【Daily Question】Chemical Engineering Principles 535: Resin Working Layer (March 22)
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This post was last edited by Zaihui Kangqiao on 2017-3-22 at 08:30. The Chemical Engineering Theory section is launching a \"One Question per Day\" campaign starting today, aimed at helping everyone reinforce their basic knowledge in chemical engineering. Subsequent campaigns will cover topics such as \"Chemical Engineering Principles,\" \"Mass Transfer and Separation,\" \"Chemical Engineering Thermodynamics,\" and \"Chemical Engineering Processes.\" We hope for your active support~~~ Replies to the \"One Question per Day\" campaign can be viewed directly at **; the thread will be closed after 1 day! ! To encourage everyone’s continued participation this year! You get 3 wealth rewards just for participating, and an additional 4 wealth points for correct answers~~~ Short answer question: What is the working layer of ion exchange resin? Answer: When water flows through the resin layer, due to the limitations imposed by the ion exchange rate, it takes a certain thickness of the layer for the ion concentration in the water to drop to the desired level; this is what happens during this process. Ions in water continuously diffuse into the interior of the resin particles; this layer of resin is commonly referred to as the working layer.
Ion exchange resins are insoluble polymer compounds with a network structure and functional groups (active groups that can exchange ions). They are usually spherical particulate matter.
It refers to the resin layer that is currently in use; once it becomes deactivated, it is regenerated
It is an insoluble polymer compound with functional groups (active groups containing exchangeable ions), possessing a network structure.
As water flows through the resin layer, due to the limitations imposed by the ion exchange rate, it takes a certain thickness of the layer for the ion concentration in the water to drop to the desired level; this is what happens during this process. Ions in water continuously diffuse into the interior of the resin particles; this layer of resin is commonly referred to as the working layer.
As water flows through the resin layer, due to the limitations imposed by the ion exchange rate, it takes a certain thickness of the layer for the ion concentration in the water to drop to the desired level; this is what happens during this process. Ions in water continuously diffuse into the interior of the resin particles; this layer of resin is commonly referred to as the working layer.
As ion exchange proceeds, the ion exchange zone gradually moves downward into the resin layer, resulting in three layers within this resin layer: the resin layer above the exchange zone is saturated with Ca2+ and has lost its exchange capacity; as water passes through this layer, its quality does not change, and this layer is known as the deactivated layer； At the working layer, calcium ion exchange resin and sodium ion exchange resin are present together; there is more calcium ion exchange resin in the upper part and more sodium ion exchange resin in the lower part. As water flows through this layer, Ca2+ and Na+ in the water undergo exchange, resulting in the Ca2+ concentration in the output water dropping from the original concentration to 0. This layer is the area within the entire resin layer where ion exchange takes place, and the height of this area corresponds to the width of the exchange zone.
As water flows through the resin layer, due to the limitations imposed by the ion exchange rate, it takes a certain distance through the layer before the ion energy in the water reaches the desired level; this is what happens during this process. Ions in water continuously diffuse into the interior of the resin particles; this layer of resin is known as the active resin layer.
Inside the container, there is a certain height of resin, which allows ions to pass through the exchange column from top to bottom to facilitate ion exchange; this exchange column is known as the working layer of ion exchange resin.
Ion exchange resins are insoluble polymer compounds with a network structure and functional groups (active groups that can exchange ions). They are usually spherical particulate matter. The full name of an ion exchange resin consists of the classification name, the skeleton (or gene) name, and the basic name. Porous structures are divided into gel-type and macroporous types; those with a physical pore structure are referred to as macroporous resins, with the term “macroporous” added before their full name. Those classified as acidic should have “yang” added before their name, while those classified as basic should have “yin” added before their name. For example: large-pore, strongly acidic styrene-based cation exchange resin. Ion exchange resins can also be classified into styrene-based resins and acrylic-based resins based on the type of their matrix. The type of chemically active groups in the resin determines its main properties and category. First, they are divided into two main categories: cationic resins and anionic resins, which can undergo ion exchange with cations and anions in solutions, respectively. Cationic resins are further divided into strong-acidic and weak-acidic types, while anionic resins are divided into strong-alkaline and weak-alkaline types (or further into medium-strong acidic and medium-strong alkaline types).
As soon as the solution comes into contact with the resin, an ion exchange reaction begins. As the water flows, the composition of the solution and the composition of the resin keep changing. When the water flows to a certain depth, the ion exchange reaction reaches equilibrium, and the ion concentrations in the resin and the solution no longer change. At this point, from the start of the exchange reaction in the upper layer of the resin until equilibrium is reached in the lower layer, an ion exchange reaction zone of a certain height is formed, which is known as the working layer.