[Enhanced Chromate (â ¥) Removal Characteristics and Mechanism Using Graphene Oxide Immobilized Nanoscale Zero-Valent Iron Coupled with a Weak Magnetic Field (GO-nFe0/WMF)].

A green, high-efficiency mesoporous magnetic material with strong reusability and oxidation resistance, named graphene oxide immobilized nanoscale zero-valent iron (GO-nFe0), was prepared by a co-precipitation method. The structure, appearance, surface elements, and valence of GO-nFe0 were characterized via FESEM, TEM, FTIR, BET, XRD, and XPS. The characteristics and mechanism of Cr(Ⅵ) treatment in water using a weak magnetic field (WMF) coupled with GO-nFe0 (GO-nFe0/WMF) were studied. Batch experiments established that when the load mass ratio of GO to nFe0 was 1:10 under 20 mT weak magnetic field strength, the GO-nFe0/WMF system could completely remove the 10 mg·L-1 of Cr(Ⅵ) solution in 30 min, consistent with first-order dynamics. With a decrease in initial pH value and an increase in material dosage, the removal efficiency of Cr(Ⅵ) increased significantly by enhancing the release rate of Fe2+. ClO4- had no effect on the reaction, Cl- could encourage corrosion and promote the corrosion of nFe0 to release Fe2+, CO32- restrained the reaction through an increase in initial pH of the solution, and SO42- could promote the dissolution of the nFe0 surface passivation film to accelerate the reaction process. The GO-nFe0/WMF system can maintain high activity after five reuses and 30 days of exposure to air. XRD, XPS, and 1,10-phenanthroline shielding experiments proved that its great conductivity allowed GO to provide electron transfer sites to accelerate the transfer of electrons, and nFe0 could quickly release Fe2+. WMF generated a magnetic gradient force (FΔB) that pushed the paramagnetic Fe2+ ions in the diffusion boundary layer concentrated on the two poles of GO-nFe0, where the most magnetic intensity was present, to exposed active sites on both sides. The high removal rate ability of GO-nFe0 to release Fe2+ continuously was maintained.

[Degradation Mechanism of Tetracycline Using Fe/Cu Oxides as Heterogeneous Activators of Peroxymonosulfate].

A green, highly efficient, and porous copper-ferrite heterogeneous catalyst (Fe-Cu-400) with good magnetism was synthesized via a coprecipitation method. The catalysts were characterized using XRD, BET, FESEM, and EDS. The performance of Fe-Cu-400 as a catalyst was evaluated by activating peroxymonosulfate (PMS) for degradation of tetracycline (TC) in aqueous solution and investigating the influence of several water parameters. The Fe-Cu-400/PMS system showed a greater TC degradation ability, and the degradation rate of TC was enhanced with an increase in the PMS concentration and the initial pH of the coupled Fe-Cu-400/PMS system. Anions including H2PO4-, HCO3-, and Cl- promoted TC degradation, whereas NO3- showed a low inhibitory influence. In addition, Fe-Cu-400 exhibited excellent reusability towards activating PMS for TC degradation after five runs of tests. Possible mechanisms of the activation of PMS by Fe-Cu-400 and the main reactive species were proposed based on radical identification tests and XPS analysis. Furthermore, a potential degradation pathway was proposed that included hydrolysis and sequential removal of N-methyl, hydroxyl, and amine functional groups according to the results of LC-MS and TOC detections.

[Spatiotemporal characteristics of nitrogen and phosphorus in a mountainous urban lake].

Longjing Lake in Chongqing Expo Garden is a typical representative of mountainous urban lake. Based on water quality monitoring of Longjing Lake, spatiotemporal characteristics of nitrogen and phosphorus and their relations were analyzed, combined with natural and human factors considered. The results indicated that annual average concentrations of TN and TP in overall lake were (1.42 ± 0.46) mg · L(-1) and (0.09 ± 0.03) mg · L(-1), nitrogen and phosphorus concentrations fluctuated seasonally which were lower during the flooding season than those during the dry season. Nitrogen and phosphorus concentration in main water area, open water areas and bay areas of Longjing Lake were distributed with temporal and spatial heterogeneity by different regional influencing factors. The seasonal variation of the main water area was basically consistent with overall lake. Two open water areas respectively connected the main water area with the upstream region, bay areas. TN and TP concentrations were gradually reduced along the flow direction. Upstream water quality and surrounding park functional layout impacted nitrogen and phosphorus nutrient concentrations of open water areas. Nutrient concentrations of typical bay areas were higher than those of main water area and open water areas. The mean mass fraction of PN/TN and PP/TP accounted for a large proportion (51.7% and 72.8%) during the flooding season, while NO(3-)-N/TN and SRP/TP accounted for more (42.0% and 59.4%) during the dry season. The mass fraction of ammonia nitrogen and dissolved organic nitrogen in total nitrogen were relatively stable. The annual mean of N/P ratio was 18.429 ± 7.883; the period of nitrogen limitation was 5.3% while was 21.2% for phosphorus limitation.

[Distribution characteristics, trend and control strategy of Oncomelania hupensis snails in Wuhu City from 1997 to 2012].

OBJECTIVE: To understand the emerging and re-emerging trend of Oncomelania hupensis snails in Wuhu City from 1997 to 2012, so as to provide the evidence for developing schistosomiasis control strategy. METHODS: A retrospective survey was conducted. The emerging and re-emerging snail areas were investigated in various years, water systems, settings and countries (districts) based on the historical snail survey results. RESULTS: The accumulative emerging snail area from 1996 to 2007 was 3479.42 hm2, which was mainly found in marshland areas; while the accumulative re-emerging snail area was 1648.08 hm2, which was mainly concentrated on the inland areas. The longest duration from snail re-emergence to snail elimination was 26 years, and the majority of the duration ranged from 3 to 12 years. CONCLUSION: It seems impossible to avoid snail emergence and re-emergence in Wuhu City, which is closely associated with the natural environment and the implementation of schistosomiasis control measures.

Pulse Analysis as a Possible Real-Time Biomarker Complementary to SGPT and SGOT for Monitoring Acute Hepatotoxicity.

Based on the resonance theory, the pressure wave of the arterial system could reflect the physical condition of the internal organs. Experimental evidence indicates that the physical condition of organs is related to various Fourier components of the pressure pulse. We have proved that the first harmonic of the pressure-wave spectrum is closely related to the liver. In this study, Wistar rats given massive doses of acetaminophen were examined. The amplitude of the first harmonic of the blood pressure pulse, A1, was analyzed and correlated with the blood liver function indexes that examine serum glutamate pyruvate transaminase (SGPT) and serum glutamic oxaloacetic transaminase (SGOT). When A1 was below 3650 and SGPT was above 90, the kappa value was about 0.6; the probability is greater than. 999 based on a chi-square test. When A1 was below 3650 and SGOT was above 380, the kappa value was around 0.5; the probability is greater than. 999. Our results indicate that A1 may be used as a simple, real-time biomarker that is complementary to the commonly used first-line liver indicators, SGPT and SGOT levels, for monitoring acute hepatotoxicity. It promises a noninvasive, real-time liver-function monitoring method.