Ca-B-Si体系LTCC材料腐蚀行为及腐蚀机理

LTCC材料在电镀和化学镀工艺中对酸/碱镀液的耐蚀性是低温共烧陶瓷(Low Temperature Co-fired Ceramics,LTCC)材料在实际应用中需要关注的重要特性。本工作研究了HCl、H₂SO₄和NaOH溶液(0.01～2.00 mol/L)和浸泡时间(10～300 min)对Ca-B-Si体系LTCC材料腐蚀行为的影响规律。结果表明，LTCC材料在不同的酸溶液中浸泡相同时间,样品的腐蚀失重量会随着酸溶液浓度增大呈现出先增大后减小的趋势,而在碱溶液中并未观察到明显的腐蚀现象。当盐酸溶液浓度为1.00 mol/L时,LTCC材料的失重最大为54.96%。当硫酸溶液浓度为0.10 mol/L时,LTCC材料的失重最大为8.80%LTCC材料中的CaB₂O₄和CaSiO₃晶相会与酸溶液发生溶解反应进而造成腐蚀,并且随着酸溶液浓度增大,反应后样品表面富Si蚀变层的形成速度更快,进而使LTCC材料在较高浓度酸溶液中的浸泡失重量减小。LTCC材料在1 mol/L盐酸溶液和...     

超声增强对碱性品绿染料的降解

研究了溶液的pH、铸铁用量及初始浓度对碱性品绿在超声和铸铁联合作用下的降解情况。结果表明,超声的作用有助于提高染料的降解率。在联合作用的下,脱色率都在95%以上,但CODcr的除去率随溶液pH和溶液浓度的增加而减少,随铸铁用量的增加而增加。     

超声-MnO2协同降解偶氮染料酸性红B

研究了MnO2、超声(US)单独作用和MnO2 US联合作用降解偶氯染料酸性红B(ARB)的情况。随着溶液pH的降低，ARB脱色率逐渐提高。SO4^2-、NO3^-与染料分子在MnO2表面发生竞争吸附。单独采用超声(50kHz)，对于染料无任何降解作用。当采用MnO2 US联合作用时，二者产生协同效应，ARB脱色率及TOC去除率明显上升。经过4h超声处理后，MnO2平均粒径由47．5μm变为3．19μm，并且产生大量纳米级MnO2颗粒，提高了MnO2的反应活性。     

吸附法原位制备Ag/ SiO2 纳米复合材料

以纳米SiO₂ 为载体, 以其富集水的表面吸附层作为纳米反应器制备了Ag 纳米粒子, 研究了水浓度对吸附和反应的影响。体系中NaOH 加入量一定的条件下, 硅胶表面NaOH 的平衡吸附量随着水浓度(0 、0105 %、0110 %、0125 %、0150 %、1. 00 %) 的增加而增加, 且存在两个突变区域(由0 增至0105 %和由0125 %增至0150 %) 。通过XRD、TEM 分析发现生成的银粒子(或氧化银) 团聚现象随水浓度的增加而逐渐减弱, 在硅胶表面分布越来越均匀, 晶粒粒径也逐渐减小。当水浓度约为0. 50 %时, 生成的Ag 或Ag₂O 粒子粒径多数在5 nm 以下, 且均匀分布在SiO₂ 表面。根据Ag + 的还原机理和吸附过程基本原理, 认为吸附水层的形成导致生成Ag 粒子的反应场所由硅胶表面转移到吸附水层中, 造成了Ag 粒子形貌的变化。      

羧甲基淀粉基高吸水树脂去除重金属离子研究

本文以羧甲基马铃薯淀粉为原料合成了高吸水树脂,研究该高吸水树脂的合成条件和环境对其去除溶液中的重金属离子能力的影响,主要包括交联剂用量(0.1mg-0.6mg)、中和度大小(20-80%)、重金属离子起始浓度(20-100mg/L)和溶液pH值(2-6)的影响;研究结果表明:该类高吸水树脂去除溶液中重金属离子的能力随合成该树脂时交联剂用量的增加而增大,而随单体中和度增大,先增大后减小,随重金属离子初始浓度的增加,去除率增大,高吸水树脂对浓度为100mg/L的Cu2+、Zn2+、Cr(VI)溶液中重金属离子的最大去除率分别为55.5%、90.5%和88.3%。     

功率超声对小麦面粉可溶性组分形成溶液过冷度的影响

应用自行设计的超声辅助冷冻循环系统,研究了频率为25kHz、不同电功率的超声对小麦面粉可溶性组分形成溶液过冷度的影响.研究结果表明,功率超声能显著地降低小麦面粉可溶性组分形成溶液中冰结晶的过冷度,促进冰晶晶核的形成.随着超声电功率逐渐增加,小麦面粉可溶性组分形成溶液过冷度逐渐减小,即成核温度随着超声电功率的增加而增加.研究结果有助于揭示超声强化食品冷冻过程中,溶解有多种无机与有机化合物的食品复杂溶液的冰结晶机理.     

Al-Ti体系原位合成Al_3Ti/ADC12复合材料

在超声场下,以Al-Ti为反应体系,采用熔体直接反应法原位合成Al_3Ti/ADC12复合材料。研究Ti加入量、超声时间以及功率对复合材料的显微组织和力学性能的影响。结果表明:随着超声功率的逐渐增加,Al3Ti颗粒尺寸变得愈加细小,分布也变得更为均匀;并且Ti的加入能够细化基体组织中的α-Al相,使其由原来的粗大树枝状逐渐转变为细小枝晶状、蔷薇状甚至近球状。然而,随着超声时间的增加,超声效果会出现先加强后减弱的趋势。Al_3Ti/ADC12复合材料的力学性能变化趋势与其组织变化趋势相一致,当Ti添加量为3%(质量分数)、超声功率为1.5kW、超声频率为20kHz、超声时间为6min时,其综合性能较好,抗拉强度达到247.34MPa,伸长率达到2.31%,比未施加超声的复合材料分别提高了21.3%和50.0%。     

阴离子交换膜分离饮用水中Cr(Ⅵ)的研究

基于Donnan渗析原理,采用阴离子交换膜无电压作用下分离饮用水中Cr(Ⅵ).结果表明,当原水中Cr(Ⅵ)初始浓度为1.0mg/L,pH值为6.95,补偿溶液NaCl浓度为0.1mol/L,原水和补偿溶液进水流量均为2.5mL/min,膜两侧溶液搅拌强度为500r/min,水温为25℃时,阴离子交换膜对Cr(Ⅵ)的分离去除率为86.4%.采用Na2SO4作为补偿溶液时,Cr(Ⅵ)的分离去除效果降低.调节原水pH值至11.0时,阴离子交换膜对Cr(Ⅵ)的分离去除率下降至78.9%.提高膜两侧溶液搅拌强度,给体池中Cr(Ⅵ)更容易通过膜迁移分离至受体池中.水温由10℃升高至40℃,给体池中Cr(Ⅵ)剩余质量浓度由0.21mg/L下降至0.12mg/L.     

纳米微粒对乙二醇溶液过冷度的影响

利用差示扫描量热仪(DSC)研究了羟基磷灰石(HA)纳米微粒作为成核物质对乙二醇溶液过冷度的影响,实验得到了不同粒径和不同质量浓度的HA纳米微粒加入不同浓度乙二醇溶液的成核温度与熔融温度.结果表明当溶液的质量浓度在0-20%的范围内,加入纳米微粒后溶液成核温度变化不明显,但是当溶液浓度高于20%时,加入纳米微粒能显著的提高溶液的成核温度,降低溶液的过冷度.实验结果同时表明,加入纳米微粒的粒径越大、质量浓度越高,溶液过冷度的降低的越显著.     

双频复合超声强化无水葡萄糖溶液结晶成核研究

溶液结晶技术在许多领域有着广泛的应用,其中结晶成核是溶液结晶的关键环节。以无水α-葡萄糖为研究对象,采用双频复合超声(25 k Hz+40 k Hz)强化糖液结晶成核,研究了溶液浓度、超声功率和作用时间对成核速率的影响,对单频和双频作用的晶核形态进行了对比,并采用碘化钾溶液中碘的释放量研究超声空化产额。研究结果表明:在同等条件下,双频复合超声降低了溶液成核的初始浓度,提高了成核速率,同时得到粒度均匀的晶核;双频复合超声的空化产额远高于单频25 k Hz超声和单频40 k Hz超声的空化产额,双频复合超声具有协同作用。双频复合超声强化溶液成核是一种快速、高效、节能的方法。     

The degradation of landfill leachate in the presence of different catalysts by sonolytic and sonocatalytic processes

In the study, the degradation of landfill leachate by single ultrasound (sonolytic) and sonolytic combined with Fe²⁺ and TiO₂ catalysts was carried out in laboratory conditions. The effect of pH and ultrasonic wave amplitude was also investigated in terms of color removal, total organic carbon (TOC) and chemical oxygen demand (COD) from leachate by the sonolytic degradation process. In this process, the color removal efficiency was recorded as 81.81% at 620?nm, pH?=?2.0 and 70% wave amplitude. The sonocatalytic degradation of landfill leachate accompanied by different catalysts was studied by using the 70% wave amplitude at pH?=?2.0 and room temperature for 20?min. The sonocatalytic degradation of leachate by using Fe²⁺ and TiO₂ was found to be significantly higher than sonolytic degradation (p?2+ concentration increased from 1.0 to 3.0?mg/L, the COD and color removal of leachate significantly decreased (p?相似文献   

微结构对Bi_2Sr_2Co_2O_y化合物电性能的影响

通过溶胶-凝胶法制备单相Bi2Sr2Co2Oy化合物,通过添加PEG20000和超声分散对化合物粉体微结构进行调控,采用SPS烧结得到了致密的块体.探索了微结构对Bi2Sr2Co2Oy化合物电性能的影响规律.结果表明,添加PEG20000和超声分散可以明显降低Bi2Sr2Co2Oy化合物粉体的晶粒尺寸,使烧结块体的晶粒尺寸大幅度减小,从而显著提高材料的电性能.温度为873K时,添加PEG20000并超声处理所制备样品烧结块体获得了最高ZT值0.041.     

Sonocatalytic degradation of azo fuchsine in the presence of the Co-doped and Cr-doped mixed crystal TiO2 powders and comparison of their sonocatalytic activities

In order to degrade some pollutants effectively under ultrasonic irradiation, the Co-doped and Cr-doped mixed crystal TiO₂ powders, with high sonocatalytic activity, were prepared as sonocatalyst. The Co-doped and Cr-doped mixed crystal TiO₂ powders as sonocatalyst were prepared through sol–gel and heat-treated methods from tetrabutylorthotitanate, and then were characterized by XRD and TG–DTA technologies. In order to compare and evaluate the sonocatalytic activity of the Co-doped and Cr-doped mixed crystal TiO₂ powders, the low power ultrasound was as an irradiation source and the azo fuchsine was chosen as a model compound to be degraded. The degradation process was investigated by UV–vis, TOC, ion chromatogram and HPLC techniques. The results indicated that the sonocatalytic activity of Cr-doped mixed crystal TiO₂ powder was higher than that of Co-doped and undoped mixed crystal TiO₂ powder during the sonocatalytic degradation of the azo fuchsine in aqueous solution. These results may be of great significance for driving sonocatalytic method to treat non- or low-transparent industrial wastewaters.     

Isotherms,kinetics and thermodynamic studies of adsorption of Ni and Cu by modification of Al2O3 nanoparticles with natural organic matter

In this study, removal of Ni and Cu ions from aqueous media was assessed by the adsorption of Al₂O₃ nanoparticles (ANPs), with surface modification by natural organic matter (NOM). The obtained materials (NOM–ANPs) were characterized by Fourier transform infrared spectroscopy. Then, batch adsorption methods were carried out as a function of contact time, adsorbate concentration, pH and temperature. Kinetic experiments revealed that the pseudo-second-order model exhibited the best correlation with the adsorption data, the estimated maximum adsorption capacity of Ni and Cu could reach 15.38 and 62.50 mg g^?1 respectively at 303 K, displaying higher efficiency for Ni and Cu removal than previously reported adsorbent materials reported in the literature. Thermodynamic studies exposed the feasibility and endothermic nature of the system. The experimental results show the technical feasibility of NOM–ANPs, its easy synthesis, economic and a promising advanced adsorbent in environmental pollution cleanup.     

Degradation of p-nitrotoluene in aqueous solution by ozonation combined with sonolysis

p-Nitrotoluene (PNT) is a nitroaromatic compound that is hazardous to humans and is a suspected hormone disrupter. The degradation of PNT in aqueous solution by ozonation (O(3)) combined with sonolysis (US) was investigated in laboratory-scale experiments in which pH, initial concentration of PNT, O(3) dose and temperature were varied. The degradation of PNT followed pseudo-first-order kinetics, and degradation products were monitored during the process. The maximum degradation was observed at pH 10.0. As the initial concentration of PNT decreased, the degradation rate increased. Both temperature and ozone dose had a positive effect on the degradation of PNT. Of the total organic carbon (TOC) reduction, 8, 68, and 85% were observed with US, O(3), and a combination of US and O(3) after reaction for 90 min, respectively, proving that ozonation combined with sonolysis for removal of TOC is more efficient than ozonation alone or ultrasonic irradiation alone. Major by-products, including p-cresol, 4-hydroxybenzaldehyde, 4-hydroxybenzoic acid, 4-(oxomethylene) cyclohexa-2,5-dien-1-one, but-2-enedioic acid, and acetic acid were detected by gas chromatography coupled with mass spectrometry.     

Photocatalytic activity of TiO2 thin films deposited by RF magnetron sputtering

Nano-TiO₂ thin films were deposited on silicon and glass substrates by radio-frequency (RF) magnetron sputtering using TiO₂ ceramic target and characterized by X-ray diffractometer, X-ray photoelectron spectrometer, atomic force microscope, and ultraviolet-visible spectrophotometer. Photocatalytic activity was evaluated by light induced degradation of 5 ppm methyl orange solution using a high pressure mercury lamp as lamp-house. It was found that the film as deposited is polymorph, with energy gap of 3.02 eV, and can absorb visible light. The film was repeatedly used for six times in degradation of 5 ppm methyl orange, and the degradation rates of methyl orange solution are 36.566%, 33.112%, 32.824%, 32.248%, 30.521% and 28.794%, respectively. After ultrasonic treatment in de-ionized water for ten minutes, the degradation rate of methyl orange solution resumes to 33.975%.     

高能超声对Mg2 Si / AZ91D 复合材料的影响

为改善原位颗粒增强镁基复合材料的性能,采用原位合成技术制备了Mg2Si/AZ91D复合材料,通过在熔体中施加高能超声,研究了超声时间和超声功率对复合材料组织性能的影响.结果表明:随着超声时间的延长或超声功率的增大,复合材料中粗大的汉字状Mg2Si相变得细小、分布均匀,同时细小分布均匀的球化状β-Mg17Al12相增多;超声时间为6 min、超声功率为1.2 kW时,组织中呈短棒状的Mg2Si颗粒和球化状β-Mg17Al12相分布均匀,且复合材料的抗拉强度和伸长率达到最大,分别为220.5 MPa和2.6%,较未施加超声的复合材料试样提高了22.3%和38.9%;再延长处理时间或增大输出功率,组织有粗化的趋势,复合材料的抗拉性能及伸长率也呈现先升后降趋势.     

Synthesis of La-Doped CaTiO3 Perovskite Powders from the Mixture of Metal Salt Solutions by Ultrasonic Mist Combustion/Pyrolysis Processes

The CaTiO₃ and La-doped CaTiO₃ [Ca_1–x (La) _x TiO₃, x = 0.05–0.3] powders were prepared from aqueous solutions by the ultrasonic mist pyrolysis and ultrasonic mist combustion processes. Glycine provides carboxylic acid and amine groups as a fuel in the ultrasonic mist combustion process. In ultrasonic mist pyrolysis, the particles with hollow sphere morphology were obtained; whereas, particles prepared by the ultrasonic mist combustion process had a dense solid morphology with low porosity. The ultrasonic mist combustion process using metal nitrates and glycine as the fuel for a starting material has proved to be a simple and unique approach to preparing dense CaTiO₃ powder and a solid solution of CaTiO₃ with lanthanum.     

Case study of the sonochemical decolouration of textile azo dye Reactive Black 5

The decolouration and mineralization of reactive dye C.I. Reactive Black 5, a well-known representative of non-biodegradable azo dyes, by means of ultrasonic irradiation at 20, 279 and 817kHz has been investigated with emphasis on the effect of various parameters on decolouration and degradation efficiency. Characterization of the used ultrasound systems was performed using calorimetric measurements and oxidative species monitoring using Fricke and iodine dosimeter. Experiments were carried out with low frequency probe type, and a high-frequency plate type transducer at 50, 100 and 150W of acoustic power and within the 5-300mg/L initial dye concentration range. Decolouration, as well as radical production, increased with increasing frequency, acoustic power, and irradiation time. Any increase in initial dye concentration results in decreased decolouration rates. Sonochemical decolouration was substantially depressed by the addition of 2-methyl-2-propanol as a radical scavenger, which suggests radical-induced reactions in the solution. Acute toxicity to marine bacteria Vibrio fischeri was tested before and after ultrasound irradiation. Under the conditions employed in this study, no toxic compounds were detected after 6h of irradiation. Mineralization of the dye was followed by TOC measurements. Relatively low degradation efficiency (50% after 6h of treatment) indicates that ultrasound is rather inefficient in overall degradation, when used alone.     

超声协同微球型Bi2O2CO3降解罗丹明B的研究

Bi_2O_2CO_3是一种Bi类半导体催化剂,文章研究了它的超声催化性能。首先,采用水热法制备了微球型的Bi_2O_2CO_3,利用X射线衍射(X-ray Diffraction, XRD)、扫描电子显微镜(Scanning Electron Microscope, SEM)、紫外-可见漫反射光谱对样品的晶体结构、微观形貌、光学特性进行了表征。然后,以罗丹明B(Rh B)作为模型污染物,通过研究超声催化降解罗丹明B来评测Bi_2O_2CO_3的超声催化性能。研究了催化剂的浓度(Ccatalytic)、初始罗丹明B染料的浓度(CRhB)和超声功率(P)等实验因素对超声催化降解效率的影响。得出在Ccatalytic=3 g·L-1,CRhB=10 mg·L-1和P=400 W条件下降解罗丹明B的效率最高,其最高降解效率可以达到91.7%。