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481.
The capabilities of chitosan and chitosan-EGDE (ethylene glycol diglycidyl ether) beads for removing Acid Red 37 (AR 37) and Acid Blue 25 (AB 25) from aqueous solution were examined. Chitosan beads were cross-linked with EGDE to enhance its chemical resistance and mechanical strength. Experiments were performed as a function of pH, agitation period and concentration of AR 37 and AB 25. It was shown that the adsorption capacities of chitosan were comparatively higher than chitosan-EGDE for both acid dyes. This is mainly because cross-linking using EGDE reduces the major adsorption sites -NH3+ on chitosan. Langmuir isotherm model showed best conformity compared to Freundlich and BET. The kinetic experimental data agreed very well to the pseudo second-order kinetic model. The desorption study revealed that after three cycles of adsorption and desorption by NaOH and HCl, both adsorbents retained their promising adsorption abilities. FT-IR analysis proved that the adsorption of acid dyes onto chitosan-based adsorbents was a physical adsorption. Results also showed that chitosan and chitosan-EGDE beads were favourable adsorbers and could be employed as low-cost alternatives for the removal of acid dyes in wastewater treatment. 相似文献
482.
利用中国数字地震台网(CDSN)5个台站的波形资料,采用功率谱密度估计方法,提取了智利地震激发的地球球型自由振荡,并与地球初步参考模型(PREM)的理论自由振荡周期进行对比,发现球型振荡振型周期与地球初步参考模型预测的球型自由振荡周期基本吻合。所得结果可以进一步用来研究地震震源机制和地球内部结构,并对大地震的震源破裂分布给出一定的约束。 相似文献
483.
为适应江苏省财政资金绩效评价工作需要,定量、科学地评价环保专项资金项目实施成效,本文以江苏省省级节能减排(重点污染排放治理)专项引导资金项目为例,探讨了项目绩效评价个性指标设计方法。基于SMART原则设计并形成一套个性指标体系,包括资金效益、项目产出和环境效益三方面内容,共13项评价指标。该指标体系按不同类别分别对减排资金项目的绩效进行客观评价,既反映了项目实施成效,也满足了宏观管理需求,可为今后相关工作的开展提供依据。 相似文献
484.
考虑液固耦合储液罐非线性地震反应分析 总被引:1,自引:0,他引:1
利用ADINA有限元软件研究了考虑液固耦合的立式圆筒形锚固储液罐非线性地震反应.通过分析计算1000m3储液罐自振特性,储液罐的加速度峰值沿罐壁高度变化趋势,罐壁的应力分布等反应,初步揭示其破坏机理,分析结果为储液罐的抗震设计提供重要的参考依据. 相似文献
485.
486.
城市生态保护红线划定方法与实践 总被引:7,自引:4,他引:3
基于近10年来我国城市(群)地区生态保护红线划分的实践经验,结合环境总体规划的探索,提出了一套城市生态保护红线体系与划分方法。首先,按照"识-评-落-合"的技术流程,划定城市生态功能红线。其次,通过识别大气环境和水环境的重要性,敏感性和脆弱性,划定环境质量红线。第三,基于合理的模型方法计算大气环境、水环境和自然资源承载力,分析测算环境资源开发上限。最后,借助GIS软件实现这三条红线的空间叠加,综合划分出生态保护红线。上述生态保护红线体系,与现有的各部门空间和资源管理制度能进行充分有序的衔接,可以作为促进新型城镇化健康发展的资源环境管理基础平台。 相似文献
487.
Wan Syaheedah Wan Ghazali Siti Amrah Sulaiman Aniza Abdul Aziz Harmy Mohamed Yusoff 《毒物与环境化学》2015,97(8):1017-1024
Free radicals induced by cigarette smoking have been linked to an increase in oxidative stress resulting in smoking-related cardiovascular diseases. However, the possible effect of honey that has antioxidant property in improving oxidative stress status among smokers has not yet been reported. Hence, this study was to determine the effects of 12-week Tualang honey supplementation on F2-isoprostanes, superoxide dismutase, glutathione peroxidase, catalase, and total antioxidant status among chronic smokers. A total of 32 non-smokers and 64 chronic smokers were recruited from Quit Smoking Clinic and Health Campus, Universiti Sains, Malaysia. Smokers were randomized into two groups (n = 32/group) namely smokers without supplementation and smokers with honey supplementation (20 g/day) for 12 weeks. Blood was obtained from non-smokers and smokers at pre-intervention and from smokers at post-intervention. During pre-intervention, the levels/activity of F2-isoprostanes, total antioxidant status, and catalase were significantly higher while superoxide dismutase and glutathione peroxidase were lower in smokers than non-smokers. During post-intervention, in supplemented smokers, there were significant decrease in F2-isoprostanes and increase in total antioxidant status, glutathione peroxidase and catalase levels/activities compared with pre-intervention. This study indicates that honey supplementation improves oxidative stress status suggesting a beneficial role of honey in reducing the risk of cardiovascular diseases. 相似文献
488.
With a variety of ecosystem services, river ecosystem plays an important role in the process of human society development. On the other hand, health condition of most aquatic ecosystems is seriously threatened by human activities. Restoring and maintaining a healthy ecosystem has already become a vital goal of river management. As a basis of river management, river health assessment is therefore particularly important. Based on indices of physics, chemistry and aquatic organisms, this research tried to establish a comprehensive evaluation system of aquatic ecological health suitable for the situation of Shaying River Basin. The system included 6 factors including riparian zone, river morphology, nutrients, oxygen balance, periphyton and benthic macroinvertebrates, which were defined into 19 indices reflecting the aquatic ecological health from different aspects. The assessment results indicated that the health condition of overall basin was normal, varying among different parts of the region, with Shahe River, Lihe River and Beiru River in the upper part sub-healthy, and Jialu River in the same part sub-sick. The middle region was generally in normal or sub-sick level; the health condition of the lower part was comparatively better due to a good condition. Within the indices, the nutrients and benthic macroinvertebrates were the major constraining factors to the health condition of Shaying River Basin for their poor health condition. The health conditions showed significant differences among the rivers (P < 0.01), with Jialu River being the worst. The result indicated that the aquatic ecological health of Shaying River Basin is affected by many factors, with urban and industrial sewage being the main ones, And that different protective measures should be employed for rivers of different conditions. The result can provide theoretical basis for the ecological restoration of Shaying River Basin and reasonable exploitation and conservation of the water resource of the whole Huaihe River Basin. 相似文献
489.
电子鼻检测污染土壤中挥发性氯代烃的适用性研究 总被引:4,自引:3,他引:1
开发了一套以光离子化传感器(PID)为核心的电子鼻系统,用于污染土壤中挥发性氯代烃的快速检测.用气相色谱(GC)分析评价了预处理管对苯系物等干扰物质的去除效果;用标准气体发生装置发生不同浓度的四氯乙烯和三氯乙烯气体,比较评价了电子鼻与GC检测结果的吻合程度及测试重现性.在此基础上,选取我国长三角地区三类典型水稻土进行模拟污染土壤的通风净化实验,评价了电子鼻系统用于实时监测挥发性氯代烯烃污染土壤修复进程的可行性.结果表明:①采用RAE-SEP卤代烃分离管进行预处理,甲苯、乙苯等苯系干扰物的去除率可达80%~97%,而四氯乙烯和三氯乙烯等挥发性氯代烃的选择性透过率高于90%;②电子鼻对不同浓度四氯乙烯和三氯乙烯气体的定量检测结果与GC结果相近,线性拟合斜率为1.012,相关系数R2〉0.99;③电子鼻对三类典型土壤通气脱附过程中污染物浓度的变化趋势的实时监测结果与GC检测结果基本一致,判定系数R2〉0.99(n=47).因此,该电子鼻系统有望用于挥发性氯代烯烃污染土壤的快速检测,提高污染场地的风险评估和修复效率. 相似文献
490.