Environmental–geochemical characteristics of Cu in the soil and water in copper-rich deposit area of southeastern Hubei Province, along the middle Yangtze River, Central China

In this study, the natural Cu background concentration and Cu natural and anthropogenic contamination in soil, water and crop were investigated systematically in Huangshi area. The results show that regional geology is the dominant factor controlling the natural Cu background concentration in soil and water, and that pH is important to control the vertical distribution of Cu in soil under the same geographical and climatic conditions. The mineralization of rock bodies causes the natural Cu increase in soil and water, whereas, a large number of mining–smelting plants and chemical works are the main sources of Cu anthropogenic contamination. Cu in naturally and anthropogenically polluted soil displays differences in total and available contents, vertical distribution patterns and physico-chemical properties, the same happens in water.     

Mercury contamination in vicinity of secondary copper smelters in Fuyang, Zhejiang Province, China: Levels and contamination in topsoils

In the present study, we aim to investigate the extent of soil contamination by Hg, particularly by anthropogenic Hg, and tentatively estimate the total Hg (Hg_T) accumulation in topsoils (0-15 cm) in Fuyang, Zhejiang Province—a secondary Cu smelter of China. The results show that the levels of soil Hg in the vicinity of the smelters have been substantially elevated following local smelting activities. The spatial distribution of soil Hg in this area reveals a rapid decrease as the distance from the smelter reaches 1.5 km, which is probably due to the quick deposition process of particulate Hg and reactive gaseous Hg emitted from the smelters. The total accumulation of Hg_T in the topsoils of the study area of 10.9 km² is approximately 365-561 kg and of which 346-543 kg might be contributed by anthropogenic emission alone with an annual emission of 17.3-27.2 kg Hg to the topsoils.     

通过改进节点性能确保火灾下钢框架结构的鲁棒性(英文)

介绍了钢框架结构火灾下鲁棒性的背景知识,建议对于非常重要的建筑结构,抗火安全设计必须包括通常设计中尚未考虑到的意外破坏模式。文章辨识了结构意外破坏的不同模式,并提出了保证结构安全性的可行方法。本文主要介绍了如何利用梁的悬链线效应,使荷栽从受损结构重新分配到相邻结构,该效应是梁受弯承载力状态的一种转变。为确保钢梁中悬链线效应的充分发展,最重要的是要保证节点具有足够的抗拉承栽力与转动能力。本文提出了一种节点转动能力需求的量纲分析方法,并根据一些试验结果,介绍了英国常用的梁柱节点可到达的转动能力。虽然一些延性较好的节点在升温时能够达到10°的转动能力,但当钢的温度非常高时,其仍不能满足使悬链线效应充分形成时所需要的转动能力(>15°)。随后,讨论了如何提高节点的转动能力,包括:采用具有较好延性的节点(例如开反向槽口的节点),改进节点的细部构造(如将节点的受拉区移近至受压区,并为螺栓开槽型孔)和采用更强的、延性更好的由耐火钢制成的螺栓。这些提出的节点技术需要与节点在其他设计要求下的性能要求相协调(如刚度),为满足不同的结构性能要求,找到最优的节点设计方法,仍需要更深入的研究。     

纯弯荷载下厚型钢结构防火涂层破损的试验研究和数值分析

厚型钢结构防火涂层因其耐火性好、性能稳定而成为最常用的防火保护形式之一,但厚型防火涂层易在地震和冲击等作用下发生破损和脱落,这将影响钢结构的抗火性能。为了认识厚型钢结构防火涂层的破损模式,本文对涂有厚型防火涂料的钢板件进行了纯弯荷载试验,运用有限元分析软件AN SY S对试验全过程进行了模拟分析,并与试验结果相对比。结果表明:受弯构件压区涂层的破损模式主要为涂层-钢板界面破损,拉区涂层的破损模式与涂层厚度有关,当涂层厚度较薄时,主要为涂层内部拉裂,涂层厚度较厚时,主要为涂层-钢板界面破损;涂层厚度越厚,界面破损出现得越早;若在涂层上贴置应变片,会使涂层的界面裂缝和横向裂缝提早出现。     

大空间建筑火灾下钢索的力学反应参数分析

钢索在大空间建筑火灾升温条件下的力学反应是评价索网结构抗火性能的关键依据。基于非线性有限元方法,建立了钢索在高温下的力学分析模型,模拟了大空间建筑火灾升温历程中钢索力学反应全过程,用参数分析方法得到影响钢索在火灾升温历程中力学反应的关键因素。结果表明:在大空间建筑火灾升温历程中,钢索的水平张力呈下降的趋势;随着钢索的预应力比增加、温度场非均匀性的增强和跨度的增加,其水平张力下降速率增大;荷载比的增加对水平张力下降速率影响较小。上述结论与钢索水平张力的解析解一致,可为索网结构抗火性能分析提供参考。     

火灾下型钢混凝土异形柱温度场分析

为了分析型钢混凝土异形柱的耐火极限及火灾后的力学性能,为试验研究做好充分的前期准备,本文采用有限元分析软件ANSYS对型钢混凝土异形柱截面温度场进行数值模拟,得出了柱截面在不均匀受火情况下的温度场分布规律。结果表明,在两面受火的情况下,L形柱的凹角处的温升低于其它部位;由于型钢的存在,加快了柱截面内部温度的热传导;距离受火面相同的深度处的混凝土与型钢的温度不同,因此有必要研究损伤差异对承载力和两者粘结滑移造成的影响。     

Removal of Ni(II) and Cu(II) ions using native and acid treated Ni-hyperaccumulator plant Alyssum discolor from Turkish serpentine soil

Alyssum discolor biomass was collected from serpentine soil and was used for removal of metal ions. The plant species grown on serpentine soils are known to be rich with metals ions and thus have more capability for accumulating heavy metals. Native and acid-treated biomass of A. discolor (A. discolor) were utilized for the removal of Ni(II) and Cu(II) ions from aqueous solutions. The effects of contact time, initial concentration, and pH on the biosorption of Ni(II) and Cu(II) ions were investigated. Biosorption equilibrium was established in about 60 min. The surface properties of the biomass preparations were varied with pH, and the maximum amounts of Ni(II) and Cu(II) ions on both A. discolor biomass preparations were adsorbed at pH 5.0. The maximum biosorption capacities of the native, and acid-treated biomass preparations for Ni(II) were 13.1 and 34.7 mg g⁻¹ and for Cu(II) 6.15 and 17.8 mg g⁻¹ dry biomass, respectively. The biosorption of Ni(II) and Cu(II) ions from single and binary component systems can be successfully described by Langmuir and Freundlich isotherms. When the heavy metal ions were in competition, the amounts of biosorbed metal ions on the acid treated plant biomass were found to be 0.542 mmol g⁻¹ for Ni(II) and 0.162 mmol g⁻¹ for Cu(II), the A. discolor biomass was significantly selective for Ni(II) ions. The information gained from these studies was expected to indicate whether the native, and acid-treated forms can have the potential to be used for the removal and recovery of Ni(II) ions from wastewaters.     

污泥基活性炭吸附Cu2+的应用研究

以城市污水处理厂剩余污泥为原料,以ZnCl₂为活化剂制取污泥基活性炭。以此污泥基活性炭为吸附剂,对含Cu²⁺的废水进行了吸附实验研究。考察了溶液pH值、Cu²⁺的起始浓度对Cu²⁺离子吸附量的影响;利用等温吸附实验作出吸附等温线,并考察了污泥基活性炭吸附剂吸附Cu²⁺的动力学方程。实验结果表明,污泥基活性炭对Cu²⁺具有良好的吸附性能。吸附的最佳pH值为5;吸附符合Langmuir和Freundlich吸附等温方程,吸附为优惠吸附,吸附量随着吸附质溶液浓度的增加而增大;吸附平衡时间为4 h,吸附动力学符合二级动力学方程。     

废镀锌板炼钢粉尘的浸出过程

为了解决废镀锌板冶炼粉尘造成的资源浪费和环境污染的问题,首先研究了用硫酸浸出该类粉尘中有价金属的过程。在不同温度条件下,控制浸出时间、液固比和硫酸浓度等因素,将粉尘中以不同形式存在的锌浸出。常温条件下,苏钢粉尘中赋存于氧化锌中的锌被全部浸出;高温强酸条件下,常温浸出过程中未被浸出的,赋存于铁酸锌中的锌几乎被全部浸出,浸出率达到98%。     

改性钢渣处理低浓度氨氮废水

采用正交实验法,以氨氮去除率为指标,设计5因素4水平正交实验;采用恒温振荡方法对高温活化改性钢渣做了吸附低浓度氨氮影响因素的研究;得出以下结论：改性钢渣吸附低浓度氨氮影响因素的重要性顺序为：氨氮初始质量浓度〉钢渣粒度〉改性方法 〉溶液pH〉吸附时间,经过改性,提高了钢渣处理低浓度氨氮废水的能力,其中经过700℃高温活化改性效果最佳;高温改性钢渣对低浓度氨氮的吸附过程符合Langmuir方程,相关系数为0.9993,作用机理为表面吸附,即单层吸附,理论饱和吸附量为2.8491 mg/g。