固废可溶盐含量检测方法技术探讨

从生产实际出发,在《填埋场污染物控制标准》无固废可溶盐含量限值和检测方法指导的前提下,开展了固废可溶盐含量检测方法技术探讨。通过几种方法比较,确定悬浮物法可准确测得固废可溶盐含量。试验成功提高了检测分析对固废安全填埋的有效指导作用,降低了环境事故风险,具有较大的环保效益。

地表水中含沙量测定方法选择

本文叙述了黄河万家寨水库地表水中含沙量的测定方法的选择,经过一个月的大量实验,得出了适合含沙量的常规分析方法以及校正实验的方法.

Simulation of Solid Suspension in a Stirred Tank Using CFD-DEM Coupled Approach＊

Computational fluid dynamics-discrete element method(CFD-DEM) coupled approach was employed to simulate the solid suspension behavior in a Rushton stirred tank with consideration of transitional and rotational motions of millions of particles with complex interactions with liquid and the rotating impeller. The simulations were satisfactorily validated with experimental data in literature in terms of measured particle velocities in the tank.Influences of operating conditions and physical properties of particles(i.e., particle diameter and density) on the two-phase flow field in the stirred tank involving particle distribution, particle velocity and vortex were studied.The wide distribution of particle angular velocity ranging from 0 to 105r·min 1is revealed. The Magnus force is comparable to the drag force during the particle movement in the tank. The strong particle rotation will generate extra shear force on the particles so that the particle morphology may be affected, especially in the bio-/polymer-product related processes. It can be concluded that the CFD-DEM coupled approach provides a theoretical way to understand the physics of particle movement in micro- to macro-scales in the solid suspension of a stirred tank.

Synthesis and characterization of single-phase nanocrystalline Ag_2Al particles

Single-phase Ag2Al intermetallic nanoparticles, and Ag and Al metallic nanoparticles were synthesized by the flow-levitation （FL） method. Measurements of d-spacings from X-ray diffraction and electron diffraction confirmed that the intermetallic nanoparticles had the hexagonal Ag2Al structure. The morphology, crystal structure and chemical composition of Ag2Al nanoparticles were investigated by transmission electron microscopy, X-ray diffraction and induction-coupled plasma spectroscopy. A thin amorphous coating was formed around the particles when exposed to air. Based on the XPS measurements, the surface coating of the Ag2Al nanoparticles could most likely be aluminum oxide or silver aluminum oxide. Therefore, the single-phase nanocrystalline Ag2Al intermetallic compound particles can be produced by adjusting some experimental parameters in FL method.

Behavior of different phosphorus species in suspended particulate matter in the Changjiang estuary

Suspended particulate matter （SPM） collected in the Changjiang （Yangtze River） estuary in June 2006 was separated into five fractions via water elutriation： clay-very fme silt （〈8 μm）, fine silt （8-16 μm）, medium silt （16--32 μm）, coarse silt （32~53 μm） and sand （〉63 μm）. The SPM and fractionated particles were sequentially analyzed by a modified SEDEX sequential extraction method to obtain six species of phosphorus： exchangeable or loosely-sorbed P, organic P, Fe-bound P, authigenic P, detrital P and refractory P. The results indicated that all particulate phosphorus species except for detrital P were negatively correlated to particle size; a high detrital P content was found in coarse silt and very coarse silt. From the inside of the river mouth to the gate of the fiver mouth, organic P, Fe-bound P and refractory P in the suspended particles decreased and a higher amount of exchangeable P appeared around the gate of the fiver mouth. From the gate of the river mouth to the sea, exchangeable P and organic P in suspended panicles increased distinctly. The total particulate P flux into the estuary from the Changjiang River was about 45.45×10^8μmol/s during sampling. Of this, about 8.27×10^8μmol/s was associated with the ＂truly suspended＂ fraction. The bio-available particulate P flux was about 13.58×10^8μmol/s. Of this, about 4.24 ×10^8μmol/s w as transported by ＂truly suspended＂ particles.

Improved Production of Paclitaxel from Suspension Culture of Taxus chinensis var. mairei by in situ Extraction with Organic Solvents

The production of paclitaxel from suspension culture of Taxus chinensis var,mairei was improved by in situ extraction with organic solvents to avoid feedback repression and product degradation.Oleic acid and dibutyl phthalate were proved to be suitable solvents .The optimal volumetric percentage of organic solvents in the culture medium was found to be around 8%,and the favorable time for their introduction was at the exponential phase of cell growth,Paclitaxel production with the in situ extraction was ca 3-fold of that without extraction.

A new method for the estimation of fine-sediment resuspension ratios in estuaries-taking the turbidity maximum zone of the Changjiang(Yangtze) estuary as an example

Based on the principle of conservative matter removal in estuary,a new method is proposed for estimating the ratio of sediment resuspension in estuaries with fine suspended sediments in the turbidity maximum zone(TMZ) of the Changjiang(Yangtze) estuary during 2005.Results show that there was a range of 18.7%±27.9% to 73.9%±22.5% per annum of total suspended particulate matter(SPM),with an average of 49.2%.Nearly half of the particulate matter in the TMZ originates from sediment resuspension.This indicates that sediment resuspension is one of the major mechanisms involved in formation of the TMZ.Compared with traditional method for calculating these ratios in the estuary,this new method evaluates the dynamic variation of SPM content carried by river runoff from the river mouth to the ocean.The new method produced more reliable results than the traditional one and could produce a better estimation of resuspension flux for particulate matter in estuaries.

Radiation-Chemical Situation of the Waters of the Middle Reach of the River Yenisei （Russian Federation）

The results of monitoring the radiation-chemical situation in the middle reach of the Yenisei River located in the nearest zone of the influence of the Mining and Chemical Combine of Rosatom have been described in the paper. Using different physico-chemical methods, it has been found that uranium and tritium content in the water exceeds the background values of the flood plain of the River Yenisei. It has been shown that a wide range of radionuclides of different genesis flows into the waters of the Yenisei River. It has been demonstrated that radionuclides are transported by the water flow in the form of molecular solution or with suspended matter. In this case, the suspended matter consists of pelitic finely dispersed mineral particles, plant and organic detritus and living biological objects （for example, worms）. It has been shown that the main contribution to radionuclide and metal accumulation is made by humic substances covering the panicles of the suspended matter and actively participating in the formation of complexes with radionuclides and heavy metals. As a result of this work, the artificial radionuclide inflow into the ecosystem of the River Yenisei has been evidenced.