Simultaneous removal of Cu(II) and Cr(VI) by Mg–Al–Cl layered double hydroxide and mechanism insight

Mg–Al–Cl layered double hydroxide (Cl-LDH) was prepared to simultaneously remove Cu(II) and Cr(VI) from aqueous solution. The coexisting Cu(II) (20 mg/L) and Cr(VI) (40 mg/L) were completely removed within 30 min by Cl-LDH in a dosage of 2.0 g/L; the removal rate of Cu(II) was accelerated in the presence of Cr(VI). Moreover, compared with the adsorption of single Cu(II) or Cr(VI), the adsorption capacities of Cl-LDH for Cu(II) and Cr(VI) can be improved by 81.05% and 49.56%, respectively, in the case of coexisting Cu(II) (200 mg/L) and Cr(VI) (400 mg/L). The affecting factors (such as solution initial pH, adsorbent dosage, and contact time) have been systematically investigated. Besides, the changes of pH values and the concentrations of Mg²⁺ and Al³⁺ in relevant solutions were monitored. To get the underlying mechanism, the Cl-LDH samples before and after adsorption were thoroughly characterized by X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. On the basis of these analyses, a possible mechanism was proposed. The coadsorption process involves anion exchange of Cr(VI) with Cl⁻ in Cl-LDH interlayer, isomorphic substitution of Mg²⁺ with Cu²⁺, formation of Cu₂Cl(OH)₃ precipitation, and the adsorption of Cr(VI) by Cu₂Cl(OH)₃. This work provides a new insight into simultaneous removal of heavy metal cations and anions from wastewater by Cl-LDH.     

量化风险评估(QRA)在海上生产设施风险管理中的应用

本文结合在胜利海区实施的量化风险评估工作，对量化风险评估在海上风险管理中的应用作一个简单的介绍。     

矿井火灾避灾与救灾最优路径研究

首先对有烟巷道和安全地点的判定方法进行了描述,然后对最佳避灾与救灾路线的定义进行了说明;综合考虑火灾救援各影响因素,提出了当量长度的概念及其求解方法,并引入到避灾与救灾路径优化模型中,建立了矿井火灾救援辅助决策支持系统。最后以河南新峰煤矿为例,基于Matlab仿真软件求解最优路径,运行结果可以为矿井火灾救援提供决策支持。     

珠江河网水产品中菊酯类农药残留调查及健康风险评价

2012年8月在珠江河网采集水产品样品(13种鱼,4种虾和2种贝),采用超声波提取-气相色谱法对样品中菊酯类农药(PYRs)进行残留检测,并对鱼类PYRs暴露水平进行健康风险评价。结果显示,鱼类肌肉、虾类和贝类中PYRs质量分数分别介于ND~3.05μg·kg-1、0.05~1.13μg·kg-1和0.69~1.20μg·kg-1(ND为未检出,以湿重计),平均值分别为0.90μg·kg-1、0.41μg·kg-1和0.99μg·kg-1。虾类和贝类中PYRs的检出率均很高,除联苯菊酯在虾类体内检出率为75%外,其他菊酯均为100%,鱼类肌肉中氯菊酯检出率最高,达到100%。氯菊酯在鱼类肌肉和贝类中的检出量最高,分别占总菊酯质量分数的52.2%和55.4%,溴氰菊酯在虾类中检出量最高,分别占总菊酯质量分数的33.0%;对居民通过食物摄入的PYRs进行食用暴露风险评估,结果表明,珠江河网水产品中PYRs人体健康危害的年总风险评价介于3.96×10-13~1.21×10-10a-1,水产品的安全消费量为5.54×104kg·d-1,水产品中的PYRs的健康危险风险很小。     

加强发证检验工作确保海上石油生产安全

针对国家关于海上石油天然气生产设施检验和石油作业安全管理的相关规定,结合胜利油田开展发证检验工作的实际情况。对当前海上石油生产设施发证检验过程中存在的问题进行了探究,并提出了相应的对策建议。     

不同部位梧桐生物质炭对水溶液中镉吸附的机理

为了探究梧桐不同部位废弃物所制备的生物质炭(皮、枝、叶)对Cd²⁺的吸附效率和稳定修复的机理,以此为园林废弃物炭化利用在重金属污染修复方面的应用提供科学依据.利用实验室模拟法,通过高温煅烧法制备梧桐不同部位生物质炭,采用元素分析仪、比表面积及孔隙分析(BET)、X射线衍射仪(XRD)、扫描电镜/能谱(SEM/EDS)及衰减全反射红外光谱(ATR-IR)等技术研究不同反应时间、重金属浓度和溶液初始pH条件下生物质炭对Cd²⁺吸附效果的影响,并运用四步萃取法和脱附实验分析生物质炭上Cd²⁺的吸附形态和稳定性.3种生物质炭都在8 h左右达到吸附平衡,最终吸附量依次为树皮炭>枝条炭>叶片炭;溶液初始浓度为0.5—2 g·L^-1时Cd²⁺的吸附量呈增长趋势,在2.5—3g·L^-1时逐渐平缓;生物质炭Cd²⁺吸附量均随着pH的升高而升高,但在pH值为5—8时,吸附的趋势逐渐平稳;树皮炭的酸溶态和非生物利用态的稳定Cd形态要高于枝条炭和叶片炭;比表面积不是影响梧桐生物质炭吸附Cd²⁺的主要影响因素,吸附动力学,ATR,XRD和重金属形态萃取均证实Cd碳酸盐类矿物生成是主导吸附机理;3种生物质炭的脱附量在4 h后逐渐趋于平衡,其中脱附量最大为叶片炭,最小为树皮炭.梧桐不同部位的初始性质对生物质炭吸附Cd²⁺具有明显的影响,其中梧桐皮具备更高的吸附量和重金属稳定形态,并且相比其他种类生物质炭有明显优势.因此,从吸附效果和生产成本的角度,本研究建议以梧桐皮为主,枝条和叶片为辅的生物质炭对重金属Cd进行修复治理.     

On eco-planning for an eco-demonstration park (EDP) and sustainability

The background, concept, connotation, principles, and methods of eco-planning for an Eco-Demonstration Park (EDP) and sustainability were examined based on a case study of the Luhua EDP in the Chongming Island of Shanghai, China, which is an important part of Shanghai Eco-city planning and construction in the 21st century. By analyzing natural, social and economic conditions, calculating population using the land capacity eco-model, eco-function zoning, and eco-construction, an innovative eco-industrial structure and technical chain were formulated. A comprehensive eco-planning scheme for the EDP was proposed, including planning and management strategies for subsystems of efficient industry, good quality human settlement, high standard eco-construction and eco-tourism as well as effective environmental protection and attractive landscape. The EDP should be an area with coordinated and sustainable economic, social and environmental subsystems. Eco-planning for the EDP should be a very important part of eco-city planning and sustainability. The paper aims to set up a theoretical framework and practical basis for eco-planning and promoting harmony between human and nature.     

Study on the damage statistical strength criterion of backfill with crack under thermo-mechanical coupling

ABSTRACT

Aiming at backfill with crack under the thermo-mechanical (TM) coupling, the concepts of crack macro-damage, loading meso-damage, thermal meso-damage, and total damage of backfill were proposed. Based on the statistical damage theory, considering the coupling effects of temperature, load and initial crack, a damage evolution model of backfill with crack under TM coupling effects was established. Based on this, the strength criterion of backfill with crack considering the effects of thermal and mechanical coupling was constructed by multivariate function full differential method. The research shows that: (1) The theoretical curves of damage evolution model and strength criterion of backfill with crack under TM coupling are in good agreement with the test curves, which verifies the rationality of the model. (2) The initial thermal damage decreases first and then increases with increasing temperature, reaches a minimum value at 40°C, and generally shows a “V” -shaped distribution law. The coupling effect of temperature and crack aggravates the total damage of the backfill. (3) The strength criterion can reflect the relationship between the stress and strain of each limit state and the parameters of backfill with crack under different temperature conditions and can provide a certain reference for the evaluation of the stability of backfill with geological defects such as joints and crack in deep high temperature mines.     

城市污泥桨叶式干化优化实验研究

桨叶式干化是一种高效的污泥干化处理技术,为了降低污泥含水率达到污泥减量减容效果,同时为后期的工程化应用提供依据和参考,实验采用倾斜盘式桨叶干燥机,以北京市污水处理厂污泥为研究对象,研究了不同滞留时间、污泥供给量、干燥机换热面积等因素对桨叶式干化处理后蒸发速度和污泥含水率的影响,并从处理效率以及与工程化应用数据对比分析等多方面考核,确定最佳工艺运行条件：使用0．5—0．8MPa的蒸气,蒸发速率达到14～21．8kg／（m^2·h）时,干化处理后污泥含水率〈40％。     

微波纳米磁粉协同作用处理污泥的研究

将粒径范围在10～20 nm之间的磁粉加入到原污泥中,在微波场中辐射,考察0.5～5 min辐射时间内污泥可生化性能、沉降性能和脱水性能的改善效果.结果表明,在微波和纳米磁粉的协同作用下,污泥快速发生水解,5 min内VSS溶解率达到34.62%,COD溶出率达到13.38%,在显微镜下观察到污泥微生物细胞发生了破裂;...