脉冲变频电磁场对水华鱼腥藻生长的效应

对脉冲变频电磁场作用下,扫描频率和磁感应强度的变化对水华鱼腥藻细胞活性和生长的影响进行了研究。结果显示,扫描频率从25~27 Hz增大到1~60 kHz时,磁场对藻细胞活性的抑制作用减小,但增大到60 kHz以上,磁场对藻细胞产生强烈抑制作用,累积水力停留时间4 min的藻样在48 h培养时间内已失去活性停止生长。扫描频率为50~100 Hz和1~60 kHz时,累积水力停留时间2 min的藻样,细胞受到磁场刺激生长加快;只有累积水力停留时间＞6 min,才表现出对藻活性的抑制作用。磁感应强度增大至120 G,磁场对细胞活性产生明显抑制作用,增大磁感应强度有利于对细胞活性和生长的抑制。     

污泥活性炭的制备及其对溶液中Cr6+的吸附

以城市污水厂剩余污泥为原料,采用ZnCl2作活化剂,热解制备污泥活性炭。实验结果表明,制备污泥活性炭的最佳条件热解温度为550℃,ZnCl2溶液浓度为3mol／L,ZnCl2溶液体积与污泥质量比（mL／g）为2．5：1,热解时间为25min。用所制备的污泥活性炭吸附溶液中的Cr6＋最佳吸附条件为：吸附时间90min,Cr6＋初始质量浓度50mg／L,污泥活性炭加入量0．2g,溶液pH2,在此条件下,Cr6＋去除率达99．9％。污泥活性炭对溶液中Cr6＋的吸附等温线属于I型,等温吸附方程可用Langmuir模型和Freundlich模型来拟合。     

磷钨酸催化合成混合二元酸二丁酯

采用混合二元酸和正丁醇为原料,以自制磷钨酸为催化剂,甲苯为带水剂,合成了混合二元酸二丁酯.通过均匀设计和单因素实验研究得到混合二元酸二丁酯合成的最佳工艺条件:n(正丁醇):n(混合二元酸)为3.0,催化剂与混合二元酸的质量比为2.2%,甲苯在反应体系中的质量分数为22%,反应时间为2.0 h.在最佳工艺条件下反应的酯化率为99.44%.     

构建珠三角区域循环经济圈

随着珠三角地区经济的快速发展,人口、资源与环境之间的矛盾日益尖锐,制约着该地区可持续发展.分析该问题出现的原因,认为构建珠三角区域循环经济体系,才是珠三角可持续发展的必然选择.提出在以下三方面构建珠三角循环经济圈:一是加强珠三角城市群的整合力度,细划城市群内各城市的职能分工.形成广泛的协作关系;二是消除行政壁垒,建立城市群协调机制,建立直属中央的区域环保监测部门;三是完善区域循环经济的立法体系.     

考虑燃烧作用的隧道火灾三维数学模型

采用预设概率密度函数模型考虑燃烧的过程,构建了一种描述隧道火灾过程中燃油燃烧、烟气流动和传热的三维数学模型。应用该模型模拟了台缙高速公路苍岭特长隧道在释热率为50MW、风速分别为0～2m／s条件下的火灾过程,并通过室内模型燃烧试验验证了其有效性。与相同条件下热源模型计算结果的比较表明：无论通风条件如何,燃烧释放的大量烟气均会在火源上方形成一高速烟流区,而热源模型由于忽略了燃烧过程,在风速≥1m／s的条件下将无法刻画出该区域。高速烟流区抑制了纵向风流与高温烟流的混合,控制着火源近区的流场结构,是造成烟气回流和分层运动现象的主要因素之一。     

Organochlorine pesticides and polybrominated diphenyl ethers in irrigated soils of Beijing, China: Levels, inventory and fate

Limited information on the levels, inventory and fate of Organochlorine pesticides (OCPs) and Polybrominated diphenyl ethers (PBDEs) in the soils irrigated by sewage or wastewater is available. In this study, variation in concentrations, profiles and fate of OCPs and PBDEs were investigated using soil samples collected from a region irrigated by sewage, mixed water and clean water in the east of Beijing, China. No significant variation was observed among groups, except for penta-BDEs. The measured ΣOCPs and ΣPBDEs residues ranged from 6.4 to 171.2 ng g⁻¹ (dw) and 501.9 to 3310.7 pg g⁻¹ (dw), respectively. ΣDDTs and BDE-209 were the most abundant congeners accounting for about 76% of ΣOCPs and 93% of ΣPBDEs. Concentrations of hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethane (DDTs) and its major degradation products, and hexachlorobenzene (HCB) ranged from 1.2 to 11.4 ng g⁻¹ (dw), 4.0 to 155.6 ng g⁻¹ (dw) and 0.3 to 3.4 ng g⁻¹ (dw), respectively. The major DDT degradation products were p,p′-DDT and p,p′-DDE. The major hexachlorocyclohexane (HCH) isomer in irrigated soils is β-HCH, reflecting its higher affinity to solids and resistance to degradation than other isomers. Both α-HCH/β-HCH and p,p′-DDT/p,p′-DDE ratios were log-normally distributed and negatively correlated to log(ΣHCHs) and log(ΣDDTs), respectively, suggesting no significant recent application of OCPs. Individual BDE congeners, ΣPBDEs and ΣOCPs were significantly correlated with total organic carbon (TOC). Moreover, a good correlationship between ΣPBDEs and black carbon (BC) was obtained but not between ΣOCPs and BC. Sewage irrigation did not have obvious effect on their contaminant levels and inventory of OCPs and PBDEs.     

新型MnOx/CNTs催化剂低温选择性催化还原NO

采用等体积浸渍法制备了MnOx/CNTs催化剂,用于低温NH3选择性催化还原(SCR)NO的实验.使用BET,FT-IR,TEM和XRD对催化剂进行表征,结果表明:碳纳米管经混酸超声分散,增加了羧基活性基团,锰氧化物颗粒分布较均匀.在模拟烟气条件下,考察了催化剂的MnOx负载量、煅烧温度及质量和烟气流速比(W/F)对NO脱除率的影响.煅烧温度为773 K,MnOx负载量为10%时,NO脱除率达到98.56%;W/F为2～3 mg/(mL·min-1)时NO的脱除率更高.     

Heat stress increases the efficiency of EDTA in phytoextraction of heavy metals

Solution culture and pot experiments were carried out to investigate the effects of root damage on phytoextraction of heavy metals. In hydroponics, roots of corn (Zea mays L.) seedlings were pretreated with heating stress, and then were exposed to 250 microM Pb+250 microM EDTA solutions for 7d. The results showed that the preheating treatment significantly increased Pb transportation from roots to shoots. In pot experiments, the effect of hot EDTA solution (95 degrees C) on the accumulation of heavy metal in the shoot of corn and pea (Pisum sativum L.) was also examined. Compared to normal EDTA (25 degrees C) treatment, application of hot EDTA solution to the soil surface increased the total removal of Pb in shoots of corn and pea by about 8- and 12-fold, respectively, in an artificially multimetal-contaminated soil. In addition, hot EDTA solution increased the shoot Cu removal by about 6-fold for corn and 9-fold for pea, respectively, in a naturally Cu-contaminated soil. These results suggested that exposure of roots to high temperature could increase the efficiency of EDTA on the accumulation of heavy metals in shoots. This new approach can help to minimize the amount of chelate applied in the field and reduce the potential risk of heavy metals' leaching.     

温度、体重对皱纹盘鲍耗氧量和排氨量的影响

皱纹盘鲍的耗氧量和排氨量的实验结果表明：温度和体重对鲍的耗氧量和排氨量有明显的影响,且两固子间存在着交互作用,皱纹盘鲍的个体耗氧量「Ｑ（Ｏ）／ｍｇｈ＾－１」和排氧量「Ｑ（Ｎ）／μｍｏｌｈ＾－１」与温度（θ／℃）和湿重（ｍ／ｇ）存在下列关系：Ｑ（Ｏ）＝０．０１２４ｍ＾０．８５５６１．０８５３＾θ,Ｑ（Ｎ）＝０．０２０７ｍ＾０．８５５６１．０８５３＾θ。２０℃皱纹盘鲍存在代谢的转变点。     

GDZ型锅炉烟气脱硫除尘脱水雾装置

文章介绍适用中小型燃煤锅炉的ＧＤＺ型锅炉了脱硫除尘设备,它在设计思路上是全新的,原理上突破目前所采取的使用大量水喷淋水循环的模式。具有体积小,吵采取水循环,处理费用低、集脱硫、除尘、脱水雾为一体,处理效率高,耐磨抗腐蚀的特点,是有较强的生命力,很有发展前任的环保产品。