交联壳聚糖膜吸附直接染料的性能研究

以戊二醛为交联剂,采用流延法制备交联壳聚糖膜作为吸附剂,对3种不同直接染料水溶液进行吸附脱色处理,实验表明,刚果红的去除率可达96%,直接紫B、直接绿BE的去除率均可达81%。交联壳聚糖膜对刚果红的吸附符合Langmuir方程(R2=0.999),对直接绿和直接紫的吸附符合Freundlich方程,相关系数均大于0.99;吸附过程动力学符合二级反应,R2均为0.999。     

天然气管道局部等效应力及塑性变形评估

为了研究腐蚀及地面运动对埋地天然气管线安全性的协同影响,以X80管道为研 究对象,模拟腐蚀缺陷及土壤力作用于管道之上,利用有限元方法对有腐蚀缺陷与预应 变情况下的管道局部等效应力及塑性变形进行评估,结果表明腐蚀缺陷的深度对局部应 力和应力分布影响非常明显,在失效压力预测中起着决定性作用。随着腐蚀深度的增加 ,应力集中增强,导致内表面和外表面的等效应力大小进一步分化,腐蚀深度的增加对 管道内表面的等效应力的影响很大,但对有效塑性应变的影响却不大。模拟管道上施加 有纵向应变的土壤力,不论拉伸与压缩的情况下,都会降低管道的失效压力,在施加拉 伸预应变下的管道失效压力小于压缩预应变下的。塑性变形首先发生在外表面处,并扩 展到腐蚀缺陷相邻区域,管道内表面也具有一定的塑性变形,但强度低。     

基于瓦斯抽采关键封孔参数及新型封孔材料应用研究

针对煤层瓦斯抽采封孔参数选取不合理,传统封孔材料封堵钻孔周边裂隙效果差等主要问题,采用数值模拟、实验室试验及工程实践等多种手段,分析不同封孔方式的漏气效果,研究封孔时效性对瓦斯抽采的影响,完成最优实验配比及性能测试,验证了现场瓦斯抽采效果。结果表明:全封孔方式抽采效果优于半封孔,合理控制封孔时效性,钻孔周边围岩破坏减少,封孔效果提高;正交试验确定材料最优配比即复合早强剂0.3%、复合缓凝剂0.5%、膨胀剂0.03%、水灰比1.2;试样周围充斥着交叉、贯通的“网状结构”钙矾石,且呈现多而密的粗棒状结构;材料具备塑性变形特性,持续变形量大;与矿方原封孔材料相比,新型封孔材料封孔后瓦斯抽采浓度提高193.3%,抽采周期明显延长,抽采效果显著提高。     

Characterization of electrode fouling during electrochemical oxidation of phenolic pollutant

• Electrode fouling is characterized by non-destructive characterization. • Electrode fouling is highly dependent on electrochemical process. • Active chlorine can prevent the formation of polymeric fouling film. Electrode fouling is a problem that commonly occurs during electro-oxidation water purification. This study focused on identifying the fouling behavior of Pt electrode associated with the formation of polymeric layer during electro-oxidation of phenol. The in situ electrochemical measurements and non-destructive observation of the electrode morphology were reported. The results demonstrated that the electrode fouling was highly dependent on thermodynamic process of electrode that was controlled by anode potential. At anode potential lower than 1.0 V vs SHE, the direct electro-oxidation caused the electrode fouling by the formation of polymeric film. The fouling layer decreased the electrochemically active surface area from 8.38 cm² to 1.57 cm², indicated by the formation of polymeric film with thickness of 2.3 mm, increase in mass growing at a rate of 3.26 μg/cm²/min. The degree to which the anode was fouled was independent of anion in the electrolyte. In comparison, at anode potential higher than 2.7 V vs SHE, the anions (e.g., chloride) could exert a major influence to the behavior of electrode fouling. The presence of chloride was shown to mitigate the fouling of electrode significantly through preventing the formation of polymeric film by active chlorine (e.g., Cl• and Cl₂) produced from anodic oxidation of chloride. Since chloride is the most abundant anionic species existing in both natural and engineered water system, this study not only offers a deep insight into the mechanism of electrode fouling, but also suggests strategies for anti-fouling in the presence of chloride in electro-oxidation process.     

附着态TiO2光催化降解壬基酚的研究

采用sol-gel法制备TiO2薄膜,以该薄膜为催化剂,研究了在H2O2存在的条件下,对内分泌干扰物质壬基酚的光催化降解反应。分别研究了pH值、H2O2的加入量,壬基酚的初始浓度以及光照时间对降解反应的影响。结果表明：在pH=5,30mg／L的H2O2中对初始质量浓度为20mg／L壬基酚的溶液光照180min有较好的降解效果。     

我国塑料包装废物的产生和回收特性及管理对策

通过现场调查和资料调研,分析了塑料包装废物的流向和环境特征,总结了塑料包装废物回收的基本特点和经验教训,论述了塑料包装废物回收模式特点,深入分析了回收过程中存在的问题,并提出了加强塑料包装废物回收的管理对策. 结果表明:塑料包装是塑料制品中的重要构成部分,由于质量轻、回收体积大,不易回收,我国每年产生大量的塑料包装废物,城市生活垃圾填埋场成为塑料包装废物的主要流向和污染源. 目前我国塑料包装废物回收依托的是进城务工的个体回收者,与现阶段的国情相符合. 塑料污染问题不是短期内能解决的,必须采取长期的综合管理对策,如进行源头减量化、制定鼓励回收利用的经济政策、采取适宜的无害化处置方式等.      

吸附过程中流场分布对液膜扩散传质影响模型的研究

在总结流场条件影响吸附传质过程的同时,提出了流场分布影响液膜扩散传质的物理模型,指出不同的流场分布,液膜厚度变化不同,传质阻力也就不同,从而导致传质效果的不同. 通过对传质方程中流速的物理意义进行重新定义,同时引入流场效应系数(Z),对传统的液膜扩散控制传质模型进行了修正,使模型中参数的物理意义更明确,并用13X沸石对Ca2＋的吸附实验验证了该模型的合理性. 结果表明,13X沸石对Ca2＋的吸附传质效率与搅拌转速和叶片大小成正比,即与流场分布密切相关,其中流场分布比较规则的二次流场吸附传质效率最高;此外初始ρ(Ca2＋)越高,传质越快,吸附效果越好,但流场分布影响越小,归结原因是此时传质动力的影响占据主导作用,超过了液膜阻力的影响,进而掩盖了流场分布对传质的影响.      

Farm size and land-use policy: An oregon case study

Farmland conversion has become an important public policy issue in the United States and in many other countries. An important part of policy considerations in farmland protection programs is the minimum parcel size for farm-related land divisions and dwelling units. The rationale for establishing size thresholds varies considerably among jurisdictions. This article reviews the policies and criteria used in the United States and several other countries, discusses the policy implications of different types of objectives, and presents the results of a case study in Oregon. The case study was the first attempt by an Oregon county to articulate a set of measurable criteria to quantify a definition of commercial agriculture for land-use applications. The criteria and data base used in the model provide a systematic procedure to process permit applications in an objective, consistent manner. The ordinance was adopted in February 1988 and has worked successfully since that time. The article summarizes permit activity under the new ordinance and comments on its effectiveness.     

Properties of Starch/PVA Blend Films Containing Citric Acid as Additive

Starch/polyvinyl alcohol (PVA) blend films were prepared successfully by using starch, polyvinyl alcohol (PVA), glycerol (GL) sorbitol (SO) and citric acid (CA) for the mixing process. The influence of mixing time, additional materials and drying temperature of films on the properties of the films was investigated. With increase in mixing time, the tensile strength (TS), elongation (%E), degree of swelling (DS) and solubility (S) of the film were equilibrated. The equilibrium for TS, %E, DS and S value was 20.12 MPa, 36.98%, 2.4 and 0.19, respectively. The mixing time of equilibrium was 50 min. TS, %E, DS and S of starch/PVA blend film were examined adding glycerol (GL), sorbitol (SO) and citric acid (CA) as additives. At all measurement results, except for DS, the film adding CA was better than GL or SO because hydrogen bonding at the presence of CA with hydroxyl group and carboxyl group increased the inter/intramolecular interaction between starch, PVA and additives. Citric acid improves the properties of starch/PVA blend film compared to glycerol and sobitol. When the film was dried at low temperature, the properties of the films were clearly improved because the hydrogen bonding was activated at low temperature.     

中小型燃煤锅炉水膜除尘废水回用技术的试验研究

根据现有中小型燃煤锅炉水膜除水废水回用处理过程中存在的问题，经过试验，选择最佳药剂，给出混凝条件，并推荐处理工艺。使用该工艺可节约水资源，减少环境污染，具有较好的经济效益和推广价值。