Optimization of the Preparation Method of K–Selective Manganese Oxide for Assessing the Availability of Soil K

Ayumi Matsuda, Yuki Mori, Shin-Ichiro Wada
2016 Journal of the Faculty of Agriculture Kyushu University  
Heating mixed solutions containing manganese sulfate, ammonium peroxodisulfate and ammonium sulfate at a molar ratio of 1:1:5 at 150°C gave NH 4 -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 NH 4cryptomelane was detected. Column washing with 6 mol/L nitric acid was found to be suitable for exchanging NH 4 + with H + . The H-exchanged cryptomelanes were highly selective for K and the
more » ... 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.
doi:10.5109/1564102 fatcat:jo72onkot5bmvd7cdwnhyvtice