铁和铝氧化物涂层砂的过滤与吸附性能评价

总结性地对3种不同氧化物涂层砂和未涂层砂的表面特性、过滤和吸附性能进行了比较与分析,明确了适用范围。改性滤料的高温加热和碱性沉积两种制备方法中,涂铁宜选前者,涂铝宜用后者。涂层砂的比表面积增大,吸附容量增加,使石英砂表面电荷的带电性质改变,有利于水中杂质的去除。涂铁砂适合于除氟和除砷及除有机物;涂铝砂适合于除浊、除有机物和除锌。     

Different behaviours in the solubilization of polycyclic aromatic hydrocarbons in water induced by mixed surfactant solutions

Water solubility of polycyclic aromatic hydrocarbons (PAHs), viz, naphthalene and phenanthrene, in micellar solutions at 25 °C was investigated, using two series of different binary mixtures of anionic and nonionic surfactants. Tween 80 and Brij-35 were used as nonionic surfactants whereas fatty acids or amphiphilic cyclodextrins (Mod-β-CD) synthesized in our laboratory were used as anionic ones. Solubilization capacity has been quantified in terms of the molar solubilization ratio and the micelle-water partition coefficient, using UV-visible spectrophotometry. Anionic surfactants exhibited less solubilization capacity than nonionics. The mixtures between Tween 80 and Mod-β-CD did not show synergism to increase the solubilization of PAHs. On the other hand, the mixtures formed by Tween 80 and fatty acids at all mole fractions studied produced higher enhancements of the solubility of naphthalene than the individual surfactants. The critical micellar concentration of the mixtures of Tween 80/sodium laurate was determined by surface tension measurements and spectrofluorimetry using pyrene as probe. The system is characterized by a negative interaction parameter (β) indicating attractive interactions between both surfactants in the range of the compositions studied.     

Mechanisms and chemistry of dye adsorption on manganese oxides-modified diatomite

The investigations into structural changes which occur during adsorbent modification and the adsorption mechanisms are essential for an effective design of adsorption systems. Manganese oxides were impregnated onto diatomite to form the type known as δ-birnessite. Initial investigations established the effectiveness of manganese oxides-modified diatomite (MOMD) to remove basic and reactive dyes from aqueous solution. The adsorption capacity of MOMD for methylene blue (MB), hydrolysed reactive black (RB) and hydrolysed reactive yellow (RY) was 320, 419, and 204 mg/g, respectively. Various analytical techniques were used to characterise the structure and the mechanisms of the dye adsorption process onto MOMD such as Fourier transform infrared (FTIR), X-ray diffraction (XRD) and atomic absorption spectrometry (A.A.). A small shift to higher values of the d-spacing of dye/MOMD was observed indicating that a small amount of the dye molecules were intercalated in the MOMD structure and other molecules were adsorbed on the external surface of MOMD. Two mechanisms of dye adsorption onto MOMD were proposed; intercalation of the dye in the octahedral layers and adsorption of the dye on the MOMD external surface. Moreover, the results demonstrated that the MOMD structure was changed upon insertion of MB and RY with an obvious decrease in the intensity of the second main peak of the MOMD X-ray pattern.     

丽江市古城区污水处理厂扩建工程的启动调试及运行

丽江市污水处理厂扩建工程处理规模为1万m3/d,采用了改良型ICEAS工艺。该污水处理系统的启动调试内容,包括调试前的准备工作以及活性污泥的培养与驯化。活性污泥培养驯化历时50 d左右,活性污泥絮体基本形成,生物相基本稳定,处理效果显著,出水各项指标达标。在进水BOD低营养源不足的不利条件下,成功完成了该污水处理厂的启动调试和活性污泥培养驯化,对指导污水厂的调试运行有着重要的意义。     

改性天然高分子絮凝剂的研究与应用现状展望

改性天然高分子絮凝剂因具有原料来源广泛、价值低廉、无毒、易于生物降解、无二次污染等优点，受到了国内外众多研究工作者的重视和开发应用。本文扼要的介绍了国内近年来的改性天然高分子絮凝剂方面的研究和应用情况，对其前景进行了展望，并就我国今后在此方面的研究工作提出了一些建议。     

HDTMA改性蒙脱土对苯酚的吸附及机理研究

利用十六烷基三甲基溴化铵(HDTMA)改性蒙脱土处理含酚废水．了解不同改性量有机蒙脱土吸附苯酚的能力。结果表明．改性蒙脱土按照分配机理吸附苯酚．改性蒙脱土改性量高和水溶液中苯酚浓度高．其吸跗的苯酚数量大。1．0CEC(阳离子交换容量)改性蒙脱土对水溶液中苯酚去除率达到76％。改性蒙脱土中有机物对苯酚的吸附存在协同作用．因此．改性蒙脱土吸附苯酚的增加速率要超过其中HDTMA增加的速率。在试验的苯酚浓度下．改性蒙脱土对苯酚吸附符合Freundlich吸附模式．不符合Langmuir吸附模式。     

Synthesis of highly effective absorbents with waste quenching blast furnace slag to remove Methyl Orange from aqueous solution

Water quenching blast furnace slag(WQBFS) is widely produced in the blast furnace iron making process. It is mainly composed of CaO, MgO, Al_2O_3, and SiO_2 with low contents of other metal elements such as Fe, Mn, Ti, K and Na. In this study, WQBFS was treated with grinding, hydrochloric acid acidification, filtration, filtrate extraction by alkali liquor and a hydration reaction. Then BFS micropowder(BFSMP), BFS acidified solid(BFSAS) and BFS acid-alkali precipitate(BFSAP) were obtained, which were characterized by X-ray diffraction, scanning electron microscopy, X-ray fluorescence and Brunauer-Emmet-Teller(BET)specific surface area. The decoloration efficiency for Methyl Orange(MO) was used to evaluate the adsorptive ability of the three absorbents. The effects of adsorptive reaction conditions(p H and temperature of solution, reaction time, sorbent dosage and initial concentration) on MO removal were also investigated in detail. The results indicated that BFSAP performed better in MO removal than the other two absorbents. When the p H value of MO solutions was in the range 3.0–13.0, the degradation efficiency of a solution with initial MO concentration of 25 mg/L reached 99.97% for a reaction time of 25 min at 25°C.The maximum adsorption capacity of BFSAP for MO was 167 mg/g. Based on optimized experiments, the results conformed with the Langmuir adsorption isotherm and pseudo-second-order kinetics. Among inorganic anions, SO_4~(2-)and PO_4~(3-)had significant inhibitory effects on MO removal in BFSAP treatment due to ion-exchange adsorption.     

改性TiO2对X-3B的光催化性能及其降解动力学研究

以活性艳红X-3B为模型化合物,比较了改性前后TiO2光催化活性的变化.试验结果表明,通过改性大大提高了TiO2的光催化活性,Fe3+和Ag+的掺杂量均有一个最佳值,在试验的掺杂范围内Fe3+和Ag+的最佳掺杂量分别是0.1%和0.05%.对其宏观降解反应动力学的研究表明,X-3B在TiO2、Fe3++TiO2和Ag++TiO2 3种催化剂上的光催化降解动力学均能很好地符合Langmiur-Hinshelwood动力学模型.其表观反应速率常数的大小顺序依次是Ag++TiO2＞Fe3++TiO2＞TiO2;吸附平衡常数则是Fe3++TiO2和Ag++TiO2两者基本相等,两者均比纯TiO2大2～3倍.     

Involving local farmers in rehabilitation of degraded tropical forests: some lessons from Ghana

The role of community-based plantation development in forest rehabilitation and poverty alleviation is a pressing issue for the government of Ghana. In this paper, we present an analysis of the prospects of a community-based plantation using taungya systems and indigenous trees as means to forest rehabilitation and livelihood improvement in Ghana. The project management strategies, communication process and incentive mechanism and their impact on local participation are discussed with the aim to recommending a mechanism through which local farmers can best be involved in rehabilitation of degraded sites in the future in Ghana. Data were collected through a survey using personal interviews of 431 farming households and ten key informants from ten communities living in scattered hamlets in and around forests reserves. The results show a high rate of local participation in project tree planting activities. Four years after the project’s initiation, about 250 ha of plantations had been established using twelve priority indigenous and one exotic species and farmers had indicated improvement in their farming practices and availability of food and forest products. Restoring forest quality as a timber resource and associated values, getting money, food stuff and timber and non-timber for domestic use, and having access to fertile land for farming were the top three issues prioritised by respondents as motivational factors for engaging in the project activities. Overall, this project demonstrates that reversing tropical forest degradation is possible. For this we need local involvement in tree domestication combined with activities that addresses livelihood needs and environmental concerns. This case also demonstrates the prospects of utilising indigenous tree species, not only exotic species that dominated tree planting in the past, for plantations and landscape rehabilitation in Ghana. Readers should send their comments on this paper to BhaskarNath@aol.com within 3 months of publication of this issue.     

改性聚合硫酸铁的絮凝特性及其应用

本文较详细地介绍了改性聚合硫酸铁的絮凝机理、净水性能、质量指标、应用范畴及其注意事项,并使用珠江水对几种主要的无机高分子絮凝剂进行了性能测试,结果表明,改性聚合硫酸铁的生产成本最低,净水效果却最显著.