Preparation Polyelectrolyte Complexes of Chitosan-Polyacrylic Acid-Modified Iron Sand Leachate for Proton Exchange Membranes

ABSTRACT

Polyelectrolyte complex (PEC) of chitosan (Chi) and poly (acrylic acid) (PAA)-modified iron sand leachate were prepared and considered for applicability as a proton exchange membrane in fuel cells. Chi-PAA-hematite blended in different weight ratios and the resulting membranes were treated to enable the formation of the polyelectrolyte. The membranes of Chi-PAA polyblend were treated using iron sand leachate and reveal high ion exchange capacity (IEC), proton conductivity, water uptake, and good mechanical stability. The result of research indicated that the membrane with 40 wt% of Chi and 60 wt% of PAA blend which its conductivity of 6.10 × 10^?2 S cm^?1 was potentially for a proton exchange membrane in fuel cell applications.     

The inhibitive effect of poly(p‐toluidine) on corrosion of iron in 1M HCL solutions

In recent years, polymer amines have been recognized as an excellent corrosion inhibitors for iron in acid solutions. In this work, the inhibitive effect of p‐toluidine and poly(p‐toluidine) on corrosion of iron in 1M HCl has been studied by the electrochemical methods such as impedance, linear polarization, Tafel polarization techniques. The effectiveness of poly(p‐toluidine) was found to be high in comparison with that of monomer. The results showed that p‐toluidine and poly(p‐toluidine) suppressed both cathodic and anodic processes of iron dissolution in 1M HCl. The inhibition efficiency of both p‐toluidine and poly(p‐toluidine) were found to increase with the inhibitor concentrations. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

硫铁矿烧渣制高纯氧化铁红的研究

研究了以广东云浮硫铁矿烧渣经浮选法制得的铁红五级品为原料,采用化学絮凝法除二氧化硅,制取高纯度的氧化铁红的工艺技术。其过程主要包括:硫酸亚铁的合成,絮凝除二氧化硅等杂质,碳酸亚铁的合成,后处理。考察了制备过程中,氨水的加料次序、pH、反应温度和时间、搅拌速度等因素对产品收率和纯度的影响。结果表明,所得产品三氧化二铁质量分数为99.45%,二氧化硅质量分数<0.0096%。产品可用作软磁铁氧体的原料。     

Two-step flotation recovery of iron concentrate from Donganshan carbonaceous iron ore

The flotation of pure and natural carbonaceous iron ore samples in the oleate flotation system was investigated. Starch can depress hematite effectively in a wide pH range, but cannot depress siderite efficiently in neutral conditions. The flotation recovery of pure hematite, siderite, and quartz in the oleate-starch-CaCl₂ system is significantly different when the slurry pH varies from 4 to 12. A novel two-step flotation process was developed for the separation of iron concentrate from Donganshan carbonaceous iron ore through which the siderite concentrate is first recovered and the high quality hematite concentrates with relative high iron recovery can be obtained in the second step flotation. The siderite concentrate may be utilized directly or undergo further concentration steps to increase iron grade.     

含砷废水砷铁分离的研究

以氢氧化钠作为沉淀剂,对含砷废水进行选择性沉淀研究,考察了pH值、搅拌速度、温度等因素对砷、铁分离效果的影响,确定了合适的工艺条件：温度25℃,pH=13.5,搅拌速度500 r/min.此工艺条件下铁的回收率达到99.9%以上,实现了砷、铁的有效分离.     

二价铁离子对零价铁还原硝基苯的影响

为了解地下水环境中铁离子对零价铁(zero valention)还原作用的影响,采用批次实验,研究不同质量浓度二价铁离子对ZVI还原硝基苯的影响,利用HPLC和GC-MS作为分析工具,观测反应过程中硝基苯的质量浓度,同时跟踪溶液中Fe2+、pH、ORP的变化.结果表明,有无Fe2+存在,硝基苯均可被ZVI还原为苯胺,Fe2+没有改变还原产物;溶液中投加Fe2+后,ZVI还原硝基苯的反应速率明显加快,溶液中Fe2+对于还原反应起促进作用;溶液中Fe2+对ZVI体系pH起缓冲作用,含有Fe2+的ZVI体系ORP下降明显.反应动力学分析表明,硝基苯的还原反应符合假一级动力学模型,表观速率常数kobs值随Fe2+质量浓度的升高而增加,Fe2+离子的存在有助于ZVI对硝基苯的还原.     

Mg2+掺杂的LiFePO4材料的共沉淀合成与表征

提出了一种采用共沉淀法合成镁掺杂的锂离子正极材料LiFePO4的新方法,研究了合成条件,采用XRD,SEM,循环伏安测定,电化学阻抗谱分析,以及充放电测试对合成的材料作了表征分析．结果表明,采用共沉淀合成方法可以获得性能良好的LiFePO4;Mg^2＋掺杂对LiFePO4结构没有产生明显的影响,但掺杂量的大小对LiFePO4的放电性能有较大影响．     

基于模块化神经网络的铁水硅含量预测系统

目的 提出基于模块化神经网络的铁水硅含量预测方法,改善系统控制性能指标.方法 采用模块化神经网络预测控制策略,建立模块化神经网络预测模型,按输入物理量的性质构成4个神经网络模块,再由预测神经网络输出铁水硅含量的预测值,从而控制炉温.结果 提高了学习效率和泛化能力,有效地改善了模型的预测精度.结论 模块化神经网络铁水硅含量预测模型,将同类量进行了模块划分,通过对铁水硅含量预测,可提高炉温的控制精度和动态跟踪能力,具有结构简单、实时性好、预测精度高等特点.     

灰口铸铁给水管道内壁腐蚀试验

目的 灰口铸铁给水管道运行过程必然造成内壁发生不同程度的腐蚀,通过实验研究内腐蚀各影响因素,分析灰口铸铁供水管道腐蚀变化规律.方法 在调查分析埋地供水管道腐蚀状况及腐蚀原因的基础上,对灰口铸铁试片进行室内挂片实验,分别考虑不同溶解氧、pH值、余氯和流速的条件下的腐蚀速率.同时对灰口铸铁管的内壁腐蚀产物进行电子扫描电镜分析和X-射线衍射分析,确定内壁腐蚀结构成分.结果 pH＜5和pH＞11时腐蚀速率分别呈线性递增和线性递减趋势,水中溶解氧在初始50 h内消耗速度呈直线增加变化,随后DO消耗速度几乎不变,余氯对腐蚀过程有促进作用,流速与铸铁管道的腐蚀速率成正比例关系.结论 pH值、溶解氧、余氯、流速和侵蚀性CO2是引起灰口铸铁供水管道内腐蚀的主要原因.     

内蒙古阿拉善额日登基性岩体中超低品位铁矿石特征及选矿工艺研究

通过合适的选矿工艺,将超低品位铁矿石中的铁选出成为可利用的资源,为解决铁矿石资源紧张提供新的、广阔的来源.调查了内蒙古阿拉善地区基性岩中铁矿石铁的质量分数分布情况,并分析了额日登基性岩体磁性异常区中含铁辉长岩特征,对其中的超低品位铁矿石进行分选工艺试验,确定了可行的工艺流程.