低浓度双氧水提高原油污染土壤氧化效果的实验研究

在两种不同Fe~(2+)浓度和6种双氧水投加浓度的Fenton条件下,对5种原油污染土壤进行了氧化实验.结果表明,投加225 mmol/L低浓度双氧水可促进土壤中短链烃C_(11)-C_(20)的氧化去除,Total Petroleum Hydrocarbon(TPH)的氧化率高达38%.这是由于在低浓度双氧水(150～225 mmol/L)条件下H_2O_2分解时间长且产氧率低,从而能产生高强度的·OH,此时,短链烃C_(11)-C_(20)的解析与氧化达到平衡,因而能被大量氧化去除.而高双氧水投加浓度(300～900 mmol/L)条件下,H_2O_2分解时间短且产氧率高,仅能产生低强度·OH.这使得长链烃来不及氧化,水相残余的浓度较高.     

基于图像的废电路板高值元器件识别定位方法

随着电子产品的快速更新,需要回收处理的废弃电路板的数量也不断上升.近年来,图像处理和机器视觉技术发展迅速,基于机器视觉的高值元器件自动拆解技术逐渐成为废电路板回收处理领域的热门研究方向.为提高对废电路板芯片识别定位的准确率,提出一种基于图像的识别定位方法.首先获取废电路板的图像,通过对图像的预处理,提取边缘特征,最后绘制出轮廓并拟合,根据目标轮廓的面积和中心对元器件进行识别定位.该方法具有自适应的特点,能满足不同电路板元器件的识别定位,为废电路板上高值元器件的智能拆解打下基础.     

阳极溶出伏安法测定半光亮镍镀液中磺基水杨酸

研究磺基水杨酸在玻碳电极上的电化学行为,并确定溶出伏安法对其进行测定的实验条件。通过考察底液、底液浓度、富集电位、富集时间等因素对峰电流的响应情况,确定最佳实验条件。表明:在0.05mol/L的KCl底液中于0.1V富集3min后,进行阳极扫描,扫描范围0～2V,扫描速率为0.1V/s,发现磺基水杨酸在三电极系统玻碳电极上产生一灵敏的氧化峰,峰电位为1.5V。在1×10-4～4×10-3mol/L范围内磺基水杨酸与峰电流呈良好线性关系,检出限达8.8×10-5mol/L。将该方法用于测定半光亮镍镀液中的磺基水杨酸的浓度,结果令人满意.     

差示脉冲溶出伏安法测定粮食中叶酸的研究

利用差示脉冲溶出伏安技术和叶酸在电极表面的吸附特性,建立了测定痕量叶酸的电化学分析方法．方法具有快速、简便、灵敏度高、干扰少的优点．在不富集的实验条件下,差示峰电流与叶酸浓度在3.39×10-8～3.73×10-7mol/L范围内呈良好线性关系;而在-0.25V电位吸附富集70s条件下,其线性范围为6.78×-10～2.27×10-8mol/L,检测限达1.0×10-11mol/L。将该方法应用于小米和玉米中微量和痕量叶酸的测定,结果满意,回收率在94%～102%之间．     

废铅蓄电池湿法再生过程PbO2的还原研究

研究了亚硫酸钠、硫代硫酸钠、双氧水、Fe^2＋四种不同的还原剂在相同条件下对PbO2的还原效果,并研究了矿浆浓度、反应时间、还原剂浓度、温度对最佳还原剂还原效果的影响。结果表明,四种不同的还原剂还原能力依次为：硫代硫酸钠〉亚硫酸钠〉硫酸亚铁〉双氧水;以硫代硫酸钠作为还原剂的最佳还原条件为还原剂浓度0.8 mol/L,矿浆浓度20%,反应温度80℃,反应时间60 min,此时PbO2还原率可达82.97%。     

润湿剂对PS和ABS的浮选分离效果及其作用机制

针对聚苯乙烯(polystyrene,PS)和丙烯腈-丁二烯-苯乙烯共聚物(acrylonitrile butadiene styrene,ABS)混合物分选困难问题,利用自制浮选设备探讨了润湿剂对PS和ABS(包括原生料、再生料和电子废弃物拆解料)可浮性的影响及其作用机制.结果表明,润湿剂对PS和ABS原生料的可浮性影响很小,但对其再生料和电子废弃物拆解料的上浮率影响较大,不同润湿剂的作用效果存在明显差异,这与再生料、电子废弃物拆解料颗粒表面的主要官能团有关,红外光谱分析结果对此提供佐证;在溶气罐压力为0.22 MPa、浮选液流量为10 L/min的实验条件下,质量浓度为40 mg/L的单宁酸可以有效分离PS和ABS再生料;质量浓度为30 mg/L的十二烷基硫酸钠可以有效分离PS和ABS电子废弃物拆解料.     

电子元器件对氧化亚铁硫杆菌浸提废旧印刷线路板铜的影响研究

以拆解与未拆解电子元器件的废旧印刷线路板为对象,研究电子元器件对细菌浸出废旧印刷线路板金属铜的影响。分析发现,未拆解电子元器件的印刷线路板在加酸有菌浸出时铜的浸出率为95.8%;而经过拆解处理后,是否加酸对细菌浸出线路板无明显影响,铜的浸出率在加酸与未加酸下分别为97.1%与92.5%,拆解电子元器件的线路板比未拆解线路板更易浸出,通过加入稀硫酸,能使未拆解线路板铜浸提达到较好的效果。     

苎麻碱氧一浴法脱胶工艺优化研究

用氢氧化钠浸泡苎麻代替传统的酸处理工序,采用二次旋转回归设计方法对碱量、助剂量和双氧水量与残胶率、纤维白度和断裂强度之间的关系进行了探讨,经实验得到最优工艺参数:碱液浓度:1.2(g/L);助剂浓度:7.9(g/L);双氧水浓度:16.0(ml/L).     

黄麻碱氧一浴一步法脱胶漂白短流程工艺

采用碱氧一浴一步法对黄麻脱胶漂白新工艺进行研究，初步探讨了碱与双氧水同浴脱胶漂白原理，以及双氧水氧化木质素原理。实验中首次采用镁离子做助剂，同时在强碱浴双氧水稳定剂的作用下，使碱氧一浴脱胶达到最佳功效。用正交方案将影响脱胶漂白效果较大的3个主要因素：NaOH质量浓度、双氧水和稳定剂用量进行工艺条件的优化，得出最佳方案为：NaOH为48g/L，H2O2为10g/L，稳定剂用量5g/L。     

离子交换法从发酵液中提取丙酮酸

选择122树脂用于丙酮酸发酵液的脱色,在发酵液丙酮酸量浓度为60g／L,pH3.0、脱色空间流速为1．8mL/(mL.h)的条件下可取得较好的脱色效果。丙酮酸损失率低于6％,从8种碱性阴离子交换树脂中筛选出330弱碱性阴离子树脂（氯型）,用于从发酵液中提取丙酮酸,考察了不同操作条件对固定床离子交换效果的影响。上柱料液PH的变化对流出曲线的形状影响不大,当上柱料液的PH和丙酮酸质量浓度分别控制在4．0和40g/L,可以获得较高的有效体积交换容量（分别为0．534mol/L树脂和0．530mol/L树脂）。实验范围内体积流量对交换过程的影响不大,在较低的离子交换空间（0．44mL/(mL.h))G下有效体积交换容量高（0．604mol/L树脂）。考察了固定床洗脱工艺条件对洗脱效果的影响。当洗脱剂盐酸的浓度为2mol/L、洗脱空间流速控制在0．44mL/mL.h)左右时洗脱效果较好,采用较佳的工艺条件进行固定床单柱操作,实验得到离子交换单元的丙酮酸收率为97．0％。     

Decoioration and mineralization of yeast wastewater by using Ce-Fe/Al2O3 as heterogeneous photo-Fenton catalyst

Decoloration and mineralization of yeast wastewater were investigated by using Ce-Fe/Al2O3 as a heterogeneous photo-Fenton catalyst in fluidized bed reactor in order to solve the problem of yeast wastewater discharge. The experimental results were assessed in terms of total organic carbon（TOC） reduction. The operational and reaction conditions affecting the efficiencies of TOC removal such as initial pH value, H2O2 concentration, catalyst loading and UV power were studied. The results show that TOC is reduced from 347.6 mg/L to 10.8 mg/L, color is changed from 500 units to 0 under the conditions as follows： initial pH value 6. 0, H2O2 concentration of 1. 000 g/L, catalyst loading of 5 g/L, reaction duration of 120 rain and reaction temperature of 30 ℃. The irradiated Ce-Fe/Al2O3 catalyst was complexed with 1,10-phenanthroline and then it was subjected to Fourier transform infrared spectroscopy and diffuse reflectance spectroscopy to confirm the formation of Fe（Ⅱ） in the solid state. Heterogeneous photo-Fenton reaction proves to be effective for the treatment of yeast wastewater.     

微气泡O3/H2O2深度处理某化工园区二级出水效能与机制

化工园区废水经过二级处理后,仍含有多种有毒污染物,依然对生态环境存在较大风险,为此,建立微气泡O₃/H₂O₂深度处理工艺,研究某工业园区二级出水处理效能,确定最佳工艺参数,探究污染物降解机制,并对处理出水进行毒性评价。结果表明：在pH为7.3、臭氧投加量为60 mg/L、H₂O₂初始投加量为114 mg/L、反应时间为15 min条件下,微气泡O₃/H₂O₂对二级出水中有毒污染物具有良好的降解效果,COD和TOC去除率分别达到47.41%和46.61%;微气泡O₃能够显著提高臭氧利用效率,缩短反应时间;与普通O₃曝气相比,臭氧利用率提高10%,反应时间缩短2/3;微气泡O₃/H₂O₂工艺过程中,有机物去除过程遵循表观二级反应动力学;电子顺磁共振(EPR)技术证明羟基自由基(·OH)参与有机物的降解过程,H...     

光助芬顿法降解印制电路板脱膜废液

研究表明,采用UV/Fenton均相光催化氧化体系降解印制电路板脱膜废液效果好.在H2O2用量为1倍理论药量,Fe":H2O2(摩尔比)=1:20,光照时间为80 min,脱膜废液COD去除率可达80%.光助芬顿体系降解脱膜废液的诸多影响因素中,重要性次序依次为H2O2投药比＞FeSO4/H2O2的比值＞光照时间.     

Synthesis of γ-Al2O3 nanoparticles by chemical precipitation method

Highly pure active γ-Al₂O₃ nanoparticles were synthesized from aluminum nitrate and ammonium carbonate with a little surfactant by chemical precipitation method. The factors affecting the synthesis process were studied. The properties of γ-Al₂O₃ nanoparticles were characterized by DTA, XRD, BET, TEM, laser granularity analysis and impurity content analysis. The results show that the amorphous precursor Al(OH)₃ sols are produced by using 0.1 mol/L Al(NO₃)₃ · 9H₂O and 0.16 mol/L (NH₄)₂CO₃ · H₂O reaction solutions, according to the volume ratio 1.33, adding 0.024% (volume fraction) surfactant PEG600, and reacting at 40 °C, 1 000 r/min stirring rate for 15 min. Then, after stabilizing for 24 h, the precursors were extracted and filtrated by vacuum, washed thoroughly with deionized water and dehydrated ethanol, dried in vacuum at 80°C for 8 h, final calcined at 800 °C for 1 h in the air, and high purity active γ-Al₂O₃ nanoparticles can be prepared with cubic in crystal system, O _H ⁷ -FD3M in space group, about 9 nm in crystal grain size, about 20 nm in particle size and uniform size distribution, 131. 35 m²/g in BET specific surface area, 7 – 11 nm in pore diameter, and not lower than 99.93% in purity. Foundation item: Project(03JJY3015) supported by the Natural Science Foundation of Hunan Province     

Preparation of TiO2 photocatalyst loaded with V2O5 for O2 evolution

TiO₂ photocatalysts loaded with V₂O₅ were prepared via a modified hydrolysis process, and characterized by X-ray diffraction, transmission electron microscopy, Raman spectra and diffuse reflectance UV-Vis spectra measurements. The photocatalytic activity of V₂O₅/TiO₂ was investigated by employing splitting of water for O₂ evolution. The results indicate that V₂O₅ loading can pronouncedly improve the photocatalytic activity of TiO₂ with Fe³⁺ as an electron acceptor under UV or visible light irradiation. The optimum mass fraction of the loaded V₂O₅ is 8%, and the largest speed of O₂ evolution for 8%V₂O₅ (mass fraction) loaded TiO₂ catalyst is 118.2 μmol/(L·h) under UV irradiation, and 83.7 μmol/(L·h) under visible light irradiation.     

Molar heat capacities of La2Mo2O9 and La1.9Sr0.1MO209-δ

The molar heat capacities of La2Mo209 and La1.9Sr0.1MO209-δ were obtained using the differential scanning calorimetry （DSC） technique in a temperature range from 298 to 1473 K. The DSC curve of La2Mo209 showed an endothermal peak around 834 K corresponding to a first-order monoclinic-cubic phase transition, and the enthalpy change accompanying this phase transition is 5.99 kJ/mol. No evident endothermal peak existed in the DSC curve of La1.9Sr0.1MO209-δ, but a broad thermal anomaly existed in its heat capacity curve at around 832 K. In addition, the heat capacity values of La2Mo209 and La1.9Sr0.1MO209-δ began to decrease at 1196 and 1330 K, respectively. The non-transitional heat capacity values of La2Mo209 and La1.9Sr0.1MO209-δ were formulated using multiple regression analysis in two temperature ranges.     

Corrosion resistance of plasma sprayed NiCrAl+(ZrO2+Y2O3) thermal barrier coating on 18-8 steel surface

The corrosion resistance of NiCrAl+(ZrO₂+Y₂O₃) thermal barrier coating, formed with the plasma spraying technique, on the 18 - 8 steel surface was investigated. The phase structure and morphology of the coating were analyzed by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical corrosion behavior of the coating in 1.0 mol/L H₂SO₄ solution was studied by using electrochemical measurement methods. The results show that the gradient plasma spraying coating is composed of the NiCrAlY coating and the (ZrO₂+Y₂O₃) top coating, and the coating thickness is 360 μm. The microhardness of coating reaches 1 100 HV. The corrosion resistance of the plasma sprayed coating of the 18 - 8 steel surface is about 5 times as great as that of the original pattern. The corrosion resistance of the coating is enhanced notably. Foundation item: Project (5040202140) supported by Scientific Research Common Program of Beijing Municipal Commission of Education     

Electrodeposition of Ni-Co-Fe2O3 composite coatings

Ni-Co-Fe₂O₃ composite coatings were electrodeposited using cetyltrimethylammonium bromide (CTAB)-modified Watt’s nickel bath with Fe₂O₃ particles dispersed in it. The effects of the plating parameters on the chemical composition, structural and morphological characteristics of the electrodeposited Ni-Co-Fe₂O₃ composite coatings were investigated by energy dispersive X-ray (EDS) spectroscopy, X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The results reveal that Fe₂O₃ particles can be codeposited in the Ni-Co matrix. The codeposition of Fe₂O₃ particles with Ni-Co is favoured at high Fe₂O₃ particle concentration and medium stirring, and the deposition of Co is favoured at high concentration of CTAB. Moreover, the study of the textural perfection of the deposits reveals that the presence of particles leads to the worsening of the quality of the observed 〈220〉 preferred orientation. Composites with high concentration of embedded particles exhibit a preferred crystal orientation of 〈111〉. The more the embedded Fe₂O₃ particles in the metallic matrix, the smaller the sizes of the crystallite for the composite deposits.     

Preparation, characterization and photocatalytic behavior of WO3-TiO2/Nb2O5 catalysts

TiO2/Nb2O5 photocatalyst loaded with WO3 (WO3-TiO2/Nb2O5) was prepared by a modified hydrolysis process, and characterized by X-ray diffractometry, transmission electron microscopy, Raman spectra and UV-Vis diffuse refraction spectroscopy. The photocatalytic activity of WO3-TiO2/Nb2O5 was investigated by employing splitting of water for O2 evolution. The results indicate that WO3 loading can pronouncedly improve the photocatalytic activity of TiO2/Nb2O5 by using Fe3 as an electron acceptor under UV irradiation. The optimum molar fraction of the loaded WO3 is 2%, and the largest speed of O2 evolution for 2% WO3-TiO2/Nb2O5 catalyst is 151.8 μmol/(L·h).     

碳钢电极在Al_2O_3纳米流体中的腐蚀行为研究

采用电化学阻抗谱和极化曲线研究了碳钢电极在以模拟冷却水为基液的Al_2O_3纳米流体中的腐蚀行为.实验结果表明,Al_2O_3纳米颗粒对碳钢的腐蚀有一定的抑制作用;Al_2O_3纳米流体中碳钢电极的耐蚀性能随着温度的升高而降低,添加分散剂十二烷基苯磺酸钠(SDBS)对碳钢也有一定的缓蚀作用,当SDBS的用量超过一定值时,对碳钢的缓蚀性能开始下降.