吉林某弹药销毁场土壤炸药污染调查及其赋存状态研究

研究吉林某军事弹药销毁场土壤炸药污染程度以及炸药在土壤中的赋存状态,为炸药和重金属污染土壤修复提供针对性策略。采集了某弹药销毁厂焚烧销毁区表层土壤样品,分析了其理化性质和常见重金属元素含量,测试了土壤全样和不同颗粒度土壤样品中炸药污染物的含量,并结合热重-傅里叶变换红外光谱(TGA-FTIR) 对炸药污染土壤样品热力学行为的表征,探讨了炸药污染物的赋存状态,炸药和重金属组合污染特征等。土壤中含有高浓度的TNT、DNT、ADNT、RDX等炸药污染物及其降解产物,并表现出土壤细颗粒富集趋势,其中土壤全样中TNT总浓度达到了1.66×104 mg·kg-1,远远高于EPA推荐的土壤TNT指导限值,RDX超过了以土壤环境为目标的指导限值;销毁活动还造成了土壤中Pb、Cu、Zn重金属浓度的升高,分别为400 mg·kg-1,318 mg·kg-1,1030 mg·kg-1。土壤中受到重金属和有机质等因素的影响,土壤中经过长期老化的炸药污染物的热解行为明显不同于自由态的炸药分子,热解温度升高、过程延长。在销毁区炸药污染土壤的修复中,应加强炸药污染物与重金属相互作用的研究,并在修复治理实践中采取协同修复的策略。     

基于长期定位监测的稻田土壤理化变化和镉污染风险评价

土壤镉(Cd)污染及由此造成的水稻籽粒Cd超标是近年来我国农业环境和农产品安全领域面临的一项重要问题,对人体健康造成严重威胁。为明确Cd在稻田土壤理化变化和镉污染风险评价及相互关系,通过51个定位监测点连续5年对水稻籽粒和其对应的根系土壤进行协同监测。结果表明,监测区域内土壤酸化比较严重,土壤养分含量较高,年度之间差异不明显。土壤总Cd变化范围为0.067~1.260 mg·kg-1;土壤有效Cd含量变化范围为0.018~0.992 mg·kg-1;水稻籽粒Cd含量变化范围为0.003~1.170 mg·kg-1,籽粒Cd富集系数变化范围为0.013~2.396。5年内总体上土壤Cd与水稻籽粒Cd污染、潜在生态风险指数(Ei)及健康风险评价(HQ)较低并呈下降趋势,但土壤Cd生物活性较高。随机森林模型(Random forest mode)分析显示土壤性质显著影响土壤总Cd和有效态Cd,土壤交换能力是影响水稻籽粒对Cd吸收的主要因子。当pH≤6.5时,随着土壤pH值升高,土壤总Cd含量、土壤有效Cd含量及水稻籽粒Cd含量均升高,但当pH值≥6.5时,随着土壤pH值升高,土壤总Cd含量、土壤有效Cd含量及水稻籽粒Cd含量却均下降。研究结果可为受污染耕地分类管控和水稻安全生产提供科学依据。     

ICP-OES法测定快递包装中5种金属元素

快递包装采用硝酸-过氧化氢,微波辅助消解,采用电感耦合等离子体发射光谱法（ICP-OES）同时测定快递包装中铅、镉、砷、锌、铜五种重金属元素含量。五种元素的仪器检出限在0.2mg·kg-1-1.0 mg·kg-1之间,6次重复性相对标准偏差（RSD）在0.2%-1.4%,加标回收率在80.2%-90.3%之间。10批次快递包装中有铅、锌和铜元素检出。该方法检出限低、快速、准确,适用于快递包装中5种金属元素的测定。     

锌在不同植物种苗中的吸收效应分析

为探讨植物种苗对水体中锌的吸收效应,采用实验室内培养方法,选择了玉米等7种作物种苗为受试品种,研究了不同植物对锌的吸收。结果表明,除棉花外,各类作物在5 d内可使水体中锌含量明显降低,黑芝麻、玉米、水稻植物幼苗的根中分别积累了高达19.8、18.8、15.9mg.g1,地上部茎叶中积累了8.2、10.1、7.1 mg.g1的锌。提出选择具有"超量积累倾向"的作物种苗进行环境水体中锌污染的植物修复。     

长期口服硝酸稀土对大鼠腺垂体生长激素细胞的影响

为查明La(NO3)3和农用混合稀土"常乐"长期服用后对大鼠腺垂体中生长激素细胞功能和结构的影响,Wistar大鼠口服不同剂量La(NO3)3和"常乐"后,检测血清中生长激素水平的变化,观察腺垂体中生长激素细胞的超微结构。发现口服6个月后,20mg·kg-1组生长激素水平明显低于对照组,0.2及0.1mg·kg-1组则明显增高;停服1个月后,0.2,0.1mg·kg-1组血清中生长激素水平显著高于对照组。口服6个月后,20mg·kg-1组生长激素细胞内分泌颗粒明显减少,线粒体肿胀,粗面内质网腔明显扩张,细胞核变形;停服1个月后,20mg·kg-1组各种改变有所恢复,0.1mg·kg-1组生长激素细胞分泌颗粒较密集。     

分根法研究镧对水稻生长及其生理参数的影响

用分根营养液培养法研究了镧对水稻生长及其促进作用的生理机制。结果表明:低浓度镧(0 05～1 5mg·L-1)提高水稻产量,增加实粒数;随着镧浓度从0 05增加到0 75mg·L-1,镧降低第一片完全展开叶和根中过氧化氢酶(CAT)活性;当镧浓度为0 75～9mg·L-1时,镧显著降低叶和根中超氧化歧化酶(SOD)活性;0 75mg·L-1镧增加叶中赤霉素(GA)和吲哚乙酸(IAA)含量,0 75和3mg·L-1镧增加根中细胞分裂素(iPAs)和IAA含量,但降低脱落酸(ABA)含量;秧苗移栽后46d,0 25～6mg·L-1镧显著增加叶片气孔导度;秧苗移栽后59和83d,当镧浓度分别为15和6mg·L-1时,镧显著降低叶片气孔导度;镧对叶片叶绿素(Chl)含量、叶和根中蛋白质,脂质过氧化产物丙二醛(MDA)含量没有发现显著作用。还讨论了镧促进水稻生长和消除超氧阴离子(·O2-)的可能机制。     

硫丹在土壤中的降解特性与污染修复模拟研究

硫丹是具有很高毒性的有机氯农药,历史上我国硫丹产量较大,因此急需硫丹污染场地的修复技术．在实验室条件研究了硫丹在土壤中的降解行为,使用模拟生物堆降解研究了硫丹污染土壤的生物堆修复和化学修复条件．结果表明：在土壤介质中,α-硫丹可部分转化为β-硫丹：硫丹为微生物好氧降解;添加秸秆和绿肥及适当的通气可促进硫丹的降解;添加EM菌或葡萄糖和硝酸铵或复合肥均会抑制硫丹降解．碱性条件有利于硫丹快速降解,因而向污染土壤中添加石灰是一种高效的化学修复方法．     

硫氰酸盐结晶紫光度法测定痕量锌(Ⅱ)

在保护胶体的存在下,[Zn(SCN)4]2-碱性染料形成的离子缔合物可溶于水,可不用萃取而直接在水溶液中进行测定[1]。本文研究了在 0.10~0.25mol·L-1硫酸介质中,[Zn(SCN)4]2- 络阴离子与结晶紫形成离子缔合物,在保护胶体聚乙烯醇(平均聚合度1 750±50)存在下,可不用萃取而直接在水溶液中测定锌的方法[2]。1　试验部分1.1　主要仪器与试剂72G型分光光度计硫酸:2.75 mol·L-1锌(Ⅱ)标准溶液:按常规配制成 1 mg·mL-1,使用时稀释成含0.5 mg·L-1标准工作溶液。硫氰酸钠溶液:75 g·L-1结晶紫溶液:0.5 g·L-1抗坏血酸 硫脲溶液:将 5 g抗坏…     

稀土元素在土壤-水稻体系中的迁移与吸收累积特征

通过在天然水稻土中施用不同浓度稀土开展为期两年的水稻盆栽实验,在不同生长期系统观测了水稻植株样品的生物量,同时利用ICP-MS测定了土壤及水稻植株各器官中14种稀土元素的含量,并对植株体内稀土含量分布模式及各器官对土壤中稀土的富集与分异进行了对比研究。结果表明,无论苗期还是成熟期,当外施稀土量超过400 mg.kg-1时,水稻植株生物量即开始呈下降趋势,当外施稀土达500mg.kg-1时,生物量降低10%左右,水稻远低于旱作植物小麦对土壤中外施稀土的耐受能力。对照水稻各器官稀土分布模式与对照土壤相似,均呈轻稀土富集,中、重稀土相对亏损型,Eu轻度负异常;但与土壤不同,水稻根部的Tb及地上部各器官的Eu,Tb均出现正异常。土施大量稀土(400~1200 mg.kg-1)对水稻土及稻根的稀土分布模式有显著影响,对茎、叶略有影响,对籽粒影响不明显。植株各器官对土壤稀土的累积能力依次为根>叶>茎>穗轴、谷壳>籽粒。对照水稻根部对土壤中各稀土元素的吸收积累能力大致相同,仅对Tb有更强的选择性吸收。地上部各器官对中、重稀土的累积能力大于轻稀土,并多数对Eu及Tb有更强的累积。水稻的根部及叶、茎对外施稀土有更强的吸收累积能力,随外施稀土浓度增加,其富集系数随之增高,而穗轴和谷壳、籽粒的富集系数变化不大。植株各器官及籽粒对外施稀土中的Nd都表现出更强的吸收累积作用。     

恒温平台石墨炉原子吸收光谱法测定土壤中镉

正常土壤中镉的含量为0.03～0.3mg·kg~(-1),一般不会超过1mg·kg~(-1)。镉和锌的化学性质相似,都会随水中CaCO_3的沉积而沉淀。所以在石灰岩和石灰岩发育的土壤中富含锌,也可能含有较多的镉。当土壤受到电镀、染料、电池等工厂的废弃物污染后,含镉量会异常地增高。如果土壤的pH值较高,并含有多量的碳酸钙则镉不易迁移;而在酸性土壤中镉的迁移性较强,危害也更大。土壤环境质量标准规定,一般农田、蔬菜地、果园、牧场等土壤,当pH值小于7.5时,含镉量不能超过0.30mg·kg~(-1)。 测定土壤中镉的一般过程是:先将样品消解,然后用萃取一火焰原子吸收法测定,操作较繁琐。Slavin W等提出的恒温平台石墨炉(STPF)技术是一项近乎无干扰的先进技术,它包括快速电子测量技术、使用装有L'vov平台的热解涂层石墨管、最大功率原子化、峰面积测量、准确的背景扣除、原子化阶段停气、使用基体改进剂等。本文将它应用于土壤中镉的测定,重现性和准确度均较理想。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.