钛基PbO2电极的制备及其电催化性能

采用电沉积方法制备了铁掺杂Ti/SnO_2 Sb_2O_3/PbO_2电极,并用X-射线衍射、扫描电子显微镜和极化曲线对其进行了表征,以亚甲基蓝为目标有机物,考察了其电催化氧化性能。结果表明,中间层的引入和铁的掺杂显著提高了钛基PbO_2电极的电催化氧化能力;反应过程中电极表面产生的羟基自由基对亚甲基蓝的氧化去除起着主要作用。     

聚苯胺负载纳米金催化剂的研究进展

综述了聚苯胺(PANI)负载纳米金催化剂的制备方法,包括PANI载体的合成及负载纳米金颗粒(AuNPs)的方法,介绍了PANI的不同形貌和AuNPs的不同空间负载位置对AuNPs的稳定性及催化活性的影响,分析了AuNPs吸附和原位还原两种不同负载方式的机理及优缺点,探讨了PANI与负载的AuNPs之间电荷转移和相互作用...     

西红柿催化红外去皮过程三维传热模型的建立和设备能耗计算

为提高西红柿红外干法去皮的加工性能,本研究建立了红外辐射加热的三维传热模型,利用该模型对西红柿红外去皮过程中表面和内部不同位置的温度进行预测,并通过比较温度预测值和实测值来验证模型的拟合度;进一步通过能耗计算对比分析两种不同的红外设备,筛选出较优的红外设备。结果表明,与静态催化红外设备相比,燃气-滚轮传送式催化红外设备可以实现对西红柿表皮的快速加热（表面最高温度为60.32℃）,且西红柿表面温度分布更均匀（最大温差约6.44℃）;内部温度增幅较低（内部最高温度为49.10℃）,且内部温度分布也较均匀（最大温差约18.25℃）。模型预测值与实测值之间的拟合较好（R2≥0.93）,且两者之间的估计标准误差EESE值较低（0.13～10.80℃）,表明三维传热模型的拟合效果良好,能够很好地反映不同红外设备下西红柿表面和内部的温度分布。与静态式催化红外设备相比,燃气-滚轮传送式催化红外设备更优,即缩短了16.60%的加工时间,又节约了34.80%的能耗,更高效节能,在果蔬去皮领域具有广阔的应用前景及工业化推广价值。     

提取方法对大豆油脂体组成及氧化稳定性的影响

以大豆为原料,比较缓冲溶液法、水相法和酶法3种提取方法对大豆油脂体提取率、组成、脂肪酸组成、磷脂、生育酚、ζ-电势和粒径的影响,以及对大豆油脂体氧化稳定性的影响.试验结果表明,酶法提取大豆油脂体的提取率(19.74±0.14)％显著高于缓冲溶液法(12.76±0.14)％和水相法(6.67±0.32)％的提取率(P<0...     

镁合金微弧氧化工艺及陶瓷层耐蚀性能研究

通过单因素试验讨论了镁合金微弧氧化电解液各组分对成膜的作用,得到电解液最佳配方:10g/L(NaPO3)6,5g/LNH4F,6g/LKOH,6mL/LC3H8O3。用扫描电镜(SEM)、X射线衍射(XRD)和能谱(EDS)分析了陶瓷膜层的表面形貌、截面形貌、相组成及元素组成;采用点滴试验、交流阻抗和盐雾试验考察了陶瓷层的耐腐蚀性能。结果表明:膜层表面分布着大量均匀的放电微孔,孔径在1~3μm之间,膜层截面内层与基体过渡部分呈犬牙交错状态,结合良好;膜层由大量非晶态相及少量MgO组成,耐蚀性能优良。P与F元素的存在,证明了电解液组分较好地参与了微弧氧化反应。     

硅微粉氧化性质研究

考察了硅微粉在空气、水、聚乙二醇(PEG)以及PEG水溶液几种介质中的氧化行为,并分析比较了两种不同切割过程所产生的硅微粉屑的氧化情况。结果显示:200℃下干燥空气中硅微粉不发生明显氧化;在高于80℃的水中放置10d,硅微粉发生明显氧化,形成非晶SiO2。与水及水溶液相比,PEG能在一定程度上阻止硅微粉的氧化。另外,带锯切割中产生的硅微粉屑氧化严重,而多线切割中产生的硅微粉切屑无明显氧化。     

Thiogenistein—Antioxidant Chemistry,Antitumor Activity,and Structure Elucidation of New Oxidation Products

Isoflavonoids such as genistein (GE) are well known antioxidants. The predictive biological activity of structurally new compounds such as thiogenistein (TGE)–a new analogue of GE–becomes an interesting way to design new drug candidates with promising properties. Two oxidation strategies were used to characterize TGE oxidation products: the first in solution and the second on the 2D surface of the Au electrode as a self-assembling TGE monolayer. The structure elucidation of products generated by different oxidation strategies was performed. The electrospray ionization mass spectrometry (ESI-MS) was used for identifying the product of electrochemical and hydrogen peroxide oxidation in the solution. Fourier transform infrared spectroscopy (FT-IR) with the ATR mode was used to identify a product after hydrogen peroxide treatment of TGE on the 2D surface. The density functional theory was used to support the experimental results for the estimation of antioxidant activity of TGE as well as for the molecular modeling of oxidation products. The biological studies were performed simultaneously to assess the suitability of TGE for antioxidant and antitumor properties. It was found that TGE was characterized by a high cytotoxic activity toward human breast cancer cells. The research was also carried out on mice macrophages, disclosing that TGE neutralized the production of the LPS-induced reactive oxygen species (ROS) and exhibits ABTS (2,2′-azino-bis-3-(ethylbenzothiazoline-6-sulphonic acid) radical scavenging ability. In the presented study, we identified the main oxidation products of TGE generated under different environmental conditions. The electroactive centers of TGE were identified and its oxidation mechanisms were proposed. TGE redox properties can be related to its various pharmacological activities. Our new thiolated analogue of genistein neutralizes the LPS-induced ROS production better than GE. Additionally, TGE shows a high cytotoxic activity against human breast cancer cells. The viability of MCF-7 (estrogen-positive cells) drops two times after a 72-h incubation with 12.5 μM TGE (viability 53.86%) compared to genistein (viability 94.46%).     

Removal of an Azo Dye from Wastewater through the Use of Two Technologies: Magnetic Cyclodextrin Polymers and Pulsed Light

Water pollution by dyes is a huge environmental problem; there is a necessity to produce new decolorization methods that are effective, cost-attractive, and acceptable in industrial use. Magnetic cyclodextrin polymers offer the advantage of easy separation from the dye solution. In this work, the β-CD-EPI-magnetic (β-cyclodextrin-epichlorohydrin) polymer was synthesized, characterized, and tested for removal of the azo dye Direct Red 83:1 from water, and the fraction of non-adsorbed dye was degraded by an advanced oxidation process. The polymer was characterized in terms of the particle size distribution and surface morphology (FE-SEM), elemental analysis (EA), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), infrared spectrophotometry (IR), and X-ray powder diffraction (XRD). The reported results hint that 0.5 g and pH 5.0 were the best conditions to carry out both kinetic and isotherm models. A 30 min contact time was needed to reach equilibrium with a qmax of 32.0 mg/g. The results indicated that the pseudo-second-order and intraparticle diffusion models were involved in the assembly of Direct Red 83:1 onto the magnetic adsorbent. Regarding the isotherms discussed, the Freundlich model correctly reproduced the experimental data so that adsorption was confirmed to take place onto heterogeneous surfaces. The calculation of the thermodynamic parameters further demonstrates the spontaneous character of the adsorption phenomena (ΔG° = −27,556.9 J/mol) and endothermic phenomena (ΔH° = 8757.1 J/mol) at 25 °C. Furthermore, a good reusability of the polymer was evidenced after six cycles of regeneration, with a negligible decline in the adsorption extent (10%) regarding its initial capacity. Finally, the residual dye in solution after treatment with magnetic adsorbents was degraded by using an advanced oxidation process (AOP) with pulsed light and hydrogen peroxide (343 mg/L); >90% of the dye was degraded after receiving a fluence of 118 J/cm²; the discoloration followed a pseudo first-order kinetics where the degradation rate was 0.0196 cm²/J. The newly synthesized β-CD-EPI-magnetic polymer exhibited good adsorption properties and separability from water which, when complemented with a pulsed light-AOP, may offer a good alternative to remove dyes such as Direct Red 83:1 from water. It allows for the reuse of both the polymer and the dye in the dyeing process.     

用聚3,4-乙撑二氧噻吩对聚丙烯腈进行导电改性的研究

采用原位化学氧化聚合方法在聚丙烯腈纤维表面生成聚3,4-乙撑二氧噻吩,制备得到纤维表面均匀覆盖聚3,4-乙撑二氧噻吩的改性导电纤维,其电导率约为1×10-3S/cm。纤维表面与导电聚合物的相互作用改善了原纤维的耐热性能,并对其力学性能没有造成伤害。     

GC-MS测定环己烷氧化液中有机酸和酯的含量

采用气相色谱-质谱联用法(GC-MS)测定环己烷氧化液中的有机酸和有机酯的含量。在GC-MS分析条件下环己烷氧化液直接进样,通过毛细管柱DB-1701,60 m×0.15 mm×0.25μm分离,由电子轰击源选择离子监测模式下进行检测。结果表明:有机酸和有机酯的标准曲线相关系数大于0.98,相对标准偏差均小于7.0%,回收率为94.9%～98.6%。