磷酸活化纺织固体废弃物制备活性炭及表征

以纺织固体废弃物为原料,磷酸为活化剂,采用一步活化法制备活性炭。采用正交实验研究了磷酸浓度、浸渍时间、活化温度和活化时间对活性炭吸附性能的影响,得到最佳工艺条件,借助氮吸附等温线、BET方程、BJH方程、SEM和FTIR分析了活性炭孔结构和表面化学性质。结果表明:最佳工艺条件为磷酸浓度40%(质量分数)、浸渍时间24h、活化温度500℃、活化时间30min。最佳条件下活性炭碘值为967mg/g,亚甲基蓝值为112mL/g,BET比表面积为1107.51m2/g,总孔容积为1.239cm3/g,中孔容积为1.024cm3/g,中孔占82.65%。活性炭表面具有羟基、羰基、内酯基和多种含磷官能团。     

异养硝化-好氧反硝化菌WXZ-8的脱氮产物N_2O和N_2研究

研究了异养硝化-好氧反硝化菌WXZ-8(Bacillus cereus)的异养硝化性能,并采用GC-ECD(Gas Chromatography-Electron Capture Detector)、GC-TCD(Gas Chromatography-Thermal Conductivity Detector)方法分别测定了脱氮过程中的气体产物N2O和N2。为了改进密封反应的溶氧条件,采用纯氧密封摇瓶培养和空气密封摇瓶培养两个对照条件下进行培养。结果表明:(1)空气密封瓶实验条件下,WXZ-8产生的N2O为0.00945mg,N2为9.5005mg,分别占从水体中脱除的氮的0.047%和47.09%,另外,同化合成的氮含量占48.74%;(2)纯氧密封瓶实验条件下,WXZ-8产生的N2O为0.00463mg,N2为9.686mg,分别占从水体中脱除的氮的0.024%与49.57%,同样,同化合成的氮含量占49.23%。两组对照实验表明,WXZ-8菌是一株高效、产生低水平量N2O的性能良好的异养硝化-好氧反硝化菌,且纯氧培养条件更有利于控制N2O的逸出。     

粉煤灰储能复合材料的实验研究

通过吸附、熔融浸滞将粉煤灰、月桂酸复合制备得到复合相变储能材料。通过DTA/TG、SEM测试分析,相变储能材料的相变峰值温度为46.01℃,且在44.0℃～55.0℃范围内有一个较大的吸热峰,可实现相变吸放热,且热稳定性好,粉煤灰基本不影响其热性能。微相结构显示粉煤灰能有效吸入大量的月桂酸,具有较好的吸附结合能力。     

Combined fluorescence and electrochemical investigation on the binding interaction between organic acid and human serum albumin

Human serum albumin (HSA) is a plasma protein responsible for the binding and transport of fatty acids and a variety of exogenous chemicals such as drugs and environmental pollutants. Such binding plays a crucial role in determining the ADME (absorption, distribution, metabolism, and excretion) and bioavailability of the pollutants. We report investigation on the binding interaction between HSA and acetic acid (C2), octanoic acid (C8) and dodecanoic acid (C12) by the combination of site-specific fluorescent probe, tryptophan intrinsic fluorescence and tyrosine electrochemistry. Two fluorescent probes, dansylamide and dansyl-L-proline, were employed in the displacement measurement to study fatty acid interaction with the two drug-binding sites on HSA. Intrinsic fluorescence of tryptophan in HSA was monitored upon addition of the fatty acids into HSA. Electrocatalyzed response of the tyrosine residues in HSA by a redox mediator was used to investigate the binding interaction. Qualitatively, observations made by the three approaches are very similar. HSA did not show any change in either fluorescence or electrochemistry after mixing with C2, suggesting there is no significant interaction with the short-chain fatty acid. For C8, the measured signal dropped in a single-exponential fashion, indicative of independent and non-cooperative binding. The calculated association constant and binding ratio is 3.1×106 L/mol and 1 with drug binding Site I, 1.1×107 L/mol and 1 with Site II, and 7.0×104 L/mol and 4 with the tryptophan site. The measurement with C12 displayed multiple phases of fluorescence change, suggesting cooperativity and allosteric effect of C12 binding. These results correlate well with those obtained by the established methods, and validate the new approach as a viable tool to study the interactions of environmental pollutants with biological molecules.     

硝酸-高氯酸消解——原子荧光法测定茶叶中的硒

建立硝酸-高氯酸消解-原子荧光法测定茶叶中的硒的方法,硒浓度在0．00～40．00μg／L范围内与荧光强度呈线性关系,线性方程为y=31．2647,线性相关系数r=0．9996。样品6次定结果的相对标准偏差为3．9％,加标回收率为90．8％-95．2％。环境标准物质测定结果与标准值相吻合。     

Bioaccumulation of cadmium bound to humic acid by the bivalve Meretrix meretirx Linnaeus from solute and particulate pathways

Humic acid is an important pool of heavy metals in sediments.Generally,the presence of refractory humic matter in aquatic systems would decrease the bioavailability of Cd and hence control the bioaccumulation of Cd in benthic animals.In the present work,we applied a suspending system to determine the relative importance of particulate and dissolved fractions of humic acid as Cd sources for the bivalve Meretrix meretrix and to investigate the difference of bioaccumulation characteristics of Cd adsorbed on di...     

Selective removal of 2,4-dichlorophenoxyacetic acid from water by molecularly-imprinted amino-functionalized silica gel sorbent

A molecularly-imprinted amino-functionalized sorbent for selective removal of 2,4-dichlorophenoxyacetic acid(2,4-D) was prepared by a surface imprinting technique in combination with a sol-gel process.The 2,4-D-imprinted amino-functionalized silica sorbent was characterized by FT-IR,nitrogen adsorption and static adsorption experiments.The selectivity of the sorbent was investigated by a batch competitive binding experiment using an aqueous 2,4-D and 2,4-dichlorophenol(2,4-DCP) mixture or using an aqueous 2...     

纳米催化剂Pd/SnO_2的制备及催化还原硝酸盐反应的调控

采用热分解法制备了SnO2载体,并用浸渍法制备了Pd/SnO2催化剂.同时,采用X射线衍射仪(XRD)、透射电镜(TEM)、扫描电镜(SEM)及BET比表面积仪等对所制载体和催化剂材料进行了分析表征.结果表明,热分解法和浸渍法都能够获得纳米材料,SnO2及Pd/SnO2的粒径均在9～10nm左右,比表面积分别达到144.99m·2g-1和147.36m·2g-1.在以甲酸为还原剂的Pd/SnO2催化还原硝酸盐体系中,在Pd与SnO2负载比为2%～7%,反应温度为20～50℃和甲酸投加量4.0～24.0mmol·L-1的条件下,催化活性为0.70～9.48mg·min-·1g-1,且催化活性随着负载比、温度和甲酸投加量的增大而增大,随着pH的升高先升后降,最佳pH为3.反应温度升高及pH降低都能够提高Pd/SnO2的选择性.甲酸-Pd/SnO2催化还原硝酸盐体系中还原反应的调控策略为:反应温度宜控制在40～50℃内,这样可同时获得较高的催化活性和选择性,温度过高对催化活性和选择性影响很小,温度过低则会同时降低催化活性和选择性;控制pH为3时,可以获得最大的催化活性及较好的选择性,pH升高会降低Pd/SnO2的催化活性和选择性,pH降低会导致催化活性迅速降低,但对选择性影响不大;甲酸与硝酸盐的物质的量比宜大于4:1,此时可以有效地抑制pH的上升,同时获得较高的催化活性和选择性,甲酸与硝酸盐的物质的量比小于4:1时,会同时降低Pd/SnO2的催化活性和选择性.     

Degradation of acid fuchsine by a modified electro-Fenton system with magnetic stirring as oxygen supplying

The current modified electro-Fenton system was designed to develop a more convenient and e cient undivided system for practical wastewater treatment. The system adopted a cathode portion that employed magnetic stirring instead of common oxygen gas di usion or gas sparging to supply oxygen gas for the electrolyte solution. Key factors influencing the cathode fabrication and activity were investigated. The degradation of acid fuchsine with a self-made graphite-polytetrafluorethylene cathode was studied using a spectrophotometer. It was found that the cathode generated hydrogen peroxide with high current e ciency and the hydrogen peroxide yield of the cathode did not decay after 10 times reuse. With the Pt anode at a ferrous ion concentration of 0.5 mmol/L, a pH of 3, and using magnetic stirring, dye decolorization could be rapidly accomplished but the destruction of benzene rings and intermediates was fairly di cult. With a Fe anode, dye degradation was more complete.     

Characteristics of contaminants in water and sediment of a constructed wetland treating piggery wastewater e uent

Constructed wetland (CW) is the preferred means of controlling water quality because of its natural treatment mechanisms and function as a secondary or tertiary treatment unit. CW is increasingly applied in Korea for secondary e uent of livestock wastewater treatment. This study was conducted to recognize the characteristics of contaminants in the accumulated sediment at the bottom soil layer and to reduce the phosphorus release from sediments of the free water surface CW for the treatment of secondary piggery wastewater e uent from a livestock wastewater treatment facility. The results revealed that the dominant phosphorus existence types at near the inlet of the CW were non-apatite phosphorus (59%) and residual phosphorus (32%) suggesting that most of the particles of the influent are made up of inorganic materials and dead cells. Sediment accumulation is important when determining the long-term maintenance requirements over the lifetime of CW. Continuous monitoring will be performed for a further assessment of the CW system and design.