[Characteristics of Nitrogen and Phosphorus Losses and Runoff in a Typical Purple Soil Watershed in the Three Gorges Reservoir Area].

To understand the runoff pollution characteristics of the typical purple soil small watershed in the Three Gorges Reservoir (TGR), the rainfall-runoff duration under typical land use types of the Xinzheng watershed and the nitrogen (N) and phosphorus (P) concentrations in the outlet runoff of each catchment were dynamically monitored, and the loss rule of N and P in the rainfall runoff in the small watershed in the TGR was investigated and analyzed. The results showed that the losses of runoff N and P were 13.69 kg·(hm2·a)-1 and 1.50 kg·(hm2·a)-1, respectively. N and P in agricultural fertilizers and rainfall scouring were the main causes of runoff pollution in the Xinzheng watershed. The average concentration of total nitrogen (TN) and total phosphorus (TP) reached 10.05 mg·L-1 and 1.10 mg·L-1, far exceeding the occurrence standard of eutrophication, which should be cause for concern. The nitrate nitrogen (NN) and particulate phosphorus (PP) in the rainfall were 69.47 kg and 6.83 kg on August 15, 2010, accounting for 53.91% and 53.78% of TN and TP, respectively. The NN and AN were 6.68 kg and 5.61 kg, respectively, in the rainfall on August 26, 2010, accounting for 37.74% and 31.69% of TN and PP was 1.36 kg, accounting for 57.63% of TP, indicating that nitrogen loss was mainly through the soluble state, while phosphorus migration was dominated by particulate matter. Heavy rainfall in the Xinzheng watershed had a significant impact on the loss of nitrogen and phosphorus. This was related to the properties of purple soil, such as thin soil layer, frequent cultivation and relatively loose soil.

Spatiotemporal distribution and risk assessment of organotins in the surface water of the Three Gorges Reservoir Region, China.

The water quality security of the Three Gorges Reservoir during different operating periods has been a subject of recent concern. This study is the first to report the spatiotemporal variability of organotins (OTs) in surface water under dynamic water level conditions in the Three Gorges Reservoir Region (TGRR). TGRR surface water was collected during three monitoring campaigns to analyze butyltins (BTs) and phenyltins (PTs) using a gas chromatography-mass spectrometry system. Our results showed that TGRR surface water was polluted by BTs and PTs, with mono-OTs being the dominant species. A wide range of BTs and PTs concentrations was observed across the study area, but tributyltin (TBT) displayed extensive spatial distribution, and the highest concentrations consistently occurred in the downstream region of the TGRR study area, with a maximum of 393.35 ng Sn/L in Zigui (S27). The total OTs contamination level decreased over time. The diphenyltin concentration exhibited significant seasonal variation, while other OTs showed seasonal changes only during two monitoring campaigns, with the exception of dibutyltin. An ecological risk assessment indicated that both TBT and triphenyltin posed risks to aquatic organisms in TGRR surface water. We urgently recommend continuous monitoring and further measures to prevent and control OTs pollution in the TGRR.

Identification and analysis of Triphenyltin chloride with surface enhanced Raman scattering spectroscopy.

Triphenyltin (TPhT) is a kind of organotin compounds which have been used ubiquitously as herbicide, pesticide, and fungicide in agriculture. The present study provides the possibility to detect and monitor TPhT with normal Raman spectroscopy and surface enhanced Raman scattering (SERS) spectroscopy. Firstly, the complete vibrational Raman spectra characterization of TPhT along with the IR spectroscopy were reported for the first time. Then a wide range of pH values were carried out to choose the optimal pH value in TPhT detection by using Raman spectroscopy. Afterwards, Raman spectra of various TPhT solutions were collected and analyzed. The results indicate that the optimal pH value for TPhT detection by Raman spectroscopy is 5.5, and with silver nanoparticles (Ag NPs) as SERS substrate is an effective technique for trace TPhT detection with an enhancement by 5 orders of magnitude and the detection limit can be as low as 0.6 ng/L within less than 30 s. Finally, in this study, the residual of TPhT on apple peel was investigated by casting different concentrations of TPhT on apple peel under the current optimized condition. The result demonstrates that TPhT could be detected based on its SESR spectra at 6.25 ng/cm(2) in standard solutions.

[Analysis of Endocrine Disruptor: Triphenyltin Chloride with Raman Spectroscopy].

Triphenyltin Chloride (TPhT) is one of the only two kinds of metal compounds known in the endocrine disruptors. TPhT is widely used in industry, agriculture and transportation fields, which can cause great impact on soil, marine and inland freshwater environment. This experiment collects the Raman signal of TPhT standard powders by applying laser confocal Raman spectroscopy to explore the feasibility of the method and to acquire optimized parameters. In this paper, we combined the application of laser confocal Raman spectroscopy with TPhT physical property. Due to different functional groups of TPhT molecules shows different vibration modes, the Raman spectra was divided into three wavenumber areas(1 500~3 200, 900~1 500 and 100~900 cm-1) to attribute and analyze their assignments of the Raman peaks, obtaining the characteristics of TPhT vibration modes and the corresponding characteristic peaks. Finally, a standard Raman spectra library was established with the spectral range between 100~3 200 cm-1. The results showed that the Raman spectra with high signal-to-noise ratio can be obtained in a short time when the laser power options decayed to 0.5% of the original power (500 mW) after 10s exposure and 2 times integration. Strong Raman signals observed in the Raman spectroscopy at 212, 332, 657, 997 and 1 577 cm-1 could be used as the characteristic peaks of TPhT in Raman detection. Otherwise, the co-occurrence of the Raman peaks at 657 and 997 cm-1 can be considered as the presence of TPhT in complex environmental samples. Experimental results are given to identify the presence of TPhT. The results would be used to identify the presence of TPhT residual in real environmental samples, which provide a theoretical basis and data base on Raman spectroscopy.

Enhanced nitrogen and phosphorus removal by an advanced simultaneous sludge reduction, inorganic solids separation, phosphorus recovery, and enhanced nutrient removal wastewater treatment process.

An advanced wastewater treatment process (SIPER) was developed to simultaneously decrease sludge production, prevent the accumulation of inorganic solids, recover phosphorus, and enhance nutrient removal. The feasibility of simultaneous enhanced nutrient removal along with sludge reduction as well as the potential for enhanced nutrient removal via this process were further evaluated. The results showed that the denitrification potential of the supernatant of alkaline-treated sludge was higher than that of the influent. The system COD and VFA were increased by 23.0% and 68.2%, respectively, after the return of alkaline-treated sludge as an internal C-source, and the internal C-source contributed 24.1% of the total C-source. A total of 74.5% of phosphorus from wastewater was recovered as a usable chemical crystalline product. The nitrogen and phosphorus removal were improved by 19.6% and 23.6%, respectively, after incorporation of the side-stream system. Sludge minimization and excellent nutrient removal were successfully coupled in the SIPER process.

Direct sensing of fluoride in aqueous solutions using a boronic acid based sensor.

Binding of the fluoride ion triggers aggregation of a pyreneboronic acid-catechol ensemble in acidic aqueous solutions, giving rise to intense excimer emission, allowing for sensitive fluoride ion sensing at ppm levels, with an apparent fluoride binding constant higher than 10(3) M(-1) which is unprecedented for boronic acid sensors in water.

Glucose sensing via aggregation and the use of "knock-out" binding to improve selectivity.

Aggregates of an amphiphilic monoboronic acid bearing a hydrophobic pyrene fluorophore were employed for highly modulating, sensitive, and selective ratiometric fluorescent sensing of glucose in aqueous solution. The selectivity for glucose was improved by "knock-out" binding of fructose by phenylboronic acid.

Ordered honeycomb microporous films from self-assembly of alkylated guanosine derivatives.

Ordered honeycomb microporous films have previously been fabricated from polymeric macromolecules. We report here the successful fabrication of them from the supramolecular self-assembly of small molecules, alkylated guanosine derivatives. The ribbonlike self-assembly of the guanosines in CHCl3 is found to be the intrinsic structure that forms regular microporous structure via Bénard-Maragoni convection. Factors such as substrate, solvents, guanosine concentration, and solvent evaporation temperature are revealed to be able to control the size of the formed micropores, which in turn allows for the wettability of the honeycomb film surface to be modulated. These microporous materials exhibit excellent ability of loading organic dyes that eventually leads to the fabrication of luminescent honeycomb films. As structures of both the small molecules that can assemble and their self-assemblies can be varied and controlled, extended applications of this supramolecular method are expected to lead to microporous films of interesting functions.