Optimization of the preparation method of K-selective manganese oxide for assessing the availability of soil K

Ayumi Matsuda, Yuki Mori, Shin Ichiro Wada

Research output: Contribution to journalArticle


Heating mixed solutions containing manganese sulfate, ammonium peroxodisulfate and ammonium sulfate at a molar ratio of 1:1:5 at 150°C gave NH4-cryptomelane. The higher the starting manganese concentration, the higher the purity of the products. At a concentration of 0.5 mol/L any products other than NH4-cryptomelane was detected. Column washing with 6 mol/L nitric acid was found to be suitable for exchanging NH4 + with H+. The H-exchanged cryptomelanes were highly selective for K and the K adsorption capacity increased as the volume of nitric acid used for washing increased. The maximum adsorption capacity achieved in this study was about 800 mmol/kg.

Original languageEnglish
Pages (from-to)189-193
Number of pages5
JournalJournal of the Faculty of Agriculture, Kyushu University
Issue number1
Publication statusPublished - Feb 1 2016


All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Agronomy and Crop Science

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