外源物质对李氏禾超富集铬的作用

通过水培实验发现,施加EDTA、CTAB、SA对铬超富集植物李氏禾地上部分和地下部分的铬含量及生理特性产生不同的的影响。EDTA使叶绿素含量上升,SOD/POD、SOD/CAT的活性比降低,抗氧化酶系统的平衡略有恢复,MDA含量降低,同时促进Cr6+从根部向地上部分运输及积累,根系铬含量降低,总体铬含量仍有较大地提高;CTAB使叶绿素降低,酶活性比值升高,抗氧化酶系统失衡加剧,MDA含量增加,并有效促进根部对Cr的吸收和积累,总体铬含量有大幅度提高;水杨酸可使叶绿素含量、酶活性比值有所恢复,减少MDA的积累,对Cr6+的吸收和运输无显著影响。研究结果既可以为提高超富集植物的修复效率提供科学依据,同时也为研究超富集植物富集重金属铬的生理机制提供良好的线索,在理论和技术上均具有重要价值。     

聚乙二醇和海藻酸钠混合固定化硝化细菌研究

采用聚乙二醇(PEG)和海藻酸钠(SA)作为混合固定化载体材料对硝化细菌进行包埋固定化.结果表明,PEG和SA质量分数分别为6％和4％时,其溶液黏稠度、成球效果及机械强度、传质性能等方面都均为最佳.另外,固定化小球扫描电镜显示球体为外密内疏的结构,这满足体内细胞泄漏少、外面细胞难以进入的条件.将所得最佳性能的固定化小球与游离菌体进行模拟废水降解对比试验,经过7d处理后废水中氨氮和亚硝态氮质量浓度都明显下降,且固定化颗粒的降解率要明显高于游离菌株,此时氨氮的去除率为90％,亚硝态氮去除率为80％.     

Comparison of Two Manual Methods of Nitrogen Dioxide Determination in Ambient Air

Sodium arsenite (modified Jacobs and Hochheiser method; hereafter referred as SA), the most widely used manual monitoring method for determination of nitrogen dioxide (NO₂) in ambient air, particularly in developing countries has been evaluated and compared with US EPA recommended equivalent method of TGS-ANSA (hereafter referred as ANSA). NO₂ concentrations generated from laboratory test atmosphere were analyzed by these two methods and were compared statistically. Laboratory evaluations showed that SA method has high sensitivity to different sampling conditions, which normally vary during actual field monitoring. Hence, correction factors for absorption efficiency were estimated for SA and ANSA methods. Absorption efficiency of NO₂ in SA method was found to be much lower (64%) as against the reported value of 82% at the method recommended sampling conditions, whereas for ANSA method, it was found 1.0 as against the reported value of 0.93. After applying derived correction factors, both the methods produced almost similar concentration values of NO₂.     

Adsorption mechanism of phenolic compounds from aqueous solution on hypercrosslinked polymeric adsorbent

The adsorption of two phenols, namely, phenol and salicylic acid(SA) onto a water-compatible hypercrosslinked polymeric resin (NJ-8) were studied in terms of pseudo-second-order and first order mechanisms for chemical sorption as well as an intraparticle diffusion mechanism process. Kinetic analysis showed that the intraparticle diffusion process was the essential rate-controlling step. The activation energies of sorption have also been evaluated with the pseudo-second-order and intraparticle diffusion constants, respectively. Adsorption equilibrium data were well fitted by the Langmuir, Freundlich and Redlich-Peterson isotherms. Adsorption was exothermic and basically of a type of transition between physical and chemical character. The sorption capacity was higher for SA due to its more hydrophobic. Phenol has a higher adsorption enthalpy since it could form stronger hydrogen bonding on NJ-8.     

水杨酸诱导黄瓜抗黑星病抗性的部位差异和时效性

寻找能够诱导植物产生抗病性的天然的生物活性物质制剂已成为作物保护研究的重点［１］．水杨酸（ＳＡ）外源处理可诱导一些重要农作物产生针对真菌、细菌、病毒病害的局部或系统性抗性,因而倍受关注［２］．黄瓜黑星病是黄瓜保护地栽培过程中的一种主要病害,寻找能防治此病且不污染环境的生物农药并研究其作用规律已成为当务之急．本文简报以黄瓜植株和黑星病菌的互作系统为材料,观察ＳＡ对黄瓜抗黑星病抗性的诱导作用及其诱导抗性在植株不同位置的差异和时效差异．１　材料与方法１．１　实验材料１．１．１　供试植物　　黄瓜品种为对…     

海藻酸钠/锆@钙水凝胶的制备及其对磷的吸附研究

利用简便的方法制备了一种新型的海藻酸钠/锆@钙（SA/Zr@Ca）水凝胶材料,采用SEM、XRD对该材料进行了表征,并通过拟合吸附等温模型及吸附动力学模型,结合XPS和Zeta电位分析,研究了该材料对磷酸盐吸附的性能和机理.结果表明,该材料为非晶态的无定型材料.在溶液初始pH为2～7时,SA/Zr@Ca对磷酸盐(以PO₄^3-计)的吸附量均大于60 mg·g^-1,pH=2时,吸附性能最佳(124.23 mg·g^-1).HCO₃^-、SO₄^2-和NO₃^-对SA/Zr@Ca水凝胶吸附磷酸盐的影响不大,其中,NO₃^-在pH=3的条件下对磷的吸附有轻微抑制作用,在pH为5～7时,则对磷的吸附具有促进作用.吸附动力学过程更符合粒子内扩散模型,吸附热力学过程符合Redlich-Peterson模型,且随温度的升高,反应的ΔGθ降低,说明该吸附...     

不同材料固定香菇废弃菌柄对铅和镉的吸附

研究了用聚乙烯醇-海藻酸钠(PVA-SA),海藻酸钠(SA)和琼脂三种材料固定香菇(Lentinus edodes)废弃菌柄制作成吸附小球的理化特性,初步比较了三种小球和自由菌粉的吸附能力,在此基础上进一步分析了PVA-SA香菇小球吸附Pb2+和Cd2+的动力学。结果表明,PVA-SA香菇小球的成球性,机械强度和耐酸性最好。固定小球的吸附能力比自由菌粉的有所下降,以Cd的吸附率降低幅度较大,PVA-SA香菇小球和SA香菇小球对Pb的吸附率降低幅度较小,吸附率分别为92.4%和92.7%,对Cd的吸附率分别为55.9%和58.66%。伪二级动力学模型能够很好的拟合固定小球对Pb2+和Cd2+吸附的动力学过程,相关系数R2分别为0.9999和0.9904,由伪二级动力学方程得到的Pb2+和Cd2+理论平衡吸附量qe分别为0.4926和0.1448mg/g,跟实验测定获得的数据0.4635mg/g和0.1423mg/g相近。     

PCDD/Fs-induced oxidative damage and antioxidant system responses in tobacco cell suspension cultures

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) are ubiquitous contaminants and can be considerably accumulated by natural plants. In order to elucidate the biochemical and physiological responses of plant to PCDD/Fs, tobacco Bright Yellow-2 (BY-2) cells were selected as model plant and treated with time- and concentration-dependent PCDD/Fs. The toxic effect and oxidative stress caused by PCDD/Fs were evident, which could be indicted by the reduction in fresh mass, the increase in malondialdehyde (MDA) content, and the damage of tobacco cell ultrastructure. PCDD/Fs tolerance was correlated with changes in antioxidant system and hormones of tobacco cells. Superoxide dismutase (SOD) and peroxidase (POD) exhibited peak enzyme activities at the PCDD/Fs concentration of 1000 ng WHO₉₈-TEQ g⁻¹ fresh weight. Glutathione reductase (GR) enzyme activity increased monotonically at high level PCDD/Fs, but the activity of catalase (CAT) was only slightly affected at all treatment. Meanwhile, the exposure to PCDD/Fs resulted in the changes of hormones content. With the increase of exposure concentration of PCDD/Fs, the levels of indole-3-acetic acid (IAA) and abscisic acid (ABA) increased, whereas the concentration of jasmonates (JAs) decreased. The above results suggest that tobacco cells had the ability to cope with the oxidative stress induced by low concentration of PCDD/Fs through increasing the activities of antioxidant enzymes and alternating plant hormones levels. However, oxidative stress and toxicity would burst out when plant cells were exposed to the high levels of PCDD/Fs.     

焦化厂不同粒径土壤中PAHs的赋存特征

为分析典型焦化污染场地不同粒径土壤中PAHs的累积及其与土壤有机碳含量（TOC）、比表面积（SA）等土壤性质的相关性，对北京焦化厂长期受PAHs污染的土壤进行粒度分级[P1（0.5~1.0 mm）、P2（0.25~0.5 mm）、P3（0.15~0.25 mm）、P4（0.106~0.15 mm）、P5（0.075~0.106 mm）、P6（<0.075 mm）]，测定了各粒径土壤的理化性质及土壤中USEPA优先控制的16种PAHs的浓度，探究PAHs在不同粒径土壤中的累积特征，并通过PAHs质量分数及土壤部分理化性质的曲线拟合结果分析PAHs的赋存特征。结果表明：各粒径土壤中16种PAHs均有检出，其最高质量分数大多出现在P1粒径土样，最低质量分数出现在 P4、P5中。各粒径土壤中2~3（低）环 PAHs、ΣPAHs16质量分数变化趋势相似，均为 P1>P2>P3、P4、P6>P5(P<0.05)，4（中）、5~6（高）环PAHs趋势类似，均为P1、P2>P3>P6>P4、P5(P<0.05)。比表面积（SA）、总有机碳（TOC）、可溶解性有机碳（DOC）与各类PAHs的质量分数呈现一定的相关性，各类PAHs质量分数随SA的增大呈先增大随后减小趋势，最大质量分数所对应的SA为38~41 m2·g-1，随TOC的增加呈先减小随后增大趋势，最小质量分数所对应的TOC为7.0~8.7 g·kg-1。不同粒径土壤颗粒中，基于污染物毒性当量因子（TEF）的等效质量分数与污染物实际质量分数变化趋势并不相同，ΣPAHs16实际质量分数变化趋势为P1>P2、P3、P4、P6>P5(P<0.05)，而其等效质量分数则为P1、P2、P3、P4、P6>P5(P<0.05)。     

两种释碳材料的制备及其性能研究

应用固定化技术制备了包埋淀粉的聚乙烯醇(PVA)释碳材料和海藻酸钠(SA)释碳材料,采用红外光谱和扫描电镜对其物化特性进行分析,研究了二者的释碳性能以及作为碳源对硝态氮的去除效果.结果表明,PVA释碳材料中淀粉混合较好,释碳过程满足二级动力学方程,单位质量材料释放的饱和COD达到99.60mg/(g·L).在温度为18~22℃,pH7.2~8.0,硝态氮浓度为35mg/L的条件下,PVA释碳材料的平均反硝化速率为18.5g/(m3·d),SA释碳材料的平均反硝化速率为15.5g/(m3·d),在稳定运行15d后,出水硝态氮浓度逐渐升高,脱氮效果开始下降.