10 Questions
The consequence of the reactions that takes place between the surface functional groups on soil organic matter (humus) and/or on broken (exposed) crystal edges of layer silicates with the ions in the soil solution. The forms of reactions and the ions so released (ionized) from the surface functional groups that is mainly a characteristic of soil organic matter (humus fraction) and from the broken edges of both silica and alumina sheets of silicate minerals differ depending on the soil environment, mainly soil pH. 6 i. Broken edges of the layer silicates: Predominantly in 1:1 (kaolinite) minerals (50% or more of the total charge) and very little (5-10% of the charge) in 2:1 clays. The quantity of this type of charge depends on the pH of the soil, thus called pH dependent charge. Under acid (low pH) soil condition, the broken edge is positively charged because of the excess H+ associated with it. As pH increases, H+ ions are neutralized (H+ + OH- = H2O) and the negative charge on the edge increases. Ionization of Surface….Cont’d ii. Dissociation of H+ from surface functional groups: Such as from carboxylic acid (-COOH = COO- + H+) and phenolic (- C 6H4OH ═ -C6H4O- + H+) groups. This source as with the broken edges is a pH-dependent charge, and is associated with the complex organic molecules associated with humus or soil organic matter.
Groups
The broken edge is positively charged because of the excess H+ associated with it. As pH increases, H+ ions are neutralized (H+ + OH- = H2O) and the negative charge on the edge increases. Ionization of Surface….Cont’d ii. Dissociation of H+ from surface functional groups: Such as from carboxylic acid (-COOH = COO- + H+) and phenolic (- C 6H4OH ═ -C6H4O- + H+) groups. This source as with the broken edges is a pH-dependent charge, and is associated with the complex organic molecules associated with humus or soil organic matter.
Edge
This source as with the broken edges is a pH-dependent charge, and is associated with the complex organic molecules associated with humus or soil organic matter.
Charge
The quantity of this type of charge depends on the pH of the soil, thus called pH dependent charge. Under acid (low pH) soil condition, the broken edge is positively charged because of the excess H+ associated with it.
Dependent
As pH increases, H+ ions are neutralized (H+ + OH- = H2O) and the negative charge on the edge increases. Ionization of Surface….Cont’d ii. Dissociation of H+ from surface functional groups: Such as from carboxylic acid (-COOH = COO- + H+) and phenolic (- C 6H4OH ═ -C6H4O- + H+) groups.
Increases
Explain the process of ion exchange and its applications in water treatment and chemical purification.
Ion exchange is a reversible interchange of ions in an insoluble solid with ions in a surrounding solution. It is used for softening or demineralizing water, purifying chemicals, and separating substances. The process involves solid polymeric ion-exchange resins and encompasses various processes of exchanging ions between two electrolytes. It is widely applied for purification and separation of industrially and medicinally important chemicals.
What are the typical materials used as ion exchangers?
Typical ion exchangers include ion-exchange resins (functionalized porous or gel polymer), zeolites, montmorillonite, clay, and soil humus.
Differentiate between cation exchangers and anion exchangers.
Cation exchangers exchange positively charged ions (cations), while anion exchangers exchange negatively charged ions (anions).
What are amphoteric exchangers capable of, and how are they commonly used?
Amphoteric exchangers can exchange both cations and anions simultaneously. This simultaneous exchange is often performed in mixed beds containing a mixture of anion- and cation-exchange resins, or by passing the solution through several different ion-exchange materials.
What is the significance of ion exchange in the context of soil and its environment?
Ion exchange plays a significant role in soil in terms of the charge on broken crystal edges of layer silicates and the release of ions from surface functional groups. The type and quantity of charge depend on the soil pH, and the process is associated with complex organic molecules present in humus or soil organic matter.
This quiz covers the ionization of surface functional groups, focusing on the reactions between surface functional groups on soil organic matter and exposed crystal edges of layer silicates with ions in the soil solution. It also explores the forms of reactions and ions released, which are characteristic of soil organic matter and broken edges of layer silicates.
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