Eggshell nano-particle potential for methyl violet and mercury ion removal: Surface study and field application

A nano-scale sorbent was produced from eggshell wastes for sorption of Hg(II) and methyl violet (MV) from aqueous solutions and real wastewaters. The properties of the nano-particles were fully determined using SEM, DLS, FTIR, XRD, BET, TGA, AFM, EDAX, mapping, and TEM analyses. The adsorbent structure mainly contained carbonate and silica. The effects of influential parameters including temperature, contact time, initial contaminants concentration, sorbent dose, and initial pH on the removal efficiency were investigated. The maximum sorption efficiency of Hg(II) and MV occurred at pH of 6 and 9 and temperatures of 25 °C and 55 °C, respectively. Freundlich model could be interpreted the equilibrium data of the sorption process of both contaminants. The maximum sorption capacity of Hg(II) and MV using eggshell nano-particles was obtained as 116.27 mg/g and 123.45 mg/g, respectively. The dynamic behavior of the process was studied using two kinetic models. The sorption system performance was also examined and t_1/2 were determined as 4.34 min for Hg(II) and 4.97 min for MV. The sorption process of Hg(II) and MV was exothermic and endothermic, respectively. Effective sorption after seven cycles and successful treatment of landfill leachate and textile wastewater with eggshell nano-particles confirms its adequacy.     

沉淀法制备条件对ZrO_2纳米微粒性质的影响

综述了国内外沉淀法制备纳米ZrO2微粒的条件控制及相应的产品性质,综合分析了制备过程中锆盐浓度、稳定剂盐(Y3+、Mg2+、Ca2+、Ce4+等)的浓度及种类、pH值、沉淀处理和热处理等操作对产品性质的影响,并总结了相应的影响机理;根据材料科学发展方向及市场要求,对ZrO2纳米微粒制备领域研究的重点和热点进行了展望。     

PVA和PEG对电子束辐照制备的Fe3O4纳米粒子的影响

常温常压下不加入任何催化剂，用两种不同的活性剂聚乙烯醇（Polyvinyl alcohol，PVA）和聚乙二醇（Polyethylene glycol，PEG），在水溶液中通过电子束辐照可以成功地制备纳米Fe3O4粒子。通过紫外可见光分光光度计（Ultraviolet-visible spectrophotometer，UV）、X射线衍射（x-ray diffraction）、透射电子显微镜（Transmission electron microscopy，TEM）对辐照后的样品的光学特性、结构、形貌、大小进行表征。发现不同的活性剂对纳米粒子的尺寸会产生影响。     

由光子相关谱反演微粒体系粒径分布方法的分析与比较

在光子相关法测量微粒体系粒度分布技术中,反演算法的选择及其正确使用是很关键的。本文中首先概要介绍了目前流行的累积量法(Cumulants)、双指数拟合法(DE)、非负最小二乘法(NNLS)、CONTIN算法和指数采样分析法(ES)等几种反演算法。然后利用计算机模拟产生的光子相关谱对这几种算法的性能进行了详细的对比研究。结果表明:在无噪声的情况下,对于单分散的微粒体系,除DB外,其它4种算法均能给出较准确的平均粒径,而分布宽度以NNLS为最佳。对间隔明显且峰较尖锐的双峰分布微粒体系,除累积量法外,其它4种算法均有可能分辨出双峰的存在,DE对峰高的估计最准,而NNLS对双峰的分辨力最强,CONTIN算法对双峰的分辨力最弱。对于分布较宽的多分散微粒体系,DE无能为力,累计量法也不适用,较为适用的是ES、NNLS和CONTIN算法。     

溶剂热还原法制备的镍纳米颗粒

以乙二胺作溶剂,在聚四氟乙烯内衬的不锈钢反应釜中,用KBH4还原NiCl2制备镍纳米颗粒。反应温度为160℃,反应时间为10h。X射线粉末衍射(XRD)结果显示,产物为单相的面心立方晶镍。透射电子显微镜(TEM)结果显示,产物为尺寸均匀的球形颗粒,颗粒直径在30~50nm,颗粒分布均匀,表面光洁。镍纳米微粉的矫顽力为9.89kA/m。     

纳米颗粒对井壁混凝土耐久性能的影响

为了改善矿山井壁混凝土的耐久性能,利用2种纳米颗粒作为外掺材料制备混凝土试件,并开展强度、耐磨性和干缩性试验。结果表明,纳米材料在提高井壁混凝土抗压和抗弯强度的同时,也改善了耐磨性能和干缩性能;双掺NS和NC颗粒的含量为3%和2%的水工混凝土具有最优的耐冲磨性能,耐磨测试的磨损量仅为0.64 kg/m^2,比参照组磨损量降低了85%;与普通水泥砂浆相比,双掺2%NS和3%NC的水泥砂浆干缩率提高了128%,此配比为改性的最优组合;从改性前后的混凝土微观形貌发现纳米颗粒的填充效应和火山灰反应是混凝土耐磨性能提升的主要原因,黏结作用和表面反应是干缩性能提高的主要原因。     

磁性催化剂Na2O·SiO2/Fe3O4的制备及其催化酯交换反应

以Na2SiO3为活性物质,以纳米Fe3O4为磁核制备磁性固体碱催化剂Na2O·SiO2/Fe3O4,通过正交实验,得到催化剂的最佳制备条件为：硅与铁的摩尔比2.5,晶化时间2h,煅烧温度350℃,煅烧时间2.5h,并通过震动样品磁强计（VSM）对催化剂的磁性进行表征。结果表明,所制备的催化剂Na2O·SiO2/Fe3O4具有较好的磁性和顺磁性,抗水性能优于传统均相碱催化剂;将其应用于棉籽油酯交换反应制备脂肪酸甲酯的最优工艺参数为：醇油摩尔比7：1,催化剂加入量5%,反应温度65℃,反应时间1h,搅拌速度400r/min,在此条件下,催化棉籽油酯交换反应转化率为99.6%,连续使用11次后活性仍在90%以上。     

光触媒空气滤纸及其性能研究

主要介绍了光触媒材料二氧化钛的发展及特性,讨论了光触媒空气过滤纸的加工工艺及杀菌消毒除臭性能实验,结果表明TiO2光触媒空气过滤纸具有明显的抗菌杀毒除臭的效果,是良好的环境卫士。     

纳米颗粒对新拌水泥浆体性能的影响

研究了单掺纳米SiO2、纳米粘土、纳米Al2O3、纳米CaCO3颗粒对新拌水泥浆体标准稠度用水量、凝结时间、流动性的影响。研究发现t纳米SiO2、纳米粘土、纳米Al2O3导致水泥浆体标准稠度用水量不同程度的增加,且纳米颗粒掺量越大标准稠度用水量越大;纳米颗粒使水泥浆体粘聚性增大,相同水胶比时掺入纳米颗粒使浆体流动性降低;纳米SiO2、纳米CaCO3、纳米Al2O3促进了水泥水化,使初凝和终凝时间提前,但纳米粘土表现出一定的缓凝作用。     

Preparation and Characterization of Fe3O4 Magnetic Nano-particles by 60Co γ-ray Irradiation

By using a new method, ^60Co γ-ray irradiation, Fe3O4 magnetic nano-particles were successfully synthesized at room temperature under ambient pressure. The structure, morphology and magnetic properties of these nanoparticles were characterized by X-ray diffraction （XRD）, transmission electron microscope （TEM） and vibrating sample magnetometer （VSM）, respectively. The radiation formation mechanism was also discussed. The results show that the absorbed dose can greatly influence the structure, morphology and magnetic properties of the products. XRD and TEM studies show that the product prepared by γ-ray irradiation （10 kGy） is pure FesO4 phase and the mean diameter of these nano-particles is about 21 nm. The Fe3O4 nano-particles synthesized by γ-ray irradiation （10 kGy） are mainly in small cubic shape and the size uniformity of these particles is good.