Leaching (chemistry)

For other uses, see Leaching.

Leaching is the process of a solute becoming detached or extracted from its carrier substance by way of a solvent.[1]

Leaching is a naturally occurring process which scientists have adapted for a variety of applications with a variety of methods. Specific extraction methods depend on the soluble characteristics relative to the sorbent material such as concentration, distribution, nature, and size.[1] Leaching can occur naturally seen from plant substances (inorganic and organic),[2][3] solute leaching in soil,[4] and in the decomposition of organic materials.[5] Leaching can also be applied affectedly to enhance water quality and contaminant removal,[1][6] as well as for disposal of hazardous waste products such as fly ash,[7] or rare earth elements (REEs).[8] Understanding leaching characteristics is important in preventing or encouraging the leaching process and preparing for it in the case where it is inevitable.[2]

In an ideal leaching equilibrium stage, all the solute is dissolved by the solvent, leaving the carrier of the solute unchanged.[1] The process of leaching however is not always ideal, and can be quite complex to understand and replicate,[6] and often different methodologies will produce different results.[9]

Leaching occurring in a cement wall due to natural weathering events.
  1. ^ a b c d Richardson, J. F.; Harker, J. H.; Backhurst, J. R. (2002), Richardson, J. F.; Harker, J. H.; Backhurst, J. R. (eds.), "CHAPTER 10 - Leaching", Chemical Engineering (Fifth Edition), Chemical Engineering Series, Butterworth-Heinemann, pp. 502–541, doi:10.1016/b978-0-08-049064-9.50021-7, ISBN 9780080490649
  2. ^ a b Tukey, H.B. (1970). "The Leaching of Substances from Plants". Annual Review of Plant Physiology. 21 (1): 305–324. doi:10.1146/annurev.pp.21.060170.001513. ISSN 0066-4294.
  3. ^ Dubus, I.G.; Beulke, S.; Brown, C.D. (2002). "Calibration of pesticide leaching models: critical review and guidance for reporting". Pest Management Science. 58 (8): 745–758. doi:10.1002/ps.526. ISSN 1526-4998. PMID 12192898.
  4. ^ Addiscott, T. M.; Wagenet, R. J. (1985). "Concepts of solute leaching in soils: a review of modelling approaches". Journal of Soil Science. 36 (3): 411–424. doi:10.1111/j.1365-2389.1985.tb00347.x. ISSN 1365-2389.
  5. ^ Bärlocher, Felix (2005), Graça, M.A.S.; Bärlocher, Felix; Gessner, M.O. (eds.), "CHAPTER 5 - Leaching", Methods to Study Litter Decomposition: A Practical Guide, Springer Netherlands, pp. 33–36, doi:10.1007/1-4020-3466-0_5, ISBN 9781402034664
  6. ^ a b Rohwerder, T.; Gehrke, T.; Kinzler, K.; Sand, W. (2003). "Bioleaching review part A: Progress in bioleaching: Fundamentals and mechanisms of bacterial metal sulfide oxidation". Applied Microbiology and Biotechnology. 63 (3): 239–248. doi:10.1007/s00253-003-1448-7. ISSN 1432-0614. PMID 14566432. S2CID 25547087.
  7. ^ Iyer, R. (2002). "The surface chemistry of leaching coal fly ash". Journal of Hazardous Materials. 93 (3): 321–329. doi:10.1016/S0304-3894(02)00049-3. ISSN 0304-3894. PMID 12137992.
  8. ^ Peelman, S.; Sun, Z.H.I.; Sietsma, J.; Yang, Y. (2016), "CHAPTER 21 - Leaching of Rare Earth Elements: Review of Past and Present Technologies", Rare Earths Industry, Elsevier, pp. 319–334, doi:10.1016/b978-0-12-802328-0.00021-8, ISBN 9780128023280, retrieved 2019-10-17
  9. ^ Perket, C.L.; Webster, W.C. (1981). "Literature Review of Batch Laboratory Leaching and Extraction Procedures". In Conway, R.; Malloy, B. (eds.). Hazardous Solid Waste Testing: First Conference. (West Conshohocken, PA: ASTM International 1981): ASTM. pp. 7–7–21. doi:10.1520/stp28826s. ISBN 978-0-8031-0795-3. ISSN 1040-3094 – via in Hazardous Solid Waste Testing: First Conference. {{cite book}}: |journal= ignored (help)CS1 maint: location (link)