表面活性剂对水性油墨胶体稳定性的影响

对阳离子、阴离子、两性和非离子表面活性剂对水性油墨胶体稳定性的影响进行了探讨。结果表明:(1)在水性油墨胶体溶液中加入十六烷基三甲基溴化铵(CTAB)浓度为0.14 mmol/L时,Zeta电位由初始的-37.9 mV变为12.7 mV;当CTAB浓度为0.86 mmol/L时,Zeta电位上升到34.1 mV。pH对CTAB的作用效果有较大影响,当CTAB浓度为0.5 mmol/L时,将体系pH从初始值3.3调节至11.7,Zeta电位相应地从38.6 mV降至23.7 mV,炭黑粒子的平均粒径最大增加值达13 nm。(2)加入十二烷基磺酸钠(SDS)的浓度为1 mmol/L时,Zeta电位达到-38.2 mV,而炭黑粒子的平均粒径下降了2 nm。(3)加入椰油酰胺丙基氧化胺(CAPO)的浓度为0.01 mol/L时,Zeta电位在体系pH约为6.0时达到等电点;体系pH为3.2时,Zeta电位达到最大值28.5 mV,炭黑粒子平均粒径最大增加幅度为9 nm。(4)加入脂肪醇聚氧乙烯(7)醚(AEO-7)的浓度为0.1 mol/L时,体系Zeta电位从-37.9 mV变为-16.3 mV,炭黑粒子平均粒径从初始的154 nm增至240 nm。加入AEO-9得到与AEO-7相同的影响趋势。     

环境因素对纳米银体系稳定性的影响

为了提高纳米银抗菌剂在储存和运输过程中的稳定性,延长产品有效期,以苯扎溴铵为保护剂、硼氢化钠为还原剂制备了纳米银溶液,分别在不同温度、紫外光照和初始pH条件下储存不同时间,以UV-Vis光谱和动态光散射法考察了纳米银溶液粒径和Zeta电位的变化情况.结果表明,随着储存温度的升高,纳米银胶团更容易发生团聚,导致溶液稳定性降低;纳米银溶液经紫外光辐照后,会出现粒径增加,Zeta电位绝对值降低的现象;提高纳米银溶液初始pH不利于胶体体系的稳定性,而降低初始pH有助于提高胶体体系稳定性.因此,可采取降低环境温度、避光和酸化等措施来提高纳米银溶液在储存过程中的稳定性.     

环境因素对纳米银体系稳定性的影响

为了提高纳米银抗菌剂在储存和运输过程中的稳定性,延长产品有效期,以通过苯扎溴铵为保护剂、硼氢化钠为还原剂制备的纳米银溶液为对象,分别在不同温度、紫外光照和初始pH条件下储存不同时间,期间以紫外-可见光谱和动态光散射法研究纳米银溶液粒径和Zeta电位的变化情况。结果表明,随着存储温度的升高,纳米银胶团更容易发生团聚,导致溶液稳定性降低;纳米银溶液经受紫外光辐照后,会出现粒径增加但Zeta电位绝对值降低的现象;提高纳米银溶液初始pH不利于胶体体系的稳定性,而降低初始pH有助于提高胶体体系稳定性。总之,为了提高纳米银溶液在存放过程中的稳定性,可以采取降低环境温度、避光和酸化等措施。本研究所得结果可作为纳米银溶液生产、运输和储存时选择合理工艺参数和材料的依据。     

乳化油废水稳定性研究

研究了不同条件(静置时间、温度、pH值、添加电解质、表面活性剂)下模拟乳化油废水Zeta电位和粒径的变化规律,探讨了影响乳化油废水稳定性的因素.实验结果及分析表明,适当的静置、低温、弱酸性条件以及加入电解质均可降低乳化油废水的稳定性,加入表面活性剂则会增加乳化油废水的稳定性,实验选用的四种表面活性剂中阴离子表面活性剂比阳离子表面活性剂对乳化油的稳定效果更好.     

酸量和温度对拟薄水铝石胶溶过程的影响

利用Zetasizer Nano ZS电位-粒度仪和Turbiscan红外分散稳定仪等实验仪器考察了拟薄水铝石酸胶溶过程中溶胶的Zeta电位、电导率、胶粒粒径的变化规律以及胶溶温度变化对胶溶过程的影响。结果表明,拟薄水铝石胶体溶液Zeta电位大于30 mV,得到稳定的拟薄水铝石胶体;最佳酸铝比在0.15～0.25时,拟薄水铝石溶胶粒径约70 nm;提高胶溶温度有利于胶溶反应的进行。     

聚醋酸乙烯酯乳液电荷稳定性研究

通过研究乳液聚合条件对聚醋酸乙烯酯（PVAc）乳胶粒子大小、粒径分布以及乳液Zeta电位的影响,得出：在强酸性条件下,不易制得稳定PVAc乳液;在弱酸性条件下制得乳液的乳胶粒子粒径较小,粒径分布较宽,且存在两种电性相反电荷;在中性条件下所制得的乳胶粒径较大,分布较窄,存在两种Zeta电位;在碱性条件下制得的乳胶粒径最大,分布最窄,且只存在一种Zeta电位。     

电渗析装置调控胶体粒径的试验研究

为探究电渗析装置对胶体的粒径调控效果，以分子胶体牛血清白蛋白(BSA)和粒子胶体九水偏硅酸钠(Na₂SiO₃·9H₂O)为研究对象，结合电渗析过程中电压、电导率、pH值及Zeta电位等参数的变化分析胶体粒径变化的原因，探究了电渗析作为胶体粒径调控装置的可行性，并通过调整电流密度确定其调控范围，以达到精准调控的目的。结果显示，在200 A/m²电流密度下电渗析对2种胶体的粒径调控范围最广，能将分子胶体BSA从370.51nm调控到33 380 nm，将粒子胶体Na₂SiO₃·9H₂O从660.72 nm调控到41 920.5 nm；当电流密度为50 A/m²时，粒径调控范围发生变化，BSA从239.82 nm到8 050 nm,Na₂SiO₃·9H₂O从317.4 nm到21 363.5 nm。故通过调整电流密度能改变粒径调控范围，通过把控试验结束时...     

固体纳米脂质微粒的制备及性能表征

采用EIP(相转变体积)转相法,以单甘酯为脂质原料,复配硬脂醇醚-25,制备了固体纳米脂质微粒(SLN)及其悬浮液,通过对乳化温度及固体纳米脂质微粒组成的研究,优化了制备条件,表征了固体纳米脂质微粒的形貌特征、粒径及Zeta电位分布,同时又研究了其离心、储存及稀释稳定性.结果表明,在乳化温度为60℃,脂质原料与乳化剂的质量比为1:1条件下制得的固体纳米脂质微粒平均粒径为169nm,粒子呈圆形,分布均一,Zeta电位为-6.18 mV,且具备良好的离心、储存及稀释稳定性.     

纳米氧化锌在水介质中的分散性能研究

纳米粉体的分散性能对提高分散体系的导热性能具有重要意义,试验选用纳米粒子在水介质中的Zeta电位和水合粒径来表征体系的分散稳定性,探讨不同分散剂种类及其浓度以及不同pH条件对ZnO水悬浮液稳定性的影响,并分析其作用机理.结果表明:Zeta电位与水合粒径有良好的对应关系,Zeta电位绝对值越高,水合粒径越小,表明体系分散稳定越好.pH值、分散剂种类及加入量是影响纳米ZnO水相体系分散稳定性的主要因素,不同的分散剂最佳分散条件不同.在 0.1% ZnO-H2O纳米流体中,在 pH=11.4,加入 0.05%十二烷基苯磺酸钠(SDBS)分散剂,悬浮液的稳定性最佳.     

空气纳米气泡的稳定性及理化特性

空气纳米气泡（Air-NBs）的理化特性是其广泛应用的基础。本文利用纳米粒度-zeta电位分析仪研究了水力空化原理产生的Air-NBs的理化特性,即粒径分布和zeta电位,考察了装置运行压力、电解质浓度、pH和温度对Air-NBs理化特性的影响;同时考察了去离子水和CaCl₂溶液中Air-NBs稳定性。结果表明：纳米气泡发生器的压力越大,其产生的Air-NBs的小粒径比例更大,且电解质的加入有助于气泡粒径的缩小。随着溶液中电解质浓度、pH和温度的升高,溶液中Air-NBs的平均粒径逐渐减小,但气泡间的聚结作用会导致其粒径随时间逐渐增大;通过对两种溶液中Air-NBs粒径的实时监测发现其能在溶液中存在5天之久。胶体稳定（DLVO）理论和zeta电位效应可以合理阐释溶液中Air-NBs的稳定性。     

Threshold flux in fouling of OF membranes by colloidal iron

Fouling of 50 kDa MWCO OF membranes by iron colloid solutions was studied under constant pressure conditions and constant flux conditions at pH 5 and 7 and at various iron concentrations. By using measurements of both deposit density and changes in the transmembrane zeta potential, threshold fluxes were found that were significantly lower than the critical flux based on the increase in membrane resistance. Results are consistent with the initial phase of fouling involving pore blockage followed by cake filtration-like behavior. The dependence of fouling rate on iron colloid concentration can best be understood by realizing that only a small fraction of the iron colloid is of a size that contributes to fouling.     

Effect of Pore Size and Particle Size Distribution on Granular Bed Filtration and Microfiltration

Abstract

The paper reviews the effect of particle size distribution and pore size distribution on granular bed filter and crossflow microfiltration performance. The experimental results of the granular bed filter with pollen particles in suspension showed that the presence of large particles improved the filter efficiency of smaller particles in suspension. Microfiltration results with bi and tri‐modal latex suspensions showed that the permeate flux and the quality were significantly affected by the particle size and its distribution, especially when the particle size was smaller than the pore size of the membrane. The mathematical model simulation results of granular bed filtration show that media pore size distribution is an important parameter of filtration for the particle removal and pressure drop across the filter.     

高性能粒度调配水泥及其在混凝土中的应用研究

通过设计和调配水泥组分的细度和颗粒分布,制备了一种高性能粒度调配水泥,并测试了该水泥及其配制的混凝土的物理力学性能。试验结果表明:粒度调配水泥的标准稠度用水量与普通球磨水泥相当;在相同熟料含量条件下,粒度调配水泥比对比水泥的抗压强度提高3～4MPa;在混凝土应用中,粒度调配水泥和普通球磨水泥相比具有更为明显的性能优势,利用粒度调配水泥配制的C60高强混凝土不但工作性能良好,而且力学性能优异,28d抗压强度达到了96.1MPa。     

颗粒粒径和膜孔径对陶瓷膜微滤微米级颗粒悬浮液的影响

通过测定颗粒悬浮液通过陶瓷微滤膜时的参透通量及污染阻力,确定了陶瓷膜处理微米级颗粒悬浮液时,颗粒粒径和膜孔径对微滤过程的影响和膜污染机理,获得了微米级颗粒悬浮液微滤过程中膜孔径的选择方法。     

Particle separation performance by use of electrical hydro-cyclone

A special electrical hydro-cyclone is developed and tested. In the underflow collection box of the hydro-cyclone, it has a central metal rod electrode and a cylindrical metal wall between which the desired DC electrical potential or no potential is applied. Effect of central rod diameter and length on separation cut size was examined. The aqueous suspensions of silica particles with a median diameter of 754 nm were tested using a 20 mm-diameter hydro-cyclone without underflow.

It was found that the zeta potential of particles increased proportionally with the value of pH. The electrical potential exhibits a stronger effect when the suspension indicates high pH value. The cut size decreases with the increase of initial pH values. This result is due to the increased negative zeta potential under high pH condition and negatively charged particles are easily collected by electrostatic force.

The cut size decreases with the increase of electrode diameter. The cut size becomes smallest under high pH, large electrode diameter and long electrode length conditions. For the negatively charged particles, the center electrode should be negative polarity and outer cylindrical wall should be positive. By use of the electrostatic force, the cut size decreases about 9.2% smaller compared to the standard case without electrostatic force.     

前驱物裂解法低温制备碳化硅陶瓷膜

将碳化硅(SiC)粉体和一定量聚碳硅烷(polycarbosilane,PCS)、蒸馏水、聚丙烯酰胺(polyacrylamide,PAM)、聚丙烯酸(polypropylene acid,PAA)混合球磨以制备水性SiC浆料并测定了SiC粒子的动电位及粘度;将浆料均匀涂在SiC支撑体上,在1100℃真空条件下烧成,制备了SiC陶瓷膜并测定陶瓷膜的孔径分布及纯水通量及观察其形貌.研究结果表明:涂膜所用的浆料在pH值为11左右时,SiC粒子动电位最大达到-40 mV,浆料表观粘度最小为20 mPa·s,制备的陶瓷膜孔径大小集中在1μm左右,纯水通量达40 m3/(m2·h).     

Limiting flux in skimmed milk ultrafiltration: impact of electrostatic repulsion due to casein micelles

The variations of the limiting flux during skimmed milk ultrafiltration were studied under various physicochemical environments (pH, ionic strength, chemical nature of added salts). The evolutions were explained taking into account the physicochemical characteristics (size distribution, zeta potential) of the casein micelles, that is the main components of the fouling layer formed at the membrane surface. It was shown than in the pH range from 5.6 to 6.7, the limiting flux was linearly related to the zeta potential of the casein micelles regardless of the way used to obtain the zeta potential variation (addition of HCl, CaCl₂ or NaH₂PO₄): the higher the zeta potential of casein micelles (neutral pH), the greater the limiting flux. Under these operating conditions, the variations of hydrophobic interactions were negligible. The variation of the permeability of the deposit layer, composed of retained casein micelles, was therefore mainly governed by electrostatic interactions due to the casein micelles.     

硫酸钛液稳定性分析及偏钛酸粒度控制研究

测试了硫酸法钛白生产中系列浓度钛液在不同温度下的稳定性;并根据系列稳定性数据调节水解工艺,在水解初期适当延长升温时间,水解后期加入适量的稀碱液。用激光粒度分析仪、扫描电子显微镜测定偏钛酸的粒度分布及粒子形貌。结果显示,调节工艺后得到的偏钛酸粒度分布曲线的半峰宽缩小,整体均匀性较好;扫描电子显微镜照片显示调节工艺对小粒子的产生有明显抑制作用;水解率达到97.0%。