Boron removal from water and its recovery using iron (Fe) oxide/hydroxide-based nanoparticles (NanoFe) and NanoFe-impregnated granular activated carbon as adsorbent

This study presents information obtained by the synthesis of Fe(3) oxide/hydroxide nanoparticles sol (NanoFe) and NanoFe-impregnated granular activated carbon as adsorbents for boron removal from solutions. The research describes an adsorption method for cleaning a solution containing boron contaminants followed by recovery of the adsorbent and the adsorbed material for safe removal or further reuse. The technology provides an efficient method of boron removal from water. A marked effect of NanoFe and NanoFe-impregnated GAC adsorbents concentration and pH level on boron removal efficiency was demonstrated. At least 95–98% boron recovery efficiency is possible using NanoFe sol and Fe-impregnated GAC that in fact also recover the adsorbent for reuse. Boron adsorption onto the NanoFe-impregnated GAC adsorbent may be described by pseudo-second-order reaction kinetics and the Langmuir isotherm model. The boron adsorption capacity on iron (3) oxide nanoparticles and Fe-impregnated GAC at an equilibrium concentration of 0.3 mg/dm³ as B in the solution is much higher than these values for similar adsorbents reported in the literature.     

Effect of Constant‐Rate Reduction on the Performance of a Ternary Cu/ZnO/Al2O3 Catalyst in Methanol Synthesis

A multi‐functional flow set‐up was developed for the rate‐ and temperature‐controlled reduction of copper catalysts, their application in high‐pressure methanol synthesis and the determination of the copper surface area by N₂O frontal chromatography. The influence of constant‐rate reduction on the catalytic properties of a ternary Cu/ZnO/Al₂O₃ catalyst was investigated. The temperature during the constant‐rate reduction was found to decrease, indicating autocatalytic kinetics, but no significant catalytic effect of the milder reduction conditions was observed compared with a slow linear heating ramp.     

Modified supercritical CO2 extraction of amine template from hexagonal mesoporous silica (HMS) materials: Effects of template identity and matrix Al/Si molar ratio

In this work, the primary amine template has been extracted from freshly synthesized hexagonal mesoporous silica (HMS) materials by means of modified supercritical carbon dioxide at 60–85 °C under 10.0–20.0 MPa. The influences of amine identity and matrix Al/Si ratio on the extraction efficiencies and structural properties of HMS thus obtained are investigated in detail. The results show that the extraction efficiency is strongly dependent on the pore size of the HMS materials produced by five different templates. For aluminium-incorporated samples, the extraction efficiency is observed to decrease with the Al/Si molar ratio since as the Al/Si molar ratio increases, more amine will get protonated and the matrix/template interactions become stronger, subsequently rendering the extraction more difficult and the efficiency decrease. The formic acid modifier has resulted in better extraction performance than methanol, yielding higher extraction efficiencies. The SFE-treated materials exhibit better structural properties like higher pore volume and specific surface area as compared to those prepared by conventional calcinations. Besides, results of pyridine adsorption and conversion of 2-propanol to propylene suggest that the SFE-treated HMS materials may have higher acidity than the directly calcined samples.     

采暖期燃煤排放对四平市空气质量的影响分析

文章于2014年4月1日~4月30日在吉林师范大学对大气污染物PM10、NOX和SO2进行监测。采暖期,PM10、NOx和SO2的浓度分别为150.9μg/m3、46.4μg/m3和27.3μg/m3,虽没有超过空气质量标准,但是其数值都比非采暖期高。采暖期PM10浓度为非采暖期的1.6倍,NOx和SO2的浓度分别为非采暖期的1.3倍和1.8倍。无论是采暖期还是非采暖期,AQI指数与PM10浓度呈强相关性,说明PM10为四平市首要大气污染物。     

钛合金表面GO/纳米ZnO复合涂层的制备及性能

为了有效解决生物医用钛合金长期植入人体后,易发生细菌感染和面临有害金属离子释放的问题,采用水热反应和涂覆方法,分别在聚多巴胺(PDA)预处理的Ti6Al4V合金表面制备了氧化石墨烯涂层(GP/T)和氧化石墨烯/纳米氧化锌复合涂层(GZP/T)。系统分析了2种涂层的物相结构、微观形貌及其在林格氏液中的耐腐蚀性能和在大肠杆菌环境中的抗菌性能。结果表明:聚多巴胺发挥“双面胶”桥接作用,有效增强了涂层与基底间的化学键合;GP/T涂层抗菌率随着GO浓度增大而增大;GZP/T纳米复合涂层相较Ti6Al4V基材具有优异的耐蚀性,该复合涂层中ZnO起主要抗菌作用。     

机载雷达天线座转台工艺方法的制定

分析了某机载雷达天线座转台的性能结构特点,提出了采用15-5PH沉淀硬化不锈钢进行该天线座制造的技术方案.并就此对15-5PH不锈钢材料进行了一系列的技术研究,包括原材料化学成分的确定、冶炼与供货状态的确定,进行了不同参数下的热处理固溶时效、退火试验,并对试验后的材料进行了金相组织分析及力学性能测试,进行了氩弧焊、电子束焊两种焊接方法的工艺试验,确定了适用于15-5PH的焊接方法及焊接参数.最后,根据以上的试验数据,制定了一套既能保证天线座转台综合力学性能,又能保证加工精度的制造工艺.     

基于流密码算法构造跳频序列簇

跳频序列的性能对跳频通信系统性能有着决定性的影响.本文基于密码学的流密码加密机制,提出构造一种跳频序列簇的方法.文中以蓝牙技术采用的E0流加密算法为例,对输出的二进制加密流进行多位组合构成跳频序列的频隙号.并在此基础上对产生的跳频序列从安全性,均匀性,线性复杂度,汉明相关性等各个方面进行了全面的理论分析和计算机仿真,证明基于流密码算法产生的跳频序列族有着优秀的性能,完全满足跳频序列簇的要求.     

介孔分子筛SBA-15-HSO3合成ETBE反应本征动力学研究

用水热法直接合成了含磺酸基的介孔分子筛SBA -15 -HSO₃ 。采用X 射线衍射、N₂ 吸附-脱附分析方法对试样进行了表征。表征结果显示, 制得的SBA -15 -HSO₃ 具有高度有序的介孔二维六角结构, 并且有较大的比表面积、孔容和孔径。以乙醇和叔丁醇为原料, SBA -15-HSO₃ 为催化剂合成乙基叔丁基醚(ETBE), 建立了反应动力学模型。反应过程在钢密封间歇反应釜中进行, 且消除了内外扩散的影响。改变原料浓度和反应温度得到了醚化反应本征动力学实验数据。线性回归得动力学方程r=kC^1.5_A C^-0.5_B , 求得频率因子为1 .3 ×10⁷ h^-1 , 活化能为52 .86 kJ/ mo l。根据机理近似推导出的动力学方程r=k′C^1.5_A C^-0.5_B , 频率因子为1 .2×10⁷ h^-1 , 活化能为52 .56kJ/ mol。因此, 可近似认为表面反应是反应的速率控制步骤。     

反应物配比对液相合成Al2O3-SiO2-CaF2系玻璃粉体特性的影响

选用AlCl3、Na2SiO3、CaCl2和NaF作为初始反应物,采用液相沉淀法合成了Al2O3-SiO2-CaF2系玻璃粉体;通过XRD、EDAX和TEM等,分析了反应物配比对液相合成Al2O3-SiO2-CaF2系玻璃粉体特性的影响.结果表明,反应物配比对粉体的形貌、尺寸、结晶状态及所含的化学元素均无影响,而对元素的相对含量有明显的影响.各粉体均含有不同比例的O、F、Al、Si、Ca元素,且均为非晶态的近球形纳米颗粒,粒子直径大约在30~70 nm范围.     

树脂封装半导体元件去毛刺喷射磨塑料研究

以悬浮聚合法制备出不饱和聚酯树脂(UP)/Al2O3复合微粒作为喷射磨塑料,对比了其与日本磨塑料的粒径、密度、硬度、热变形温度等性能指标及其在实际应用中的打磨能力、磨损率及破碎率等指标。结果表明,自制的喷射磨塑料粒子的粒径、密度和打磨能力与日本生产的磨塑料相当,而硬度、热变形温度、磨损率和破碎回收率均优于日本产品。