Extrudates of Al-Fe pillared clay catalyst suitable for packed-bed operations are evaluated for wastewater treatment via a wet oxidation process employing hydrogen peroxide as the oxidant. The reaction was carried out in a semibatch basket reactor under rather mild conditions. Operational parameters were studied under the following conditions: temperature from 25 to 90°C, atmospheric pressure, initial phenol concentration from 100 to 2000 ppm of the liquid phase, catalyst loading from 0 to 10 g/L, and input H 2 O 2 concentration from 0.15 to 0.6 mol/L. Under these conditions, the Al-Fe pillared clay catalyst achieves a total elimination of phenol and significant total organic carbon (TOC) removal. This catalyst can be used several times without any change in its catalytic properties, and hence, it would be a promising catalyst for industrial wastewater treatment. The reaction takes place to a significant extent both in the liquid phase and on the catalyst surface. Hence, apparent kinetic models were developed by formulating the reaction rate in two kinetic expressions that separately consider the homogeneous and heterogeneous contributions. Using the second-order approach for the homogeneous reaction and the Langmuir-Hinshelwood approach for the heterogeneous reaction, the developed kinetic models describe well the removal of phenol and the formed intermediate carbon over the entire range of the variables studied.

A highly selective and sensitive fluorescent sensor for the detection of hydrazine has been developed. It can trace hydrazine changes in live cells and live fish. The sensing mechanism is well rationalized with the aid of TD-DFT calculations.

Ecological evidence suggests that niacin (nicotinamide and nicotinic acid) fortification may be involved in the increased prevalence of obesity and type 2 diabetes, both of which are associated with insulin resistance and epigenetic changes. The purpose of the present study was to investigate nicotinamide-induced metabolic changes and their relationship with possible epigenetic changes. Male rats (5 weeks old) were fed with a basal diet (control group) or diets supplemented with 1 or 4 g/kg of nicotinamide for 8 weeks. Lowdose nicotinamide exposure increased weight gain, but high-dose one did not. The nicotinamide-treated rats had higher hepatic and renal levels of 8-hydroxy-2 0 -deoxyguanosine, a marker of DNA damage, and impaired glucose tolerance and insulin sensitivity when compared with the control rats. Nicotinamide supplementation increased the plasma levels of nicotinamide, N 1 -methylnicotinamide and choline and decreased the levels of betaine, which is associated with a decrease in global hepatic DNA methylation and uracil content in DNA. Nicotinamide had gene-specific effects on the methylation of CpG sites within the promoters and the expression of hepatic genes tested that are responsible for methyl transfer reactions (nicotinamide N-methyltransferase and DNA methyltransferase 1), for homocysteine metabolism (betaine -homocysteine S-methyltransferase, methionine synthase and cystathionine b-synthase) and for oxidative defence (catalase and tumour protein p53). It is concluded that nicotinamide-induced oxidative tissue injury, insulin resistance and disturbed methyl metabolism can lead to epigenetic changes. The present study suggests that long-term high nicotinamide intake (e.g. induced by niacin fortification) may be a risk factor for methylation-and insulin resistance-related metabolic abnormalities.

The wet air oxidation kinetics of an aqueous solution of phenol was studied over extrudates of an Al-Fe pillared clay catalyst in the temperature range of 90-150 °C and air pressure range of 0.8-2.5 MPa. The variables studied included reaction temperature, air pressure, solution pH, initial phenol concentration, and catalyst loading. The obtained findings are compared with those obtained using hydrogen peroxide oxidation. A group of kinetic models considering both the power-law and Langmuir-Hinshelwood approaches was evaluated to describe the catalytic kinetics of the phenol disappearance. The nonlinear dependence of the phenol conversion rate on the catalyst concentration was taken into account via the empirical power-law function of this variable. Finally, a kinetic model was discriminated on the basis of equilibrium adsorption of phenol and dissociated oxygen on two distinct types of active sites. The rate-controlling step was assumed to be the surface reaction between adsorbed reactant species. This model was able to predict well the experimental results over the entire range of the variables studied.

No abstract

Bamboo leaves of Phyllostachys nigra (PN), Lophatherum gracile (LG), and Pleioblastus amarus (PA) are three common herbs in China. In this work, a new high performance liquid chromatography (HPLC) method for the simultaneous determination of seven compounds in bamboo leaves has been developed; and PN, LG, and PA leaves were analyzed. PN showed four times as much chlorogenic acid (CA) than the other two, and contained the most isoorientin (iso-ORI) and isovitexin (iso-VIT) as well. The PA presented the most orientin (ORI) and LG covered a majority of cynaroside (CYN). We measured the antioxidant activity by scavenging the stable 2,2-diphenyl-1-pyridinohydrazinyl (DPPH) free radicals, and found that Luteolin (inhibitory concentration (IC)50 = 0.42 µM, LUT) and CYN (IC50 = 0.43 µM) showed 2–3 times higher antioxidant activity than iso-ORI (IC50 = 0.81 µM), ORI (IC50 = 0.84 µM), and other related antioxidant standards such as trolox (IC50 = 0.97 µM) and ascorbic acid (IC50 = 0.93 µM, VC). Among extracts, PN and PA showed considerable antioxidant activity, which was related well with the contents of CA, iso-ORI, and iso-VIT (p < 0.05). This study firstly provides evidence for functional antioxidant compounds of bamboo leaves based on statistical analysis of the HPLC analysis and DPPH assay, and it lays a foundation for its further development or utilization.

No abstract

No abstract