a good correlation with temperature. The acute and chronic toxicities of DCF and its degradation products were evaluated at three different trophic levels by the ECOSAR program. Most products are converted into less toxic or harmless products. Oxalaldehyde (P3) and N-(2,6-dichlorophenyl)-2-oxoacetamide (P6) are still harmful to the three aquatic organisms, which should be paid more attention in the future. • Firstly studied O 3 -initiated reactions of DCF in aqueous solution theoretically. • Thirteen addition pathways are included in the primary ozonation. • The total rate constant of ozonation for DCF was calculated. • By ecotoxicity assessment calculations, major products are proved to be harmless. [ABSTRACT FROM AUTHOR]

Prosulfocarb (PSC) is a thiocarbamate herbicide mainly used in winter cereals and a relevant aerosol precursor under OH radicals (OH) photooxidation conditions. We investigated the environmental risks, mechanisms, kinetics and products for the PSC with OH by employing theoretical chemical calculations. Two reaction types of H-abstraction and OH-addition reactions were taken into account. Whether in the atmosphere or aqueous particles, the most favorable pathway was the H-abstraction in the N-alkyl groups close to nitrogen atom. Subsequent reactions of primary intermediates were considered at different conditions. The total rate constants were determined as 2.62 × 10-10 cm3 molecule-1 s-1 and 4.96 × 10–11 cm3 molecule-1 s-1 at 298 K in atmosphere and aqueous particles, respectively. In natural water with the OH concentration of 10–15-10-18 mol l-1, the half-lives (t1/2) of PSC in the OH-initiated reactions were calculated as t 1/2 = 2.40 × 104–2.40 × 107 s. With regard to the influence on human health and the ecosystem, oxidized products of PSC were estimated to be mutagenicity negative and had no obvious bioaccumulation potential. The aquatic toxicity of PSC and its degradation products was evaluated and the assessment results showed that the degradation of PSC was a toxicity-reduced process but they were still at toxic and harmful levels. Image 1 • Degradation mechanisms of PSC with OH radicals were investigated in atmosphere and aqueous environment. • Rate constants and branching ratios of initial reactions were calculated. • The transformation of PSC initiated by OH radical was a toxicity-reduced process. • The mutagenicity and bioaccumulation effect of PSC and its degradation products were evaluated. [ABSTRACT FROM AUTHOR]

Metal-free photocatalysts for high efficient photocatalytic degradation of pollutants have attracted growing concern in recent years. Herein, relying on density functional theory (DFT) calculations, boron and phosphorus doped C 2 N layers were explored for the potential of utilization as photocatalysts for 4, 5-dichloroguaiacol (4, 5-DCG) removal. Our computations revealed that the adsorption energy of 4, 5-DCG on B@N-doped C 2 N layers were 26.56 kcal mol−1, and the Δ G ≠ of initial reactions of 4, 5-DCG with OH were also reduced onto the B@N-doped C 2 N substrates. The band gap of B@N-doped C 2 N was 2.27 eV. The obtained results showed that the doping of boron atom into C 2 N layer narrows bandgap, and retains well catalytic performance and adsorption properties. Hence, B@N-doped C 2 N layer is a promising photocatalyst for organic pollutants removal. Possible degradation pathways of 4, 5-DCG and aquatic toxicity assessment during degradation were also carried out. Products with higher toxicity would be formed and the transformation products were still toxic to three nutrient levels of aquatic organisms (green algae, fish, and daphnia). • B and P doped monolayer C 2 N were determined by theoretical study. • B@N-doped C2N layer is a promising photocatalyst for organic pollutants removal. • The adsorption capacity of boron-doped C 2 N for pollutants was enhanced. • The transformation products of 4, 5-dichloroguaiacol are still toxic. [ABSTRACT FROM AUTHOR]

Abstract: We report a general and versatile method for controlled synthesis of anisotropic gold nanostructures through the reduction of HAuCl4 by aniline in aqueous solution, without the need for an additional stabilizer or capping agent. In this approach, the reduction kinetics of AuCl− 4 can be altered by simply adjusting the initial pH and temperature, inducing the formation of a wide variety of anisotropic nanostructures such as dispersed or multilayered plates, wires with networked or paramecium-like structures, and ginger-shaped particles. AFM, TEM, XRD, EDX, FTIR, and UV–vis–NIR measurements were used to characterize the resulting gold nanostructures. Investigation reveals that in situ formed polyaniline serves effectively as a capping agent to direct the shape of gold nanostructures during the slow growth process. These as-synthesized gold nanostructures exhibit strongly shape-dependent optical properties. This facile approach may be extended to the synthesis of some other anisotropic metal nanostructures such as platinum or palladium. [Copyright &y& Elsevier]