Microwave-assisted acid extraction of the major metal elements in herbal extracts followed by flame atomic absorption spectrometric (FAAS) determination

The content of As, Cd, Cr, Cu, Fe, Hg, Mg, Mn, Pb, and Zn was determined in Rosa damascena, Vitis vinifera, Crocus sativus, and Olea europaea L. herbal extracts produced in different areas in Greece. Samples were mineralized in a closed microwave system using nitric acid, and the concentration of all metals was determined by flame atomic absorption spectrometry. The herbal extracts contained As, Cd, Cr, Hg, Mn, and Pb at concentrations below their respective limits of detection, whereas Cu, Fe, Mg, and Zn were determined in varying quantities. The proposed method is precise and accurate, thus it can be used for the determination of metals in Rosa damascena, Vitis vinifera, Crocus sativus, and Olea europaea L. herbal extracts.     

废锌锰电池制备锰锌铁氧体共沉淀粉料研究

以废锌锰电池为主要原料,辅以少量的菱锰矿和废铁屑,经同时浸出、初步除杂、深度净化和共沉淀等过程,制备出纯度高、配比接近PC30铁氧体配方且混合均匀的共沉淀粉料。实验结果表明在浸出温度80~95℃、搅拌速度120~180r/min、酸用量为理论用量的1.2~1.4倍和浸出时间3.0~4.0h的条件下,铁、锰和锌的浸出率分别为92.02%、96.14%和98.34%;共沉淀粉料中铁、锰和锌的平均含量分别为41.41%、13.92%和4.49%,推算出Fe∶Zn∶Mn=69.2∶23.3∶7.5。完全符合PC30对粉料的要求。本研究既为高档锰锌软磁铁氧体的制备创造了很好的前提条件,同时对废锌锰电池的高价值资源化利用具有重要的现实意义。     

厨余垃圾与粪便现场处理工艺研究及设计

提供一套厨余垃圾与粪便的现场处理工艺,并根据单元小试研究数据研制出中试装置,用于模拟处理一个单元居民楼的厨余垃圾与粪便。设计处理量0. 2t d ,包括真空收集、固形物厌氧消化、消化污泥造粒制肥、混合污水的厌氧好氧处理等整套处理工艺,实现了厨余垃圾及粪便的源头收集、现场减量处理,同时可产出菌肥和沼气。     

一种废气吸收新装置的传质试验

介绍了一种废气吸收装置的传质试验,该装置利用射流泵进行吸气和液气混合。在分析了喷射形式下传质吸收研究的资料后,对该装置进行了模拟废气吸收试验,结合泵的性能研究装置的传质吸收特性,对不同面积比射流泵的传质情况进行了分析。     

干旱河谷区退耕还林的意义与效益 ——以阿坝州小金县为例

在生态考察和资料调研的基础上 ,以阿坝州小金县为例 ,探讨了四川省干旱河谷区退耕还林的思路及效益 ,认为退耕还林对于干旱河谷区、生态脆弱区、旅游资源丰富地区具有重大的现实意义。     

广东韶关地区大气氮干湿沉降特征研究

2012 年4 月-2013 年9 月利用自动分离干湿沉降的采样器对广东省韶关市降雨和干沉降进行采集,分析样品降雨量、降尘量及氮营养盐干湿沉降浓度,计算各指标干湿沉降通量,利用沉降通量分析其影响因素及季节性变化趋势,为该地区大气氮沉降的通量预测及其环境管理提供支持,并为其生态环境中污染物的控制与减排提供科学依据.结果表明,观测期间总氮干沉降通量、湿沉降通量和总沉降通量平均值分别为47.73、295.7 和310.5 kg·km^-2·month^-1.氨态氮、硝酸盐氮与有机氮干沉降通量平均值分别为17.39、12.98 和17.37 kg·km^-2·month^-1,其湿沉降通量平均值分别为132.4、117.0 和46.23kg·km^-2·month^-1.总氮湿沉降通量占总氮总沉降通量平均比例为83.19%,说明总氮沉降通量以湿沉降为主.影响因素方面,总氮干沉降通量与降尘量无相关性;湿沉降受降雨量影响较大,所以受雨季影响,韶关地区4-6 月总氮湿沉降负荷较大.成分组成上,干沉降中氨态氮平均占总氮比例35.48%,硝酸盐氮平均占27.96%,有机氮平均占36.55%,因此该地区氮营养盐干沉降中以氨态氮和有机氮为主;氮营养盐湿沉降以氨态氮和硝酸盐氮为主,氨态氮平均占总氮比例46.87%,硝酸盐氮平均占40.64%,有机氮平均比例为12.49%,说明该地区湿沉降同时受到农业活动和工业活动的影响.季节变化上,氮营养盐干沉降通量由大到小依次为冬季、春季、秋季、夏季,湿沉降通量春季较高,夏秋两季较低.     

中国地区大气汞的干沉降速度

借助箱模式对汞的干沉降过程进行敏感性分析,并利用区域大气环境模式系统RegAEMS计算中国地区汞干沉降速度的时空分布特征。结果表明,森林下垫面下三类汞（气态零价汞、活性气态汞和颗粒态汞）的干沉降速度较大( 0.13、4.5和0.45 cm·s^-1),水体表面上的相对较小（0.0012,0.5和0.11 cm·s^-1）。敏感性分析发现,三类汞的干沉降速度随着近地层风速增加;降水或者地表湿度降低会导致零价汞和活性气态汞干沉降速度增加;雪盖厚度会减小气态零价汞的干沉降速度而增加活性气态汞的干沉降速度。三类汞的干沉降速度在区域上分布类似,东北以及南部地区最高,华东地区最小。季节变化上,气态零价汞、活性气态汞的干沉降速度在多数下垫面都夏季最大,冬季最小;颗粒态汞季节变化不明显。     

Deposition and resorption of organic aerosol constituents in the respiratory tract as calculated from particle size distribution data

Data on the particle size distributions of organic aerosol constituents were used as input for a study, designed to calculate the fractions of the particulate concentrations of these compounds, deposited into the respiratory tract. The known relation between the deposition probability and the particle size as described by the ICRP‐model was used. The organic constituents were from the classes of the aliphatic hydrocarbons, carboxylic acids, polycyclic and aza‐heterocyclic aromatic hydrocarbons. Aerosol samples were obtained by Hi‐Vol cascade impactor sampling at suburban, rural and sea shore background stations as well as in an industrial emission site (coke oven).

Our approach uses the measured concentrations, being average values within each impactor particle size interval, as well as the integrated average deposition probabilities. This procedure was validated experimentally for eight model distributions from the literature, for which an infinitesimal calculation of the deposited fractions was possible.

Dilution reduces total particulate concentrations in the remote areas and predominantly determines the total deposited pollutant concentrations. Of these, pulmonary and nasopharyngeal deposition are most significant and, as a first approximation, correspond largely to the relative importance of the accumulation and dispersion modes of the sampled aerosol. A particle size distribution shift toward larger particles within the accumulation mode occurs upon ageing of the aerosol and reduces the pulmonary deposited fraction of the measured compounds in the background sites, compared to the one in the suburb. The total deposited fraction, however, increases. The contributions of biogenic higher odd n‐alkanes and, to a lesser extent, of even carboxylic acids to the dispersion mode of the aerosol result in an increased nasopharyngeal deposition at the background sites mainly during summer.

Since little information on the bio‐availability of organic aerosol constituents is available in the literature, the fractions of the particulate pollutant concentrations, resorbed in the tissues from the deposited material, were calculated, assuming an average efficiency of 70% for pulmonary and of 10% for nasopharyngeal and tracheobronchial resorption. A nearly constant total resorbed fraction of 20±2% resulted, independent of the sampling station or the season chosen, in contrast with the total deposited fractions, for which significant differences were observed. The predominant pulmonary resorption as well as compensating effects of the nasopharyngeal resorption level out the relatively small differences in particle size distributions observed. Based on these data, a first estimate in nanogram of the daily intake by inhalation of the organic pollutants studied can be formulated as four times the particulate pollutant concentration, expressed in ngm^‐3.     

Dry deposition and particle size distributions of nitrate and sulfate in ambient air

This study reports the dry deposition pollutants of anion species (NO₃ ^‐ and SO₄ ^‐2) in the Ping Tung City of Southern Taiwan. Several deposition properties are discussed in this paper. It included dry deposition flux, anion species size distribution and deposition velocities. Noll Rotary Impactor (NRI) and Microorifice Uniform Deposit Impactor (MOUDI) were used to collect ambient air coarse and fine particulate. Dry deposition plate was applied to collect particle deposition flux. Dionex 2000i/SP Ion Chromatography equipped with 4 mm AG4A‐SC and AS4A‐SC column was employed to analyze the anion species. The eluent solution is 1.8 mM sodium carbonate/1.7 mM sodium bicarbonate. The measured dry deposition flux of nitrate ranged from 0.63 to 3.96 mg/m²‐day and averaged 2.12 mg/m²‐day, while the measured dry deposition of sulfate ranged from 1.17 to 9.53 mg/m²‐day and averaged 3.92 mg/m²‐day. The particle size distribution of nitrate has bimodal particle size distributions. However, the sulfate displayed uniform particle size distribution for all four sampling sites. Mean cumulative fraction (F%) of nitrate in the particle size range below 1, 2.5, 10 and 25 μm, in sequence, were 34.6%, 60.9%, 91.0% and 97.6%, respectively. However, the mean F% of sulfate in the particle size range below 1, 2.5, 10 and 25 um, in sequence, were 57.3%, 82.6%, 90.3% and 98.0%, respectively. The sulfate has more F% in the submicron particles. The mean MMD _o of nitrate and sulfate are 2.35 and 0.87 μm, respectively. The mean dry deposition velocities of nitrate and sulfate are 0.45 and 0.38 cm/sec, respectively.     

宁夏盐池四儿滩湿地-干草原植被群落稳定性研究

以宁夏盐池县四儿滩湿地-干草原为研究对象,根据四儿滩湿地植被特征,将其由湿地中心向外依次划分为湿生带、交错带、旱生带。通过2012年7—9月份的野外调查,利用改进的M.Godron稳定性测定方法,研究其植被群落的稳定性。结果表明：（1）3条样地带的植被群落稳定性交点坐标分别为(18.39,81.61)、(24.75,75.25)、(22.85,77.15),即湿生带植被群落稳定性最高(欧氏平方距离为5.1802),旱生带次之（欧氏平方距离为16.2677）,可见水分对植被群落稳定性有着正相关作用;而由于交错带位于湿生带和旱生带之间,同时湿地面积不断缩减,因而交错带处于不断演替的阶段,其植被群落稳定性最低。（2）3条样带的植被种类数量表现为,交错带数量最多（23种）,旱生带次之（21种）,湿生带的种类最少（12种）,主要与旱生带土壤含水量低,湿生带土壤盐碱化严重的现象密切相关,而交错带由于处于旱生带和湿生带之间,同时具备了土壤含水量适中,土壤盐碱化较弱的优点,故植被种类最多。整体上,四儿滩湿地植被群落趋于稳定,且植被种类较多。这与近年来盐池县实施的草场封育措施密切相关,大大降低了放牧对湿地植被的破坏,利于植被生长和恢复。此外,今年雨水较往年多,很大程度地提高了干旱半干旱区植被的覆盖率和多样性,提高其稳定性。