Reliable evidences that the removal mechanism of hexavalent chromium by natural biomaterials is adsorption-coupled reduction

For the last few decades, over 200 papers have been published in the Cr(VI) biosorption research field. Most early studies have claimed that Cr(VI) was removed from aqueous phase through an anionic adsorption, but this approach has been lost old original position. It has been newly explained that these findings were misinterpreted due to errors in measuring the concentrations of different chromium species in the aqueous phase, insufficient contact time required for equilibrium and the lack of information about the oxidation state of the chromium bound to biomaterials. Although 'adsorption-coupled reduction' is now widely accepted as the mechanism of Cr(VI) biosorption by natural biomaterials, a number of researchers still believe that Cr(VI) is removed by anionic adsorption onto the biomaterials. Therefore, the objective of this study was to show reliable evidences that the removal mechanism of Cr(VI) by natural biomaterials is 'adsorption-coupled reduction'. Sixteen natural biomaterials were used to study the Cr(VI) biosorption. Not only Cr(VI) but also total Cr in the aqueous phase were analyzed. X-ray photoelectron spectroscope was also used to verify the oxidation state of the chromium bound to the biomaterials. Finally, the removal behavior of Cr(VI) by each biomaterial was described by a kinetic model based on a redox reaction.     

从伦理教育看安全工程师职业道德

为强化安全工程师职业道德的培养,从道德问题的敏感性和处理工程伦理问题的技巧入手,将伦理教育引入职业道德教育,使安全工程师在道德层面上恪守客观公正的执业要义,并分析他们因遵守职业道德规范所遭受的非正义压力情形,提出建立职业投诉机制.针对树立生命安全的责任观,提出唤醒安全工程师对生命敬畏教育和关怀伦理教育,构建了以"道德规范驾驭职业服务"的安全工程师职业道德培养机制,并给出了职业道德培养的有效方法.     

安全生产风险预警探讨

以实现风险预警理论及技术在实际生产过程中的应用为目的,通过在油气初加工企业建立并实施安全生产风险预警的实践,讨论了安全生产风险预警机制的具体建立及实施过程,进一步探讨了风险辨识及评价的模式和方法及风险预警流程.     

城市公用管道安装监检中安全性的探讨

本文通过对城市公用管道工程的施工质量进行安装监检,结合发现的问题,指出了高压管道应重视材料验收和焊接施工组织;中压管道应防止对接焊缝微小缺陷的漏检;可采用先进仪器加强防腐质量检测的监检,督促安装单位在安装过程中做好防腐工作;钢套钢热水网直埋管道的安装监检应针对施工的特点来开展。从安全性和实用性的角度提出了有针对性的具体措施,具有可操作性。     

从九江地震看我国村镇房屋抗震设防

在总结分析九江地震震害的基础上,结合对我同华南、华东、华中、华北等一些地区村镇房屋历史震害特点及抗震能力现状调查结果的分析,指出了我国村镇房屋抗震能力薄弱的关键环节和普遍的震害规律,从工程防灾的角度论述了加强房屋抗震设防的有效性和必要性,阐述了目前我国村镇房屋抗震设防现状与口标的差距,进一步指出了加强抗震设防建设是减轻地震灾害的根本途径.     

污水土地处理CAD系统设计

针对污水土地处理设计实际,以提高设计速度和质量为目标,结合计算机辅助设计技术和软件技术的发展,采用成熟而先进的参数化设计技术及ADS开发工具,对土地处理设计中的几个关系问题进行了探讨。     

广州市区植物叶片重金属元素含量及其大气污染评价

文章通过对广州市区植物叶片中重金属元素含量的分析,研究了植物大气环境污染指数,探讨了植物叶片重金属元素含量与城市大气环境污染之间的关系。结果表明,植物叶片中Cu,Pb,Cd,Cr元素污染都较严重,在重污染区这些元素的含量明显高于清洁对照区;用植物污染指数可以综合评价大气环境质量状况;利用植物叶片内的重金属含量变化,为大气污染生物监测和环境质量评价提供了科学依据。     

香烟燃烧排放的主流烟气中PAHs的含量检测研究

研究10种不同价格香烟燃烧烟气的多环芳烃(PAHs)含量特征,结果表明,每种香烟烟气都含有多环芳烃,但是含量差别较大,平均值为405.405ng/g。在检测出来的多环芳烃中,主要是以2,3环多环芳烃为主,占据的比例达到80%左右。因此香烟烟气中的多环芳烃应该引起人们的广泛关注。     

Assessing soil and groundwater contamination in a metropolitan redevelopment project

The purpose of this study was to assess contaminated soil and groundwater for the urban redevelopment of a rapid transit railway and a new mega-shopping area. Contaminated soil and groundwater may interfere with the progress of this project, and residents and shoppers may be exposed to human health risks. The study area has been remediated after application of first remediation technologies. Of the entire area, several sites were still contaminated by waste materials and petroleum. For zinc (Zn) contamination, high Zn concentrations were detected because waste materials were disposed in the entire area. For petroleum contamination, high total petroleum hydrocarbon (TPH) and hydrocarbon degrading microbe concentrations were observed at the depth of 7 m because the underground petroleum storage tank had previously been located at this site. Correlation results suggest that TPH (soil) concentration is still related with TPH (groundwater) concentration. The relationship is taken into account in the Spearman coefficient (α).     

Characterization of the monthly variation in (1 → 3)-β-d-glucan concentrations in university laboratories

We characterize the monthly variation in (1 → 3)-β-d-glucan concentration measured over the course of 1 year, and we evaluate the characteristics of size selection using a two-stage cyclone sampler. The (1 → 3)-β-d-glucan concentrations were measured in four bio-related laboratories. A total of 156 samples were collected using a new two-stage cyclone sampler. Analysis of (1 → 3)-β-d-glucan was performed using the kinetic Limulus amebocyte lysate assay. The study showed that airborne (1 → 3)-β-d-glucan concentrations were significantly higher in laboratory D (mean ± SD 1,105?±?1,893 pg/m³) and in the spring (5,458 pg/m³). The highest concentration of (1 → 3)-β-d-glucan occurred in the spring, particularly in May.