17,314 research outputs found

    Pharmaceutical compounds in estuarine and coastal waters

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    Particulate matter concentrations and heavy metal contamination levels in the railway transport system of Sydney, Australia

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    © 2018 Elsevier Ltd Sampling campaign was conducted over six weeks to determine particulate matter (PM) concentrations from Sydney Trains airport line (T2) at both underground and ground levels using DustTrak. Dust samples were collected and analysed for 12 metals (Fe, Ca, Mn, Cr, Zn, Cu, Pb, Al, Co, Ni, Ba and Na) by atomic emission spectroscopy. Average underground PM10 and PM2.5 concentrations from inside the trains were 2.8 and 2.5 times greater than at ground level. Similarly, PM10 and PM2.5 concentrations on underground platforms were 2.7 and 2.5 times greater than ground level platforms. Average underground PM concentrations exceeded the national air quality standards for both PM10 (50 µg/m3) and PM2.5 (25 µg/m3). Correlation analysis showed a strong to moderate association between PM concentrations at ground level and background PM concentrations (r2 from 0.952 to 0.500). The findings suggested that underground PM concentrations were less influenced by the ambient background than at ground level. The metal concentrations decreased in the order of Fe, Cr, Ca, Al, Na, Ba, Mn, Zn, Cu, Ni, Co and Pb. The pollution index (PI) and enrichment factor (EF) values were calculated to identify the levels and sources of contamination in the underground railway microenvironments. PM was remarkably rich in Fe with a mean concentration of 73.51 mg/g and EF of 61.31, followed by Ni and Cr. These results noticeably indicated a high level of metal contamination in the underground environments, with the principal contribution from track abrasion and wear processes

    Insight into biochar properties and its cost analysis

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    © 2015 Elsevier Ltd. Biochars (BCs) are widely produced and used for the remediation of environmental contaminants as bio-sorbents. In this review, statistical analysis of different BC physico-chemical properties was conducted. It was observed that woody materials are the most suitable for preparing BCs, among many other potential raw materials such as food wastes and agricultural materials. Currently BCs are produced through a variety of thermal treatment processes between 300 and 900 °C, among which slow pyrolysis is widely used due to its moderate operating conditions and optimization of BC yields. Hydrothermal carbonisation (HTC) is also an effective approach for BC production under certain conditions. As pyrolysis temperature is increased, the carbon content, ash content, surface area, and pore volume tend to be increased while the yield, hydrogen, oxygen, nitrogen content, and H/C and O/C molar ratios tend to decrease. The economic feasibility of BCs depends on a range of factors from raw material price to efficient production technologies. Thus, the overall cost equation of a pilot BC production plant together with the cost equation for BC regeneration has been proposed. The future research directions of BCs are also elaborated

    Petrochemistry and mineral chemistry studies on metamorphic ultramafic rocks in Yanghou area, Zhenghe Country, Fujian Province, China

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    Petrochemistry studies indicate that the Yanghou metamorphic ultramafic rocksare composed of metamorphosed harzburgite and burgite and ultramafic cumulate . Trace element geochemistry and mineral chemistry studies on the metamorphosed harzburgite indicate that it is the relict of the depleted mantle. From systematic studies on petrochemistry , mineral chemistry and geochronology, it s concluded that the Yanghou metamorphic ultramafic rocks are components of Later Sinian-Early Paleozoic ophiolite in South China.岩石化学研究表明, 洋后变质超镁铁岩是由变质方辉橄榄岩和变质超镁铁堆积岩组成。变质方辉橄榄岩的微量元素地球化学及矿物化学特征表明, 应为亏损的残余地慢产物。通过系统的岩石地球化学、矿物化学及年代学研究, 认为洋后变质超镁铁岩可能为华南晚震旦一早古生代的蛇绿岩组成部分。published_or_final_versio

    Adsorptive removal of antibiotics from water and wastewater: Progress and challenges

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    © 2015 Elsevier B.V. Antibiotics as emerging contaminants are of global concern due to the development of antibiotic resistant genes potentially causing superbugs. Current wastewater treatment technology cannot sufficiently remove antibiotics from sewage, hence new and low-cost technology is needed. Adsorptive materials have been extensively used for the conditioning, remediation and removal of inorganic and organic hazardous materials, although their application for removing antibiotics has been reported for ~30 out of 250 antibiotics so far. The literature on the adsorptive removal of antibiotics using different adsorptive materials is summarized and critically reviewed, by comparing different adsorbents with varying physicochemical characteristics. The efficiency for removing antibiotics from water and wastewater by different adsorbents has been evaluated by examining their adsorption coefficient (Kd) values. For sulfamethoxazole the different adsorbents followed the trend: biochar (BC)>multi-walled carbon nanotubes (MWCNTs)>graphite=clay minerals, and for tetracycline the adsorptive materials followed the trend: SWCNT>graphite>MWCNT=activated carbon (AC)>bentonite=humic substance=clay minerals. The underlying controlling parameters for the adsorption technology have been examined. In addition, the cost of preparing adsorbents has been estimated, which followed the order of BCs<ACs<ion exchange resins<MWCNTs<SWCNTs. The future research challenges on process integration, production and modification of low-cost adsorbents are elaborated

    Progress in osmotic membrane bioreactors research: Contaminant removal, microbial community and bioenergy production in wastewater.

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    Renewable energy, water conservation, and environmental protection are the most important challenges today. Osmotic membrane bioreactor (OMBR) is an innovative process showing superior performance in bioenergy production, eliminating contaminants, and low fouling tendency. However, salinity build-up is the main drawback of this process. Identifying the microbial community can improve the process in bioenergy production and contaminant treatment. This review aims to study the recent progress and challenges of OMBRs in contaminant removal, microbial communities and bioenergy production. OMBRs are widely reported to remove over 80% of total organic carbon, PO43-, NH4+ and emerging contaminants from wastewater. The most important microbial phyla for both hydrogen and methane production in OMBR are Firmicutes, Proteobacteria and Bacteroidetes. Firmicutes' dominance in anaerobic processes is considerably increased from usually 20% at the beginning to 80% under stable condition. Overall, OMBR process has great potential to be applied for simultaneous bioenergy production and wastewater treatment

    下地壳及壳慢过渡带化学不均一性 -- 河北汉诺坝地区深源捕虏体元素地球化学证据

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    河北汉诺坝玄武岩中长英质麻粒岩、镁铁质麻粒岩和辉石岩捕虏体的主量元素和微量元素特征, 反映了下地壳及壳鳗过渡带组成具有高度化学不均一性。不相容元素原始地慢标准化曲线特征的差异表明捕虏体成因复杂。MgO 与不相容元素无或仅有很弱的相关性, 与相容元素的相关性则相对较明显。这些特征反映了下地壳及壳慢过渡带存在较强和多元的混合作用。捕虏体的加权平均值比基于麻粒岩地体资料估算的下地壳平均组成偏基性, 揭示了二者可能的成因差异。The major and trace element data of granulite and pyroxenite xenoliths, which are entrained in Hannuoba basalt Hebei Province, North China, suggest the highly chemical heterogeneity in the lower crust and crust-mantle transitional zone. There is no or only POor linear correlation between MgO and incompatible elements. Whereas a bit remarked correlations are observed between MgO and most compatible elements.The geochemical characteristics suggest that the strong and multiple mixing processes may have Occurred universally both in the lower crust and crust-mantle transitional zone. The weighed average composition of xenoliths shows a more mafic composition of the lower crust than that estimated from granulite data, which may imply the difference in the genesis.published_or_final_versio

    Sr, Nd Pb isotopic characteristics of granulite and pyroxenite xenoliths in Hannuoba basalts, Hebei Province, and their implications for geologic processes

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    Rb-Sr, Sm-Nd and Pb isotopic systematics are reported for granulite and pyroxenite xenoliths in Hannuoba basalts, Hebei Province. The isotopic characteristics of xenoliths suggest t hat they might have formed recently , although there is no strict constraint on the precise age. The decoupling of low Rb/Sr and high [87]Sr/[86]Sr ratios implies the multi-stage evolution history and strong mixing processes. There are close ties between granulite and pyroxenites with different mineral assemblages on the Sr-Nd, Pb-Sr and Pb-Nd correlation figures. The granulite is the common end-member o f the three kinds o f pyroxenite. Combined with the distribution of the xenoliths in space and their isotopic relationships, It is proposed that delamination can be well used to explain the ties.系统研究了河北汉诺坝玄武岩中二辉麻粒岩和辉石岩捕虏体的Sr、Nd、Pb 同位素特征。虽然未确定捕虏体的形成时代, 但同位素特征显示它们可能为较近期( 中生代以来) 形成。低的Rb/Sr 与高 的[87]Sr/[86]Sr 比值的解耦表明捕虏体的形成经历了较强的混合作用。在二元同位素相关图上, 三类具不同矿物组成的辉石岩与二辉麻粒岩有密切关系, 即二辉麻粒岩投点位置是三类辉石岩的共同端点。综合考虑捕虏体的空间分布及其在Sr 、Nd、Pb 同位素协变图上的关系, 可以认为层离作用可较好地解释这些现象。published_or_final_versio

    Sorptive removal of phenolic endocrine disruptors by functionalized biochar: Competitive interaction mechanism, removal efficacy and application in wastewater

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    © 2017 Elsevier B.V. Sorptive removal of six phenolic endocrine disrupting chemicals (EDCs) estrone (E1), 17β-estradiol (E2), estriol (E3), 17α-ethynylestradiol (EE2), bisphenol A (BPA) and 4-tert-butylphenol (4tBP) by functionalized biochar (fBC) through competitive interactions was investigated. EDC sorption was pH dependent with the maximum sorption at pH 3.0–3.5 due to hydrogen bonds and π-π interactions as the principal sorptive mechanism. Sorption isotherm of the EDCs was fitted to the Langmuir model. Sorption capacities and distribution coefficient values followed the order E1 > E2 ≥ EE2 > BPA > 4tBP > E3. The findings suggested that EDC sorption occurred mainly through pseudo-second order and external mass transfer diffusion processes, by forming H-bonds along with π-π electron-donor–acceptor (EDA) interactions at different pH. The complete removal of ∼500 μg L−1 of each EDC from different water decreased in the order: deionised water > membrane bioreactor (MBR) sewage effluent > synthetic wastewater. The presence of sodium lauryl sulphonate and acacia gum in synthetic wastewater significantly suppressed sorption affinity of EDCs by 38–50%, hence requiring more fBC to maintain removal efficacy
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