中药材黄芪中有机氮农药残留量的液相色谱检测方法

研究了中药材黄芪中有机氮农药（包括涕灭威、呋喃丹、西维因、甲霜灵）残留量的液相色谱测定方法。采用混合溶剂提取,经Florisil及中性氧化铝柱层析净化后,再经Florisil小柱进一步净化及相转移,进入HyperOSD2C18柱分析,流动相为V（乙腈）∶V（水）=38∶62的混合液。检测波长为220nm,用外标法进行定量,当添加水平为0.07×10     

受污染水稻秸秆热解产物中镉含量及溶出性研究

以镉污染土种植水稻秸秆为原料, 通过500℃不同时间(10~720min)处理制备秸秆热解产物(生物炭和秸秆灰), 测定产物中镉的含量及其溶出性. 结果表明, 水稻秸秆经热解处理后挥发镉总量的29.6%~48.4%; 样品产率随热解时间的增加而下降; 单位质量生物炭和秸秆灰中镉含量为2.35~7.05mg·kg-1和15.0~16.4mg·kg-1, 分别是水稻秸秆中镉含量(0.948mg·kg-1)的2.5~7.4倍和15.8~17.3倍; 通过不同提取剂得到镉溶出率由低到高依次为0%~43.2%(采用0.01mol·L-1 CaCl2提取)、0%~44.3%(采用Toxicity Characteristic Leaching Procedure提取)、28.8%~58.8%(采用1mol·L-1 pH5.0乙酸-乙酸钠单次提取)、35.1%~98.4%(采用1mol·L-1 pH5.0乙酸-乙酸钠连续4次提取); 随着热处理时间的延长, 样品中镉溶出率逐渐降低; 由于热解过程中镉的挥发和形态转变, 水稻秸秆转变为生物炭和秸秆灰后镉的可溶出总量(采用1mol·L-1 pH5.0乙酸-乙酸钠连续4次提取)由0.933mg·kg-1降至0.223~0.384mg·kg-1, 表明受镉污染的水稻秸秆热解转化为生物炭和秸秆灰可以有效缓解镉潜在的溶出风险.     

Characterization of Conyza bonariensis Allelochemicals against Broomrape Weeds

The study of allelopathic activity of plants and the isolation and characterization of the responsible allelochemicals can lead to the development of environment friendly alternative approaches to weed control. Conyza species are invasive weeds that use allelopathic activity as part of a successful strategy to outcompete neighboring plants. Broomrape weeds are parasitic plants that use host-induced germination and the formation of a haustorium as strategies to infect host plants. The control of broomrape infection in most affected crops is limited or non-existing. In the current study, we investigated the allelopathic activity of Conyza bonariensis organic extracts in suicidal germination and radicle growth of four broomrape species (Orobanche crenata, Orobanche cumana, Orobanche minor and Phelipanche ramosa). A bioactivity-driven fractionation of Conyza bonariensis extracts led to the identification of two germination-inducing molecules and two growth-inhibitory compounds. The germination-inducing metabolites had species-specific activity being hispidulin active on seeds of O. cumana and methyl 4-hydroxybenzoate active in P. ramosa. The growth-inhibitory metabolites (4Z)-lachnophyllum lactone and (4Z,8Z)-matricaria lactone strongly inhibited the radicle growth of all parasitic weed species studied. Some structure–activity relationships were found as result of the study herein presented.     

麦草制吸附剂对水体中不同阴离子的吸附性能

采用环氧氯丙烷、乙二胺和三乙胺对麦草秸秆进行化学改性,研究改性麦草秸秆的性能指标并重点考察其对水体中的NO3-,PO43-和Cr2O72-的吸附性能及效果.研究结果表明,改性麦草秸秆引入了带正电荷的胺基基团,可以显著提高对阴离子的吸附性能;改性麦草投加量、pH值、吸附时间和温度对吸附性能影响较大,吸附过程符合伪二级动力学方程和Langmuir等温吸附模式;改性麦草秸秆对NO3-、PO43-(P)和Cr2O72-(Cr)的最大吸附量分别为53.5、62.4和386.2mg·g-1.     

改性小麦秸杆纤维素球对苯酚吸附性能研究

本文利用制得的改性小麦秸秆纤维素球对苯酚吸附性能进行了研究。实验结果表明:改性小麦秸秆纤维素球对苯酚的吸附30min内基本达到平衡,吸附剂对苯酚吸附量随起始质量浓度的增加而增加,且呈线性关系;在T=298K、pH=5.0时,吸附剂对苯酚的吸附量达到最大。在一定浓度、温度条件下,改性小麦秸秆纤维素球吸附苯酚的过程符合Freundlich吸附模型。吸附再生实验表明,改性小麦秸秆纤维素球对苯酚有较好的吸附再生能力。并对印染废水中的苯酚进行了实际的吸附测定。     

农作物秸秆红外指纹图谱双指标序列分析

采用傅立叶红外光谱技术研究了不同地区、不同种类农作物秸秆的红外指纹图谱,对其谱带归属进行了判别分析;并利用共有峰率和变异峰率双指标序列法对农作物秸秆样品进行分析鉴别。结果表明:同种农作物秸秆化学成分相似,不同农作物秸秆化学成分差异较大,其中花生秆与其他农作物秸秆化学成分差异最大。     

Degradability of composites of low density polyethylene/polypropylene blends filled with rape straw

Composites of LDPE/PP blends and comminuted rape straw as a filler were obtained and characterized. The aging performance of these composites has been investigated. The composites were aged using various types of wet soil and selected species of mould fungi as aging environment as well as using Atlas UV 2000 apparatus as simulation of abiotic conditions. The changes between non-aged and partially degraded composites were evaluated by measuring their mechanical properties and mass change and using FT-IR spectroscopy, FT-IR/PA spectroscopy and scanning electron microscopy. The highest extent of degradation was observed after aging in compost. The band corresponding to cellulosic fibres is no longer recorded in the FT-IR spectra.     

Biodegradation of water-soluble and water-dispersible polymers for agricultural,consumer, and industrial applications—Challenges and opportunities for sustainable materials solutions

The development of more sustainable material solutions is one of the key challenges today. New materials are subject to an overall risk assessment of which their impact on the environment is an important aspect. The biodegradability of a material may support a positive risk assessment. Water-soluble and water-dispersible polymers are widely used in daily life in a very broad range of applications. In anticipation of a further tightening of regulatory requirements and as a consequence of the introduction of sustainability targets in industry, in the next decade or so, industry targets to replace the currently used and predominantly non-biodegradable high value water-soluble and water-dispersible polymers by biodegradable alternatives, wherever sustainably possible. This review provides an overview of the currently used water-soluble and water-dispersible polymers in detergent formulations for home care, in water treatment and in crop protection. These polymers have been engineered to near perfect performance at minimum costs. We address the challenges faced when introducing biodegradable alternatives in existing product value chains, and we highlight opportunities to further improve and fine-tune the biodegradation of these materials. This overview is intended to contribute to the development of novel biodegradable water-soluble and water-dispersible polymers, both at academia and industry.     

Representative commodity for five brassica vegetables based on the determination and dissipation of six pesticide residues

A Quick, Easy, Cheap, Effective, Rugged and Safe method for determination of thiophanate-methyl, carbendazim, metalaxyl, fluazifop-P-butyl, chlorpyrifos and lambda-cyhalothrin in five brassica vegetables by high performance liquid chromatography-mass spectrometry/mass spectrometry and gas chromatography-electron capture detector has been developed. The average recoveries of six pesticides in five brassica vegetables were in the range of 77.4%–117.4% with relative standard deviation of 3.7–10.8%. Residues of thiophanate-methyl, carbendazim, metalaxyl, fluazifop-P-butyl, chlorpyrifos and lambda-cyhalothrin in five brassica vegetables were studied with the developed method for the classification of crop group and selection of representative commodity of five brassica vegetables. Totally 48 open field trials on five brassica vegetables were conducted at two locations in two different seasons. The residue dynamics and final residues of the six pesticides at three preharvest intervals in different vegetables were compared. All six pesticides had the longest half-lives in cabbage (2.1–3.5 days). Residues of carbendazim (sum of thiophanate-methyl and carbendazim), metalaxyl, chlorpyrifos and lambda-cyhalothrin had similar trend in different brassica vegetables. The maximal concentrations of these pesticide residues were found in kale (0.28–10.9 mg kg^?1). Fluazifop-P-butyl residues were at low levels in all five brassica vegetables (<0.01–0.03 mg kg^?1). Cabbage, red cabbage, Brussels sprouts and kohlrabi had no significant difference in all six pesticide residues and could be classified in a subgroup of Head Brassicas. Cabbage should be selected as the representative commodity. Considering the highest residues in kale and its different morphology, kale should not be classified into the subgroup of Head Brassicas.     

作物产量构成因素通径分析方法的再商榷

本文讨论了作物产量构成因素通径分析的方法。提出按因果关系将各因素对产量的效应剖分为多个路段，并进而计算与比较其效应总和及总决定程度。在各因素的变异较大时，对数转换后再进行通径分析才合理。