Spectral Characterization of Four Kinds of Biodegradable Plastics: Poly (Lactic Acid), Poly (Butylenes Adipate-Co-Terephthalate), Poly (Hydroxybutyrate-Co-Hydroxyvalerate) and Poly (Butylenes Succinate) with FTIR and Raman Spectroscopy

Fourier transform infrared microscope and confocal Raman spectroscope were employed in this study to investigate four kinds of biodegradable plastics: poly(lactic acid),poly(butylenes adipate-co-terephthalate), poly(butylenes succinate) and poly(hydroxybutyrate-co-hydroxyvalerate), which are used more and more popularly in everyday life but can not be identified easily with other instruments. Infrared and Raman spectra of the plastics were tentatively interpreted. The indicative peaks to characterize the four polymers were also summarized. The result in this study can help the forensic scientists discriminate the plastics accurately when they occurred as trace evidences in cases, it also offers the producer and environment scientists an effective, non-invasive and fast method to characterize and identify these four polymers.     

乳品废水活性污泥沉降特性研究

针对活性污泥法处理乳品工业废水过程中产生大量活性污泥的现状,研究不同温度、pH和沉降时间对活性污泥沉降的影响,旨在阐明活性污泥沉降性能的最佳条件,最大限度降低活性污泥在污水处理系统中所占的体积。试验结果表明当污泥沉降时间为120 m in时,pH6.0,35℃条件下污泥沉降体积为54%;pH7.0,45℃条件下污泥沉降比为54%;pH8.0,45℃污泥沉降体积比为55%;pH9.0,55℃条件下污泥沉降体积为52%;pH 10.0,5℃、15℃、25℃、35℃、45℃和55℃条件下污泥沉降体积比相近,均在60%以上。结合乳品废水处理的实际情况,pH6.0~9.0,温度35℃~55℃,污泥沉降时间为120 m in,污泥沉降效果较好,体积比可达到52%~54%。     

Effect of alginate on the aggregation kinetics of copper oxide nanoparticles (CuO NPs): bridging interaction and hetero-aggregation induced by Ca<Superscript>2+</Superscript>

The stability of CuO nanoparticles (NPs) is expected to play a key role in the environmental risk assessment of nanotoxicity in aquatic systems. In this study, the effect of alginate (model polysaccharides) on the stability of CuO NPs in various environmentally relevant ionic strength conditions was investigated by using time-resolved dynamic light scattering. Significant aggregation of CuO NPs was observed in the presence of both monovalent and divalent cations. The critical coagulation concentrations (CCC) were 54.5 and 2.9 mM for NaNO₃ and Ca(NO₃)₂, respectively. The presence of alginate slowed nano-CuO aggregation rates over the entire NaNO₃ concentration range due to the combined electrostatic and steric effect. High concentrations of Ca²⁺ (>6 mM) resulted in stronger adsorption of alginate onto CuO NPs; however, enhanced aggregation of CuO NPs occurred simultaneously under the same conditions. Spectroscopic analysis revealed that the bridging interaction of alginate with Ca²⁺ might be an important mechanism for the enhanced aggregation. Furthermore, significant coagulation of the alginate molecules was observed in solutions of high Ca²⁺ concentrations, indicating a hetero-aggregation mechanism between the alginate-covered CuO NPs and the unabsorbed alginate. These results suggested a different aggregation mechanism of NPs might co-exist in aqueous systems enriched with natural organic matter, which should be taken into consideration in future studies.

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Graphical abstract Hetero-aggregation mechanism of CuO nanoparticles and alginate under high concentration of Ca²⁺

     

Effects of reciprocal hybridization on cadmium accumulation in F1 hybrids of two Solanum photeinocarpum ecotypes

In this study, farmland and mining ecotypes of Solanum photeinocarpum (a potential cadmium (Cd) hyperaccumulator plant) were reciprocally hybridized each other, and the Cd accumulation characteristics of the F1 hybrids were studied. In pot experiments, higher biomasses and Cd extraction abilities were found for two S. photeinocarpum F1 hybrids than for the parents, but the Cd contents in various organs were lower in the hybrids than the parents. However, the differences between the Cd contents in the two hybrids were not significant. The antioxidant enzyme (superoxide dismutase and peroxidase) activities were higher for the S. photeinocarpum F1 hybrids than the parents. Less DNA methylation was found in the hybrids than the parents because more demethylation occurred in the hybrids than the parents. The biomass, Cd content, and Cd extraction ability effects in field experiments were similar to the effects in the pot experiments. It was concluded that reciprocally hybridizing different S. photeinocarpum ecotypes improved the ability of S. photeinocarpum to be used to phytoremediate contaminated land.

     

Fast increasing of surface ozone concentrations in Pearl River Delta characterized by a regional air quality monitoring network during 2006-2011

Based on the observation by a Regional Air Quality Monitoring Network including 16 monitoring stations, temporal and spatial variations of ozone(O3), NO2and total oxidant(Ox) were analyzed by both linear regression and cluster analysis. A fast increase of regional O3concentrations of 0.86 ppbV/yr was found for the annual averaged values from 2006 to 2011 in Guangdong, China. Such fast O3increase is accompanied by a correspondingly fast NOx reduction as indicated by a fast NO2 reduction rate of 0.61 ppbV/yr. Based on a cluster analysis, the monitoring stations were classified into two major categories – rural stations(non-urban) and suburban/urban stations. The O3concentrations at rural stations were relatively conserved while those at suburban/urban stations showed a fast increase rate of 2.0 ppbV/yr accompanied by a NO2 reduction rate of 1.2 ppbV/yr. Moreover, a rapid increase of the averaged O3 concentrations in springtime(13%/yr referred to 2006 level) was observed, which may result from the increase of solar duration, reduction of precipitation in Guangdong and transport from Eastern Central China. Application of smog production algorithm showed that the photochemical O3production is mainly volatile organic compounds(VOC)-controlled. However, the photochemical O3production is sensitive to both NOx and VOC for O3pollution episode. Accordingly, it is expected that a combined NOx and VOC reduction will be helpful for the reduction of the O3 pollution episodes in Pearl River Delta while stringent VOC emission control is in general required for the regional O3 pollution control.     

生态适宜的城市发展空间分析方法与案例研究

综合运用生态功能区划方法和土地建设适宜性分析技术,基于地理信息系统平台建立了生态适宜的城市发展空间区域(生态主导功能区)的划分方法,依据生态保护原则和土地开发适宜度,将城市生态主导功能区划分为禁止、限制、优化和重点开发区4种类型.介绍了该方法在大连市的应用.结果表明,大连市禁止、限制、优先和重点开发区面积分别占全市域土地面积的56%、19%、12%和13%.     

亚硝态氮胁迫下菲律宾蛤仔实时定量P CR内参基因的筛选

为了更好地从基因角度研究亚硝态氮对贝类的生态毒性,需要筛选一个合适的内参基因作为参考,对其毒性相关基因进行定量表达分析。本研究以菲律宾蛤仔(Ruditapes philippinarum)作为研究对象,以亚硝态氮胁迫的鳃组织cDNA作为模板,利用geNorm软件和NormFinder软件对6个候选内参基因进行表达稳定性分析,并对2个结果做了综合赋权分析。结果显示,geNorm分析的基因表达稳定性结果为ActinCyPAEF1αUbi18STubu,NormFinder软件分析的结果为ActinUbiCyPAEF1α18STubu,最后经加权赋值法综合分析获得6个候选基因的表达稳定性为ActinCyPAUbiEF1α18STubu,即Actin为表达最稳定的基因。因此,Actin可以作为衡量亚硝态氮胁迫后菲律宾蛤仔鳃组织中基因表达的内参基因。     

Effects of intercropping with floricultural accumulator plants on cadmium accumulation in grapevine

Environmental Science and Pollution Research - Grapevine (Vitis vinifera L.) intercropping with floricultural cadmium (Cd) accumulator plants (Helianthus annuus L., Cosmos sulphureus Cav., Cosmos...     

磁性絮凝剂处理景观生态水的实验条件探讨

研究了利用粉煤灰制成的磁性絮凝剂处理景观生态水的各种单因素实验,并且用正交实验的方法对该磁性絮凝剂处理景观生态水的实验条件进行了优化选择,研究了该磁性絮凝剂处理景观生态水的一般规律。实验结果表明,当操作条件为：投加量为200mg/L,搅拌时间为1min,搅拌速度为300r/min和磁吸附时间为1.5min时,取得最佳处理效果。在此实验条件下,景观生态水的COD、总P及氨氮的去除率分别可达76.15%、59.54%与53.36%。     

分散式污水处理系统的特征及其应用

从传统的生活污水集中处理和分散式污水处理方法入手,介绍了分散式污水处理系统的概念、类型及特征,分析了分散式处理系统存在着脱氮除磷、技术性能及环境友好方面的不完善之处。提出了加强脱氮除磷研究,实现生态化、节能化、景观化、省地化是分散式污水处理系统发展的方向。