8-羟基喹啉掩蔽氢化物发生原子荧光法测定水中As(Ⅲ)和As(Ⅴ)

研究了用8-羟基喹啉(8-HQ)作为As(Ⅴ)和其他共存金属离子的掩蔽剂,氢化物发生原子荧光法(HGAFS)测定水中痕量As(Ⅲ)和As(Ⅴ)的最佳工作条件。该法的检出限为0．12μg／L,回收率为92％～104％,相对标准偏差为1．3％,有较好的抗干扰能力。此法用于实际水样的测定取得了满意结果。     

Synthesis and Crystal Structure of 2-（ 4-Decarboxydehydroabietyl）- 5-p-tolyl-[ 1,3,4 ]-oxadiazole

2-（4-Decarboxydehydroabietyl）-5-p-toyl-[1,3,4]-oxadiazole, C28H34N2O, has been synthesized and characterized by IR, NMR, elemental analysis and single-crystal X-ray diffraction method. The crystal belongs to the orthorhombic system, space group P212121 with a = 6.1351（5）, b = 14.8495（19）, c = 25.9050（2） A, V = 2360.0（4） A3, Z = 4, Mr = 414.57, Dc = 1.167 Mg/m^3, 2 = 0.71073 A,μ（MoKa） = 0.070 mm^-1, F（000） = 896, the final R = 0.0452 and wR = 0.1076 for 1647 observed reflections with I 〉 2σ（I）. There are five rings in the crystal structure of the title compound, but the oxadiazole ring is non-coplanar with the benzene ring D.     

In situ Remediation of Petroleum Contaminated Groundwater by Permeable Reactive Barrier with Hydrothermal Palygorskite as Medium

The permeable reactive barrier(PRB) has proven to be a cost-effective technique to remediate the petroleum contaminated groundwater at a northeast field site in China. In this study, the geology, hydrogeology and contamination characterization of the field site were investigated and the natural hydrothermal palygorskite was chosen as a reactive medium. Furthermore, the adsorption of the total petroleum hydrocarbons(TPH) in the groundwater onto hydrothermal palygorskite and the adsorption kinetics were investigated. The results indicate that the removal rates of TPH, benzene, naphthalene and phenantharene could all reach up to 90% by hydrothermal palygorskite with a diameter of 0.25―2.00 mm that had been thermally pretreated at 140 ℃. The adsorption of TPH onto hydrothermal palygorskite after pretreatment followed a pseudo-second-order kinetic model and a Langmuir adsorption isotherm, suggesting that the theoretic adsorption capacity of hydrothermal palygorskite for adsorbate could be 4.2 g/g. Scanning electron microscopy(SEM), infrared spectroscopy(IR), X-ray diffraction(XRD) and X-ray fluorescence spectroscopy(XRF) were carried out to analyze the adsorption mechanism. The results reveal that hydrothermal palygorskite is a fibrous silicate mineral enriched in Mg and Al with large surface area and porosity. The dense cluster acicular and fibrous crystal of hydrothermal palygorskite, and its effect polar group ―OH played an important role in the physical and chemical adsorption processes of it for contaminants. This study has demonstrated hydrothermal palygorskite is a reliable reactive medium for in situ remediation of petroleum contaminated groundwater at field sites.     

高岭土成型体水热转化无粘结剂4A分子筛研究

以煤系高岭土与碳质造孔剂、凹凸棒石增强剂加水混匀成型,经高温焙烧活化,水热反应转化4A分子筛,重点探讨了成型体的活化制度及造孔剂的作用机制.结果表明,造孔剂过量会使成型体的强度降低,欠量则不能形成丰富的前驱孔通道,无法保证晶化液进入体内充分反应;成型体的煅烧温度过低和/或时间过短,高岭石及造孔剂得不到充分分解,而温度过高和/或时间过长,会使偏高岭土的活性降低,且使前驱孔通道塌陷,皆影响分子筛的转化.高岭土与11;造孔剂和3;增强剂加水混匀并滚制成φ3mm的小球,在750℃锻烧3h,形成多孔活化体,再经水热转化可形成结晶良好、晶体互联交织生长的4A分子筛聚集体,宏观上保持原有的球形未变,其抗压碎力达115 N/颗,静态水吸附率达23.75;.     

KDP晶体水溶液微结构和界面吸附行为研究

本文采用分子动力学模拟方法研究了磷酸二氢钾(KDP)晶体水溶液的微观分子结构以及生长基元的界面吸附行为.在分子动力学模拟中,水分子采用简单点电荷(三节点)模型,钾阳离子为带电硬球模型,磷酸二氢根离子采用七节点模型,计算了KDP水溶液的构型能,对比分析了(010)和(001)两个晶面的生长速率.研究结果发现:在饱和温度附近体系的局域粒子数密度有剧烈涨落,过饱和溶液的比热显著高于不饱和溶液的比热,表明在饱和温度以下KDP溶液经历了结晶相变过程;磷酸二氢根阴离子生长基元在(010)和(001)两个晶面生长行为的研究表明(010)面生长速率明显高于(001)面,得到了与实验和从头计算相符的结果.     

高纯度树状大分子聚酰胺-胺的合成与表征

以乙二胺为核,通过Michael加成,与丙烯酸甲酯交替反应,合成了0.5代到5.0代聚酰胺 胺树状大分子。 利用傅里叶变换红外光谱、核磁共振氢谱、液相色谱和元素分析等对各代产品进行了表征,探索了反应温度、时间及反应物配比对产物的影响,确定生成聚酰胺-胺(PAMAM)的半代产物时反应温度为25 ℃,整代产物时反应温度为35 ℃;0.5G的反应时间为18 h,1.0G、1.5G的反应时间为24 h,2.0G、2.5G反应36 h,3.0G、3.5G反应48 h,4.0G、4.5G反应3 d,5.0G反应4 d。 分离提纯是树状大分子制备中遇到的最大困难,通过选择性溶剂萃取的方法对产品分离纯化,筛选出乙醚作萃取剂、甲醇作溶剂交换剂,大大提高了产品的纯度。     

Mn-CCA-CPC浊点萃取火焰原子吸收法测定水环境中锰

使用浊点萃取的方法分离富集水环境中痕量的锰离子,创新性地使用钙羧酸(CCA)与阳离子表面活性剂氯代十六烷基吡啶(CPC)为络合剂与锰离子形成更稳定的三元络合物,以TritonX-114为萃取剂浊点萃取分离富集水环境中的痕量锰,同时采用火焰原子吸收法进行测定,建立了测定水环境中痕量锰的新方法。对影响浊点萃取的主要因素如pH、TritonX-114的用量、CCA用量、CPC用量、NaCl用量、共存离子影响、加热温度、加热时间、离心时间、冰浴时间进行了优化。在优化的实验条件下,Mn2+-CCA-CPC体系分离富集锰有很好地效果,能够很好的克服基体干扰,浊点萃取体系在锰含量0.3～1.5 mg·L-1时呈现良好的线性关系。方法的灵敏度为1.939 mg·L-1,精密度为0.39%,检出限为(3σ)0.27 μg·L-1。测定自来水与井水中的锰含量的结果为33.5和64.5 μg·L-1,同时做加标回收实验,回收率在99.1%～101.5%之间。符合国际标准,因此该方法能够成功应用到水环境中的锰含量的测定,结果令人满意。     

锂离子对稀土掺杂氧化物的红外激光诱导热辐射的影响

由于具有较高的可见波段荧光效率,基于稀土掺杂氧化物的红外激光诱导热辐射具有重大的应用潜力。进一步提高红外诱导热辐射效率具有重大的实用价值。设计了一种改善稀土掺杂氧化物材料中红外诱导热辐射效率的方案,即通过掺杂改性杂质,既可以改变稀土离子周围局域晶场的对称性;同时又引入了晶格缺陷。对应的效果包括：一方面,可以通过增强稀土离子周围的晶场强度来提高稀土元素对于入射光子的吸收能力;另一方面,可以利用晶格缺陷作为猝灭中心来增加材料的热转化能力,最终将显著提高杂质改性材料的光热转化效率,即获得更加高效的红外诱导热辐射材料。为了验证设计方案的可行性,利用溶胶-凝胶方法合成了不同浓度的镱离子和锂离子的共掺杂样品,通过XRD及TEM测试分析了杂质对样品结构的影响,并且基于荧光发射光谱具体研究了杂质掺杂浓度对热辐射效率的影响。该工作为高效稀土掺杂热辐射材料的制备提供一定的参考。     

QuEChERS-高效液相色谱-串联质谱法测定植物源食品中氯啶菌酯和丙炔恶草酮残留

建立了QuEChERS前处理-高效液相色谱-串联质谱(HPLC-MS/MS)同时检测植物源食品中氯啶菌酯和丙炔恶草酮残留量的分析方法。样品经酸化乙腈提取,采用乙二胺-N-丙基硅烷(PSA)和氨基(NH₂)吸附剂净化。以0.1%(v/v)甲酸水(含2 mmol/L乙酸铵)-甲醇(2:8, v/v)为流动相,在0.25 mL/min流速下等度洗脱,采用C₁₈色谱柱分离,电喷雾正离子电离(ESI⁺)、多重反应监测(MRM)模式质谱检测。以保留时间和特征离子对(母离子和两个碎片离子)信息比较进行定性,基质匹配外标法定量。结果表明:在葡萄、葡萄干、马铃薯、大米、番茄、油菜籽6种基质中,氯啶菌酯和丙炔恶草酮在各自线性范围内线性关系良好(相关系数r²均大于0.996)。氯啶菌酯的定量限(LOQ)(以S/N≥10计)为0.5 μg/kg,丙炔恶草酮的定量限为1.0 μg/kg。在1、2、10倍LOQ 3个添加水平下,氯啶菌酯的平均回收率为71.6%~112.1%,相对标准偏差为2.6%~12.1%;丙炔恶草酮的平均回收率为77.6%~118.8%,相对标准偏差(RSD)为3.6%~14.3%。该方法高效快捷、灵敏、准确,适用于植物源性食品中氯啶菌酯和丙炔恶草酮的快速检测。     

Trichloroacetic Acid Removal by a Reductive Spherical Cellulose Adsorbent

A novel spherical cellulose adsorbent with amide and sulphinate groups was used for a first reduction of trichloroacetic acid(TCAA) and a subsequent adsorption of generated species, haloacetic acids. The removal mechanism involved TCAA reduction by sulphinate groups and the adsorption of the haloacetic acids through electrostatic interaction with amide group. Investigation of product formation and subsequent disappearance reveals that the reduction reactions proceed via sequential hydrogenolysis, and transform to acetate ultimately. Adsorption of haloacetic acids was ascertained by low chloride mass balances(89.3%) and carbon mass balances(75.1%) in solution. The pseudo-first-order rate constant for TCAA degradation was (0.93±0.12) h^-1. Batch experiments were conducted to investigate the effect of pH value on the reduction and adsorption process. The results show that the reduction of TCAA by sulphinate groups requires higher pH values while the electrostatic attraction of haloacetic acids by amino group is favorable in more acidic media.