Contribution of black carbon to nonlinearity of sorption and desorption of acetochlor on sediment

In order to investigate the contribution of various black carbon (BC) contents to nonlinearity of sorption and desorption isotherms for acetochlor on sediment, equilibrium sorption and desorption isotherms were determined to measure sorption and desorption of acetochlor in sediment amended with various amounts of BC. In this paper, two types of BC referred to as BC400 and BC500 were prepared at 400°C and 500°C, respectively. Higher preparation temperature facilitated the formation of micropores on BC to enhance its sorption capacity. Increase of the BC content obviously increased the sorption amount and reduced the desorption amount for acetochlor. When the BC500 contents in total organic carbon (TOC) increased from 0 to 60%, Freundlich sorption coefficient (K _f) increased from 4.07 to 35.74, and desorption hysteresis became gradually obvious.When the content of BC in TOC was lower than 23%, the sorption isotherm had a significant linear correlation (p = 50.05). In case of desorption, a significant nonlinear change could be observed when the content of BC was up to 13%. Increase of BC content in the sediment would result in shifting the sorption-desorption isotherms from linearity to nonlinearity, which indicated that contribution of BC to nonlinear adsorption fraction became gradually remarkable.     

桔皮吸附水中残杀威的研究

为研究改性桔皮吸附水中残杀威的吸附性能和吸附机理,实验考察了不同条件(提取液pH、残杀威浓度、吸附剂用量、吸附时间和盐离子浓度)对残杀威吸附效果的影响。研究发现,由于改性剂破坏了桔皮表面活性基团,从而降低了桔皮吸附剂对残杀威的吸附效果。实验结果还表明,当溶液pH在2~4时残杀威更利于被吸附剂吸附;在25℃的条件下,吸附剂对残杀威的吸附在40 min左右达到平衡;当残杀威浓度为61.46 mg/L时,100 mL残杀威溶液中吸附剂的最佳投加量为0.2 g;低盐离子浓度有利于对残杀威的吸附。桔皮吸附剂对残杀威的吸附规律可用Langmuir吸附等温式描述。     

^15N isotope fractionation in an aquatic food chain： Bellamya aeruginosa （Reeve） as an algal control agent

15N isotope tracer techniques and ecological modeling were adopted to investigate the fractionation of nitrogen,its uptake and transformation in algae and snail(Bellamya aeruginosa Reeve).Different algal species were found to differ in their uptake of nitrogen isotopes.Microcystis aeruginisa Ktz.demonstrated the greatest 15N accumulation capacity,with the natural variation in isotopic ratio(δ 15N) and the isotope fractionation factor(ε,‰) being the highest among the species investigated.The transformation and utilization of 15N by snails differed depending on the specific algae consumed(highest for Chlorella pyrenoidosa Chick.,lowest for M.aeruginisa).When snails was seeded in the experimental pond,the algae population structure changed significantly,and total algal biomass as well as the concentration of all nitrogen species decreased,causing an increase in water transparency.A model,incorporating several chemical and biological parameters,was developed to predict algal biomass in an aquatic system when snails was present.The data collected during this investigation indicated that the gastropods such as snails could significantly impact biological community and water quality of small water bodies,suggesting a role for biological control of noxious algal blooms associated with eutrophication.     

三维电极法处理氯苯废水

采用三维电极法处理氯苯废水。研究了外加槽电流、停留时间、氯苯初始质量浓度、废水初始pH等对氯苯去除率的影响。实验结果表明：外加槽电流增大,氯苯去除率明显提高;停留时间延长,氯苯去除率提高;而废水初始pH和氯苯初始质量浓度的变化对氯苯去除率影响不大。在外加槽电流为2．0A、氯苯初始质量浓度为1～200mg／L、停留时间为40～60min、废水初始pH为7的条件下,氯苯去除率达83％以上。并探讨了氯苯的电化学降解机理。     

低温等离子体氧化氨气影响因素及动力学研究

采用电晕放电低温等离子体处理模拟氨气恶臭气体,考察了输入功率、初始浓度、气体湿度、停留时间等因素对降解效果和能量效率的影响,同时对反应过程进行了动力学研究。研究表明,输入功率以及停留时间对氨气降解的影响是积极的,但能量效率随着两者的增加先增大后减小。氨气的降解率随着初始浓度的增加而降低,而能量效率随着输入功率的增加而增加。氨气降解率和能量效率均随着气体湿度的增加而增加,当气体湿度为45%时达到最大值,然而随着气体湿度的进一步增加,其降解率和能量效率反而降低。反应尾气中臭氧浓度随着输入功率的增加而不断升高,而氨气的存在却使臭氧浓度有不同程度的降低。对电晕放电低温等离子体处理NH3的反应动力学进行了分析,得到NH3的反应速率常数为kNH3=0.0707 m3/(W·h)。     

Catalytic hydrothermal depolymerization of nylon 6

Depolymerization of nylon 6 to produce ε-caprolactam using an environmentally friendly heteropoly acid catalyst was studied at temperatures between 553 and 603 K in water. The products of depolymerization were analyzed qualitatively and quantitatively by means of mass spectrometry and high-performance liquid chromatography. The results showed that the depolymerized product was mainly ε-caprolactam with a little 6-aminocaproic acid and oligomers. The phosphotungstic heteropoly acid used as a catalyst can improve the hydrolysis rate and yield of ε-caprolactam. The optimum hydrolysis conditions for ε-caprolactam yield were as follows: phosphotungstic heteropoly acid content, 3%; reaction temperature, 573 K; and reaction time, 85 min. Under these conditions, the yield of ε-caprolactam was 77.96%. In the temperature range 553–603 K, the activation energy of 3% phosphotungstic heteropoly acid-catalyzed depolymerization was evaluated as 77.38 kJ/mol, which is lower than the 86.64 kJ/mol value for no catalyst.     

大熊猫乳汁水解氨基酸含量的测定分析

收集了一只16岁圈养大熊猫产后d 2,d 3,d 5~9,d 11,d 12和d 17的乳汁样品各1个共计10个,并测定了其17种水解氨基酸(AA)的含量.结果表明,所有样品中G lu的含量最高,其次是Leu、Pro、Asp、Ser等,G ly含量最低.产后d 2~d 6的乳汁样品中AA含量稍有波动,除G ly和Cys外,其余含量从d 7~d 17呈逐渐升高的趋势;除Thr和G ly外,d 12或d 17乳汁样品中其余AA(d 12乳样中Asp除外)的含量都高于d 2的含量.d 2~d 6乳汁中Thr、G ly、Phe和Asp与总AA的比值极显著和显著高于d 7~d 17的(P<0.01和P<0.05),而G lu、Pro和A la(都为非必需氨基酸)比值极显著和显著低于d 7~d 17的(P<0.01和P<0.05).乳汁中非必需氨基酸与必需氨基酸比值(NEAA/EAA)平均值为1.55±0.05.NEAA和EAA都有随泌乳天数延长而逐步升高的趋势.图1表4参11     

中国羊胡子草、水蜈蚣二属果皮微形态特征的比较

利用扫描电镜对国产莎草科羊胡子草、水蜈蚣二属果皮微形态特征进行了比较观察和描述．根据果皮纹饰的差异，可将二属划分为两个类型：类型Ⅰ，具网状纹饰；类型Ⅱ，具网瘤状复合纹饰．在类型Ⅱ中，根据每一网眼中的瘤状突起数目及是否具小疣状附属物又可分为两个亚型．即网、单瘤亚型和网、复瘤亚型．研究结果表明：羊胡子草、水蜈蚣二属果皮微形态特征具有多样性、复杂性和稳定性等特点，可作为上述二属种间区别的依据．该研究对于探讨莎草科属间亲缘关系和系统发育也有一定意义     

桦木内生真菌的分离与代谢产物的抑菌活性

通过琼脂块法和滤纸片法,对白桦Betula platyphylla、棘皮桦B.dahurica、硕桦B.costata和柴桦B.fruticosa）的内生真菌产生抑菌物质的特性进行研究,结果表明分离自白桦3年生枝条的内生真菌拟茎点霉Phomopsis sp.BP103381表现出较强的抑菌物质形成能力。采用正交设计优化了BP103381的培养条件,在含有40 g/L蔗糖、3 g/L NaNO3、1 g/LMgSO4的改良查氏液体培养基中,在pH值6.5、28℃条件下发酵培养9 d,有利于抑菌活性物质的形成。BP103381产生的抑菌活性物质具有较好的温度稳定性,但是酸碱变化对抑菌物质的活性影响较大,BP103381产生的抑菌物质在pH为5.0~7.0时活性较强。     

石灰石-石膏湿法吸收系统高效运行的分析

为解决我国日趋严重的大气污染,石灰石-石膏法脱硫技术在电力行业二氧化硫控制上得到广泛应用。为了保证石灰石-石膏法FGD工艺的良好运行,重点从吸收设备结构和操作上分析了影响该法运行的因素,并阐述了保证吸收操作效果的措施,特别是针对腐蚀和结垢堵塞问题提出了解决的观点。