Effect of sorbed and desorbed Zn（II） on the growth of a green alga （ Chlorella pyrenoidosa）

Toxic effect of Zn（II） on a green alga （Chlorella pyrenoidosa） in the presence of sepiolite and kaolinite was investigated. The Zn-free clays were found to have a negative impact on the growth of C. pyrenoidosa in comparison with control samples （without adding any clay or Zn（II））. When Zn（II） was added, the algae in the presence of clays could be better survived than the control samples, which was actually caused by a decrease in Zn（II） concentration in the solution owing to the adsorption of Zn（II） on the clays. When the solution system was diluted, the growth of algae could be further inhibited as compared to that in a system which had the same initial Zn（II） concentration as in the diluted system. This in fact resulted from desorption of Zn（II） from the zinc-contaminated clays, although the effect varied according to the different desorption capabilities of sepiolite and kaolinite. Therefore the adsorption and desorption processes of Zn（H） played an important part in its toxicity, and adsorption and desorption of pollutants on soils/sediments should be well considered in natural eco-environmental systems before their risk of toxicity to aquatic organisms was assessed objectively.     

大孔吸附树脂（XH－1）处理含酚废水的研究

本文就ＸＨ－１型大孔吸附树脂对含酚废水处理性能进行了研究，探索了吸附平衡时间，确立了吸附体系Ｆｒｅｕｎｄｌｉｃｈ等温式，找到了树脂在不同再生剂中最佳工艺条件，发现了吸附、脱附过程分别具有二级和一级反应动力学特征，并得到其表现活化能．     

以苛性法软化油田采出水用作锅炉给水的处理新工艺

在应用蒸汽开采重油（稠油）生产中，常因采出水不需回注而带来环境保护上的问题。较适宜的处置方法是将采出水处理后作为发生蒸汽的锅炉给水。而软化具高矿化度的采出水使其符合硬度指标要求极为严格的锅炉用水，是处理工艺中关键技术之一。本文对美国当前在这方面的一般处置方法作了综合性介绍，着重介绍了Belridge油田水软化处理厂采用苛性法和弱离子交换法这一新工艺的成功经验。     

密闭液封堵条件下的瓦斯解吸规律实验研究

瓦斯严重威胁着煤矿的安全生产,煤层瓦斯解吸规律与矿井瓦斯灾害关系非常密切。本文首先提出了密闭液封堵条件下的瓦斯解吸实验原理,制定了相应的实验方案;然后,开展了密闭液封堵条件下的煤芯瓦斯解吸规律实验;最后,进行了密闭液封堵煤芯瓦斯的现场取芯试验。研究结果显示,与自由状态下解吸相比,密闭条件下的瓦斯解吸量呈现不同程度的降低,效果显著;在取芯过程中,密闭液能够包裹煤芯,该测定技术所获得的煤芯瓦斯解吸量与残存量之和,比普通煤芯取样法平均提高了9%。因此,利用该技术所测得的煤层瓦斯含量,其可靠性与准确率更高。     

Adsorption behavior of RH‐5992 insecticide onto sandy and clay loam forest soils

Abstract

Adsorption‐desorption behavior of RH‐5992 [Mimic®, N'‐t‐butyl‐N'‐(3,5‐dimethylbenzoyl)‐N‐(4‐ethylbenzoyl) hydrazine] in sandy and clay loam forest soils was studied using the batch equilibrium method. Adsorption was higher in the clay loam soil than in the sandy loam, and increased linearly with RH‐5992 concentration, but decreased with increasing pH and temperature. The adsorption data fit better to the Freundlich, than to the Langmuir equation. The K_D (linear adsorption constant) and K_F (Freundlich constant) were similar for each soil at 5, 15 and 25°C and decreased with increase of temperature, indicating that the enthalpy of adsorption was negative. The exponent of the Freundlich equation was close to unity for both soils at all three temperatures. The low E_a (energy of activation) indicated a diffusion‐controlled process during the initial stages of adsorption. The desorption isotherm differed from that of adsorption, and the linear desorption constant, K_D(d), was ca 25 times higher than the K_D, indicating that adsorption of RH‐5992 was not readily reversible. Evaluation of thermo‐dynamic parameters confirmed the presence of strong bonds between the solute and soil. These findings suggest that RH‐5992 has a limited potential for downward mobility leading to groundwater contamination.     

A sandy loam soil as a natural control for Pb contamination

The Pb (II) adsorption/desorption mechanism onto a natural sandy loam soil was studied by batch experiments at different pHs (3.0, 4.5, 6.0), at different ionic strength (0, 0.02 and 0.1 M) and with different electrolytes solutions of NaCl, NaAcO and NaNO₃. Pb was strongly adsorbed onto the soil due to the formation of a mix of inner-sphere and outer-sphere complexes. Experimental adsorption data fitted Freundlich and Langmuir isotherms. The desorption results with 0.1 M Mg (NO₃)₂ and 0.1 M NaAcO solutions corroborated the mechanisms proposed. The strong binding of Pb (II) to high affinity sites on soil minerals seems to be responsible for the extent of hysteresis. The sandy loam soil under study thus constitutes a natural control for Pb contamination.     

Variations in surface functional groups, carbon chemical state and graphitization degree during thermal deactivation of diesel soot particles

The thermal deactivation of diesel soot particles exerts a significant influence on the control strategy for the regeneration of diesel particulate filters (DPFs). This work focused on the changes in the surface functional groups, carbon chemical state, and graphitization degree during thermal treatment in an inert gas environment at intermediate temperatures of 600°C, 800°C, and 1000°C and explore the chemical species that were desorbed from the diesel soot surface during thermal treatment using a thermogravimetric analyser coupled with a gas-chromatograph mass spectrometer (TGA-GC/MS). The surface functional groups and carbon chemical state were characterized using Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The graphitization degree was evaluated by means of Raman spectroscopy (RS). The concentrations of aliphatic C–H, C–OH, C=O, and O–C=O groups are reduced for diesel soot and carbon black when increasing the thermal treatment temperature, while the sp²/sp³ hybridized ratio and graphitization degree enhance. These results provide comprehensive evidence of the decreased reactivity of soot samples. Among oxygenated functional groups, the percentage reduction during thermal treatment is the largest for the O–C=O groups owing to its worst thermodynamic stability. TGA-GC/MS results show that the aliphatic and aromatic chains and oxygenated species would be desorbed from the soot surface during 1000°C thermal treatment of diesel soot.     

Characteristics of mercury desorption from sorbents at elevated temperatures

This study investigated the dynamic desorption characteristics of mercury during the thermal treatment of mercury-loaded sorbents at elevated temperatures under fixed-bed operations. Experiments were carried out in a 25.4 mm ID quartz bed enclosed in an electric furnace. Elemental mercury and mercuric chloride were tested with activated carbon and bauxite. The experimental results indicated that mercury desoption from sorbents was strongly affected by the desorption temperature and the mercury–sorbent pair. Elemental mercury was observed to desorb faster than mercuric chloride and activated carbon appeared to have higher desorption limits than bauxite at low temperatures. A kinetic model considering the mechanisms of surface equilibrium, pore diffusion and external mass transfer was proposed to simulate the observed desorption profiles. The model was found to describe reasonably well the experimental results.     

粉尘云最小点火温度测试实验系统设计

通过对Godbert -Greenwald恒温炉分析与改造 ,设计了粉尘云最小点火温度实验装置 ,并建立了相应的测试系统。调试结果表明 ,该实验系统扬尘均匀性、温控精度及结果可重复性能良好