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421.
采用银杏叶和桑叶提取液制备了改性类Fenton反应催化剂并进行了表征分析,研究了溶液初始p H、反应温度、催化剂加入量、甲基橙初始质量浓度等因素对甲基橙降解率的影响,同时考察了催化剂的重复使用效果。表征结果表明:制备出的催化剂为Fe_2O_3和Fe OOH的混合物;桑叶改性催化剂的粒径分布较银杏叶改性催化剂均匀,粒径较小,比表面积较大。实验结果表明:在初始p H为6.23、反应温度60℃、催化剂用量1 g/L、甲基橙初始质量浓度100 mg/L的条件下,银杏叶改性催化剂的甲基橙降解率为99.40%,桑叶改性催化剂的甲基橙降解率为99.96%;碱性条件下,甲基橙降解率仍接近100%,扩宽了反应的p H适用范围,为碱性条件下处理偶氮染料提供了新思路;催化剂重复使用6次之后,甲基橙降解率仍可达到99%。根据反应前后溶液的紫外-可见吸收光谱,初步探讨了降解机理。 相似文献
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某矿区农田土壤重金属潜在生态风险评价及形态分析研究 总被引:2,自引:0,他引:2
对广西某矿区农田土壤中的Cd、Pb、Zn、Hg进行潜在生态风险评价及存在形态分析.结果表明,研究区域Cd为极强危害程度,Pb和Hg为很强危害程度,Zn为中等危害程度,所有采样点位均处于很强危害程度,其中主要的贡献来自于Cd.形态分析结果表明,Cd以可交换态为主,Pb以碳酸盐态和铁锰氧化态为主,Zn以残渣态、有机结合态和铁锰氧化态为主,Hg以残渣态和有机结合态为主.次生相与原生相分布比值法与潜在生态风险评价法评价结果存在差异,两种方法的评价结果均应加以考虑. 相似文献
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在前期研究的基础上,应用计算机技术建立绿色建筑植物资源信息系统(Green Building Plant Resources Information System,GBPRIS),该系统包括植物基本特征数据库、植物生态功能数据库、植物群落数据库和评价体系数据库4个基础数据库.共收录500种植物和上海常见48个植物群落的信息,将植物的生物学特性、生态习性及各项生态功能信息规范化、数字化输入,降低了绿色建筑适生植物选择的专业性要求,并具有多途径搜索、快速查询文档和图片的功能,既能用于对现有绿化体系进行评价,有针对性地提出改进意见,也可用于对建筑室外绿化规划设计进行预评价,为绿色建筑的绿化配置提供科学参考. 相似文献
427.
Jin Ma Li-bo Pan Qin Wang Chun-ye Lin Xiao-li Duan Hong Hou 《Environmental geochemistry and health》2018,40(1):295-301
A total of 60 children (31 males and 29 females) between the ages of 3 and 12 years were randomly selected from Lanzhou City in Gansu Province, northwest China. Hand (soil/dust) SD samples from these children were collected using hand wipes. We determined the approximate amounts of hand SD and the concentrations of three tracer soil elements (Ce, Y, and V) in these samples. The approximate amounts of hand SD ranged from 42.28 to 173.76 mg, with a median value of 85.42 mg. In addition, the mean amounts of hand SD estimated using the concentrations of Ce, Y, and V in the samples were 4.63, 3.43, and 3.42 mg, respectively. The amount of hand SD varied greatly among the age groups: primary school children had more hand SD than kindergarten children, males had more hand SD than females, and children from rural areas had more hand SD than those from urban areas. The rates of daily ingestion of hand SD for kindergarten and primary school children were estimated to be 7.73 and 6.61 mg/day, respectively. 相似文献
428.
Wenjun Qin Manuel Dekermenjian 《Journal of the Air & Waste Management Association (1995)》2013,63(8):1177-1183
Abstract Loss of filtration efficiency in a fabric filter baghouse is typically caused by bag failure, in one form or another. The degree of such failure can be as minor as a pinhole leak or as major as a fully involved baghouse fire. In some cases, local air pollution regulations or federal hazardous waste laws may require estimation of the total quantity of particulate matter released to the environment as a result of such failures. In this paper, a technique is presented for computing the dust loading in the baghouse exhaust when one or more bags have failed. The algorithm developed is shown to be an improvement over a previously published result, which requires empirical knowledge of the variation in baghouse pressure differential with bag failures. An example calculation is presented for a bag-house equipped with 200 bags. The prediction shows that a small percentage of failed bags can cause a relatively large proportion of the gas flow to bypass the active bags, which, in turn, leads to high outlet dust loading and low overall collection efficiency from the baghouse. 相似文献
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Simultaneous measurements of arsenic and sulfide using diffusive gradients in thin films technique (DGT) 总被引:2,自引:0,他引:2
Lv Xu Qin Sun Shiming Ding Mengdan Gong Chaosheng Zhang 《Environmental geochemistry and health》2018,40(5):1919-1929
Diffusive gradients in thin films technique (DGT) is a dynamically passive sampling technique which has been applied increasingly to the environmental monitoring field. In the preliminary period, the DGT with zirconium hydroxide-silver iodide as the binding phase (ZrO-AgI DGT) has been developed for the determination of sulfide (S(II)). On this basis, this paper developed its determination method for inorganic arsenite (As(III)) to further realize the simultaneous and high-resolution measurements of labile inorganic As and S(II) in sediments. ZrO-AgI binding gel had a strong ability in adsorbing and fixing As(III), showing a linear increase in the initial 12.5 min. After saturation of S(II) on ZrO-AgI binding gel, the adsorption rate and adsorption capacity of As(III) reduced by 8 and 14%, respectively. A stable elution rate (89.1 ± 2.2%) was obtained by extraction of As(III) on the binding gel using a mixture solution of 1.0 M NaOH and 1.0 M H2O2 (1:1). The DGT capacity of As(III) determined by the ZrO-AgI DGT was 23.6 μg cm?2. DGT uptakes of As(III) were independent of pH (4.0–9.0) and ionic strength (0.01–100 mM), and they did not interfere with each other during the uptake process. Simultaneous measurements of labile As and S(II) in four sediment cores of Taihu Lake (China) with ZrO-AgI DGT showed that they had similarly vertical distributions in the top 16-mm layer in one core and in the whole profile up to the 35 mm depth in two cores. It likely reflected a simultaneous release of As and S(II) in sediments by synchronous reduction of As-hosted oxidized iron and sulfate, respectively. The simultaneous decreases of labile As and S(II) from their co-precipitation (e.g., As2S3) were not obvious in deeper sediment layer through the measurement with ZrO-AgI DGT. 相似文献