Abiotic Sorption: How Minerals Interact With Ions and Molecules
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Abiotic Sorption: How Minerals Interact With Ions and Molecules
- 2. Introduction
- 7. Depend on: Surface area & amount of sorption “sites” Relative attraction of sorptive to sorbents Mineral surfaces can have: Permanent structural charge Variable charge
- 8. Minerals which are precipitated can also interact with other molecules and ions at the surface Attraction between a particular mineral surface and an ion or molecule due to: Electrostatic interaction (unlike charges attract) Hydrophobic/hydrophilic interactions Specific bonding reactions at the surface
- 9. OH OH OH2 H+ OH OH OH OH H+ Mineral surface has exposed ions that have an unsatisfied bond in water, they bond to H2O, many of which rearrange and shed a H+ ≡S- + H2O ≡S—H2O ≡S-OH + H+
- 11. Sorption processes in soil
- 12. Sorptives and Sorbents in Soils
- 16. 2-Sorptive and Sorbent Charge
- 19. 3-Solution pH
- 20. 4-Sorptive size
- 21. General overview of sorption processes occurring in soil sorbate sorptive sorbent
- 23. Plant growth and development largely depend on the combination and concentration of mineral nutrients available in the soil as a result of sorption. Plants often face significant challenges in obtaining an adequate supply of these nutrients to meet the demands of basic cellular processes due to their relative immobility.
- 24. For instance, adding fertilizer to a soil will increase the solution potassium (K+) concentration and subsequently increase the amount of K sorbed by the solid phase. Conversely, as growing plants uptake K+ from the soil solution, this will drive desorption of the sorbate K+ from the soil. In this way, the soil serves as a nutrient reserve for plants and soil organisms.
- 27. Mining, manufacturing, and the use of synthetic products (e.g. pesticides, paints, batteries, industrial waste, and land application of industrial or domestic sludge) can result in heavy metal contamination of urban and agricultural soils. Heavy metals also occur naturally, but rarely at toxic levels.
- 28. Excess heavy metal accumulation in soils is toxic to humans and other animals. Exposure to heavy metals is normally chronic due to food chain transfer. Acute poisoning from heavy metals is rare through ingestion or dermal contact, but is possible. Chronic problems associated with long-term heavy metal exposures are:
Notas do Editor
- These 2 words are deifineseparatly as
- Diffuse Layer: The region of ion adsorption near a sorbent surface that is subject to diffusion with the bulk solution. Diffuse layer ions are not immediately adjacent the surface, but rather are distributed between the inner, Stern layer ions and the bulk solution by balance of electrostatic attraction to the sorbent and diffusion away form the sorbent.Stern Layer: The layer of ions adsorbed immediately adjacent to a charged sorbent surface. Ions in the Stern layer can be directly bonded to the sorbent through covalent and ionic bonds (inner-sphere complexes) or held adjacent to a sorbent through strictly electrostatic forces in outer-sphere complexes.
- terms like ‘‘sorptive,’’ ‘‘sorbate,’’ and ‘‘sorbent’’ are used to refer, in the order, to the free solute in solution, solute which undergo sorption by solid material ~soil, sediment, etc.!, and the sorbing phase.
- For instance, adding fertilizer to a soil will increase the solution potassium (K+) concentration and subsequently increase the amount of K sorbed by the solid phase. Conversely, as growing plants uptake K+ from the soil solution, this will drive desorption of the sorbate K+ from the soil. In this way, the soil serves as a nutrient reserve for plants and soil organisms.
- Recycling in natural systems is one of the many ecosystem services that sustain and contribute to the well-being of human societies. Ecosystems employ biodiversity in the food webs that recycle natural materials, such as mineral nutrients, which includes water, Nitrogen, Carbon, Sulfur, Phosphorous, Oxygen.
- Soil stores, moderates the release of, and cycles nutrients, pesticides, herbicides and elements. During these biogeochemical processes, analogous to the water cycle, nutrients can be transformed into plant available forms, held in the soil by sorption, or even lost to air or water.
- Mining, manufacturing, and the use of synthetic products (e.g. pesticides, paints, batteries, industrial waste, and land application of industrial or domestic sludge) can result in heavy metal contamination of urban and agricultural soils. Heavy metals also occur naturally, but rarely at toxic levels.