Characteristics of Interlayer Materials in Non-Allophanic Volcanic Ash and Red Yellow Soils from Japan

Abstract

The characteristics and properties of interlayer materials from 10 non-allophanic (Melanudand) and red yellow soils (Alfisols and Ultisols) from three locations in Japan were studied by chemical extractions and x-ray diffraction (XRD) analyses. Allophane was dissolved from clay samples using 0.15 M acid oxalate solution while silicon and aluminum were dissolved using both 0.15 M acid oxalate and 0.3 M sodium citrate solutions. XRD analyses were done for the treated and untreated samples. For the chemically extracted samples, the clay samples were treated with bicarbonate citrate solution for the removal of iron oxides after the dissolution treatments then saturated with K and Mg ions for XRD analyses. Results of the XRD patternd of the untreated and treated samples indicated the interlayer materials as a hydroxy-interlayered form for vermiculite (HIV). Between the two dissolution treatments, the 0.3 M sodium citrate treatment was found to be more effective in removing the interlayer materials than the 0.15 M acid oxalate treatment by allowing interlayer expansion and collapse.