Abiotic sorption

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<ul><li> 1. Abiotic Sorption</li></ul> <p> 2. Introduction 3. Abiotic factors 4. What is sorption? 5. Sorption include 6. Depend on: Surface area &amp; amount of sorption sites Relative attraction of sorptive to sorbentsMineral surfaces can have: Permanent structural charge Variable charge 7. 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 8. OHOH OH2H+OHOH OH OHH+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 SH2O S-OH + H+ 9. Sorption processes in soil 10. Sorption processes in soil 11. Sorptives and Sorbents in Soils 12. 2-Sorptive and Sorbent Charge 13. 3-Solution pH 14. 4-Sorptive size 15. General overview of sorption processes occurring in soil sorbatesorptivesorbent 16. 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. 17. 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. 18. 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. 19. 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:</p>