高吸附性能介孔磁性复合碳球的制备

以正硅酸乙酯(TEOS)为硅前驱体,间苯二酚-甲醛树脂(RF)为碳源,在表面活性剂十六烷基三甲基溴化铵(CTAB)的辅助作用下,采用原位聚合法制备了介孔磁性复合碳球Fe3O4@C-M。考察了醇水比〔V(乙醇)∶V(水)〕、表面活性剂用量、TEOS用量和水热温度(HT)对碳球的形貌、粒径和表面孔结构的影响。在84 mL乙醇/水混合液〔V(乙醇)∶V(水)=3∶4〕、CTAB 0.6 g、TEOS 4 mL、水热温度100℃下制备得到Fe3O4@C-M,采用TEM、XRD、XPS、BET、TGA、VSM对其进行表征。结果表明,Fe3O4@C-M的比表面积为553m2/g,较不引入硅前驱体时制备的磁性复合碳球Fe3O4@C-0增大1.7倍,介孔孔容占比由18%增大到83%。考察Fe3O4@C-M对红霉素的吸附性能,饱和吸附量为255 mg/g;用乙酸正丁酯对吸附后材料进行再生,5次循环再生后吸附量维持在初始吸附量的85%以上。     

交联壳聚糖对废水中Cu2+的吸附性能

以壳聚糖为原料制备交联壳聚糖吸附剂,并将其用于吸附废水中的Cu2+,考察了交联剂的用量、溶液中Cu2+初始浓度、pH、温度和时间等对交联壳聚糖吸附性能的影响。结果表明,壳聚糖与交联剂的用量比为m(壳聚糖)∶V(甲醛)∶V(戊二醛)=1.5g∶6mL∶4.5mL、溶液pH为6,溶液中Cu2+初始浓度为5mmol/L时吸附效果最佳,且吸附量随着温度升高而增加,吸附表现为吸热过程。     

改性活性炭/碳纳米管复合电极脱盐性能研究

采用改性CNT*作为CDI电极导电剂,制备AC*/CNT*复合电极,考察其脱盐性能。利用BET、FTIR和TEM对AC或CNT的表面结构、官能团种类和分散性进行分析。利用电化学工作站和SEM对复合电极的比电容、阻抗和表面形貌进行分析。结果表明,通过改性,AC*的比表面积达到672.48 m2/g,增加了29.43%;CNT*的比表面积为117.39 m2/g,下降了9.94%,但其分散性得到有效改善。根据循环伏安测试和静态脱盐实验结果 ,按AC*∶CNT*∶PVDF=7.2∶0.8∶2质量比制备的电极效果最好,比电容高达130.48 F/g,比吸附量达到7.29 mg/g。     

改性活性炭/碳纳米管复合电极脱盐性能研究

采用改性CNT*作为CDI电极导电剂,制备AC*/CNT*复合电极,考察其脱盐性能。利用BET、FTIR和TEM对AC或CNT的表面结构、官能团种类和分散性进行分析。利用电化学工作站和SEM对复合电极的比电容、阻抗和表面形貌进行分析。结果表明,通过改性,AC*的比表面积达到672.48 m2/g,增加了29.43%;CNT*的比表面积为117.39 m2/g,下降了9.94%,但其分散性得到有效改善。根据循环伏安测试和静态脱盐实验结果 ,按AC*∶CNT*∶PVDF=7.2∶0.8∶2质量比制备的电极效果最好,比电容高达130.48 F/g,比吸附量达到7.29 mg/g。     

3_十四烷氧基_2_羟丙基三乙基氯化铵在大庆油砂表面吸附性能

季铵盐由于其良好的性能,日益受到人们的重视,在油田、食品和日用化工等领域已得到广泛的应用。研究了地层温度下(45 ℃),3 十四烷氧基 2 羟丙基三乙基氯化铵(TPAC)在大庆油砂表面的静态吸附性能,考察了液固比、吸附时间和浓度对静态吸附量的影响。结果表明,TPAC溶液在大庆油砂表面达到静态饱和吸附时：液固比为20∶1;浓度为1.84 mmol/L;吸附时间为6 h,吸附等温线为S型曲线。当TPAC的浓度达到1.10 mmol/L时,形成单分子层饱和吸附;当浓度增加至1.84 mmol/L达到双分子层饱和吸附,饱和吸附量为13.21×10^-6 mol/g。研究季铵盐吸附性能为季铵盐在油田中的应用打下良好的基础。     

镍钒复合催化剂的制备及其光催化性能

采用浸渍法制备了Ni-V-O/SiO2催化剂,并对其进行了XRD、UV-Vis和吡啶吸附FTIR等表征。在紫外光照下考察了催化剂热处理温度和Ni、V质量比对甲醇和CO2光催化羰基化性能的影响。结果表明,m(Ni)∶m(V)=6∶4,并于60℃热处理的Ni-V-O/SiO2催化剂对羰基化产物——甲酸甲酯(MF)和碳酸二甲酯(DMC)的总选择性达到了77.6%;吡啶吸附红外光谱表征结果显示,该样品表面存在L酸性位,经计算,表面L酸的含量达到了1.85 mmol/g。催化剂的表面L酸强度是影响羰基产物选择性的主要因素。     

聚丙烯酸/氧化石墨烯复合水凝胶制备及对亚甲基蓝吸附

以丙烯酸(AA)为原料,二丙烯酸酯(Pul DA)分散的氧化石墨烯(GO)纳米胶粒(GO-Pul DA)为增强剂,N,N'-亚甲基双丙烯酰胺(BIS)为交联剂,通过自由基共聚合制备了一系列结构均一的聚丙烯酸/氧化石墨烯复合水凝胶(PAA/GO-Pul DA)。考察了BIS质量浓度、GO质量浓度以及溶液pH值对复合水凝胶力学性能、吸水性和亚甲基蓝(MB)吸附量的影响。结果表明,当GO质量浓度从0.1 g/L增加至1.0 g/L时,复合水凝胶拉伸强度从5.0 k Pa增加至10.4 k Pa,断裂伸长率高于100%,当GO的质量浓度为0.3 g/L时,复合水凝胶的断裂伸长率最高为151%;复合水凝胶表现出pH敏感的高吸湿性,pH从3.0增加至6.8时,平衡溶胀比(SRe)变化可达386 g/g,pH=6.8时最大SRe高达490 g/g。当溶液pH值从3.0增加至11.0时,PAA/GO-Pul D对MB的平衡吸附量(qe)可增加1 400~1 500 mg/g,pH=11.0时最大的qe高达1 789 mg/g。复合水凝胶对MB的吸附行为符合准一级动力学模型。5次吸附-解吸附循环后,相对于首次吸附,PAA/GO-Pul D对MB的吸附能力仍保持高达60%,解吸附效率高于90%。     

高强高模维纶纤维的表面修饰及其在水泥中的分散性

目前高强高模维纶纤维由于缺乏合理的分散方案且分散性不佳，极大地限制了在工程领域的应用。为了解决这一问题，采用聚乙烯醇磷酸酯（TFOPVA）分散剂对高强高模维纶纤维进行表面涂层改性处理，并以此为基础制备维纶纤维/水泥基复合材料。利用X射线光电子能谱仪（XPS）、场发射扫描电子显微镜（SEM）、万能材料试验机、纤维强伸度仪（XQ-1A）等对改性前后的维纶纤维的分散性及其复合材料的力学性能进行测试和表征。结果表明：当TFOPVA上浆质量分数和吸附量分别为1%和5mg/g时纤维分散效果最佳；维纶纤维短丝在水泥基体中的分散系数提高33.3%；TFOPVA处理后的维纶纤维单丝断裂强度增加4.5%，与维纶纤维之间能牢固结合；TFOPVA改性后的维纶纤维/水泥复合材料的抗压强度和抗折强度相比改性前分别提高了27.9%和21.2%。     

表面修饰聚乙烯亚胺的壳聚糖微球对十二烷基苯磺酸钠的吸附特性

采用乳化交联法制备交联壳聚糖微球(CCS),在其表面接枝聚乙烯亚胺(PEI),得到系列具有不同离子交换容量(IEC)的PEI修饰交联壳聚糖微球(PEI-CCS),对其进行表征,考察了其对十二烷基苯磺酸钠(SDBS)的静态吸附特性. 结果表明,PEI-CCS平均粒径为85 mm,IEC最高达1275 mmol/g,远高于CCS的418 mmol/g. 酸性条件下,PEI-CCS的胺基质子化,带正电荷,能与溶液中的阴离子吸附结合,对SDBS有良好的吸附能力. 吸附过程自发放热,可用准二级动力学模型和Langmuir吸附等温模型描述. PEI-CCS对SDBS的最大吸附量随IEC增加而增大,IEC=1275 mmol/g的PEI-CCS的最大吸附量为1487.61 mg/g,是CCS最大吸附量(510.20 mg/g)的2.92倍,吸附-脱附7次循环后,吸附量下降17.8%. PEI-CCS具有良好的重复使用性.     

不同表面活性剂对氧化石墨烯分散性的影响

采用超声分散和吸光光度法,考察了十二烷基磺酸钠(SDS)、十二烷基苯磺酸钠(SDBS)和吐温80三种不同表面活性剂对氧化石墨烯在水溶液中分散性的影响。结果表明:随着水溶液中表面活性剂的浓度增加,氧化石墨烯分散液的电导率也随之增加,表明添加表面活性剂能够有效提高其分散性。当溶液中SDBS浓度为1.2 mmol/L时,氧化石墨烯分散液的电导率为0.997 mS/cm。加入SDBS后的氧化石墨烯分散液放置45 h后,吸光度略微降低,表明SDBS这种表面活性剂具有良好的分散稳定能力。     

CO2 capture efficiency in post‐combustion using MWNT‐PAA in a packed bed column

The adsorption capacity of polyaspartamide (PAA) and multi‐wall carbon nanotubes with polyaspartamide (MWNT‐PAA) was investigated through a packed bed column with the flowing of flue gas composed of 15 % CO₂, 5 % O₂ and the balance N₂. The adsorption performed at 25 °C, 110 kPa and inlet gas flow rate of 60 mL/min resulted in high CO₂ adsorption capacity of 5.70 and 10.20 mmol‐CO₂/g for PAA and MWNT‐PAA, respectively. The adsorption kinetics was very high, so 7 min were enough for the effluent gas to reach the breakthrough after saturation. The consistency of adsorbents in recurring regeneration was successful through a continuous TSA system of 10 cycle adsorption‐desorption with temperatures of 25–100 °C. The evaluation of heat through differential scanning calorimetry (DSC) resulted in exothermic adsorption with heat release of 45.14 kJ/mol and 124.38 kJ/mol for PAA and MWNT‐PAA, respectively. The heat release was found favourable to promote the desorption as the temperature could rise after adsorption. This is an advantage for energy efficiency, as it depicts the potential of energy recovery. Thus, both adsorbent PAA and MWNT‐PAA were demonstrated to be promising for CO₂ adsorption capture in post‐combustion.     

离子交换树脂吸附苯酚的性能研究

研究了717强碱阴离子交换树脂对苯酚的吸附性能。结果表明,在pH=10~13时,吸附能力最好。等温吸附符合Freundlich和Langmuir经验式。在293~313 K条件下,苯酚吸附量为220~260 mg/g的吸附焓变为-13.69~-12.02 kJ/mol,吸附自由能变为-7.02~-7.21 kJ/mol,吸附熵变为-22.76~-15.37 J/(K.mol)。吸附动力学符合Lagergren准二级速率方程,吸附速率常数为8.5×10-4~2.74×10-3g/(mg.min),吸附活化能为44.1 kJ/mol。303 K下其静态累积饱和吸附容量为399.8 mg/g(4.253 mmol/g)。用0.05 mol/L HCl溶液能定量洗脱苯酚,洗脱率达99%。     

苯甲醛、苯甲酸的紫外光谱特性及含量测定方法研究

研究了苯甲醛、苯甲酸的紫外吸收特性,建立了同时测定两者含量的方法。发现了以无水乙醇为溶剂,苯甲醛、苯甲酸及其混合物在234 nm处的吸收值只与两者总浓度有关,250 nm处的吸收值与苯甲醛浓度成正比。给出了含量的计算公式为:C苯甲醛=9.074×10-5A250(mol/L),C苯甲酸=1.168×10-4A234-9.074×10-5A250(mol/L)。混合物的检出限为0.17×10-5mol/L,苯甲醛的检出限是0.435 6×10-6mol/L。苯甲醛的平均RSD为0.86%,平均加标回收率是100.1%,相对误差值为1.24%;苯甲酸的平均RSD为0.41%,平均加标回收率是100.7%,相对误差值是-0.37%。     

C_9 FK的表面活性测定

用吊片法和自制改进的最大泡压法分别测定了全氟庚氧基全氟亚乙基磺酸钾(C9FK)溶液的平衡和动态表面张力,计算得出该种表面活性剂形成胶束的标准热力学函数△Hmθ、△Smθ、△Gmθ分别为16．98 kJ／mol、218．29 J／mol·K、-48．22 kJ／mol。结合Word-Tordai方程,计算得到在不同条件下的表观扩散系数Da和吸附势垒Ea。实验证明,增大表面活性剂的浓度、降低温度、以及无机盐(NaCl)的加入都会使扩散系数减小,吸附势垒增大,从而不利于吸附的进行。当表面活性剂的浓度小于等于1×10-6 mol/L时,该体系属于扩散控制模型,而浓度大于 1×10-6 mol/L时,在吸附初期(t→O)属于扩散控制,后期均属于混合控制模型。     

Electrochemical determination of Pb<Superscript>2+</Superscript> using a carbon nanotube/Nafion composite film-modified electrode

A carbon nanotube/Nafion composite film modified electrode is described for the sensitive and convenient determination of Pb²⁺. In the presence of 1% Nafion, multi-walled carbon nanotubes (MWNT) were successfully dispersed into ethanol by ultrasonication. After evaporating the ethanol, a MWNT/Nafion composite film-modified electrode was achieved. The resulting MWNT/Nafion film modified electrode possesses high cation exchange capacity, large surface area, strong adsorption ability and catalytic activity. Compared with the unmodified electrode and Nafion film-modified electrode, the MWNT/Nafion film-modified electrode remarkably increases the stripping peak current of Pb²⁺. Furthermore, the influences of supporting electrolyte, volume of MWNT/Nafion suspension, accumulation potential and accumulation time were investigated. The striping peak current of Pb²⁺ is proportional to its concentration over the range 8.0 × 10⁻⁸ to 6.0 × 10⁻⁶ mol L⁻¹. The limit of detection (S/N = 3) is as low as 5.0 × 10⁻⁹ mol L⁻¹. Finally, this newly developed method was used to determine Pb²⁺ in water samples.     

Separation of Acetic Acid‐Water Mixtures through Poly(Vinyl Alcohol)/Poly(Acrylic Acid) Alloy Membranes by Using Evapomeation and Temperature Difference Evapomeation Methods

Abstract

Separation of acetic acid‐water mixtures by using evapomeation (EV) method were carried out over the full range of compositions at temperatures varying from 30 to 55°C using poly(vinyl alcohol)/poly(acrylic acid) (PVA/PAA) (75/25) (v/v) alloy membranes. PVA/PAA membranes gave separation factors of 110–5711 and permeation rates of 2.3×10^?4–1.53×10^?1 kg/m²h, depending on the operation temperature and feed mixture composition. The temperature dependence of the permeation in EV was expressed by the Arrhenius type expression and the activation energy was calculated as 9.15 kcal/mol. More efficient EV technique, which is called temperature difference evapomeation method (TDEV) was also applied to PVA/PAA membranes to separate acetic acid‐water mixtures; high permeation rates (1.7×10^?3–3.0×10^?1 kg/m²h) and separation factors (1335–8924) were obtained for each of the studied feed compositions. Azeotropic mixture of acetic acid and water was also separated by TDEV method with a separation factor of 297 and permeation rate of 1.50×10^?1 kg/m²h.     

聚亚甲基蓝/碳纳米管修饰电极阳极溶出伏安法测定痕量锡

研究了聚亚甲基蓝/碳纳米管修饰电极通过阳极溶出伏安法测定痕量Sn2+的电分析方法。Sn2+通过与电极表面的亚甲基蓝吩噻嗪环上S和N原子发生螯合作用而富集在电极表面,同时在-1.20 V(vs.SCE)还原成Sn0,当电极电势从-1.20 V向-0.30 V扫描时,被还原的Sn0从电极表面溶出。碳纳米管与亚甲基蓝的协同作用,使得Sn2+在该修饰电极上有良好的响应。Sn2+的溶出峰电流与其浓度在0.2×10-3~0.1 mmol/L浓度范围内呈良好的线性关系,检测限为0.1×10-3mmol/L。     

Improvement of electrical conductivity with phase‐separation in polyolefin/multiwall carbon nanotube/polyethylene oxide composites

Electrical conductivity developments of polypropylene (PP)/multiwall carbon nanotube (MWNT) and polybutene (PB)/MWNT composites were carried out with polyethylene oxide (PEO) phase‐separation behavior for the polymeric materials. The low conductivity (8.47 × 10^?8 S cm^?1) of PP(98%)/MWNT (2%) was drastically increased up to 1.56 × 10^?3 S cm^?1 by only 2% PEO(96%)/MWNT(4%) loading. The drastic improvement originated from the formation of an electrical connector structure with the PEO/MWNT domain. The PB(93%)/MWNT(7%) conductivity was also improved by the PEO(92%)/MWNT(8%) loading although the conductivity improvement effect was lower than that of the PP/MWNT. The Raman spectra showed that the MWNT dispersity in the PB was poorer than that in the PP, resulting in the formation of a PEO/MWNT connector structure only at higher loading. In addition, a PEO/carbon black composite was able to produce the connector structure for the PP/MWNT as well as the PEO/MWNT. These results indicated that the highly conductive composites could be produced with smaller MWNT amounts. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Characteristics of the Surfactant Properties of Sf—Polyelectrolyte Complexes Based on Carboxymethylchitin

High surface activity of mixed solutions of carboxymethylchitin (CMCT) and tetradecyltrimethylammonium bromide (TAB) is observed in the concentration range in which both components are not surface-active. The synergistic effect of the concentration curve of the surface pressure is due to cooperative (not competitive) adsorption on the interface of TAB and CMCT.     

季铵盐双子表面活性剂的合成和表面活性

以吗啉和溴代烷为原料,合成了两种季铵盐双子表面活性剂(m-6-m,m=10,12),并用IR和1HNMR表征了其结构。测得28℃时,12-6-12和10-6-10的表面张力(γCMC)分别为26.45 mN/m和25.55 mN/m;临界胶束浓度(CMC)分别为1.0 mmol/L和3.1 mmol/L;pC20值分别为3.48和3.03;比表面过剩(Γmax)分别为2.72×10-6mol/m2和2.80×10-6mol/m2;分子最小截面积(Amin)分别为0.611 nm2和0.593 nm2。结果表明,该季铵盐双子表面活性剂与相同离子头基及烷基链的单季铵盐表面活性剂相比,CMC低一个数量级,γCMC相差不大。