Solvent-free mechanochemical mild oxidation method to enhance adsorption properties of chitosan

• Solvent-free chitosan oxidation is obtained by rapid mechanochemical reaction. • Different oxidants induce very diverse physicochemical changes on chitosan. • Oxidized chitosan with persulfate or percarbonate has improved adsorption capacity. • Uptake on oxidized chitosan with persulfate is 125-fold faster than on pristine one. Oxidation has been profitably utilized to improve some properties of chitosan. However, only solvent-based oxidation procedures have been proposed so far, which are hardly feasible at industrial scale in an economic way because of product recovery cost. In this study, a solvent-free, rapid, and effective oxidation method is proposed. It is based on direct solid-state reaction between chitosan and oxidant powder in a mechanochemical reactor. Results prove that by short high energy ball milling (<3 h) it is possible to achieve diverse physicochemical modifications employing different reagents. Apart from polysaccharidic chain shortening, persulfate provokes high amorphization and induces formation of ketonic groups; percarbonate heightens deacetylation degree, preserving in part crystallinity; calcium peroxide merely deprotonates amino groups and increases amorphization degree. Adsorption tests with the azo-dye reactive red 2 show that adsorption capacity of chitosan co-milled with persulfate (974 mg/g milled product), which is the best performing adsorbent, is twice that of pristine chitosan, while adsorption rate is outstandingly boosted (125 times).     

浅谈我国的防护服装

随着工业的飞速发展，人们在工作、生活中面临着越来越多的威胁。如物理因素（高温、低温、风、雨、水、火、粉尘、静电、放射源等）、化学因素（毒剂、油污、酸、碱等）和生物因素（昆虫、细菌、病毒等）。为了抵御这种威胁，减少不必要的损失，人们运用了各种防护装备，防护服就是其中重要的一种。它能有效地保护作业人员现场作业免受环境中物理、化学、生物等因素的伤害。但是传统的工作服无论是从性能还是款式上均不能适应现代化生产的需要，随着科学技术的发展和人们生活质量的提高，     

正压气力除灰系统管道的设计及工程应用

正压气力除灰系统的管道设计原则是按照现场条件、系统布置来确定管长，综合考虑系统运行能耗和管道的造价来确定管径，以物料启动速度、输出管道速度为边界条件来确定变径点。以内蒙古某电厂为例，给出了具体设计计算方法和计算结果，为管道设计的工程应用提供了依据。     

立体仓库故障自诊断研究

结合立体仓库结构特点 ,分析了立体仓库故障机理 ,构建了立体仓库故障自诊断系统的总体框架 ,并在分析研究其数据采集处理系统、实时监测控制系统及自诊断专家系统的基础上 ,运用VisualBasic6 0在Windows系统下 ,实现了立体仓库故障的自诊断功能     

Environmental bioavailability of hydrophobic organochlorines in sediments—A review

A number of hydrophobic organochlorines, such as hexachlorobenzene and polychlorinated dibenzo‐p‐dioxins/dibenzofurans (PCDD/Fs), have been reported to be persistent and bioaccumulative; however, their availability to biota appear to be limited due to strong sorption to soil/sediment and sequestration with age. Studies to date have shown that the bioavailability of hydrophobic organic chemicals (HOCs) in sediments is highly variable, depending not only on a chemical's lipophicity (K_ow), but also molecular steric conformation and sediment characteristics. A subdomain of sediment organic carbon, so‐called black carbon (BC), which has much higher affinity to planar HOCs than amorphous organic carbon, has been found to be the predominant repository of many HOCs. The sediment/soil‐bound HOCs are composed of a rapid and reversible desorbing labile fraction and a slow‐desorbing, or resistant‐to‐desorbing, nonlabile fraction. The latter can account for up to 98 percent of the total. A number of chemical extraction methods have been under development to measure the actual bioavailable concentrations in soil/sediment and have shown some correlation to the results of bioaccumulation and/or biodegradation tests. To date, most of the published studies on this subject have focused on polynuclear aromatic hydrocarbons (PAHs). This review summarizes the governing processes and the testing methodologies relevant to the environmental bioavailability of hydrophobic organochlorines in soils and sediments. © 2004 Wiley Periodicals, Inc.     

若干企业职业安全投资现状分析

安全投资的经济效益，主要表现为潜在的经济效益。文章分析了安全投资的构成、现状、投向，以及与事故经济损失、发展生产的关系。     

Modelling impacts of alternative farming management practices on greenhouse gas emissions from a winter wheat–maize rotation system in China

Agricultural production plays an important role in affecting atmospheric greenhouse gas concentrations. Field measurements were conducted in Quzhou County, Hebei Province in the North China Plains to quantify carbon dioxide (CO₂) and nitrous oxide (N₂O) emissions from a winter wheat–maize rotation field, a common cropping system across the Chinese agricultural regions. The observed flux data in conjunction with the local climate, soil and management information were utilized to test a process-based model, Denitrification–Decomposition or DNDC, for its applicability for the cropping system. The validated DNDC was then used for predicting impacts of three management alternatives (i.e., no-till, increased crop residue incorporation and reduced fertilizer application rate) on CO₂ and N₂O emissions from the target field. Results from the simulations indicated that (1) CO₂ emissions were significantly affected by temperature, initial SOC, tillage method, and quantity and quality of the organic matter added in the soils; (2) increases in temperature, initial SOC, total fertilizer N input, and manure amendment substantially increased N₂O emissions; and (3) temperature, initial SOC, tillage, and quantity and quality of the organic matter added in the soil all had significant effects on global warming. Finally, five 50-year scenarios were simulated with DNDC to predict their long-term impacts on crop yield, soil C dynamics, nitrate leaching losses, and N₂O emissions. The modelled results suggested that implementation of manure amendment or crop residue incorporation instead of increased fertilizer application rates would more efficiently mitigate GHG emissions from the tested agro-ecosystem. The multi-impacts provided a sound basis for comprehensive assessments on the management alternatives.     

应对国际竞争，建设低碳企业

涉及经济模式、生活方式、竞争规则乃至国家权益的“低碳经济”在全球愈演愈烈。中国作为全球最大的发展中国家、碳排放量最大的国家之一,更是全球发展速度最快、经济总量领先的国家,如何有效应对资源、气候与环境带来的挑战和压力,赢得国际竞争主动权,以加速推进全面建设小康社会伟大战略目标的进程,是一个重要而紧迫的时代命题。中央企业是国民经济的核心骨干力量,代表着国家竞争力,是发展低碳经济的重要力量,应在国家可持续发展战略指引下,大力开展建设低碳企业的试点工作,担当起建设资源节约型、环境友好型社会的主力军,为促进经济结构调整和增长方式的转变,为加快提高国家竞争力作出重要贡献。     

印染废水中反硝化聚磷菌的筛选及其脱氮除磷特性的研究

为研究反硝化聚磷菌的生物学特性和脱氮除磷能力,从印染废水中分离筛选出3株高效反硝化聚磷菌,经鉴定分别属于克雷伯氏菌属（Klebsiella）、肠杆菌属（Enterobacter）、链球菌属（Streptococcus）。将分离出来的反硝化聚磷菌富集培养,在缺磷培养液中厌氧培养24h,然后取少量培养液于4000rpm离心出菌体,投加于富磷培养液中厌氧培养24h,检测培养液中硝酸盐氮和磷的浓度变化。测得克雷伯氏菌A1的脱氮率为86．67％,除磷率为77．01％;肠杆菌A2的脱氮率为91．7％,除磷率为92．98％;链球菌A3的脱氮率为79．32％,除磷率为89．4％。     

浅析山西乡镇煤矿的生态环境问题及防治对策

在对山西省长治市乡镇煤矿的普查基础上,发现乡镇煤矿的煤炭开采导致周围生态环境加速恶化。选择典型乡镇煤矿对其生态环境问题进行详尽的调查和分析,得出山西乡镇煤矿采煤造成的主要生态环境问题是水资源破坏、大气环境污染、煤矸石堆积、地表沉陷与滑坡等地质灾害、土壤性质改变及土壤侵蚀加剧等。针对这些问题提出乡镇煤矿生态环境防治对策,以期为山西乡镇煤矿生态环境综合治理提供借鉴。