A novel proton-gradient-transfer acid complexes as an efficient and reusable catalyst for fatty acid esterification

In this work, a series of novel proton-gradient-transfer acid complexes (PGTACs) were developed. Their physicochemical properties, including thermal stability, melting point, and Hammett acidity, were measured. The effects of catalyst loading, reaction temperature, and substrate expansion on the catalytic performance were systematically studied. It is found that the combination of bidentate N-heterocycle and H2SO4 (1:2 M ratio) could form simultaneously N–H covalent bond and N…H hydrogen bond, which makes the PGTACs excellent catalysts integrate the advantages of strong acids (high catalytic activity) and ionic liquids (phase separation) in the esterification reaction. Moreover, these PGTACs can be reused by convenient phase separation without obvious diminution of catalytic activity. It is concluded that these PGTACs are potential alternative candidates for esterification reaction in the process of industrial catalysis.     

Risk assessment and monitoring of dinotefuran and its metabolites for Chinese consumption of apples

Residues of dinotefuran and its metabolites, 1-methyl-3-(tetrahydro-3-furylmethyl)urea (UF) and 1-methyl-3-(tetrahydro-3-furylmethyl)guanidine (DN), in apple were investigated using a “QuEChERS” (quick, easy, cheap, effective, rugged, safe) pretreatment and liquid chromatography–tandem mass spectrometry. Limits of detection (LODs) and quantification (LOQs) of dinotefuran, UF, and DN in apples were 0.011–0.960 and 0.037–3.200 μg/kg, respectively. The average recoveries of dinotefuran, UF, and DN in apple ranged from 70.0 to 83.6% with relative standard deviations less than 13%. A formulation of 20% water-dispersible dinotefuran granules was sprayed at 1–1.5-fold the recommended dose 3–4 times on apple trees. Total terminal residues of dinotefuran in apple were less than 2 mg/kg, which is the maximum residue limit (MRL) set by Japan. When following the recommended application guidelines, dinotefuran is unlikely to present significant health concerns to the Chinese population because the risk quotient (RQ) is less than 100%. This work could provide guidance for the safe use of dinotefuran and serve as a reference for the establishment of a maximum residue limit of dinotefuran in apple in China.     

红壤上直接施用磷矿粉的增产效果和改土作用

综述了红壤上施用磷矿粉对油菜产量、土壤铝毒和土壤化学性质的影响，认为磷矿粉直接施用于酸性土壤上，除增加土壤有效磷含量从而提高作物产量外，还能提高土壤ｐＨ值，增加交换性钙含量和降低交换态铝含量，增加土壤负电荷量，是一种低投入的土壤改良剂，在有条件的地区宜予推广。     

Study on determination of iron,cobalt, nickel,copper, zinc and manganese in drinking water by solid-phase extraction and RP-HPLC with 2-(2-quinolinylazo)-5-diethylaminophenol as precolumn derivatizing reagent

A new method for the determination of iron, cobalt, nickel, copper, zinc and manganese in drinking water by the reversed-phase high-performance liquid chromatography (RP-HPLC) with 2-(2-quinolinylazo)-5-diethylaminophenol (QADEAP) as precolumn derivatizing reagent was studied in this paper. The iron, cobalt, nickel, copper, zinc, and manganese ions react with QADEAP to form color chelates in the presence of cetyl trimethylammonium bromide (CTMAB) and acetic acid-sodium acetic buffer solution medium of pH 4.0. These chelates were enriched by solid-phase extraction with a Waters Nova-Pak C18 cartridge and eluted the retained chelates from the cartridge with tetrahydrofuran (THF). The enrichment factor of 100 was achieved. Then the chelates were separated on a Waters Nova-Pak C18 column (3.9 x 150 mm, 5 microm) by gradient elution with methanol (containing 0.2% of acetic acid and 0.1% of CTMAB) and 0.05 mol L(-1) acetic acid-sodium acetic buffer solution (containing 0.1% of CTMAB) (pH 4.0) as mobile phase at a flow rate of 0.5 ml min(-1), and monitored with a photodiode array detector from 450 approximately 700 nm. The detection limits (S/N = 3) of iron, cobalt, nickel, copper, zinc and manganese are 0.8, 1.1, 0.9, 1.1, 1.5 and 2.0 ng L(-1), respectively, in the original sample. This method can be applied to determination at the microg L(-1) level of iron, cobalt, nickel, copper, zinc and manganese in drinking water with good results.     

汉江上游斜坡破坏的变异

本文从工程地质观点出发,分析汉江上游斜坡一带的天然地质条件及其斜坡破坏的基本形式和原因,从理论上探讨由于经济-工程活动而引起其在天然地质过程方面的变异及效应这一环境工程地质问题。     

Effects of organic acids on copper and cadmium desorption from contaminated soils

A study was conducted to investigate the effect of organic acids on Cd and Cu desorption from natural contaminated soils (NCS) with permanent contamination by metal smelters and from artificial contaminated soils (ACS) derived from an artificial amendment of Cd to three representative zonal soils in Central China. Results showed that the desorption of Cd in either NCS or ACS, with the increment of tartrate or citrate concentration in desorption solution, can be characterized as a valley-like curve. The presence of tartrate or citrate at a low concentration (< or =0.5 mmol/l) inhibited Cd desorption from these two types of soils, whereas the presence of organic acids at high concentrations (> or =2 mmol/l for citrate and about > or =15 mmol/l for tartrate) apparently promoted Cd desorption. The desorption curve of Cu by tartrate solution with different tartrate concentrations can also be characterized as a valley-like curve, while the desorption of Cu in the presence of citrate was directly enhanced with the increment of citrate concentration. With the enhancement of initial pH value from 2 to 8 in the presence of citrate, Cu desorption ratio decreased at the first stage, then increased, and then decreased again. A valley and a peak sequentially appeared in the Cd or Cu desorption curve with initial pH value increment. Compared with citrate, the desorption ratio of Cd or Cu from NCS or ACS was directly decreased in the presence of tartrate, with the enhancement of the pH value from 2 to 8. Cd or Cu desorption was clearly enhanced when the electrolyte concentration of KNO3 or KCl increased in the presence of 2 mmol/l tartrate. Moreover, a higher desorption ratio of Cd or Cu was shown with KCl electrolyte than with KNO3 electrolyte with the same concentration. Based on these observations, we suggest that bioavailabilities of heavy metal can be promoted with selected suitable types and concentrations of organic acid amendment and reasonable field condition.     

涝洼农区畜牧业生产现状与发展对策—以监利县为例

分析了监测县涝洼农区发展节粮型畜牧业的有利条件和存在的问题，提出了充分利用本地自然资源，发展节粮型畜牧业的对策。     

污泥颗粒化快速启动厌氧氨氧化反应器的探讨

厌氧氨氧化工艺处理成本低,被认为是有应用前景的废水脱氮技术.但是,厌氧氨氧化菌生长缓慢,厌氧氨氧化反应器启动困难.探讨了几种快速启动厌氧氨氧化反应器的方法,包括投加颗粒污泥、惰性载体、絮凝剂及多价阳离子等,并对其作用机理进行了分析.     

静态环境下阿特拉津的生物降解研究

从农药厂阿特拉津生产车间污泥中分离出菌种AT菌,进行了系列降解实验.不同温度的降解实验表明,在4～20℃的实验温度范围内,AT菌能够降解代谢污染质,并随温度的升高,降解能力增强.20℃时降解率为38.84%;AT菌在外加氮源、碳源及以阿特拉津为惟一碳源和氮源等条件时对农药污染质阿特拉津均具有降解能力,且在以阿特拉津为惟一氮源(外加碳源)条件下的降解效果最好,此时的降解率为30.39%.