预富集技术在原子吸收光谱环境分析中的应用

原子吸收光谱法是分析环境水样中金属离子含量的有效方法之一。在测定时往往需要对样品进行前处理,然后再进行测定。文章介绍了近些年较新的一些分离富集技术在原子吸收光谱分析环境中金属离子时的应用,分析了离子交换树脂在样品中金属离子富集分离过程中的研究近况,评述了固相萃取、析相微萃取、单滴液滴微萃取、分散液液微萃取、离子液体萃取、浊点萃取等多种萃取方式在样品预富集中的应用进展,综述了活性炭、纳米粒子、淀粉、分子筛等吸附剂在富集环境水样中金属元素的应用现状,同时还对在线富集技术与流动注射分析技术联用在金属元素分析中的应用进展进行了评述。     

DNA提取方法对活性污泥微生物多样性PCR-DGGE检测的影响

评价超声波法、2种基于SDS的裂解法、改进的化学裂解法、微波法和冻融 玻璃珠 溶菌酶 SDS等6种DNA提取方法对活性污泥微生物多样性PCR-DGGE检测的影响.结果表明,2种不同的DNA纯化方式(溶液和胶纯化)及PCR扩增方式(直接和巢式PCR)对DGGE结果没有明显的影响,但不同的DNA提取方法对DGGE结果有明显的影响,其中2种基于SDS裂解法的DGGE条带较多,其提取的DNA产量(14.85μg/g湿重)和纯度(OD260:OD280＞1.80)也最高;改进的化学裂解法和微波法次之;超声波法、冻融 玻璃珠 溶菌酶 SDS法较少.研究表明,DNA提取方法是影响活性污泥微生物多样性PCR-DGGE检测结果的关键因素,基于SDS的裂解法是用于活性污泥微生物多样性PCR-DGGE研究的一种简便、可靠的总DNA提取方法.     

TiO2 nanotubes as solid-phase extraction adsorbent for the determination of polycyclic aromatic hydrocarbons in environmental water samples

An analytical method based on TiO2 nanotubes solid-phase extraction (SPE) combined with gas chromatography (GC) was established for the analysis of seven polycyclic aromatic hydrocarbons (PAHs): acenaphtylene, acenaphthene, anthracene, fluorene, phenanthrene, fluoranthene and pyrene. Factors a ecting the extraction e ciency including the eluent type and its volume, adsorbent amount, sample volume, sample pH and sample flow rate were optimized. The characteristic data of analytical performance were determined to investigate the sensitivity and precision of the method. Under the optimized extraction conditions, the method showed good linearity in the range of 0.01–0.8 g/mL, repeatability of the extraction (RSD were between 6.7% and 13.5%, n = 5) and satisfactory detection limits (0.017–0.059 ng/mL). The developed method was successfully applied to the analysis of surface water (tap, river and dam) samples. The recoveries of PAHs spiked in environmental water samples ranged from 90% to 100%. All the results indicated the potential application of titanate nanotubes as solid-phase extraction adsorbents to pre-treat water samples.     

湘中锑矿区土壤重金属锑的污染特征

文章研究调查了冷水江锡矿山锑矿区、桃江板溪锑矿区、桃江马迹塘锑矿区、桃江武潭锑矿区、安化符竹溪金锑矿区及安化渣滓溪锑矿区及周围土壤中锑的含量及形态分布.结果表明:各矿区土壤中总锑含量范嗣为185.6-2 081.3 mg/kg,大大超过了土壤中锑的背景值,表明各矿区土壤已被严重污染.采用Tessier逐级提取法对土壤中...     

废弃线路板热解油中酚类物质的提取与分离

将FR-4型废弃线路板热解,并对热解油中含量最多的组分-酚类物质进行分离提取.比较研究线路板热解油的分离提取方法,探索出"碱液处理-酸化-萃取-减压蒸馏"的新方法,对分离出的组分进行GCMS(气质联用)测试.结果显示运用该方法对FR-4型线路板的热解油进行提取分离,得到的总酚占热解油的62.0%,其中苯酚的最高纯度可达...     

有机质对土壤气相抽提去除四氯化碳效率的影响

某重要岩溶地下水源地因附近农药厂排放含四氯化碳污水而受到严重污染,实验采用土柱通风试验模拟土壤气相抽提(SVE),研究环境温度为20℃,通风速率为40mL/min,土壤含水率10%,而土壤有机质含量分别为3.02%和0.13%条件下的两种供试土壤中四氯化碳污染物的去除过程.结果表明,土柱通风能有效去除土壤中的四氯化碳污...     

Antimony smelting process generating solid wastes and dust：Characterization and leaching behaviors

A large amount of solid waste has been produced by the antimony smelting process in the＂World Capital of Antimony＂, Xikuangshan area in China. This study comprehensively investigated the physical and chemical characteristics of the various solid wastes, as well as the leaching behavior of the solid wastes, which included water-quenched slag,arsenic-alkali residue, desulfurized slag and blast furnace dust. These four types of waste were enriched in a variety of heavy metals and metalloids and more specifically with As and Sb levels up to 8.6 × 104 and 3.16 × 105mg/kg, respectively, in arsenic-alkali residue. For desulfurized slag and water-quenched slag, the leaching concentration of Sb significantly exceeded the acceptable limits during the leaching tests using the toxicity characteristic leaching procedure and the synthetic precipitation leaching procedure. In addition, As leaching in arsenic-alkali residue was extraordinarily hazardous, being three orders of magnitude higher than the regulatory level of As. According to the results of the extraction tests, all the tested wastes were classified as hazardous waste.     

Evaluation of soil washing process with carboxymethyl-β-cyclodextrin and carboxymethyl chitosan for recovery of PAHs/heavy metals/fluorine from metallurgic plant site

Polycyclic aromatic hydrocarbons(PAHs)/heavy metals/fluorine(F) mixed-contaminated sites caused by abandoned metallurgic plants are receiving wide attention. To address the associated environmental problems,this study was initiated to investigate the feasibility of using carboxymethyl-β-cyclodextrin(CMCD) and carboxymethyl chitosan(CMC) solution to enhance ex situ soil washing for extracting mixed contaminants. Further,Tenax extraction method was combined with a first-three-compartment model to evaluate the environmental risk of residual PAHs in washed soil. In addition,the redistribution of heavy metals/F after decontamination was also estimated using a sequential extraction procedure. Three successive washing cycles using50 g/L CMCD and 5 g/L CMC solution were effective to remove 94.3% of total PAHs,93.2% of Pb,85.8% of Cd,93.4% of Cr,83.2% of Ni and 97.3% of F simultaneously. After the 3rd washing,the residual PAHs mainly existed as very slowly desorbing fractions,which were in the form of well-aged,well-sequestered compounds; while the remaining Pb,Cd,Cr,Ni and F mainly existed as Fe–Mn oxide and residual fractions,which were always present in stable mineral forms or bound to non-labile soil fractions. Therefore,this combined cleanup strategy proved to be effective and environmentally friendly.     

2-萘酚生产废水综合治理与资源化利用工程实例

针对2-萘酚生产废水p H值低、色泽深,亚硫酸盐和萘磺酸盐高、COD浓度高的特点,采用酸化脱硫-两级络合萃取-氧化絮凝工艺处理,介绍了专利工艺的流程设计,给出了主要工艺设计参数及投资运行成本。工程运行结果表明,该工艺设计合理、技术成熟、处理效果稳定,2-萘酚生产废水经处理后达到GB 8978—1996《污水综合排放标准》一级排放标准要求;回收的萘磺酸钠固体可返回2-萘酚生产系统套用;反萃取黑液经蒸发浓缩,合成的减水剂产品各项指标达到或超过GB 8076—2008《混凝土外加剂》高效减水剂指标要求。     

热强化气相抽提对不同质地土壤中苯去除的影响

研究应用电阻加热强化气相抽提技术对砂土、壤土和黏土中苯去除效果的影响及作用机制.与常规抽提结果相比,在热强化处理作用下气相抽提对砂土和壤土中苯的去除效率提高了13.1%和12.3%,处理时间分别降低75%和14%.热强化处理使得黏土含水率下降,土壤渗透率升高,黏土颗粒表面羧基和乙基的吸收峰消失,有机质含量减少,苯的去除效率与对照相比提高了34%.对于砂土和壤土,热强化主要是通过促进苯在土体中扩散来提高去除效率,从而实现在较短时间内污染物质的大量去除;而对于黏土则是通过降低土壤颗粒表面有机基团的含量,从而降低污染物和土壤颗粒的吸附能力,并通过降低含水率和升高渗透率从而提高土壤中气体的扩散性能,以达到增强气相抽提效果的目的.