Adsorption of a dye on clay and sand. Use of cyclodextrins as solubility-enhancement agents

Laboratory-scale studies were aimed at elucidating the physico-chemical aspects on the removal process of crystal violet (CV) from waters and solid substrates. The laponite clay (RD) and sand were chosen for the double aim at investigating them as CV adsorbents for water treatment and as substrates which mime the soil components. Sand is very effective in removing CV from waters. The cyclodextrins (CDs) were exploited as solubility-enhancement agents to remove CV from the solid substrates. They are powerful solvent media because they extract the CV from sand forming water-soluble CV/CD inclusion complexes and do not show affinity for sand. Optimum performance was shown by the modified CDs (i.e. hydroxypropyl-β-cyclodextrin and methyl-β-cyclodextrin). A linear correlation between the logarithm of the equilibrium constant for the CV/CD inclusion complexes formation (K_cpx) and the maximum amount of CV extracted from sand in the columns experiments at a flow rate of 1.5 ml min⁻¹ was drawn. This relationship predicts that CDs with K_cpx < 180 M⁻¹ are not suitable for CV removal from sand. CDs failed to displace CV from RD because they generate the formation of RD clusters where CV remains entrapped.     

Preparation and Characterization of Cellulose/Polypropylene Composite Using an Oxidatively Degraded Polypropylene

In this work, an oxidatively degraded polypropylene (DgPP) was studied as a novel coupling agent for fibrous cellulose (FC)/polypropylene (PP) composite. An optimal preparation time of PP thermal oxidative degradation was 18 h at 130 °C, and the DgPP had functional groups such as γ-lactone and acid groups. The spherulite observation of the DgPP suggested miscibility for the undegraded PP. The addition of the DgPP presented the transparency improvement of FC/PP composite, and this behavior was found to be originated from the grafted DgPP, which was produced by the esterification reaction between the of FC and the DgPP. The scanning electron microscope (SEM) observation showed that the grafted DgPP coated the FC surface, and the tensile strength of the FC/PP composite increased by an appropriate amount of the DgPP addition. These results suggested that the DgPP was suitable for the coupling agent of FC/PP composite.     

细水雾中雾滴和高温环境的热质交换研究

由雾滴的表面的组分方程和能量方程入手,探讨雾滴在静止的高温环境中的热质交换及生存时间。应用折算薄膜理论,通过特征时间的比较,提出雾滴与高温环境主要通过沸腾机制实现热质交换;考虑滴径与速度变化的耦合作用,应用数值方法研究雾滴在强迫对流环境中与高温环境的热质交换情况。结果表明:对于滴径较小的雾滴不可能达到火焰区或可燃物表面实施火焰冷却和表面冷却,其灭火作用主要依赖于汽化吸热。     

Inhibition effects of aluminum dust explosions by various kinds of ammonium polyphosphate

In this work, vinyltriethoxysilane (A151) and 3-aminopropyltriethoxysilane (KH550) were used to modify ammonium polyphosphate (APP), showing that the dispersibility of APP could be improved remarkably by A151 and KH550. The maximum explosion pressure of aluminum dust explosion decreased with the addition of APP, A151-APP (APP-A) and KH550-APP (APP-B), with the exception of the case where the inerting ratio (α) of APP-A was less than 0.4. After the addition of APP-B, there was little difference in flame propagation behavior and explosion pressure compared with that of adding APP, indicating that APP-B could retain the inhibition performance of APP compared with APP-A. When the inerting ratios of APP, APP-A and APP-B were 1.2, 1.4 and 1.4, respectively, the aluminum dust explosion could be completely inhibited. The explosion residues of aluminum dust/APP mainly consisted of Al₂O₃, P-containing and N-containing compounds. It could be analyzed that APP exerted the inhibition effect through both chemical and physical effects.     

改善环保疏浚底泥脱水干化效能的实验研究

采用以硫酸亚铁(FeSO4)为主要成分的复合脱水剂作为疏浚泥浆脱水剂(以下简称脱水剂),黄沙、炉渣、煤灰、石灰和粉煤灰分别作为疏浚底泥干化改良剂进行实验研究。结果表明,在脱水剂投加量为100 mg/L条件下,可以提高沉淀效率约20%;在投加脱水剂及5%石灰、粉煤灰、炉渣改良剂的条件下,底泥比阻值下降50%～70%;初期渗水速率提高6%～68%;与原泥相比,以黄沙、炉渣、煤灰为改良剂的底泥,经过4个月干化期后,承载力提高了30%～150%。本研究为疏浚底泥快速脱水干化提供了一种可行的技术途径。     

聚氨脂泡沫填缝剂生产工艺火灾危险性分析与对策

以聚氨脂泡沫填缝剂基本生产原理及其特点为基础,对生产原料进行火灾危险性分析,结果表明:该类生产场所的火灾危险等级应划分为甲类;提出聚氨酯泡沫填缝剂生产中存在的安全问题及原因;运用危险度评价法对聚氨脂泡沫填缝剂生产工艺的火灾危险性进行了定量的安全评价,得出聚氨脂泡沫填缝剂生产工艺的危险程度为高度危险;并从建筑设计、防火管理和生产工艺等方面提出了预防火灾事故发生的对策。     

石墨炉法测定铅的基体改进剂的选择

通过一系列实验，选择了石墨炉法测定铅的最佳基体改进剂，并确定了使用该基体改进剂的最佳灰化温度和原子化温度。     

飞灰螯合剂中挥发性污染物的释放

采集了4个市售飞灰螯合剂样品，分析其在20，40℃下挥发性污染物的释放规律.结果表明，释放的挥发性污染物主要有甲醛、乙醛、苯、异戊醛/异丙醇、甲硫醇、乙硫醇等；其中3个螯合剂样品甲醛的释放浓度在20℃为748~1325 μg/L-螯合剂，占释放的易挥发污染物的68%~96%（质量比），在40℃为4282~6822 μg/L-螯合剂，占释放的易挥发污染物的87%~95%（质量比）.随着温度升高，释放的挥发性污染物种类变多，部分污染物浓度增加，40℃时，4个螯合剂样品释放的易挥发污染物浓度比20℃时增加了142%~444%.元素分析、拉曼光谱和热重分析结果表明，4个螯合剂的主要有效成分相似，为二硫代氨基甲酸盐类物质.因此，推测这种飞灰螯合剂在稀释和飞灰稳定化过程中，对工作人员的健康可能有潜在的危害风险，应收集释放的气体并进行处理；且在飞灰填埋过程中，可能会导致渗滤液中NH₄⁺-N等物质的浓度升高，增加渗滤液的处理难度.     

Formation of aerobic granules in the presence of a synthetic chelating agent

This paper examines the development of aerobic granular sludge in the presence of a synthetic chelating agent, nitrilotriacetic acid (NTA), in sequencing batch reactors (SBR). The growth of seed sludge at 0.26 mM, 0.52 mM and 1.05 mM of NTA was found to be significantly lower as compared to that in the absence of NTA. Aerobic granulation was significantly enhanced in the three SBRs (R2, R3 and R4), which were fed with 0.26 mM, 0.52 mM and 1.05 mM of NTA as a co-substrate, in comparison to the acetate-alone fed SBR (R1). After 2 months of operation, the mean diameter of the biomass stabilized at 0.35 mm in R1 (acetate alone), as compared to 2.18 mm in R4 (1.05 mM NTA+acetate). NTA degradation was established in SBRs, with almost complete removal during the SBR cycle. Batch experiments also showed efficient degradation of NTA by the aerobic granules.     

Extraction of heavy metals from e-waste contaminated soils using EDDS

Environmental contamination due to uncontrolled e-waste recycling activities is drawing increasing attention in the world. Extraction of these metals with biodegradable chelant [S,S]-ethylenediaminedisuccinic acid (EDDS) and the factors influencing extraction efficacy were investigated in the present study. Results showed that the addition of EDDS at low pH (5.5) produced higher metal extraction than that at high pH (8.0) solution. Metal speciation analysis indicated that Cu was completely complexed with EDDS at different pH conditions with various amounts of EDDS applied. For Pb and Zn, at low EDDS dose of 0.304 mol/kg soil, they were present as Pb- and Zn-EDDS. However, at high EDDS dose of 1.26 mol/kg soil, most of Pb was bound with dissolved organic matter. Ca and Al were found to be strong competitors for trace metals to EDDS at low application dose and low pH condition.