Some of them, such as HFO and HAO, are precipitated in highly porous poorly crystalline or amorphous forms and therefore are good adsorbents used for example in water treatment.[5]
Some others are gels.
Hydrous oxide films may be used an various applications such as electrocatalysis, supercapacitors, and sensors.[6][7]
HFO and HAO may also result from oxidative weathering of rocks to produce iron an aluminum hydrous oxide clay soils.[8]
^Weiser, H. B. (1923). "Hydrous Oxides. V". The Journal of Physical Chemistry. 27 (6): 501–532. doi:10.1021/j150231a001.
^Heitner-Wirguin, C.; Albu-Yaron, A. (1966). "Hydrous oxides and their cation exchange properties—II Structure and equilibrium experiments". Journal of Inorganic and Nuclear Chemistry. 28 (10): 2379–2384. doi:10.1016/0022-1902(66)80129-X.
^Karthikeyan, K.G; Elliott, Herschel A. (1999). "Surface Complexation Modeling of Copper Sorption by Hydrous Oxides of Iron and Aluminum". Journal of Colloid and Interface Science. 220 (1): 88–95. Bibcode:1999JCIS..220...88K. doi:10.1006/jcis.1999.6507. PMID10550244.