Use of TNSAC in phosphate adsorption studies and relationships. Isotherm relationships and utility in the field

There is a need for developing low cost, easily and abundantly available, yet efficient, adsorbents for the removal of phosphates during the tertiary treatment of wastewaters. The tamarind nut shell activated carbon (TNSAC) prepared on a laboratory scale has been used to evaluate its performance for phosphate adsorption. This paper describes the laboratory production of this adsorbent material in its various forms, and discusses the effects of the TNSAC process variables (the unrinsed and rinsed forms of the TNSAC and the impregnation ratio) on its performance in adsorbing phosphate. The material has been shown to be a good alternative adsorbent. As much as 95% phosphate removal by the unrinsed TNSAC is possible in about 30 min under the test conditions. The phosphate adsorbing capacity is about two times higher for the unrinsed TNSAC in comparison to the rinsed TNSAC. The adsorption rates, however, transit to extremely low rates towards the end when equilibrium conditions could be attained in about 2 h contact time. The phosphate removal mechanics are adsorption and precipitation/ion exchange when unrinsed TNSAC is used, and adsorption alone for the rinsed TNSAC. The maximum phosphate removal is found to take place at an impregnation ratio of 1.0 for both forms of the TNSAC.     

Lake-Level Change and Water Balance Analysis at Lake Qinghai,West China during Recent Decades

Lake Qinghai, the largest saline lake with an area of 4,260 km² (2000) and average depth of 21 m (1985) in West China, has experienced severe decline in water level in recent decades. This study aimed to investigate water balance of the lake and identify the causes for the decline in lake level. There was a 3.35-m decline in water level with an average decreasing rate of 8.0 cm year⁻¹ between 1959 and 2000. The lake water balance showed that mean annual precipitation between 1959 and 2000 over the lake was 357 ± 10 mm, evaporation was 924 ± 10 mm, surface runoff water inflow was 348 ± 21 mm, groundwater inflow was 138 mm ± 9 and the change in lake level was −80 ± 31 mm. The variation of lake level was highly positively correlated to surface runoff and precipitation and negatively to evaporation, the correlation coefficients were 0.89, 0.81 and −0.66, respectively. Water consumption by human activities accounts for 1% of the evaporation loss of the lake, implying that water consumption by human activities has little effect on lake level decline. Most dramatic decline in lake level occurred in the warm and dry years, and moderate decline in the cold and dry years, and relatively slight decline in the warm and wet years, therefore, the trend of cold/warm and dry climate in recent decades may be the main reasons for the decline in lake level.     

基于遗传神经网络的电站锅炉飞灰含碳量预测

针对锅炉飞灰含碳置影响因素复杂．实时测量难度大．精度低，提出了一种基于遗传神经网络的预测方法，并用于某电厂，结果表明，该方法是有效的。     

Supercritical fluid extraction of daphne (Laurus nobilis L.) seed oil

Laurus nobilis L., commonly known as daphne tree, is an evergreen that belongs to the Lauraceae family. Daphne trees produce grape-sized shiny purplish berries having three parts: flesh, skin, and an inner kernel (single seed). This study examines supercritical CO₂ (SC-CO₂) extraction of oil from daphne seeds. The oil yield of ground seeds varied from 14 to 28% depending on the method and particle size used for oil recovery. Yields were similar for both petroleum ether and SC-CO₂ extraction. The extraction yield decreased significantly with increasing particle size. The amount of extract collected increased exponentially with increasing SC-CO₂ pressure. The highest extraction yield was obtained at the highest temperature studied, 75°C. More than 45% of the oil was lauric acid. SC-CO₂ is a viable technique to obtain high-purity L. nobilis L. seed oil, which is a potential ingredient for the cosmetic industry.     

碳纳米管及其批量制备研究进展

从碳纳米管的优异性能和应用出发,综述了碳纳米管的制备方法以及我国目前在碳纳米管研究中面临的问题;分析了碳纳米管产业化对的我国纳米技术产业化发展的积极意义,特别介绍了清华-南风纳米粉体产业化工程中心开发的、具有我国自主知识产权的纳米聚团流态化技术。     

铜冶炼企业金银回收率计算方法的选择

针对某厂金、银总平衡情况，分别采用平衡法和连乘法计算金、银回收率，得出两种不同的结果，文章分析了产生不同结果的原因，探讨不同的企业如何根据自身特点，选择与之相适应的金、银回收率计算方法，以便准确地反映本企业的回收率实际水平。     

Development of a Magnetic Suspension Densimeter and Measurement of the Density of Toluene

The development of a magnetic suspension densimeter that has been built for measurement of the density of compressed liquid at pressures up to 30 MPa in the temperature range 20 to 150°C is described. The densimeter was first built by the author and his coworkers at NIST. We describe here further improvements made on a second system built at NMIJ based on the same principle. The densimeter uses a small coil suspended from an electronic balance. Within the coil is placed a sample cell in which the pressurized sample and a buoy, which is a permanent magnet, are enclosed. For measurement of density, balance readings are recorded (1) with the buoy at rest and (2) with the buoy in magnetic suspension. The measurement procedure is basically a hydrostatic weighing, which is simpler than those of conventional magnetic densimetry. As an example, measurements of toluene density performed as part of an inter-laboratory comparison are presented. The data agreed with reliable literature values to within a few hundredths of a per cent.     

Synthesis and Characterization of Nanosized ZSM-5 Zeolite with Mesoporous Carbon Nanotube as Templates

Preparation of nanocrystalline ZSM-5 has been proven possible with carbon matrix by using confined space synthesis. In combination with the hydrothermal method, by the use of a mesoporous carbon nanotube as the inert support material, ZSM-5 with SiO₂/Al₂O₃ ratios of 100 was successfully synthesized with an average crystal size of 27 nm. Their structures were preliminarily characterized by x-ray power diffraction (XRPD) and infrared spectroscopy (IR), and scanning electron microscopy (SEM), respectively. At the same time, we put forward the mechanism about the confined space synthesis in terms of the results.