强化吸附性生物膜处理洗浴废水实验研究

通过纯种分离获得LAS优势降解菌,以活性炭纤维为载体挂膜形成强化吸附性生物膜进行洗浴废水处理实验研究;并在动态实验条件下,与单纯活性炭吸附和普通吸附性生物膜处理工艺进行了对比。实验结果表明:在相同的反应条件下,强化吸附性生物膜对LAS、COD的去除率比普通吸附性生物膜高7.63%和4.2%;当进水流量为1.5 L/h,HRT为4 h,曝气量为1.5 mg/L时,其对洗浴废水中LAS、COD和NH3-N的去除率分别为87.14%、85.87%和74.89%。     

A City for Education

Ameena Ahmadi is Architecture Manager at the Qatar Foundation, overseeing the development of the masterplan and facilities of Education City in Doha, a multi-institution educational campus, incorporating schools and universities. Ahmadi describes how education is a significant cornerstone for Qatar's national transition ‘to a knowledge-based’ economy from a ‘hydrocarbon-based’ one. This is symbolised by substantial investment in the flagship Education City with its Arata Isozaki masterplan and its individual schools and universities designed by premier international architects.     

Sulfoxylated methyl esters as potential components of liquid formulations

Sulfoxylated methyl esters (Φ-MES) are obtained via sulfoxidation of fatty acid methyl esters with SO₂, O₂, and ultraviolet light of appropriate wavelength. These products may be used as co-surfactants with linear alkylbenzene sulfonate and alkyl ether sulfate, either in heavy-duty or in hand dishwashing liquids. Standard hand dishwashing formulations based on Φ-MESC₁₆ are presented and discussed with regard to solubility, viscosity, performance, and skin compatibility. The experimental results obtained indicate that the above-mentioned products can be regarded as potential components for liquid formulations.     

烷基苯磺酸钠在环境中自然降解的研究进展

烷基苯磺酸钠(LAS)在环境中的自然降解行为一直是环境保护界研究的重点.阐述了LAS在环境(水体、土壤)中的自然降解过程及降解机理,分析了LAS的分子结构、初始浓度及环境中微生物数量、温度、供养量、pH值等主要因素对LAS降解效率的影响,以期为LAS的扩大应用及其污染治理提供参考和依据.     

α-磺基脂肪酸甲酯钠盐(MES)在洗洁精中的应用

在洗洁精配方中,采用MES与LAS、AES复配作为主表面活性剂,不但可以减少AES添加量,而且可以不使用洗洁精配方中常用的增稠剂6501,在保持洗洁精质量(去污力、低温稳定性、粘度)同时,使配方成本更加合理.     

碳纤维／锂铝硅（LAS）玻璃陶瓷的界面结构及界面反应

用TEM,EDAXJ SAD,XPS,SEM等手段,分别对两种成分的锂铝硅(LAS)系统玻璃陶瓷(LAS_I和LAS(?))为基材在不同热压时间下获得的具有不同强度和韧性的碳纤维补强复合材料的界面及从复合材料萃取出来的纤维表面进行了研究。短时同热压的碳纤维-LAS_I界面层窄,界面较致密,而长时同热压,界面层变宽且疏松。碳纤维-LAS(?)存在较宽的气体扩散层界面,界面区还含有由界面反应生成的NbC颗粒,较长时间的热压,界面层变窄,NbC颗粒沉积在纤维上,改善了界面结构。界面反应和界面结构的形成及其对复合材料性能的影响进行了分析和讨论。     

Influence of calcium concentration in the washing liquor on detergency performance of linear alkylbenzene sulfonate

The effect of the concentration of linear alkylbenzene sulfonate (LAS) on soil removal efficiency at various water hardnesses was studied. The present investigation indicates that: (i) For each LAS concentration, a calcium ion concentration interval exists, defined by 0.78<(Log(LAS)/Log(Ca))<0.85, where the detergency reaches a maximum; (ii) 24 h after having been prepared, the solutions present either clear solutions (water appearance), milky solutions (without precipitate in the bottom of the bottle), or clear solutions with precipitate in the bottom of the bottle. The milky solutions correspond to the defined interval. The solutions where the relationship LAS/Ca is defined are located, surprisingly in a precise zone of the LAS-calcium solubility diagram. The study has been carried out with and without ionic strength buffering, and the addition of electrolyte moves the maximum detergency performance interval to higher calcium concentrations.     

Exposure of the marine deposit feeder Hydrobia ulvae to sediment spiked with LAS congeners

The lethal and sub-lethal toxicity of LAS congeners to the mollusc gastropod Hydrobia ulvae were assessed in spiked sediment bioassays. This complements the little knowledge available to date on mixture effects in the sediment compartment. The LAS homologues joint effect was concentration additive (∑TU_i = 0.8-1). As opposed to the 10-d LC10 based on the sediment associated LAS concentration (91-330 mg/kg) which was independent of the homologue chain length, the LC10 based on the dissolved LAS fraction (0.804-0.068 mg/L) decreased as the homologue chain length increased from 10 to 13 carbons. The quantitative structure-activity relationship (QSAR) derived from these data was log (1/LC10 (mol/L)) = 0.64 log K_ow + 4.40 (n = 5; r² = 0.76; s = 0.24). It showed an apparent higher toxicity compared to the typical QSAR for polar narcosis in water-only systems probably due to the simultaneous exposure of the snail to LAS through the dissolved and the sediment associated fractions. The egestion rate of the surviving snails recovered after few days' exposure (1-d NOEC: 40-107 mg/kg, 9-d NOEC: 65-190 mg/kg) which suggests that the organisms were able to acclimate to LAS during the exposure.     

Using sonochemical reactor for degradation of LAS from effluent of wastewater treatment plant

Linear alkylbenzene sulfonates (LAS) are anionic surfactants, which are found in relatively high amounts in domestic and industrial wastewaters. The effectiveness of using sonochemical reactor for the degradation of LAS from effluent of wastewater treatment plant has been investigated. In this study, experiments of LAS solution were performed using methylene blue active substances (MBAS) method. The effectiveness of sonochemical reactor for LAS degradation is evaluated with emphasis on the effect of sonication time and initial LAS concentration. Experiments were carried out at initial concentrations of 0.2 mg/L, 0.5 mg/L, 0.8 mg/L and 1 mg/L, frequency of 130 kHz, acoustic power value of 400 W, temperature of 18-20 °C and pH value of 6.8-7. This study showed that LAS degradation was found to increase with increasing sonication time. In addition, as the concentration is increased, the LAS degradation rate decreases in the sonochemical reactor.     

乾安县LAS数据与未来降水关系的统计检验

在LAS输出数据的低谷常对应有降水天气出现，为确定这种关系在降水预报中是否有应用价值，对每日中午LAS数据的高值和低值和未来32h晴雨的关系作统计检验。首先根据数据随季节的变化，确定每月高和低的分界线。然后用X^2检验法，检验高值后的晴雨概率和低值后的晴雨概率有否明显区别。检验结果表明，高值和低值之后出现晴雨天气的概率差异显著，各个月得到的统计量X^2的值，全部通过X0.005^2的临界值。