腐殖酸特性及其对三卤甲烷形成的影响

以提取腐殖酸和商品腐殖酸为对象,研究了不同腐殖酸对加氯消毒后三卤甲烷生成量的影响,并对腐殖酸特性进行了分析。结果表明,伊春腐殖酸比松花江腐殖酸和商品腐殖酸具有更高的三卤甲烷生成量、生成速度和更高的卤代活性。松花江腐殖酸和商品腐殖酸中的芳香结构、不饱和双键的分子较少,分子质量较大,而伊春腐殖酸中芳香结构和不饱和双键的分子较多,分子质量较低。小分子质量和含不饱和双键的有机物通常是消毒副产物的主要前体物,因而伊春腐殖酸加氯消毒后的三卤甲烷生成量比松花江腐殖酸和商品腐殖酸高。     

蒽酮-硫酸比色法测定松花粉中粗多糖的含量

优化蒽酮-硫酸比色法测定松花粉中粗多糖含量的条件,并对分析方法进行了验证.实验优化了松花粉粗多糖的浸提时间、浸提温度、多糖的显色时间、显色温度、显色剂的用量等条件.方法的平均加标回收率为98.81%,RSD为2.01%,精密度实验RSD为1.68%,线性范围:16.5-99μg/mL.结果表明:所优化的分析方法准确、精密、简便、快速,可应用于实际样品的检测.     

无机离子对光催化降解腐殖酸的影响

研究了无机离子对光催化降解腐殖酸的影响。结果表明:Ca2+、Mg2+、HCO3-、H2PO4-都对腐殖酸的降解有一定的抑制作用。Ca2+、Mg2+将与腐殖酸络合形成金属离子—腐殖酸配合体,该配合体易于被TiO2吸附,但这种配合体将比腐殖酸更难降解;HCO3-的加入会严重抑制光催化反应的进行,这是由于HCO3-是较强的.OH清除剂;H2PO4-对腐殖酸的光催化降解有较强的抑制作用,H2PO4-与腐殖酸在TiO2表面会形成竞争吸附,从而抑制TiO2对腐殖酸的吸附,同时也是.OH和h+的清除剂。     

铜酞菁纯度的测定方法探讨

铜酞菁具有优异的耐热性、耐酸碱性、耐化学品和耐有机溶剂等性能，是一个用途广泛的有机中间体。那么如何测定其纯度?用重量法和容量法分别怎么测定?本文作者安鸿钧在文中详细介绍了该两种测定方法的测定过程及相关问题。     

K2FeO4预氧化对颤藻和腐殖酸复合絮凝相互作用的研究

采用K2FeO4预氧化复合高岭土和聚合氯化铝(PAC)混凝处理含藻和腐殖酸的混合水.结果表明,当藻浓度不变时,在一定范围内,随着腐殖酸浓度的升高,浊度、腐殖酸及藻去除率均逐渐下降.当腐殖酸浓度固定时,随着藻液浓度的升高,腐殖酸和藻去除率逐渐上升,而浊度去除率基本不变.同时考察了矿物高岭土投加量及目数、K2FeO4预氧化时间、不同污染物浓度比例对K2FeO4预氧化处理混合水效果的影响,当高岭土投加量为8 mg/L、粒径为140目时,浊度和腐殖酸、藻类的去除率分别为91.0%,80.9%和88.2%,投加量过大或目数过大,沉降性能变差,起不到良好的助凝作用.     

土壤中铵态氮的测定条件研究

对氧化镁浸提-扩散法测定土壤中铵态氮的条件进行了研究,优化了氧化镁浸提-扩散温度和时间等实验条件,用振荡器代替人工转动扩散皿,最终确定较佳的氧化镁浸提-扩散温度为26℃,时间为15h。在优化条件下,方法的相对标准偏差(RSD,n=7)在1.1%~3.3%,NH4Cl的加标回收率在92.83%~103.1%,方法操作简单,测定结果准确可靠,精密度高,尤其适用于大批量样品的检测分析。     

强化混凝技术去除腐殖酸的研究进展

综述了腐殖酸对水处理过程的影响及其与饮水水质的关系，并对采用强化混凝技术去除腐殖酸的研究进展进行了系统介绍，指出今后可从物化形态学出发去优化反应器的设计和运行。     

渗透结晶型防水材料中母料生产的质量检测

水泥基渗透结晶型防水材料中母料的纯度(即活性剂含量)对其抗渗自修复性能的优劣非常关键.基于母料中各组分在溶剂中溶解度的差异,探讨了测定母料中活性剂含量的方法.     

二氧化钛光催化降解腐殖酸的试验研究

研究了不同pH条件下二氧化钛(TiO2)对腐殖酸的吸附和光催化降解过程,重点考察了腐殖酸降解过程中UV254、A436、TOC、SUVA254、AOC的变化.结果表明:随着pH值的升高,Ti02对腐殖酸的吸附率下降;当腐殖酸初始浓度为10 mg/L、初始pH=7、二氧化钛投量为2g/L时,反应2 h后,对UV254、A436、TOC的去除率分别可达98.21%、99.11%、71.02%,SUVA254值由初始的7.58 L/(mg·m)持续降低至0.467 L/(mg·m),AOC浓度则先升高后降低.     

玫瑰茄花萼浸提液抑菌活性研究

采用热水浸提工艺取得玫瑰茄花萼浸提液,利用滤纸片法研究玫瑰茄花萼浸提液对大肠杆菌、沙门氏杆菌、金黄色葡萄球菌和枯草芽孢杆菌的抑制效果,并测定其抑菌圈、抑菌率和最低抑菌浓度。抑菌试验证实,玫瑰茄花萼浸提液具有一定的抑菌活性,且对革兰氏阴性菌的抑制作用要高于革兰氏阳性菌。     

Exhaustive degradation of humic acid in water by simultaneous application of radiation and ozone

The combination effect of ionizing radiation and ozone to degrade humic acid in water was superior to ozone and radiation alone. The humic acid treated by this combination method, followed by chlorination, produced only little trihalomethane and total organic halogen. A chain reaction mechanism was suggested for the oxidation of humic acid.     

Comparison of humic acid rejection and flux decline during filtration with negatively charged and uncharged ultrafiltration membranes

Increasingly stringent regulations for drinking water quality have stimulated the ultrafiltration (UF) to become one of the best alternatives replacing conventional drinking water treatment technologies. However, UF is not very effectively to remove humic acid due to the comparatively larger pore size compared to the size of humic acid. Fouling issue is another factor that restricts its widespread application. In this study, rejection of humic acid and flux decline were compared with essentially neutral, negatively charged version of a regenerated cellulose membrane, in which electrostatic interaction was explored for a better humic acid removal and less fouling. Solution environment, including ionic strength, pH and calcium ion concentration, affecting humic acid removal and flux decline on negatively charged and neutral membranes was also compared. Results indicated that the appropriate charge modification on the neutral UF membrane could be an effective way for better removal of NOM and reduction of the membrane fouling due to the electrostatic interactions with the combination effect of membrane pore size. Electrostatic interactions are significant important to achieve high humic acid removal and less fouling, and to improve the water quality and protect people’s health.     

Cadmium adsorption on goethite-coated sand in the presence of humic acid

Heat was employed to coat crystalline goethite onto a quartz sand surface so that the adsorbent properties of the coating could be utilized. The adsorption characteristics of cadmium and humic acid onto goethite-coated sand were examined. Results show that the goethite-coated sand surface had a higher specific surface area and more mesopores than the uncoated sand. The adsorption of both cadmium and humic acid was highly pH-dependent: cadmium adsorption increased with pH, but humic acid adsorption decreased as pH increased. The presence of humic acid resulted in increasing cadmium adsorption in a specific pH range. The order of reacting humic acid with cadmium was found to have a noticeable effect on the final adsorption capacity. The adsorption capacity of cadmium for humic acid that is adsorbed onto goethite-coated sand before reacting with a cadmium system, exceeds that of humic acid that is mixed with cadmium ions before goethite-coated sand is added.     

Trichloroethylene adsorption by activated carbon preloaded with humic substances: effects of solution chemistry

Trichloroethylene (TCE) adsorption by activated carbon previously loaded ("preloaded") with humic substances was found to decrease with increasing concentrations of monovalent ions (NaCl), calcium (until solubility was exceeded), or dissolved oxygen in the preloading solution. For a given percentage of organic carbon removal during humic acid loading, greater reductions in TCE adsorption occurred with increasing monovalent ion concentration and calcium concentration at constant ionic strength. However, this effect was related primarily to the amount of humic material adsorbed--the reduction in TCE adsorption was independent of the ionic composition of the preloading solution when compared at similar humic acid loading. Experiments were performed which showed that calcium ions can associate with humic material after the humic has been adsorbed, which subsequently reduces TCE uptake, but this effect does not dominate when calcium is present during humic loading. At sufficiently high calcium concentrations (approaching solubility), aggregation or co-precipitation of humic acid mitigated the effects of preloading. In contrast to the effects of ionic composition, the presence of dissolved oxygen did fundamentally change the mechanism by which organic macromolecules compete with TCE. TCE uptake was lower when preloading by poly(maleic acid) (PMA) occurred in the presence of dissolved oxygen, even when the amount loaded was the same. One explanation invokes a coupling mechanism promoted by the carbon surface, which results in either additional blockage of TCE sorption sites, additional site competition, or both. In all experiments, the effects of preloading were consistent with those reported previously, which have been interpreted as a loss of high-energy sites available to TCE, causing a significant reduction in the site-energy heterogeneity, and reduced uptake in the low concentration region.     

混凝-超滤去除腐殖酸的试验研究

进行了直接超滤和混凝－超滤组合工艺对腐殖酸的去除效果和膜污染状况的试验。结果表明，超滤前另混凝土预处理对腐殖酸的DOC和UV254的去除率分别从28％、40％提高到53％、78％。同时高效液相色普（HPLC）分析表明，混凝－超滤组合工艺对分子质量＜6000u的有机物的去除率提高幅度更为显著。混凝－超滤组合工艺的最佳pH值条件pH=7,通过卷扫混凝使小分子有机物结合成微絮体，降低了膜孔污染，使超滤保持了较同的渗透通量。     

Determination of soluble aluminium concentration in alkaline humic water using atomic absorption spectrophotometry

The steps of the standard method to determine soluble aluminium concentration are filtering, followed by acidifying, then analysing with the atomic absorption spectrophotometer (AAS). When applied to alkaline humic water, acidification gives rise to the formation of humic acid as a brown particulate matter. Of the total soluble aluminium in the original water, 49-61% forms complexes with the particulate humic acid upon acidification. Although the AAS is capable of detecting the binding aluminium, the particulate nature of humic acid easily induces inaccurate readings as a result of the non-uniform distribution of the particulate matter. A more precise analysis of soluble aluminium concentration of alkaline humic water is shown to be achievable in basicified solutions instead. Basicified solutions keep humic acid in the soluble form; hence maintain the homogeneity of the sample.     

Chlorination of humic substances in aqueous solution: Yields of volatile and major non-volatile organic halides

In this paper, we present the study of the effect of chlorination contact time, of the chlorine/carbon ratio and of the bromide concentration on the major halogenated products in the case of chlorinated humic substance solutions at neutral pH. The yields of chloroform, of trichloroacetic acid and of dichloro-acetic acid increase with the increase in reaction time and in chlorine dosage. Various values for the yield are given for chlorinated commercial humic acid solutions and for chlorinated solutions of aquatic fulvic and humic acids. The simultaneous presence of trihalomethanes precursors and bromides in the solution leads to the formation of organo-brominated products. Total trihalomethanes increase with the increase of bromide concentration.     

腐殖酸与盐分浓度对石灰加固土有明黏土的影响以及微观结构研究

首先从力学性质方面考察了有机质之一的腐殖酸和盐分浓度对于石灰加固土的影响。分析的结果显示对于腐殖酸含量较高的黏土由于凝硬反应被阻碍使得加固土的强度与屈服应力较小,并且由于盐分浓度较高时腐殖酸活性降低,因此随着盐分浓度的增加腐殖酸对于石灰加固土的影响减小。然后通过分析加固土的微观结构,我们讨论了石灰加固土的力学性质与微观结构之间的关联性。     

Stability of particle flocs upon addition of natural organic matter under quiescent conditions

In this research, the influence of two natural organic polymers (polysaccharide and humic acid) on the stability of colloidal aggregates was examined. The primary objective of this research was to determine whether addition of organic matter to floc suspensions results in the fragmentation or stabilization of aggregates. A second objective was to determine how the size of aggregates and the composition of organic matter influence the floc breakup or stabilization process. It was found that the stability of aggregates depended on the type of organic material present as well as floc size. For example, humic acid increased the stability of aggregates more effectively than polysaccharides of larger size. It was also found that the addition of humic acid or polysaccharide generally decreased the rate of coagulation of small aggregates but had less influence on large aggregates. In no case did the addition of polysaccharide or humic acid result in the fragmentation of particle aggregates. The existence of strong interparticle forces within flocs prevented aggregate breakup upon adsorption of natural organic polymers. The results presented here provide important new information regarding the influence of NOM on the behavior of particles in aquatic systems.