活性炭的改性及其对苯酚吸附行为的研究

通过正交试验的方法,优化活性炭的改性条件;并以活性炭为载体,氢氧化钠溶液为改性剂,在最优条件下制备改性活性炭;测定了改性前后活性炭的比表面积及表面酸性官能团的含量;考察了改性前后活性炭对苯酚的吸附行为。结果表明,在NaOH溶液浓度为0．1mol／l,浸渍时间为3h,活化时间为3h,活化温度为400℃的情况下,改性活性炭吸附效果最佳,苯酚吸附量为149．05mg／g,比未改性活性炭的吸附量提高了61．97％;NaOH-改性活性炭的比表面积为1046．10m2／g,比未改性活性炭的比表面积增加了12．42％,改性后表面的酸性基团含量降低,碱性增强;Freundlich和Langmuir二种等温线模型均能较好的反应活性炭对苯酚的吸附行为,其中Freundlich模型更为理想。     

Effects of water regime during rice-growing season on annual direct N2O emission in a paddy rice-winter wheat rotation system in southeast China

Annual paddy rice-winter wheat rotation constitutes one of the typical cropping systems in southeast China, in which various water regimes are currently practiced during the rice-growing season, including continuous flooding (F), flooding-midseason drainage-reflooding (F-D-F), and flooding-midseason drainage-reflooding and moisture but without waterlogging (F-D-F-M). We conducted a field experiment in a rice-winter wheat rotation system to gain an insight into the water regime-specific emission factors and background emissions of nitrous oxide (N₂O) over the whole annual cycle. While flooding led to an unpronounced N₂O emission during the rice-growing season, it incurred substantial N₂O emission during the following non-rice season. During the non-rice season, N₂O fluxes were, on average, 2.61 and 2.48 mg N₂O-N m⁻² day^− 1 for the 250 kg N ha^− 1 applied plots preceded by the F and F-D-F water regimes, which are 56% and 49% higher than those by the F-D-F-M water regime, respectively. For the annual rotation system experienced by continuous flooding during the rice-growing season, the relationship between N₂O emission and nitrogen input predicted the emission factor and background emission of N₂O to be 0.87% and 1.77 kg N₂O-N ha^− 1, respectively. For the plots experienced by the water regimes of F-D-F and F-D-F-M, the emission factors of N₂O averaged 0.97% and 0.85%, with background N₂O emissions of 2.00 kg N₂O-N ha^− 1 and 1.61 kg N₂O-N ha^− 1 for the annual rotation system, respectively. Annual direct N₂O-N emission was estimated to be 98.1 Gg yr^− 1 in Chinese rice-based cropping systems in the 1990s, consisting of 32.3 Gg during the rice-growing season and 65.8 Gg during the non-rice season, which accounts for 25-35% of the annual total emission from croplands in China.     

Synthesis of PVC‐TEPA‐supported proline derivative and its catalytic behavior in the direct asymmetric aldol reaction

PVC‐TEPA‐supported L ‐proline catalyst has been synthesized and characterized by IR. It is developed as an efficient catalyst for the direct asymmetric aldol reaction of unmodified ketones with various aldehydes in the presence of water at 0°C. The corresponding aldol products were obtained with high yields (up to 94%) and good enantioselectivities (up to 97% ee) on optimized conditions. Recycling investigations have shown that this material can be reused without loss of catalytic activity and stereoselectivity for at least 15 cycles. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

In situ grown fibrous composites of poly(dl-lactide) and hydroxyapatite as potential tissue engineering scaffolds

In situ grown hydroxyapatite (HA) within electrospun poly(dl-lactide) (PDLLA) fibers were initially investigated as potential tissue engineering scaffolds with respect to the mechanical performances, biomineralization capability, degradation behaviors, cell growth and differentiation profiles. The tensile strength and Young’s moduli of in situ grown composites (IGC) were 8.2 ± 1.1 and 63.5 ± 5.6 MPa, respectively, which were significantly higher than those of blend electrospun composites (BEC) with 25.2% of HA inoculation. The interactions between HA and matrix polymers were approved by the red-shifts of CO stretching and OH- stretching modes and the increases in glass transition temperatures of fibrous composites. The localization of apatite phase on the fiber surface improved the biomineralization capability and enhanced the morphological stability of the fibers and fibrous mats even when the degradation of matrix polymers was detected. The cell viability and alkaline phosphatase levels were significantly higher for composites IGC, indicating favorable scaffolds for cell proliferation and osteogenic differentiation.     

Application of HIGEE process intensification technology in synthesis of petroleum sulfonate surfactant

Petroleum sulfonate (PS) surfactant used for enhanced oil recovery was synthesized by dilute liquid sulfur trioxide and petroleum fraction (PF) of Shengli crude oil as raw materials with the application of HIGEE process intensification technology. The effects of various experimental conditions on the content of active matter and unsulfonated oil were investigated. The optimum conditions were selected as solvent/oil mass ratio 0.5, SO₃/oil mass ratio 0.525, reaction temperature 30 °C, rotating speed 1200 rpm, circulation ratio 4, reaction time 15 min and aging time 50 min under which the active matter content was up to 45.3 wt.% and the oil/water interfacial tension was as low as 4.5 × 10⁻³ mN/m. The higher product quality and higher process efficiency of this new technology is proven by a comparison with traditional STR process.     

Reaction mechanism in Ti–SiC–C powder mixture during pulse discharge sintering

During pulse discharge sintering (PDS) of Ti/SiC/C powder mixture, combustion synthesis reactions occurred at heating rates above 20 °C/min. With an increase in heating rate, combustion synthesis occurred at higher temperatures. The essential of this combustion reaction is the liquid reaction between Ti and formed Ti₅Si₃. The exothermic TiC formation during PDS process promotes this liquid reaction. We have found that the combustion reactions alone did not finish the formation reactions for Ti₃SiC₂, and further heating following the combustion reactions is necessary for the synthesis process of Ti₃SiC₂.     

水厂混凝剂投加量建模研究

通过对某水厂投药量控制以及生产数据的分析和处理,采用机理法及差分进化参数辨识法建立了混凝剂投加量的2种数学模型,并进行了检验和对比.结果表明,2种模型在低原水浊度区都较为准确可靠;在中原水浊度区,线性模型准确性优于指数模型;在高原水浊度区,指数模型准确性优于线性模型.生产过程中可将2种模型结合起来,根据原水浊度的不同分别采用不同的模型预测.将该预测值作为操作工人操作的参考值,解决了在不同操作工操作情况下混凝剂的准确投加问题,为水厂的优化运行提供了良好基础.     

负载型MoO_3/SiO_2催化合成乙酸乙酯

采用等体积浸渍法制备了MoO3/SiO2负载型催化剂,并用于催化乙醇和乙酸的酯化反应。考察了催化剂的制备条件及反应条件对醋酸转化率的影响。结果表明,催化剂适宜的制备条件为焙烧温度450℃,焙烧时间4 h,MoO3负载量为20%;适宜的反应条件为反应时间3 h、原料醇酸比为1.4︰1、催化剂用量为醋酸质量的1.9%,醋酸的转化率为79%,乙酸乙酯的选择性为100%,催化剂可重复使用。     

自动粘度仪与手动粘度仪在油品分析中的应用比较

介绍了CAV2000A动粘度仪的工作原理及测定方法,利用CAV2000自动粘度仪对润滑油、柴油、燃料油等石油产品进行运动粘度的测定,并将测定结果与现行粘度测试标准（GB／T265—1988、GB／T11137-1989）进行比较,结果表明,CAV2000自动粘度仪操作简便快速,重复性好,精度在标准方法允许的误差范围内。     

45#钢在磷酸盐颜料提取液中的电化学行为

用开路电位法、Tafel极化曲线、EIS等方法研究了45#钢在不同pH的磷酸锌、APW-I及两种复合掺杂磷酸盐颜料3.5%NaCl水提取液中的电化学行为。研究结果表明:两种复合掺杂磷酸盐颜料在不同酸碱度条件下,均显示出异常优异的腐蚀抑制性能,且是以抑制阳极为主的防锈颜料;碱性体系下,传统磷酸盐颜料APW-I的结果较为优越。