Hydrophobic calcium carbonate: an option for the value-added conversion of wastes resulting from biodiesel production

High production cost is the key issue of biodiesel industry nowadays. To low down the cost, using low-quality lipids feedstock is the most effective way. Two-step process is vastly applied to deal with those low-quality lipids to produce biodiesel. However, environmentally unfriendly wastes are formed during the process. Here we use calcium oxide residue and wastewater from biodiesel production to produce nanostructured calcium carbonate (CaCO₃) by carbonation at ambient temperature. The results show that CaCO₃ is hydrophobic and has broccoli-like morphology. It is made up of many uniform nano-rods, and each rod is composed of smaller particles with diameters about 50 nm. The idea of wastes utilization could make the biodiesel production process environmentally friendly, and the income of the produced CaCO₃ could further low down the cost of biodiesel production.     

Organic phosphorus species in surface sediments of a large,shallow, eutrophic lake,Lake Taihu,China

Organic phosphorus (P) fractions in surface sediments from a large shallow, eutrophic Lake Taihu, China, were extracted with 0.1 M NaOH after pre-treatment of the sediments with a solution composed of 0.1 M EDTA and 2% (w/v) Na₂S₂O₄. Composition of organic P in the extracts was then characterized by ³¹P nuclear magnetic resonance spectroscopy (³¹P NMR). Several P species, including phosphonates, orthophosphate, orthophosphate monoesters, phospholipids, DNA, pyrophosphate and polyphosphate, were detected in the NaOH extracts. The proportion of extracted organic P to total P in sediments was negatively correlated with total P in the water column, as were the proportions for orthophosphate monoesters and DNA. This implies that the majority of organic P in surface sediments is likely stabilized in some way, and does not directly contribute to the internal loading of P from sediments.     

滤毒罐失效指示器的研究概况

失效指示器可以用来确定滤毒罐的使用寿命,有利于滤毒罐在化学战环境中的安全有效使用.本文系统地综述了失效指示器技术领域的研究概况,并指出了其发展趋势和应用前景.     

Identification and comprehensive evaluation of a novel biocontrol agent Bacillus atrophaeus JZB120050

Abstract

Bacillus spp. have long been used as biocontrol agents because of their efficient broad-spectrum antimicrobial activity. We identified a novel strain of Bacillus atrophaeus, named JZB120050, from soil. B. atrophaeus JZB120050 had a strong inhibitory effect against Botrytis cinerea and many other phytopathogens. Gas chromatography-mass spectrometry showed that B. atrophaeus JZB120050 produced many secondary metabolites, such as alkanes, alkenes and acids; some of which were related to pathogen inhibition. Enzyme activity analysis showed that B. atrophaeus JZB120050 secreted cell-wall-degrading enzymes, including chitinase, glucanase and protease, which degraded fungal cell walls. Both the novel glucanase gene bglu and chitinase gene chit1 were cloned and heterologously expressed in Escherichia coli and the products showed strong enzyme activity. In addition, B. atrophaeus JZB120050 secreted siderophores and formed a significant biofilm. Future studies should focus on these antimicrobial factors to facilitate widespread application in the field of agricultural biocontrol.     

Study on acute toxicity and structure-activity relationship of zebrafish (Danio rerio) exposed to naphthoquinones

In this paper, we evaluated the acute toxicity of five naphthoquinone compounds, expressed as median lethal concentration at 96 h (LC₅₀) using zebrafish as a model. The five compounds were classified as harmful or very toxic. The Gaussian method was used to calculate the quantitative-chemical parameters of each compound. Based on the structure-activity relationship analysis, the interaction between the naphthoquinones and the target is likely mediated by 1-carbonyl and the hydrophobic fraction substituted in α -position of naphthoquinone via hydrogen bonding and hydrophobic interactions. Our results provide a foundation for evaluating the aquatic ecological risk and the mode of action of naphthoquinones in the environment.     

旋转填充床中催化氧化脱硫的试验研究

对在新型强化传质设备－旋转填充床中用Mn^2 催化氧化脱除烟气中SO2的工艺进行了试验研究,其脱硫率可达99％,比传统设备的氧化脱硫率提高4％－69％。该设备体积小,操作简单,具有工业化应用前景。     

环境标准与环境法律责任之间的关系探析

环境标准是环境法运行的基础,环境法律责任是环境法实施的重要保障,理清二者之间的关系对环境法的顺利实施有着非常重要的意义。通过分析环境标准的正当性和阐述法律法规对人身财产权利的固有保护,可知环境标准是判断是否承担环境法律责任的充分但非必要条件。     

翻堆对强制通风静态垛混合堆肥过程及其理化性质的影响

为了了解翻堆对堆肥过程及理化性质的影响,开展了城市污泥、猪粪强制通风静态垛堆肥试验,试验共设4个处理,分别为升温期(3d)、高温期(10d)、降温期(20d)翻堆处理和不翻堆的对照处理.结果表明:翻堆处理能降低堆肥的挥发性固体含量,减轻其在堆体剖面的差异.升温期翻堆不利于堆体DOC含量的降低及腐熟度的提高.降温期翻堆会减小再次升温速率及其所达到的最高温度.升温期和降温期翻堆,虽然有利于堆体内湿度的均匀分布,但却会缩短高温持续时间、降低堆肥的减容率和脱水率.不同时期翻堆,堆肥的pH和EC有降低的趋势,但总体而言其影响并不是特别明显.在高温期翻堆的处理中高温期持续时间长达15d,堆体减容率高达29%,再次升温的升温速率和所达到的最高温度分别为4℃·d-1和60 5℃,且与其它处理相比,其堆肥的VS、DOC和湿度都较低,GI较大.由此试验表明,高温期翻堆的堆肥处理能提高强制通风静态垛堆肥的堆肥效率和质量.     

溶解氧对OLAND生物膜反应器硝化性能的影响及其微生物种群动态研究

采用以多孔球悬浮填料为载体的限氧亚硝化生物膜处理高氨氮、低碳源的废水,通过对DO控制在0.5~1.0 mg/L,实现硝化阶段出水中的氨氮与亚硝态氮的比例达到最适值1∶(1.2±0.2),从而为后阶段的厌氧氨氧化系统提供理想的进水,进而提高氮的去除率;同时应用PCR-DGGE对硝化阶段不同时期的生物膜中微生物的种群动态变化进行了分析。研究表明,群落结构和优势种群的数量具有时序动态性,微生物多样性与废水的处理效果出现协同变化的特征。测序结果表明,在生物膜中进行氨氧化作用的主要为亚硝化杆菌(Ni-trosomonassp.)、亚硝化螺菌(Nitrosospirasp.);进行亚硝酸氧化的主要为硝化球菌(Nitrococcussp.)。