Ozonation of trace organic compounds in different municipal and industrial wastewaters : kinetic-based prediction of removal efficiency and ozone dose requirements

For the wide application of ozonation in (industrial and municipal) wastewater treatment, prediction of trace organic compounds (TrOCs) removal and evaluation of energy requirements are essential for its design and operation. In this study, a kinetics approach, based on the correlation between the second order reaction rate constants of TrOCs with ozone and hydroxyl radicals ((OH)-O-center dot) and the ozone and (OH)-O-center dot exposure (i.e., integral (sic)O-3(sic)dt and integral [(OH)-O-center dot]dt, which are defined as the time integral concentration of O-3 and (OH)-O-center dot for a given reaction time), was validated to predict the elimination efficiency in not only municipal wastewaters but also industrial wastewaters. Two municipal wastewater treatment plant effluents from Belgium (HB-effluent) and China (QG-effluent) and two industrial wastewater treatment plant effluents respectively from a China printing and dyeing factory (PD-effluent) and a China lithium-ion battery factory (LZ-effluent) were used for this purpose. The (OH)-O-center dot scavenging rate from the major scavengers (namely alkalinity, effluent organic matter (EfOM) and NO2-) and the total (OH)-O-center dot scavenging rate of each effluent were calculated. The various water matrices and the (OH)-O-center dot scavenging rates resulted in a difference in the requirement for ozone dose and energy for the same level of TrOCs elimination. For example, for more than 90% atrazine (ATZ) abatement in HB-effluent (with a total (OH)-O-center dot scavenging rate of 1.9 x 10(5) s(-1)) the energy requirement was 12.3 x 10(-2) kWh/m(3), which was lower than 30.1 x 10(-2) kWh/m(3) for PD-effluent (with the highest total (OH)-O-center dot scavenging rate of 4.7 x 10(5) s(-1)). Even though the water characteristics of selected wastewater effluents are quite different, the results of measured and predicted TrOCs abatement efficiency demonstrate that the kinetics approach is applicability for the prediction of target TrOCs elimination by ozonation in both municipal and industrial wastewater treatment plant effluents

Geometric density of states of electronic structures for local responses: Phase information from the amplitudes of STM measurement

Electronic band structures underlie the physical properties of crystalline materials, their geometrical exploration renovates the conventional cognition and brings about novel applications. Inspired by geometry phases, we introduce a geometric amplitude named as the geometric density of states (GDOS) dictated by the differential curvature of the constant-energy contour. The GDOS determines the amplitude of the real-space Green's function making it attain the ultimate expression with transparent physics. The local responses of crystalline materials are usually formulated by the real-space Green's function, so the relevant physics should be refreshed by GDOS. As an example of local responses, we suggest using scanning tunneling microscopy (STM) to characterize the surface states of three-dimensional topological insulator under an in-plane magnetic field. The GDOS favors the straightforward simulation of STM measurement without resorting to Fourier transform of the real-space measurement, and also excavates the unexplored potential of STM measurement to extract the phase information of wavefunction through its amplitude, i.e., the spin and curvature textures. Therefore, the proposed GDOS deepens the understanding of electronic band structures and is indispensable in local responses, and it should be universal for any periodic systems.Comment: 6 pages, 2 figure

Vasoconstrictive effect of Xinmailong injection in rat aorta

Background: Cockroach has been traditionally utilized in China for the therapy of cardiovascular  disorders, such as heart failure. The present study was aimed to assess the vasoconstrictive effect of  Xinmailong Injection (XML), a bioactive composite from American cockroach.Methodology: The isometric tensions of rat aortic rings were measured after acutely treated with XML. Meanwhile, the systemic blood pressures (SBPs) were recorded and the levels of the endothelium-derived cytokines in blood samples were detected after rats were administered with XML for 3 days. Protein expression for the L-type Ca2+ channels (Cav1.2) was also determined in rat thoracic aorta.Results: XML induced vasoconstrictions in rat aortic rings with or without endothelium. In addition, the vasoconstrictions due to the extracellular Ca2+ influx and the intracellular Ca2+ release were also  elevated by XML. After treatment with XML for 3 days, the level of prostacyclin (PGI2) was markedly increased whereas the levels of nitric oxide (NO) and endothelin-1 (ET-1) were not significantly changed in rats. Furthermore, expression of the Cav1.2 protein was significantly enhanced in aorta but the SBPs of  rats were not influenced.Conclusion: XML plays an important role in regulating vascular tone. The increases of the extracellular  Ca2+ influx and the intracellular Ca2+ release may contribute to the vasoconstriction induced by XML. Our findings pave the ways to the better understandings of the therapeutic effects of XML on cardiovascular system.Key words: Xinmailong Injection; American cockroach; Vasoconstriction