沉淀-水热法制备晶型规整的超细氧化锌

以硝酸锌为主要原料，采用沉淀反应结合水热处理的方法，制备出晶型规整的超细氧化锌。采用XRD、TEM和Malven粒度测试仪等对合成的产物进行了表征。研究了反应物的浓度、反应温度和时间、水热温度和时间等因素对氧化锌产物的影响，并得出了最佳制备工艺条件。     

纳米氧化锌-煅烧高岭土复合材料的制备

以煅烧高岭土和纳米氧化锌为主要原料,用水解沉淀法在煅烧高岭土表面包覆纳米氧化锌,制备一种无机复合型抗紫外材料;采用分光光度计分别测定在波长325、350、375、400nm紫外光下复合材料的紫外光吸光度。结果表明:反应温度、氧化锌包覆量、改性时间、改性剂滴加速度、矿浆浓度、煅烧温度等对纳米氧化锌-煅烧高岭土复合粉体材料的紫外光吸收性能有重要影响。在制备条件为:氧化锌包覆量为8%、反应温度为90℃、改性时间为10min、改性剂滴加速度为3mL/min、矿浆中m(水)∶m(煅烧高岭土)=10∶1、煅烧温度为400℃时,所制备的纳米氧化锌-煅烧高岭土复合粉体材料的紫外光吸收性能较好。     

以汞为反应介质制备氧化锌纳米空心球

以汞为反应介质, 表面活性剂胶束为模板, 通过锌的氧化反应制备了氧化锌空心球. 采用SEM、EDX、TG、DTA、XRD、IR等测试手段对产物的形貌和结构进行了表征, 并考察了表面活性剂对产物生长的影响. 研究表明, 氧化锌空心球为无定型结构, 壁厚为纳米尺度, 由氧化锌纳米粒子组装而成, 煅烧后转变为六方纤锌矿结构. 加入适量PEG或CTAB, 能制备出氧化锌空心球; 不加入表面活性剂、加入过量PEG或SDBS, 则不能制备出氧化锌空心球.     

界面成核-水热法制备纳米氧化锌及光吸收特性

以自制的锌型阳离子交换树脂与饱和氢氧化钙溶液反应，制备纳米氧化锌前驱体，而后采用水热法制备纳米氧化锌。采用电镜扫描观察到前驱体合成温度为40℃时，生成的氧化锌为针状晶须，反应温度为60℃时，生成氧化锌为长径比较小的短棒，长度〉200nm，直径约为100nm。XRD谱图分析表明生成产物为六方纤锌矿结构，且结晶性良好。产物在290-400nm波长范围内具有较强的光吸收性能。     

氧化锌薄膜的p型掺杂及光学和电学性质研究

为了实现氧化锌薄膜的p型掺杂,从而制备氧化锌同质p-n结,采用化学气相沉积法,以二水合醋酸锌为前驱,醋酸铵为氮源,在氧气氛下制备了氮掺杂的p型氧化锌薄膜.利用X射线光电子能谱和X射线衍射分析,表征了氧化锌薄膜的化学成分.通过霍尔效应测量证实了薄膜的p型导电特性.探讨了制备过程中温度、压强、源物质等条件对反应产物的影响,研究了薄膜的光学和电学特性,得到了p型氧化锌薄膜的吸收光谱和光致发光光谱,以及氧化锌p-n结的伏安特性曲线.     

直接沉淀法合成超细氧化锌的研究

以氯化锌为原料 ,草酸铵为沉淀剂 ,采用直接沉淀法制备超细氧化锌 ,对氧化锌的前驱体 -草酸锌的合成以及焙烧工艺进行了详细研究。试验讨论了反应温度、反应物浓度、溶液 pH值和沉淀反应时间等因素对草酸锌粒度的影响 ,以及焙烧过程中被烧温度与被烧时间对氧化锌粒度的影响 ,结果发现 ,在严格控制上述工艺参数的条件下 ,可以获得粒度 <70nm的氧化锌产品。     

超重力法制备纳米氧化锌的影响因素及其机理

通过一系列实验．研究了超重力法制备纳米氧化锌的影响因素．如反应最终pH、反应料液的初始浓度、反应物氨气和锌盐溶液之间的流量比、氢氧化锌的煅烧时间与温度、洗涤反应最终悬浮液的终点、反应最终料液的陈化时间等等对纳米氧化锌性能的影响,制备出了外观为棒状和球形的两种纳米级氧化锌。并详细地探讨了其机理。     

真空法制备纳米四针状氧化锌晶须结构和形貌的研究

以金属锌为原料,研究了真空条件下纳米四针状氧化锌晶须(T-ZnOw)的制备,考察了反应条件对氧化锌结晶形貌的影响.表面能谱证实产物只含锌和氧原子,但氧原子数少于化学计量,表明T-ZnOw在缺氧环境中生长.XRD物相分析表明:产物为纯的六方晶系纤锌矿结构;SEM研究表明:分子筛用量、反应温度、体系压力对产物的形态影响很大.     

超临界流体干燥法制备纳米ZnO的研究

氧化锌是少数可以实现量子效应的半导体,与普通氧化锌相比,纳米氧化锌具有许多特殊的性质,如无毒和非迁移性、压电性、吸收和散射紫外线能力.以廉价无机锌盐为原料,采用液相化学法结合超临界流体干燥法制备了纳米级ZnO,并采用TEM、XRD等手段对其物性进行了表征,考察了制备条件对产物粒径、形貌、收率的影响.研究结果表明:随着锌盐浓度的提高,产物粒径逐渐增大;pH值<8～9时,随着pH值增加粒径逐渐变小;pH=8～9时,粒径达到最小,继续增加体系pH值,ZnO粒子迅速长大;相同的陈化时间,陈化温度越高,ZnO的粒径越大,在相同温度下,陈化时间越长,粒径越大;SCFD可实现干燥、晶化一步完成,与普通干燥相比,SCFD法制备的纳米粒子具有粒径分布均匀,大小可控等优点.     

纳米氧化锌的制备

以硫酸锌和碳酸铵为原料,直接沉淀法制得纳米氧化锌的前驱体,然后煅烧得到纳米氧化锌.采用 TG-DTG、XRD和TEM等测试手段对其进行了表征.结果表明,前驱体为Zn4(OH)6CO3.通过控制煅烧温度、反应温度和反应物浓度可以得到不同粒径的球形纳米氧化锌.得出了最佳制备工艺条件.     

废铝合金真空蒸馏脱锌的研究

首先分析了用真空蒸馏的方法脱除废铝合金中金属Zn的可行性。对二种含Zn质量分数为10%,12.25%的废铝合金进行了真空蒸馏脱除锌的实验。最终的实验结果与理论分析是紧密一致的。本文利用真空蒸馏法脱除含锌废铝中的金属Zn,解决了废铝脱锌难的问题,且对环境友好,不会造成二次污染。     

纳米氧化锌的制备工艺研究

以均匀沉淀法作为纳米氧化锌的制备方法,通过单因素实验和正交实验,系统地分析了溶液水解反应温度、水解反应时间、原料摩尔配比、煅烧温度等对氧化锌粉体产率和粒径的影响。结果表明,最佳工艺是:以直接混合的方式混合原料液,聚乙二醇-400作表面活性剂,反应温度90℃,原料摩尔配比c(尿素)/c(硝酸锌)=3:1,反应时间5.5h,前驱体碱式碳酸锌的最佳煅烧温度为500℃。通过所制得纳米氧化锌的XRD、SEM的粒径分析,证明了所制得的纳米氧化锌晶形为六方晶相,纯度大于99.9%、平均粒径约为68nm,产率为89.6%。     

Study on growth and photoluminescence of zinc telluride crystals synthesized by hydrothermal method

Zinc telluride powders were synthesized in sodium hydroxide solution by hydrothermal method by changing the growth temperature and time. The powders were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and micro-Raman spectroscopy, respectively. The results indicate that zinc telluride crystallizes in zinc blende structure and their sizes were increased with the increase in temperature and time, and oxygen easily is incorporated into zinc telluride crystals. The photoluminescence of the powders were investigated at room temperature. The photoluminescence spectra exhibit the emission peaks related to complex defects containing zinc vacancies and impurities and excitons bound to isoelectronic oxygen traps at about 556 and 703 nm, respectively. The growth of zinc telluride crystals and the relation of the photoluminescence with the growth conditions were analyzed.     

均匀沉淀法制备碳纳米管/氧化锌复合材料的研究

采用均匀沉淀法制备了碳纳米管(CNTs)负栽氧化锌(ZnO)粒子复合材料,并利用扫描电子显微镜(SEM)、X光衍射分析(XRD)以及热失重分析(TGA)手段对复合粒子进行了表征.研究结果表明:锌离子浓度取0.4mol/L至1.0mol/L时,所得复合材料中的氧化锌粒子大小均匀细小,分散性较好,形貌以粒状为主,大小在40nm左右;纳米氧化锌粒子与碳纳米管结合力较强,CNTs/ZnO复合材料在超声作用下能够稳定存在;反应时间越长,氧化锌粒子含量越高,晶粒越大;热解温度越高,热解时间越长,氧化锌晶粒尺寸越大.     

EDTA络合法制备Ni-Zn铁氧体及其磁学性质(英文)

以金属硝酸盐为原料,通过乙二胺四乙酸(EDTA)络合法制备了尖晶石型Ni1-xZnxFe2O4(x=0.0-0.7)晶体。通过TG-DTA考察了制备过程,采用XRD、FT-IR、SEM和VSM等对产物进行了表征,研究了热处理温度和Zn取代量对晶型结构和磁学性质的影响。同传统的固相法相比(1300℃/20h),制备单相Ni-Zn铁氧体所需的焙烧温度降至700℃,焙烧时间缩短至2h。随着Zn取代量的增加,晶胞参数递增,而矫顽力(Hc)和居里温度(Tc)逐渐下降。饱和磁化强度(Ms)随Zn取代量呈先递增至x=0.4后再逐渐下降。在1.5MHz的交变磁场中,所制粒子的感应温度接近设计的居里温度,能够适于感应加热的应用。     

Deposition of zinc coatings with fluidized bed technique

Zinc is known to be an ideal coating material for steel protection aiming to improve its anticorrosion performance. Up to now, hot-dip galvanizing is the industrially used coating technique for zinc. Its high environmental impact imposes the development of alternative techniques such as fluidized bed procedure. Under this procedure zinc was deposited by inserting the substrates in the reactor at room temperature. Afterwards the reactor was heated at the process temperature (400 °C) and holding time varied from 0 min to 2 h at the final temperature. The as-coated samples were examined with Scanning Electron Microscopy (SEM) associated with Energy Dispersive Spectroscopy (EDS), Transmission Electron Microscopy (TEM) and X-ray diffraction analysis (XRD). From this process two-layered coatings were formed. The main phases observed were gamma and delta phase of the Fe-Zn phase diagram. Some of the as-received coatings are likely to provide sufficient anticorrosive protection while others are of low quality because of porous areas in their mass. In addition a comparison is made with FBR zinc coatings produced in a preheated reactor, zinc pack coatings and hot-dip galvanized coatings.     

中空ZnO微球的制备及其光催化性能

以葡萄糖和醋酸锌为原料,采用模板法制备中空ZnO微球。并对所制样品进行表征,讨论了碳微球与醋酸锌物料比、煅烧温度、煅烧时间对ZnO催化剂光催化活性的影响。结果表明:在碳微球与醋酸锌物料比为1∶2、煅烧温度500℃、煅烧时间2h条件下,所制备的中空ZnO微球直径约为3~5μm,六方晶系结构,具有较好的光催化活性。     

复合沸石抗菌材料及其抗菌性能的研究

本文利用离子交换法将沸石与具有抗菌性能的锌铜离子合成双组分抗菌沸石,研究了反应时间、温度、交换的金属溶液的浓度和沸石与金属离子溶液的固液比对抗菌剂载金属含量及抗菌性能的影响,同时也比较了单金属组分沸石与双金属沸石抗菌性能的差异。实验表明,制备锌铜双组分抗菌沸石的最佳工艺条件为：反应时间2h,温度90℃,沸石质量与金属离子溶液体积比1：10,锌铜含量相差最少则锌铜离子浓度比为1：1。     

纳米晶氧化锌微球的制备

通过醋酸锌在一缩二乙二醇中热醇解反应制备了纳米晶ZnO微球,探讨了在醋酸锌热醇解法制备过程中升温速率对醇解反应温度和ZnO微球粒径分布的影响.在此基础上采用种子法制备了ZnO微球,考察了种子液加入量和反应时间对ZnO微球粒径分布的影响,并尝试使用SJN-30硅溶胶和SiO2微球乳液为种子液制备核-壳结构ZnO复合微球.     

Seaweeds for the remediation of wastewaters contaminated with zinc(II) ions

Eleven different species of marine macroalgae were screened at different pH conditions on the basis of zinc(II) biosorption potential. Among the seaweeds, a green alga, Ulva reticulata, exhibited a highest uptake of 36.1 mg/g at pH 5.5 and 100 mg/l initial zinc(II) concentration. Further experiments were conducted to evaluate the zinc(II) biosorption potential of U. reticulata. Sorption isotherm data obtained at different pH (5-6) and temperature (25-35 degrees C) conditions were fitted well with Sips model followed by Freundlich, Redlich-Peterson and Langmuir models. A maximum zinc(II) biosorption capacity of 135.5 mg/g was observed at optimum conditions of 5.5 (pH) and 30 degrees C (temperature), according to the Langmuir model. It was observed from the kinetic data that the zinc(II) biosorption process using U. reticulata follows pseudo-second-order kinetics. Various thermodynamic parameters, such as DeltaG degrees , DeltaH degrees and DeltaS degrees were calculated and they indicated that the present system was a spontaneous and an endothermic process. The influence of the co-ions (Na(+), K(+), Ca(2+) and Mg(2+)) along with zinc(II) present in the wastewater was also studied. Desorption of zinc(II) ions from the zinc(II)-loaded biomass were examined using 0.1 M CaCl(2) at different pH conditions in three sorption-desorption cycles. A fixed-bed column (2 cm i.d. and 35 cm height) was employed to evaluate the continuous biosorption performance of U. reticulata. The column experiments at different bed heights and flow rates revealed that the maximum zinc(II) uptake was obtained at the highest bed height (25 cm) and the lowest flow rate (5 ml/min). Column data were fitted well with Thomas, Yoon-Nelson and modified dose-response models. The column regeneration studies were carried out for three sorption-desorption cycles. A loss of sorption performance was observed during regeneration cycles indicated by a shortened breakthrough time and a decreased zinc(II) uptake.