Acoustic - Electroacoustic Spectrometer (AES) for colloids characterization

所要求的声-电声光谱仪（AES）是一种主要用于确定悬浮液和乳剂中颗粒和液滴的大小和电荷的仪器。在确定悬浮液和乳剂的稳定性时，电荷和尺寸是重要的。有几种方法可以测量胶体的大小和电荷，其中大多数是利用粒子和液滴与光的相互作用（光散射）。然而，当悬浮液颜色较深或浑浊时（如沥青乳液和浓缩颗粒悬浮液），这些技术就不适用了。在这些情况下，电声光谱是最好的选择，因为它利用不同频率声波的衰减来确定粒子的大小和电荷。该方法的另一个优点是，它适用于相对浓缩的悬浮液（体积分数从0.1到40%），这意味着不需要稀释样品。其他方法，在多伦多大学和其他大学的一些实验室中很常见，需要将样品在水或其他合适的溶剂中稀释。必要的取样和稀释方法会干扰悬浮液或乳液本身的稳定性，从而在测量中产生系统误差。申请人很清楚这些局限性，因为在以前的沥青乳液稳定性、粘土和富含粘土的材料的稳定性、矿物悬浮物的稳定性、纸浆和造纸工业中使用的硫酸盐化学回收循环中携带的颗粒的稳定性的研究中已经清楚地表明了这一点。掌握适当的方法来确定胶体的大小和电荷，将有助于申请人和其他同事改进通常用于矿物开采行业的沉淀池中颗粒不稳定的方法，改进原油加工中油颗粒-水分离的方法，提高化学回收循环的效率，以及为环境和能源相关应用设计纳米颗粒。了解和改进面霜和其他外用产品的配方，以及乳化食品和从种子和其他生物质中提取油的水萃取。

The requested acoustic-electroacoustic spectrometer (AES) is an instrument that will be primarily utilized in determining the size and charge of particles and drops in suspensions and emulsions. Charge and size are important at the time of determining the estability of suspensions and emulsions. There are several methods to measure size and charge of colloids, most of them use the interaction of particles and drops with light (light scattering). However, these techniques are not suitable when the suspension is dark or turbit (as in the case of bitumen emulsions and concentrated suspensions of particles). In those cases, electroacoustic spectroscopy is the best option as it uses the attenuation of sound waves at different frequencies to determine the size and charge of particles. An additional advantage of this method is that it works best with relatively concentrated suspensions (volume fractions from 0.1 to 40%), which means that it is not necessary to dilute the sample. Other methods, common in a number of laboratories at the University of Toronto and other Universities, require the sample to be diluted in water or other suitable solvent. The necessary sampling and dilution methods interfere with the stability of the suspension or emulsion itself, thus creating systematic errors in the measurement. The applicants are well aware of these limitations as it has become clear in previous studies of bitumen emulsion stability, stability of clays and clay-rich material, stability of mineral suspensions, stability of particles carried over in kraft chemical recovery cycles used in the pulp and paper industry. Having access to a proper methodolgy of determining the size and charge of colloids will help the applicants and other colleagues improve methods of particle destabilization in settling ponds commonly used in the mineral extraction industry, improve methods of oil-particle-water separation in the processing of crude oils, improve the efficiency of chemical recovery cycles, and the design of nanoparticles for environmental and energy-related applications, understand and improve the formulation of creams and other topical products as well as emulsion-based food products and aqueous extraction of oils from seeds and other biomass.