Adsorption of fluoride by soils and minerals

摘要: The adsorption of F by soils and common hydroxyl-containing minerals found in was studied over a solution concentration range 2 to 16 mg./l. It that gibbsite, kaolinite, halloysite, precipitated Al(OH)/sub 3/, all adsorb significant amounts with release OH/sup -/, the is concentration-dependent described Langmuir equation. At an equilibrium mg./kg. as follows: alkaline soils, 59 120; acid Aiken soil, 1060; gibbsite kaolinites, 190 295, dehydrated 1400; hydrated (expanded) 1777; 32,600. Goethite, benonite (montmorillonite) vermiculite adsorbed only traces F. similar expanded together very high capacity suggest at low concentrations occurs primarily exchange OH 3/ rather than crystal lattice clay minerals. If soil having permeability were available, it might be practical remove excess from water for municipal use on system such used ground-water recharge.more » 10 references, 1 table.« less