The zeta potential of the particles is the electric potential at the boundary of the double layer on the particle surface. Zeta potentialpart 17cbse grade 12 chemistryunit 5. An electrical field is applied to the electrodes, and particles or molecules that have a net charge, or more strictly a net zeta potential will migrate towards the oppositely charged electrode with a velocity, known as the mobility, that is related to their zeta. In the colloidal chemistry literature, it is usually denoted using the greek letter zeta.
This equation strictly only applies for isolated particles of zeta potential less than around 25 mv. A schematic representation of zeta potential definition and b of the. Dependence on cation concentration, buffer and cation type, ph, cation valency, and temperature are discussed. The square of the zeta potential is proportional to the force of electrostatic repulsion between two charged particles. In each method, an average of two separate measurements was reported.
Zetasizer chapter 16 zeta potential theory c h a p t e r. This plane is the interface which separates mobile fluid from fluid that remains attached to the surface. When an electric field is applied across an electrolyte, charged particles suspended in the electrolyte are attracted towards the electrode of opposite charge. Its a measure of the electrical charge of particles are that are suspended in liquid. There may be a point where the plot passes through zero zeta potential. A colloidal system consists of a dispersed phase that is distributed uniformly in a continuous phase. Zeta potential determines if particles in liquid will stick. We at nanocomposix have published this document for public use in order to educate and encourage best practices within the nanomaterials community. Zeta potential corresponds to the energy required to detach the particle and its inner layer of counterions from the bulk.
Dvlo theory suggests that the stability of a colloidal system is determined by the sum. Document type document id version status page sop eunclpcc002 1. The zeta potential of the sample will determine whether the particles within a liquid will tend to flocculate stick together or not. Zeta potential theory zeta potential theory c h a p t e r 1 6 introduction the aim of this chapter is to describe the basic zeta potential measurement principles behind the zetasizer nano. Zeta potential analysis of nanoparticles 1 zeta potential analysis of nanoparticles january 2020, v 1. Under the influence of an electric field, charged particles will exhibit certain electrokinetic effects including electrophoresis, electroosmosis, streaming potential, or sedimentation potential. The fundamental physical principle is that of electrophoresis.
The acidity of the solution was altered using various bases. In aqueous media, the ph of the sample is one of the most important factors that affects its zeta potential. Viscous forces acting on the particles tend to oppose. However, the zeta potential of calcite is still poorly known because of the difficulty to interpret streaming potential experiments. Measuring surface zeta potential using the surface zeta potential cell. Simplifying the measurement of zeta potential using m3pals, technical note available from.
In order to discuss zeta potential in some detail, it is imperative to begin by defining the particles and systems to which zeta potential pertains. The electrostatic potential on that surface is called the zeta potential and it is that potential which is measured, when one measures the velocity of the particles in a d. Highconcentration zeta potential measurements using light. The earliest theory for calculating zeta potential from experimental data was developed by marian smoluchowski in 1903 figure \\pageindex2\. This paper summarizes theory, experimental techniques, and the reported data pertaining to the zeta potential of silica and silicon with attention to use as microfluidic substrate materials, particularly for microchip chemical separations. Zeta potential analysis of lithium ion battery electrolytes. Ep11 electric double layer edl and dlvo forces nano 202 ucsd.
Zeta potential in oilwatercarbonate systems and its impact on oil recovery during controlled salinity waterflooding. Figure 1 shows a diagram and photo of the surface zeta potential measurement cell with a height adjustable sample holder. Cont zeta potential or electrokinetic potential is defined as the difference in the potential between shear plane and electroneutral region of the solution. The reader should not assume that the content of this is complete. From a theoretical viewpoint, zeta potential is the electric potential in the interfacial double layer of a dispersed particle or droplet versus a point in the continuous phase away from the interface. There are several theories that link electrophoretic mobility with zeta potential. Particles with a positive zeta potential will bind to negatively charged surface and vice versa. A part 2 will survey the methods and techniques available to determine it and a part 3 will provide a glimpse at its practical, commercial significance. The adjustment of this parameter makes it possible to control stability of colloidal ceramic suspensions. Chapter 14 molecular weight theory introduction 141 what is static light scattering. Zeta potential of clay minerals and quartz contaminated by. The goal of this article is to provide a general overview of the basic concept of what is termed the zeta potential. Zetasizer nano page 111 11 size theory introduction the aim of this chapter is to describe the basic size principles behind the zetasizer nano series.
Zeta potential and colloid chemistry particle technology labs. In this theory, two forces are considered to impact on colloidal stability. The helmholtzsmoluchowski hs equation is widely used to estimate the apparent zeta potential from these experiments. The potential that exists at this boundary is known as the zeta potential. Zeta potential is a scientific term for electrokinetic potential in colloidal dispersions. Its measurement brings detailed insight into the causes of dispersion, aggregation or flocculation, and can be applied to improve the formulation of dispersions. Dlvo theory is a theory of colloidal dispersion stability in which zeta potential is used to explain that as two particles approach one another their ionic atmospheres begin to overlap and a repulsion force is developed. Zeta potential in oilwatercarbonate systems and its. Since zeta potential is not equal to the electric surface potential in a double layer or to the stern potential, it is often the only value that can be used to describe doublelayer properties of. Among these are the dissociation of ionogenic groups in the particle surface and the differential adsorption of solution ions into the surface region. It looks at the balance between two opposing forces elec. Influence of surface conductivity on the apparent zeta. Guide to choosing a zeta potential analyzer before you purchase a zeta potential analyzer, read our helpful guide to ensure youre selecting the right instrument for your testing needs.
For synthesis nanoparticles using different methods, zeta values were measured and found to be. Original research significance of zeta potential in the. The behavior of zeta potential of silica suspensions. Zeta potential analyses is a technique for determining the dispersion stability of nps in solution fig. This potential, which is measured in millivolts, may arise by any of several mechanisms. Zeta potential is more important than nernst potential because the electrical double layer also.
According to the dlvo theories, the aggregation of sludge flocs is primarily governed by the negative surface charge. Electrostatic repulsion between particles depends on the valze of zeta potential. The parameter that is used to describe this real, measurable potential is the zeta potential. The zeta potential of the fulvic acid 50 mgl solution as a function of solution ph is shown in fig. Study of morphology and zeta potential analyzer for the. Dlvo theory the larger the zeta potential absolute valueis, more stable the suspension can be. Theory of the zeta potential electrokinetic phenomena are responsible for several electrical properties of fluidsaturated porous materials. Electrokinetic effects and underlying theories by which electrophoretic mobility is used to calculate zeta potential are detailed. Electrophoretic light scattering els is a technique used to measure the electrophoretic mobility of particles in dispersion, or molecules in solution. Table 2 is summarizing the zeta potential measurements of samples in a solution form. It plays an important role in the theory of aggregation stability dlvo theory. Zeta potential values provide an indirect measurement of the net charge on the nanoparticle. This chapter describes a method for the measurement of the electrostatic potential at the.
Measurements made using techniques based upon each effect should give the same value for zp. However, owing to a variety of factors, this is not necessarily the case. Zeta potential describes the electrokinetic potential in colloidal dispersions and is the potential difference between the dispersion medium and the stationary fluid attached to a dispersed particle. The magnitude of the zeta potential is predictive of the colloidal stability of the solution table 3. According to this theory the electrokinetic or zetapotential is a measurable pro perty of an electrized interface. However, this equation neglects the influence of surface conductivity on streaming potential. Malvern instruments limited printed in england mrk049902 enigma business park grovewood road, malvern worcs, wr14 1xz, u. Zeta potential is measured in liquidliquid or solidliquid colloidal systems. Zeta potential is the charge that develops at the interface between a solid surface and its liquid medium. Theory on particle size measurement and zeta potential. Understanding zeta potential in suspension youtube.
This will help in understanding the meaning of the results achieved. A zeta potential was used to determine the surface potential of the silver nanoparticles. This guide covers quantitative and qualitative factors that must be considered including. Zeta potential is the electrical potential at the slipping plane. To show that the zeta potential depends not only on the ph of the solution, but also on the charge of 82 anielak a. Theory, experimental techniques, and effects on separations this paper summarizes theory, experimental techniques, and the reported data pertaining to the zeta potential of silica and silicon with attention to use as microfluidic substrate materials, particularly for microchip chemical separations. Review 1 zeta potential of microfluidic substrates. Zeta potential measurement is a technique for determining the surface charge of nanoparticles in a colloidal solution.
The zeta potential is an important parameter for a number of applications including characterization of biomedical polymers 1,2, electrokinetic transport of. Zeta potential is a measure of the magnitude of the electrostatic or charge repulsionattraction between particles and is one of the fundamental parameters known to affect stability. The dlvo theory named after derjaguin, landau, verwey and overbeek is the classical explanation of the stability of colloids in suspension. Based on dvlo theory, developed by derjaguin, verwey, landau, and overbeek. Zeta potential is the characterization of the electrokinetic potential of liquidliquid or solidliquid colloidal dispersions. Zeta potential is the effectiveness of the surface charge in solution depends upon. Zetasizer nano series user manual new york university. The hydrolyzable metal ions produce two points of zero charge pzcs, one of which is that of the soil. In its original version, however, the dlvo theory includes the additional step to calculate aggregation rates. Zeta potential is a physical property which is exhibited by any particle in. A dispersion is introduced into a cell containing two electrodes. In prior literature, it is usually denoted using the greek letter zeta. Zeta potential analyzers, classification and areas of applicability. Fundamental surface sites how many, what type solution conditions temperature, ph, electrolyte concentration useless to quote a zeta potential value without specifying suspension conditions.
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