负载纳米TiO_2凹凸棒石黏土对Ni(Ⅱ)的吸附热力学研究

利用静态吸附实验的方法,研究了负载纳米二氧化钛的凹凸棒石黏土对溶液中Ni(Ⅱ)的吸附热力学特性。结果表明,吸附等温线符合Freundlich吸附模型。根据热力学函数关系计算出吸附过程的ΔH为-26.56 k J/mol,ΔG为-5.12^-0.73 k J/mol,ΔS为-73.18 J/(mol·K),表明负载纳米二氧化钛的凹凸棒石黏土对溶液中Ni(Ⅱ)的吸附是自发、放热、熵减的过程,为物理吸附。     

凹凸棒石粘土对Ni(Ⅱ)的动态吸附研究

研究了凹凸棒石粘土对水中Ni(Ⅱ)的动态吸附性能。探讨了Ni(Ⅱ)溶液初始浓度、流速、初始pH值及吸附床高度对穿透曲线的影响,同时采用BDST模型对动态实验数据进行了线性拟合分析,对新的操作条件下的穿透时间进行了预测。结果表明,凹凸棒石粘土能够有效地去除水中的Ni(Ⅱ),随着吸附床高度的增加,穿透时间延长;而随着Ni(...     

风化煤对Ni(Ⅱ)的吸附性能研究

以景泰风化煤作吸附剂,对常温下水溶液中的Ni(Ⅱ)进行了吸附实验研究,探讨了吸附平衡、影响吸附的因素和吸附机理。结果表明,风化煤对Ni(Ⅱ)的吸附表现出Langmuir特征,在pH值6.0左右吸附效果较好,最大吸附量可达16.47mg/g。     

天祝褐煤腐植酸对Ni(Ⅱ)离子吸附性能试验

采用天祝褐煤中提取的腐植酸对Ni(Ⅱ)进行了吸附性能的研究,确定了Ni(Ⅱ)的吸附平衡时间、pH值大小及吸跗速率方程,讨论了腐植酸用量和Ni(Ⅱ)初始浓度与吸附率和吸附量的关系。     

磺化腐植酸对Ni(Ⅱ)吸附性能的热力学及动力学研究

通过磺化腐植酸对重金属Ni(Ⅱ)吸附性能的实验,研究了吸附过程中的吸附等温线,探讨了吸附热力学特征和吸附动力学模型。结果表明:在室温条件下(20~25℃),pH为5~6,吸附平衡时间120 min,磺化腐植酸对Ni(Ⅱ)吸附类型符合Freundlich吸附模型,吸附过程可用Ho准二级反应动力学模型描述。     

竹笋壳纤维对模拟水中Cr(Ⅵ)和Ni(Ⅱ)吸附性能的研究

竹笋壳是在竹笋加工过程中产生量最大的固体废弃物之一,若处理不当会造成资源浪费和环境污染问题。通过逐级利用方式,将提取棕色素和膳食纤维后的竹笋壳纤维作为吸附剂（BFs）吸附Cr(Ⅵ)和Ni(Ⅱ)。利用SEM和FT-IR对BFs表观形貌和表面官能团等理化性质进行分析;考察投加量和初始pH对吸附效果的影响,并结合吸附动力学、吸附等温线和热力学模型对吸附过程和吸附机理进行探讨。研究结果表明,BFs表面粗糙多孔且含有丰富的-OH、-SO-、C-O等官能团。在投加量分别为4.0、2.0 g/L时,BFs对Cr(Ⅵ)和Ni(Ⅱ)的去除率分别可达98.8%和96.8%。准二级动力学模型和Sips模型能够更好地拟合BFs对Cr(Ⅵ)和Ni(Ⅱ)的吸附过程,表明该吸附反应过程主要受化学作用主导,且Cr(Ⅵ)和Ni(Ⅱ)的最大理论吸附量分别为10.58、29.70 mg/g。热力学分析显示,吸附过程ΔG小于0、ΔH为正值,说明BFs对Cr(Ⅵ)和Ni(Ⅱ)的吸附为自发的吸热反应。吸附机理分析表明,静电力吸附作用和氧化还原吸附作用在BFs吸附Cr(Ⅵ)时扮演重要作用,而Ni(Ⅱ)的吸附主要基于静电吸附作用、化...     

高比表面积偏高岭土制备及其对Cr(Ⅵ)、Ni(Ⅱ)吸附性能研究

将煤系高岭土在800℃下煅烧制得高比表面积的偏高岭土,进而用于对废水中Cr(Ⅵ)、Ni(Ⅱ)的吸附。FTIR与BET等分析可得,煅烧改性后的高岭土处于非晶态,比表面积增大,总孔体积增多,由结晶度很高的有序状态变为以非晶为主的无序状态,活性大大提高。结果表明,偏高岭土对Cr(Ⅵ)的吸附实验中,pH值<6时效果更好,在体系中加入NaCl溶液能够促进吸附。pH值、NaCl溶液对偏高岭土吸附Ni(Ⅱ)影响相反。Cr(Ⅵ)、Ni(Ⅱ)之间竞争状态的存在不利于对其中单一离子的去除。两者之间离子半径、电负性、荷径比等差异导致吸附性能不同。     

羧甲基纤维素改性凹凸棒石黏土负载纳米铁去除水中Zn(Ⅱ)性能和机制

为改善纳米铁(NZVI)易氧化钝化和团聚的问题,以羧甲基纤维素钠改性的凹凸棒石黏土(CMC-ATP)为载体构建了CMC-ATP-NZVI复合材料,并对复合材料去除水中Zn(Ⅱ)的性能与机理进行了研究。结果表明:仅含33.3%(质量分数)纳米铁的CMC-ATP-NZVI与NZVI相比,对水中Zn(Ⅱ)有更快的反应速率和更高的去除效率,而成本却降低了约2/3。此外,相比未改性的ATP-NZVI复合材料,CMC-ATP-NZVI对Zn(Ⅱ)的吸附量提高了12.49 mg/g。CMC-ATP负载能够增强NZVI去除水中Zn(Ⅱ)性能的机制主要是:1) CMC-ATP的电动电位比ATP更低,因而对阳离子Zn~(2+)有更大的吸引力;2) CMC-ATP的分散作用使NZVI团聚体的尺寸变小,甚至成为单个纳米铁颗粒,因此复合材料比表面积增大,能提供更多吸附位点;3)CMC-ATP的负载提高了NZVI中F_e~0含量,因此NZVI能够充分发挥自身反应活性。CMC-ATP-NZVI去除Zn(Ⅱ)机制主要是F_e~0氧化和腐蚀产生的氧化物和羟基氧化铁表面羟基对Zn(Ⅱ)的配合作用以及Zn2+在反应后发生化学沉淀。     

凹凸棒石黏土的提纯及其吸附性能的研究

考察了凹凸棒石黏土原矿的粒径、液固比、分散剂种类及用量对江苏盱眙凹凸棒石提纯土吸附性能的影响,并进行了激光粒度检测、X射线衍射及扫描电镜等分析。结果表明,对醇类发酵废水吸附效果最佳的凹凸棒石黏土提纯条件为:常温常压下,纯水和凹凸棒石黏土的液固比为9 m L/g,分散剂为六偏磷酸钠,用量为凹凸棒石黏土质量的4%,凹凸棒石黏土的粒度为100目。提纯过程可以有效的去除白云石和石英等杂质,提高凹凸棒石黏土的纯度;在分散剂的分散作用下,可以减小凹凸棒石黏土的粒径,使其棒晶变细变短;提纯后的凹凸棒石黏土对醇类发酵废水的吸附性能得到了明显的提高。     

凹凸棒石对废水中Ni~(2+)吸附性能的研究

采用靖远凹凸棒石对废水中Ni2+离子的吸附性能进行了研究。确定了Ni2+离子的吸附平衡时间、最大吸附量对应的pH、最大吸附率对应的吸附剂用量,最大吸附量对应的Ni2+的初始浓度及吸附速率方程。实验结果显示,Ni2+离子浓度在100 mg/L下,吸附平衡时间为90 min,pH值在5~6时,凹凸棒石用量为0.8 g时吸附率达到最大值16.54 mg/g,速率方程为V=0.200 1C。     

纳米TiO2-超高分子量聚乙烯复合材料的摩擦学特性

利用MM-200型摩擦磨损实验机,考察了纳米TiO2增强超高分子量聚乙烯（UHMWPE）复合材料在生理盐水润滑下,与Co—Cr—Mo合金对摩时的摩擦磨损性能,用光学显微镜观察了材料摩擦表面磨痕形貌。结果表明,适当填充纳米TiO2可提高UHMWPE的硬度,显著降低摩擦系数,增强耐磨性。UHMWPE的磨损主要表现为粘着、犁沟及塑性变形,TiO2-UHMWPE复合材料的磨损表现为轻微疲劳磨损。     

Preparation and properties of chitosan/clay (nano)composites: a silanol quaternary ammonium intercalated clay

Chitosan/clay (nano)composites were prepared by using a special quaternary ammonium intercalating agent coupled with a silanol group to facilitate the organic clay formation. Exfoliated clay in the chitosan matrix was attained at the higher intercalant dosages through X-ray diffraction (XRD) and transmission electron microscope (TEM) analyses. Optical transmittance for the (nano)composites increased slightly with increasing the amount of intercalants in the clays. In light of the hydrophobic component on the intercalant and the effective clay content, the interfacial interaction between chitosan and modified clay may not be strong enough to render higher mechanical properties, even though the partially exfoliated clays were achieved to provide high interfacial area for the dispersed phase and the matrix. An optimum Young’s modulus was thus found for (nano)composites using modified clay at a medium dosage of intercalant, which resulted from the balance of the dispersion status and interfacial interaction. This outcome indicated high dispersion of modified clay may not guarantee high mechanical properties of (nano)composites. The antimicrobial property of chitosan against Escherichia coli (E. coli) increased further with the addition of modified clays, in which the intercalant exhibiting the antimicrobial function. The modified clay at an optimum dosage of modifier to balance the mechanical properties and antimicrobial property was attained.     

纳米TiO_2的制备及光催化性能的研究

以TiCl4为钛源,用正交实验设计方法,探究了水解法制备TiO2最佳反应条件,即烧结温度为600℃,盐酸用量为1.7 mL,pH值为8。同时研究了催化剂用量和时间对TiO2光催化降解甲基橙的降解率的影响,实验结果表明,当催化剂用量为4 g/L,光催化时间为60 min时,降解率可达到90%以上。     

Polychelates of poly(acrylic acid-co-acrylamide)with Cu(II), Co(II), and Ni(II) Synthesis and properties

SUMMARY Polychelates were obtained by addition of an aqueous solution of the poly(acrylic acid-co-acrylamide) to an aqueous solution of Cu(II), Co(II), and Ni(II). All the polychelates were insoluble in water and in common organic solvents. The polychelates were characterized by elemental analysis, FT-IR spectroscopy thermogravimetry, and showed tetrahedral arrangement for Co(II) and Ni(II). Magnetic and conductivity studies for all the polychelates were also carried out. The poly(acrylic acid-co-acrylamide) behaved as semiconductor. Received: 25 July 1997/Revised version: 1 December 1997/Accepted: 5 December 1997     

The flame‐retardance polylactide nanocomposites with nano attapulgite coated by resorcinol bis(diphenyl phosphate)

The nano attapulgite (ATP) coated by flame‐retardant resorcinol bis(diphenyl phosphate) (RDP) was prepared, and the modification effects were analyzed by scanning electron microscopy plus energy dispersive spectrometer, Fourier‐transform infrared spectra, the contact angles, and thermal gravimetry analysis. The results showed that RDP was adsorbed and formed a uniform layer on the surface of nano ATP with a content of about 25 wt%. The prepared polylactide (PLA) nanocomposites with the RDP‐coated nano ATP showed good mechanical properties, and the tensile strength of the nanocomposites containing 30 wt% of the RDP‐coated nano ATP reached 76.9 MPa in comparison with 66.2 MPa of pure PLA. The limiting oxygen index of the prepared PLA composites containing 30 wt% of the RDP‐coated nano ATP was about 24.5% and V‐0 rating was attained compared with 20.5% and with no rating of pure PLA. After the burning of the flame‐retardant PLA composites, a compact and coherent charred layer was formed; the flame‐retardance mechanism is discussed in detail. J. VINYL ADDIT. TECHNOL., 22:506–513, 2016. © 2015 Society of Plastics Engineers     

Electrical properties of Cu(II) and Ni(II): N-salicylidene polymethacrylic acid hydrazide complexes

Different types of chelated polymer complexes have been synthesized to obtain improved electrical properties. Compact discs from powders of the chelated polymers were prepared and heated in a specially designed holder. Electrical conductivity and dielectric constant of Cu(II) and Ni(II): N-salicylidene polymethacrylic acid hydrazide samples were measured at a fixed frequency (1600 Hz) throughout the temperature range 25-150°C. The AC conductivity as well as dielectric measurements showed maxima at 85°C. The water molecules which were trapped in the polymer matrix are believed to play the main role in conduction and dielectric behaviour of the polymeric material. From the AC conductance and dielectric constant measurements, the dielectric losses of these polymeric materials were calculated as a function of temperature.     

Biologically Active Co(II) and Ni(II) Complexes of N-(2-Thienylmethylene)-2-Aminothiadiazole

Co(II) and Ni(II) complexes Schiff base, N-(2-thienylmethylene)-2-aminothiadiazole have been prepared and characterized by their physical, spectral and analytical data. The title Schiff-base acts as NNS donor tridentate during the complexation reaction with these metal ions having a composition, [M(L)(2)]X(n) where M=Co(II) or Ni(II), L=, X=NO(3) (-), SO(4) (2-), C(2)O(4) (2-) or CH(3)CO(2) (-) and n=1 or 2 and show an octahedral geometry. In order to evaluate the effect anions upon chelation, the Schiff-base and its new complexes have been screened for their antibacterial activity against bacterial strains e.g., Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa.     

电沉积TiO2/Ni纳米复合涂层的微结构与性能

采用电沉积法制备出TiO2／Ni纳米复合涂层,考察了搅拌强度对TiO2质量分数的影响,分析了复合涂层的抗高温氧化性能和摩擦学性能。结果表明：当达到中等搅拌强度（3级）时,纳米复合涂层中TiO2的质量分数最大;当TiO2质量分数在9％-13．5％变化时,随着其质量分数的增加,摩擦因数增大,耐磨性增强;随着TiO2质量分数的增加,复合涂层的抗高温氧化性能增强,氧化温度达到了530℃。