包覆型纳米铜-银双金属粉研究

目前,导电胶或者电磁波屏蔽涂料用的导电性填料主要有三类,一是铜粉,二是银粉,三是铜-银双金属粉。铜粉具有来源广、价格低廉、导电性好等优点,但其抗氧化性能弱;银粉导电性与抗氧化性好,但其资源日益匮乏。大量的研究试图通过对铜粉进行表面改性来提高其性能。表面改性有两种方法,一是包膜处理,用SiO2溶胶处理铜粉,铜粉抗氧化性能提高,但其表面导电性能大大降低犤1犦;另一类方法是在铜粉表面覆盖一层导电性能与抗氧化性能均佳的银或金而制成双金属粉末犤2～5犦。制取高性能的铜-银双金属粉是该领域的研究重点。目前获得铜-银双金属粉的方…     

废聚丙烯塑料等离子体热解研究——水蒸气的加入对改善气体品质的影响

以聚丙烯为试验物料，利用N2热等离子体在等离子体反应器内进行了一系列热解试验，重点考察了气体产物成分及含量。在反应过程中加入过热水蒸气以改善气体品质，在本实验条件下，气体产物中CO与H2之和可以达到40%，C2H2可达到5%。     

固相微萃取-气相色谱/质谱测定工业废水中痕量有机物的研究

采用固相微萃取(SPME)技术结合气相色谱-质谱(GC/MS)法对石化工业废水中的痕量有机物进行检测和分析。针对废水中存在的几种主要有机物,对影响SPME的参数进行了优化。建立的方法在所测的范围内具有良好的线性(相关系数:0.981.00),检测限达0.329.1 μg/L,重复测定的相对标准偏差小于7%,回收率为78.6%125.1%。采用该方法对某石化工业废水样品中主要存在的25种痕量有机物进行测定,结果表明这是一种简便、准确的分析方法,所测得的结果可为废水的治理提供科学依据。     

Investigation of carbon-13 nuclear magnetic resonance spectra-structure correlation based on novel atomic distance-edge (ADE) vector

A set of novel graph-theoretical parameters,called the atomic distance-edge (ADE) vector,was developed.Based on the connecting C-C bond number between central carbon atom and the other ones,various carbon atoms of alkanes were classified as four types,i.e.,type 1,2,3 and 4 for primary,secondary,ternary and quaternary carbon,respectively; and then four regression equations were obtained to link carbon-13 chemical shift (CS) of each type of atoms.Furthermore,these regression models were used to predict the carbon-13 nuclear magnetic resonance spectra of alkanes and it was found that the estimated CS were in agreement with the experimental results.     

Investigation and optimization of the recovery of coal fines using oil agglomeration process: Use of waste oils from different sectors

The high cost of the bridging liquid subdues the implementation and commercialization of oil agglomeration process. To overcome this problem, waste oils from different sectors were used in this present study. The performance of the process was assessed based on the responses like ash rejection and organic matter recovery. The aim of the present study was to investigate the usage of waste oils from different sectors and to optimize and analyze the behavioral pattern showcased by different variables (pulp density, oil dosage, agglomeration time and oil type) using response surface methodology (Box-Behnken design). Experimental investigation shows that the optimum pulp density, oil dosage, agglomeration time and oil type condition obtained as 3%, 15%, 15?min and waste engine oil, respectively. At optimum condition, the % ash rejection and % organic matter recovery obtained as 63.94% and 81.8%, respectively.     

TiO2-SiO2光催化纸业废水有色有机物的降解

研究了TiO2-SiO2混合氧化物对纸业废水中有色有机物的吸附与光催化降解效率．常温下．TiO2对纸业废水中有色有机物的吸附符合Freundlich模型，Qe=0．239Ce^0.791。TiO2-SiO2混合氧化物对纸业废水中有色有机物的吸附与光催化降解效率与催化剂样品的组成有关，光催化降解效率也与TiO2-SiO2表面总酸量有关．     

Validated multi‐drug determination using liquid chromatography with tandem mass spectrometry for the evaluation of a commercial drug disposal product

Currently, there are limited effective means of drug disposal for consumers, and this creates a gateway to illicit use and environmental contamination. Here, we evaluated the efficacy of a new drug disposal product, composed from a slurry of activated carbon, which claims to sequester up to 100% of a drug's active ingredient when the loading capacity is not exceeded, making it safe to dispose in landfill. High‐performance liquid chromatography with tandem mass spectrometry was applied to quantify as many as 24 drugs (opiates, barbiturates, statins, amphetamine, and benzodiazepine drugs) in the residual solvent solution from the product. Calibration curves were established in the concentration ranges of 0.25–7.0 μg/mL and showed good linearity. The limits of detection varied from 0.001 to 0.02 μg/mL, depending on the drug. Accuracy ranged from 80 to 111% for quality control samples, with a few minor exceptions. Precision overall varied between 0.2 to 12.7%. In sample bottles tested, where active ingredient of the loaded drug was below the maximum sorption capacity stated on the label, 98 to >99.9% of the active ingredient was sequestered. Percent active ingredient adsorbed was slightly lower in bottles loaded in excess of label specifications.     

基于柑橘皮渣纳米多孔碳分散固相萃取-气相色谱法 测定果蔬中14种有机磷农药残留

以废弃柑橘皮渣为碳源,通过ZnCl2活化后高温煅烧制备了纳米多孔碳材料(NPC),将其作为吸附剂,建立了分散固相萃取净化、气相色谱法测定果蔬中有机磷农药残留的方法.扫描电子显微镜(SEM)、X射线衍射(XRD)、傅立叶红外光谱(FT-IR)、拉曼光谱及氮气吸附分析(BET)等表征显示,NPC是无定形的多孔碳材料,孔径大小为0~15 nm,比表面积和孔体积分别为1243 m2/g和1.28 cm3/g.以果蔬中14种有机磷类农药为分析对象,考察了吸附剂的用量和净化时间,并将NPC与商业化材料N-丙基乙二胺(PSA)、十八烷基硅胶键合相(C18)和石墨化碳黑(GCB)进行了对比.结果表明,NPC最佳使用量为0.01 g,净化时间只需2 min.NPC成本远低于C18、PSA和GCB,因具有丰富的孔道结构,NPC净化效果显著优于3种商业化材料.在最优条件下,14种有机磷农药在0.02~1.0 mg/L范围内的线性关系良好(R2>0.99),检出限(S/N=3)为0.63~5.30μg/kg.3个添加水平下的平均回收率为71.3%~114.7%,相对标准偏差(RSD)为0.9%~12.9%.本方法操作简便、快速、成本低,在果蔬样品前处理中具有广阔的应用前景.     

Colloidal Surface Active Maghemite Nanoparticles for Biologically Safe CrVI Remediation: from Core‐Shell Nanostructures to Pilot Plant Development

The present study is aimed at the exploration of achievable improvements for Cr^VI ex situ and in situ water remediation by using novel naked colloidal maghemite (γ‐Fe₂O₃) nanoparticles (surface active maghemite nanoparticles, SAMNs). The reliability of SAMNs for Cr^VI binding and removal was demonstrated, and SAMN@Cr^VI complex was characterized, as well as the covalent nature of the absorption was unequivocally proved. SAMNs were structurally and magnetically well conserved after Cr^VI binding. Thus, in consideration of their affinity for Cr^VI, SAMNs were exploited in a biological model system, mimicking a real in situ application. The assay evidenced a progressive reduction of revertant colonies of Salmonella typhimurium TA100 strain, as maghemite nanoparticles concentration increased, till the complete suppression of Cr^VI mutagen effect. Finally, an automatic modular pilot system for continuous magnetic removal and recovery of Cr^VI from water is proposed. SAMNs, thanks to their colloidal, binding, and catalytic properties, represent a promising tool as a reliable nanomaterial for water remediation by Cr^VI.     

Nuclear-Electron Overhauser Effect in MC800 Liquid Asphalt Solutions

Experimental results on the extrapolated ultimate enhancement factors of o-, m-, and p-xylene protons at 1.53 mT are obtained for MC800 asphalt solutions. The ultimate enhancement factors are found such as ?26.9, ?25.7, and ?11.7 for o-, m-, and p-xylene, respectively. These results show that the solvent proton Overhauser effect cannot reach the extrapolated enhancement of ?330 in the extreme narrowing case because of occurrence of small scalar interactions in addition to the dipole–dipole interactions between solvent protons and asphalt electrons. The ortho, meta, and para positions of the –CH₃ group change the nature of the interactions. The nuclear magnetic resonance (NMR) signal enhancements exhibit a sensitive behavior depending on the chemical environment differing from isomer to isomer. The solvation or association of asphalt in xylene isomers at room temperature is revealed. Quantum chemical calculations for the xylene isomers with the electronic and optical properties; absorption wavelengths, excitation energy, atomic charges, dipole moment and frontier molecular orbital energies, molecular electrostatic potential; are carried out using the density functional theory (DFT) method (B3LYP) with the 6-311G(d,p) basis set by the standard Gaussian 09 software package program. The relative importance of scalar and translational dipolar interaction parameters determined in dynamic nuclear polarization experiments is explained by the electronic structure of HOMO–LUMO of the xylene isomers.