Levels and distribution of Dechlorane Plus in coastal sediments of the Yellow Sea, North China

Dechlorane Plus (DP) has been determined in surface sediments from three Chinese coastal bays, e.g. Jiaozhou, Sishili and Taozi Bay in North China. DP concentrations ranged from <1.2 to 187 pg g⁻¹ dry weight (dw) (mean: 24.7 pg g⁻¹ dw) in Jiaozhou Bay, <1.2 to 135 pg g⁻¹ dw (mean 69.9 pg g⁻¹ dw) in Sishili Bay and <1.2 to 66.7 pg g⁻¹ dw (mean: 40.4 pg g⁻¹ dw) in Taozi Bay, respectively. Additionally, two dechlorinated species were quantified, which accounted for 0.6-5.1% of the ∑DP concentration.The f_syn values (syn-isomer/(syn- + anti-isomer)) in sediments from Jiaozhou Bay (mean 0.29) were close to the technical DP mixture (0.2-0.4), probably indicating local inputs of DP. In contrast, sediments in Sishili and Taozi Bay showed much lower f_syn values (mean 0.16). During transportation the DP isomers are subject to stereo selective degradation which partly resulted in the relative enrichment of anti-DP in coastal sediments.     

Accumulation and quantitative estimates of airborne lead for a wild plant (Aster subulatus)

Foliar uptake of airborne lead is one of the pathways for Pb accumulation in plant organs. However, the approximate contributions of airborne Pb to plant organs are still unclear. In the present study, aerosols (nine-stage size-segregated aerosols and total suspended particulates), a wild plant species (Aster subulatus) and the corresponding soils were collected and Pb contents and isotopic ratios in these samples were analyzed. Average concentration of Pb was 96.5 ± 63.5 ng m⁻³ in total suspended particulates (TSP) and 20.4 ± 5.5 ng m⁻³ in the fine fractions of size-segregated aerosols (SSA) (<2.1 μm), higher than that in the coarser fractions (>2.1 μm) (6.38 ± 3.71 ng m⁻³). Enrichment factors show that aerosols and soils suffered from anthropogenic inputs and the fine fractions of the size-segregated aerosols enriched more Pb than the coarse fractions. The order of Pb contents in A. subulatus was roots > leaves > stems. The linear relationship of Pb isotope ratios (²⁰⁶Pb/²⁰⁷Pb and ²⁰⁸Pb/²⁰⁶Pb) among soil, plant and aerosol samples were found. Based on the simple binary Pb isotopic model using the mean ²⁰⁶Pb/²⁰⁷Pb ratios in TSP and in SSA, the approximate contributions of airborne Pb into plant leaves were 72.2% and 65.1%, respectively, suggesting that airborne Pb is the most important source for the Pb accumulation in leaves. So the combination of Pb isotope tracing and the simple binary Pb isotope model can assess the contribution of airborne Pb into plant leaves and may be of interest for risk assessment of the exposure to airborne Pb contamination.     

Effects of alkyl polyglycoside (APG) on composting of agricultural wastes

Composting is the biological degradation and transformation of organic materials under controlled conditions to promote aerobic decomposition. To find effective ways to accelerate composting and improve compost quality, numerous methods including additive addition, inoculation of microorganisms, and the use of biosurfactants have been explored. Studies have shown that biosurfactant addition provides more favorable conditions for microorganism growth, thereby accelerating the composting process. However, biosurfactants have limited applications because they are expensive and their use in composting and microbial fertilizers is prohibited. Meanwhile, alkyl polyglycoside (APG) is considered a “green” surfactant. This study aims to determine whether APG addition into a compost reaction vessel during 28-day composting can enhance the organic matter degradation and composting process of dairy manure. Samples were periodically taken from different reactor depths at 0, 3, 5, 7, 14, 21, and 28 days. pH levels, electrical conductivity (EC), ammonium and nitrate nitrogen, seed germination indices, and microbial population were determined. Organic matter and total nitrogen were also measured.Compared with the untreated control, the sample with APG exhibited slightly increased microbial populations, such as bacteria, fungi, and actinomycetes. APG addition increased temperatures without substantially affecting compost pH and EC throughout the process. After 28 days, APG addition increased nitrate nitrogen concentrations, promoted matter degradation, and increased seed germination indices. The results of this study suggest that the addition of APG provides more favorable conditions for microorganism growth, slightly enhancing organic matter decomposition and accelerating the composting process, improving the compost quality to a certain extent.     

Organophosphorus flame retardants and plasticizers in the atmosphere of the North Sea

Air samples collected in the German part of the North Sea from March to July 2010 were investigated for organophosphorus compounds (OPs) being applied as flame retardants and plasticizers. The ∑₈OPs concentration ranged from 110 to 1400 pg m⁻³ while tris(2-chloroisopropyl) phosphate (TCPP) dominated all samples with individual concentrations up to 1200 pg m⁻³. The highest concentrations were observed in continental air masses showing the high influence of industrialized regions including production sites on atmospheric emissions and concentrations. The occurrence of OPs even in oceanic/Arctic air masses shows that OPs can undergo long-range atmospheric transport. Dry particle-bound deposition fluxes from 9 to 240 ng m⁻² d⁻¹ for ∑₈OPs were estimated leading to a minimum annual flux of 710 ± 580 kg y⁻¹ OPs into the German North Sea. This study presents the first occurrence of OPs in the marine atmosphere together with important information on their long-range transport potential.     

高温烧结磷石膏钙渣制备轻质碳酸钙

以磷石膏钙渣为原料,通过高温煅烧,然后经消化、精制、碳化,制成轻质碳酸钙产品.研究结果表明:高温煅烧的最佳温度为 1 000 ℃,最佳煅烧时间为 1.0 h;沉淀反应的初始反应温度为 60 ℃,Ca(OH)2乳液质量浓度为 70 g/L,CO2流量为 1.8 L/h.制备的轻质碳酸钙产品各项指标均达到 HG/T2226...     

微波-H202-膨胀石墨协同催化氧化处理甲基橙废水

为了研究膨胀石墨、微波和H2O2在催化氧化体系中的协同作用,采用微波法制备膨胀石墨,通过单因素条件实验,研究了微波、H2O2和膨胀石墨协同催化氧化法处理甲基橙废水工艺,探讨了各种因素协同作用对废水脱色效果的影响.实验结果表明,微波- H2O2 -膨胀石墨氧化体系能高效快速地降解废水中的甲基橙,在50 mL 初始pH 为...     

大气压等离子体射流对水中铜绿微囊藻的灭活作用

以铜绿微囊藻为研究对象,将空气源大气压等离子体射流(APPJ)引入到液相,构建新型的大气压等离子体射流液相反应体系,考察了不同APPJ处理方式对铜绿微囊藻的灭活效率,观察了放电处理的藻细胞形态,分析了培养基p H的变化和液相产生的主要活性物质(H2O2和O3)对藻灭活的作用,并探讨了APPJ灭活铜绿微囊藻的作用机理。研究结果表明,当电压为7 k V,空气气体流速为4 L/min,藻液吸光度约为0.200,铜绿微囊藻的灭活率达到99.16%;处理后的藻发生细胞变形和破裂;处理后的藻液中产生H2O2和O3等活性物质,同时产生大量的NO-3和NO-2离子,导致液相p H迅速下降。通过考察主要活性物质(H2O2和O3)及藻液p H因素发现,单一因素灭活效果不佳,主要活性物质(H2O2和O3)和p H的组合因素是APPJ灭活水中铜绿微囊藻的主要原因。     

铜绿微囊藻胁迫对宽叶香蒲叶片光呼吸特性的影响

采用共生培养的实验方法,通过追踪测定宽叶香蒲(Typha latifolia)叶片中叶绿素含量、净光合速率、光呼吸速率及乙醇酸氧化酶(GO)、谷氨酰胺合成酶(GS)及过氧化氢酶(CAT)的活性,研究不同初始密度铜绿微囊藻(Microcystis aeruginosa)对宽叶香蒲叶片光呼吸特性的影响。结果表明,铜绿微囊藻初始密度为1.0×104ind/m L时,宽叶香蒲叶片叶绿素含量、净光合速率、光呼吸速率及GO、GS及CAT的活性增加,说明低密度铜绿微囊藻对宽叶香蒲叶片的光合作用及光呼吸具有促进作用;铜绿微囊藻初始密度为1.0×107ind/m L时,宽叶香蒲叶片净光合速率、光呼吸速率及GO、GS及CAT的活性呈现先增加后降低的趋势,表明经过一段时间培养后,高密度铜绿微囊藻对宽叶香蒲叶片的光合作用和光呼吸呈现出抑制作用。但是在净光合速率急剧降低的时候,光呼吸速率在短时间内仍然维持在一个较高水平,说明宽叶香蒲可能通过维持或增强光呼吸在一定程度上抵抗逆境胁迫。     

页岩对污泥氨气挥发的抑制作用

氨气是城市污水污泥产生的恶臭气体之一,控制或抑制其产生是资源化利用甚至处置过程中至关重要的.通过改进氨气测量方法定量分析外掺页岩对污泥氨气挥发的抑制作用和机理,实验研究了页岩掺量、陈放形式以及环境温度对污泥氨气挥发浓度的影响.结果表明,外掺页岩对污泥氨气挥发具有明显的抑制作用,随温度升高、陈放时间延长抑制效果有所减弱但仍具有明显作用;页岩对污泥氨气挥发的抑制作用主要为对氨气的吸附作用.     

密相塔半干法烟气脱硫塔内加湿降温及其对脱硫效率的影响

为了实现密相塔半干法脱硫工艺的精确加湿进一步提高系统脱硫效率,利用推导出的传热传质计算方法,得到烟气温度降低和加水量的关系.结合3组密相塔半干法工程实际数据,发现理论计算值和实测值误差区间仅为2.9％ ～5.4％.通过选取河北某钢厂210 m2烧结烟气密相塔半干法脱硫项目实际在线检测数据,发现循环脱硫灰含湿量为3％的系统脱硫效率整体高于含湿量为5％和4％的样品,最大值达93.56％.通过粒度分析、扫描电镜、X射线衍射及差热-热重对2种不同含湿量的循环脱硫灰进行表征,结果表明,含湿量为3％的循环脱硫灰较含湿量为5％的样品粒径小、比表面积大,无团聚现象,物相分析还证实相对于含湿量为5％样品,其Ca(OH)2和结晶水含量少,几乎都是CaSO4和CaS03干态物质,因此脱硫反应进行彻底,脱硫效率较高.