Pathways for the oxidation of sarin in urban atmospheres

The nerve agent sarin has recently been deployed by terrorists in a major city. The molecule is volatile and made its way to many victims by passing as vapor through a highly reactive medium. Here we estimate rates and pathways for the removal of gas phase sarin from a generalized urban atmosphere. Only information from the open scientific literature is used. By structure reactivity comparisons with the organophosphorus pesticides, hydroxyl radical hydrogen abstraction may occur in as little as one hour. Decomposition of side chains after hydroxyl attack leads to organic oxygenates which preserve the phosphonofluoridate and so toxicity. The aqueous aerosol surface is contacted in minutes and offers access to a range of dissolved nucleophiles. Substitution displaces the fluoride leaving group, giving safe phosphoric acid analogs. Because of uncertainties in the electron distribution and in aqueous decay mechanisms, the time constants must be viewed as lower limits.     

冷原子吸收法测汞用干燥剂

试验了几种常用的干燥剂在冷原子吸收法测定水中汞时,对汞蒸气的干燥性能及对测定灵敏度的影响。结果表明,以无水氯化钙和无水高氯酸镁效果最好     

不同交联剂制备的环氧氯丙烷-二甲胺聚合物的结构及脱色性能

以环氧氯丙烷和二甲胺为原料,加入不同的胺类交联剂(乙二胺、二乙烯三胺和三乙烯四胺)合成出一系列环氧氯丙烷-二甲胺聚合物(EPI-DMA).研究了交联剂及用量对产品特性的影响;利用红外光谱(IR)和电子透射电镜(TEM)等现代分析仪器研究了EPI-DMA的结构及在水中的聚集形态;并通过烧杯实验研究了EPI-DMA对染料模拟废水和实际印染废水的处理效果.结果表明,交联剂的加入使EPI-DMA的粘度和阳离子度发生变化;不同交联剂制备的EPI-DMA的IR谱图相差不大,但在水溶液中的结构形貌不相同;EPI-DMA处理模拟活性艳红废水时以电中和和吸附架桥为作用机理,在处理还原大红废水时以电中和作用为主;在用EPI-DMA处理实际废水时脱色率和COD的去除率分别可达80%和60%.     

Evaluation of Electrokinetic Remediation of Arsenic-contaminated Soils

The potential of electrokinetic (EK) remediation technology has been successfully demonstrated for the remediation of heavy metal-contaminated fine-grained soils through laboratory scale and field application studies. Arsenic contamination in soil is a serious problem affecting both site use and groundwater quality. The EK technology was evaluated for the removal of arsenic from two soil samples; a kaolinite soil artificially contaminated with arsenic and an arsenic-bearing tailing-soil taken from the Myungbong (MB) gold mine area. The effectiveness of enhancing agents was investigated using three different types of cathodic electrolytes; deionized water (DIW), potassium phosphate (KH₂PO₄) and sodium hydroxide (NaOH). The results of the experiments on the kaolinite show that the potassium phosphate was the most effective in extracting arsenic, probably due to anion exchange of arsenic species by phosphate. On the other hand, the sodium hydroxide seemed to be the most efficient in removing arsenic from the tailing-soil. This result may be explained by the fact that the sodium hydroxide increased the soil pH and accelerated ionic migration of arsenic species through the desorption of arsenic species as well as the dissolution of arsenic-bearing minerals.     

Improved Cu and Zn sorption on oxidized wheat lignocellulose

We studied the effect an oxidizing treatment of a lignocellulosic substrate, extracted from wheat bran, on the sorption of Cu and Zn. Oxidizing agents, such as potassium permanganate (KMnO₄) or sodium periodate (NaIO₄), creates oxygenated functions, e.g. alcohol and carboxylic acid, which increase the density of functional sites and the binding capacity of lignocellulose towards copper and zinc. We found that the treatment with KMnO₄ is the most efficient, with an increase of about 30–40% metal ion binding, compared to 15–25% using NaIO₄. The investigation of the oxidation process shows that the efficiency of KMnO₄ can be attributed to its affinity towards insaturated double bonds of lignin entities. Oxidized lignocellulose is thus a promising, efficient, and cheap biomaterial for the decontamination of wastewater.     

天然高分子絮凝剂及其在水处理的应用

天然高分子絮凝剂具有传统絮凝剂和其他合成聚合物不具备的优点,现已得到国内外的广泛重视。概括了以淀粉、壳聚糖、木质素和植物胶为原料改性而成的天然高分子有机絮凝剂的研究与应用概况,并对它们在废水处理中的应用和发展进行了综述。     

高浓度豆制品废水预处理实验研究

对高浓度豆制品废水的预处理方法作了实验研究。采用调节等电点酸沉降的方法回收蛋白质,然后用聚合硫酸铁化学混凝处理上清液以降低COD的含量。实验证明了方法的可行性并得出了最佳实验条件。     

海洋环境Al-Zn-In-Mg-Ti牺牲阳极腐蚀防护研究

以Al-Zn-In-Mg-Ti牺牲阳极为研究对象,在海洋环境下做车辆的牺牲阳极腐蚀防护试验。采用电位自动记录仪采集浸入海水期间车体的动态电位,绘制时间-电位（t-E）曲线图,并分析数据;采用扫描电镜（SEM）和X射线衍射（XRD）等方法对牺牲阳极试样表面腐蚀形貌及成分进行了分析。结果发现,Al-Zn-In-Mg-Ti牺牲阳极增加了车体电位的稳定性,使车体电位部分极化到-800 mV;车体电位达到平衡的时间为7 min,加速了车体电位达到平衡的时间;Al-Zn-In-Mg-Ti牺牲阳极腐蚀产物在表面形成致密氧化层,并在干湿交替的作用下形成龟裂的裂纹,阻止了牺牲阳极的进一步反应。     

螯合剂在植物修复重金属污染土壤中的应用

向土壤中添加螯合剂促进植物对重金属的吸收是目前一项比较有发展前景的土壤修复技术。本文通过对植物修复技术的机理和特点,即对超累积植物对重金属的富集机理及植物修复技术的局限性的讨论,介绍了螯合剂在植物修复重金属污染土壤中的应用,其中详细介绍了螯合剂强化植物修复技术的机理、螯舍剂的使用方式,以及它的外部影响条件。最后对螯合剂在植物修复重金属污染土壤应用中存在的问题进行了讨论,并对未来螯合刺在该领域的研究重点进行了展望。     

堆肥过程多阶段强化接种对细菌群落多样性的影响

以生活垃圾为原料进行好氧堆肥,采用多阶段的方式强化接种功能微生物菌剂,利用PCR-DGGE方法并结合聚类分析和Shannon-Weaver指数变化来研究堆肥过程中多阶段强化接种对细菌群落多样性的影响,同时监测木质纤维素降解率的变化.结果表明,多阶段接种堆肥能有效提高堆体降温期和二次发酵期的温度;和普通接种堆肥相比可使半...