一种新型絮凝剂的制备工艺及混凝效能研究

以Al2O3和CaCO3为原料用焙烧酸溶制备工艺合成新型高效的聚合氯化铝钙,研究结果表明,提高焙烧温度,原料配比为(Al2O3)70%,酸溶时间为3h,酸用量为(20g原料)70mL时有利于新型絮凝剂制备合成反应。并以本钢转炉煤气洗涤废水为处理对象研究混凝效能。结果表明,新工艺制备的聚合氯化铝钙混凝效能优于工业聚铝。     

新工艺制备聚合氯化铝絮凝剂的实验研究

以Al2O3和CaO为原料用焙烧酸溶制备工艺合成新型高效的聚合氯化铝。研究结果表明,提高焙烧温度时有利于新型絮凝剂制备合成反应,最佳原料配比为(Al2O3)60%,最佳酸溶时间为3h。。     

Canopy interception of atmospheric chloride ion during precipitation processes in the subalpine Picea asperata plantation in the upper reaches of the Yangtze River北大核心CSCD

Increasing concentrations of chloride ions (Cl-) in the atmosphere is one of the most important global environmental factors influencing processes in terrestrial ecosystems. To understand the roles played by plantations in intercepting atmospheric Cl- in mountainous regions, a one-year field observation of precipitation and throughfall was conducted in a subalpine artificial Picea asperata plantation in western Sichuan and the dynamics of Cl- concentrations in rainfall, snowfall, and throughfall, and canopy interception on atmospheric Cl- were investigated from August 2015 to July 2016. During the observational year, 27 rainfalls and 6 snowfalls were observed and sampled. The average concentration of Cl- in the precipitation was 1.33 mg/L and the average concentrations of Cl- in rainfall and snowfall were 1.41 mg/L and 0.98 mg/L, respectively. Correspondingly, the total input of Cl- by the precipitation processes was 7.56 kg/hm2, which included 6.31 kg/ hm2 by rainfall and the remainder by snowfall. In one entire year, the total canopy interception of Cl- was 2.61 kg/hm2 and the average interception rate was 38.08%. During the rainy season, the canopy interception of Cl- was 2.20 kg/hm2 and the average rate was 38.90%, whereas during the snow season, the canopy interception of Cl- was 0.41 kg/hm2 and the average rate was 34.39%. The maximum and minimum interception rates occurred in August and September, respectively. Significantly negative correlation was found between the interception rate of Cl- and precipitation. In summary, the P. asperata plantation in the subalpine forest region of western Sichuan exerts an important role in intercepting atmospheric Cl-, which is of great significance for maintaining and improving the environment of the water conservation region in the upper reaches of the Yangtze River. Furthermore, changes in the precipitation pattern caused by global changes might affect the role of the artificial forest canopy interception on atmospheric Cl-. © 2018 Science Press. All rights reserved.     

Characterization of electrode fouling during electrochemical oxidation of phenolic pollutant

• Electrode fouling is characterized by non-destructive characterization. • Electrode fouling is highly dependent on electrochemical process. • Active chlorine can prevent the formation of polymeric fouling film. Electrode fouling is a problem that commonly occurs during electro-oxidation water purification. This study focused on identifying the fouling behavior of Pt electrode associated with the formation of polymeric layer during electro-oxidation of phenol. The in situ electrochemical measurements and non-destructive observation of the electrode morphology were reported. The results demonstrated that the electrode fouling was highly dependent on thermodynamic process of electrode that was controlled by anode potential. At anode potential lower than 1.0 V vs SHE, the direct electro-oxidation caused the electrode fouling by the formation of polymeric film. The fouling layer decreased the electrochemically active surface area from 8.38 cm² to 1.57 cm², indicated by the formation of polymeric film with thickness of 2.3 mm, increase in mass growing at a rate of 3.26 μg/cm²/min. The degree to which the anode was fouled was independent of anion in the electrolyte. In comparison, at anode potential higher than 2.7 V vs SHE, the anions (e.g., chloride) could exert a major influence to the behavior of electrode fouling. The presence of chloride was shown to mitigate the fouling of electrode significantly through preventing the formation of polymeric film by active chlorine (e.g., Cl• and Cl₂) produced from anodic oxidation of chloride. Since chloride is the most abundant anionic species existing in both natural and engineered water system, this study not only offers a deep insight into the mechanism of electrode fouling, but also suggests strategies for anti-fouling in the presence of chloride in electro-oxidation process.     

TTC-脱氢酶还原法测定铜绿微囊藻活性

利用氯化三苯基四氮唑(TTC)-脱氢酶还原法定量地测定了铜绿微囊藻细胞的活性,并对影响活性测定的因素进行了分析与研究.结果显示,TTC浓度大于0.6%时会抑制酶活性,最适TTC浓度为0.2%;脱氢酶还原反应在Tris-HCI缓冲液中能正常进行,而在磷酸盐缓冲液中受到抑制,最适pH值为7.5～8.0;培养时间和培养温度对TTC脱氧酶还原反应的影响较大,最适培养时间为8～16h,最适培养温度为30～35℃;反应不需加入非离子去垢剂,吐温20和曲拉通X-100对脱氢酶反应会产生较强抑制作用.TTC还原所生成的三苯基甲 (TPF)可采用50%乙醇提取.研究显示TTC脱氢酶还原法可以很好地进行藻细胞活性定量化测定.