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Rapid Estimation of Cation‐Exchange Capacities of Soils and Clays with Methylene Blue Exchange
Author(s) -
Wang M. K.,
Wang S. L.,
Wang W. M.
Publication year - 1996
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1996.03615995006000010022x
Subject(s) - cation exchange capacity , titration , chemistry , soil water , clay minerals , ion exchange , methylene blue , environmental chemistry , analytical chemistry (journal) , mineralogy , inorganic chemistry , soil science , geology , organic chemistry , ion , photocatalysis , catalysis
Abstract Four methods to determine the cation‐exchange capacities (CEC) of soils and clays were evaluated: (i) conventional NH 4 ‐Na exchange, (ii) methylene blue (MB) capacity with MB acid, (iii) CEC of tetrasodium pyrophosphate (TSPP), and (iv) MB‐water filter paper spot test titration methods. Eighteen surface soils (0–15 cm) from farm fields in Taiwan and four reference clays obtained from the Source Clay Repository (Clay Minerals Society, Columbia, MO) were used in this work. Under appropriate conditions of concentration, equilibration period, and flocculation of MB solutions, MB absorption can be used to determine the CEC of soils and clays. Regression analyses gave R 2 values 0.91, 0.99, and 0.74 for MB‐acid, MB‐TSPP, and MB‐water titration methods, respectively, vs. NH 4 ‐Na exchange. The CEC values of MB‐TSPP titration showed a good linear correlation with values from the NH 4 ‐Na exchange method. Thus, the method of MB‐TSPP filer paper spot‐test titration is recommended for rapid CEC determination in field test of soils.