Dissolution of amorphous matter from soils by hydrogen peroxide treatment and its effect on the consistency limits
1998
Karube, J. (Ibaraki Univ., Ami (Japan). Faculty of Agriculture) | Sato, K.
The change of carbon content, pH, dissolution of amorphous matter, and its effect on the consistency limits of soil by H2O2 treatment were measured using andosols and hedoros, or lake bottom muds. When 30 square meter of 6% H2O2 was used on 10 g of soil, the pH of the topsoil of andosol lowered from 5.8 to 4, and Hachirogata hedoro from 6.4 to 3.3. These pHs recovered when treated with an increased amount of H2O2. Oxalic acid formed by H2O2 treatment lowered the pH, and as it was combined with aluminum or iron in the soil, the pH gradually recovered. In relation to the pH drop amorphous matter dissolved. More than 80% of aluminum as free oxides or hydroxides were dissolved from hedoros during the H2O2 treatment. Hachirogata hedoro greatly changed in the plasticity chart by air-drying, but showed only a little effect of that after the H2O2 treatment. On the contrary, the effect of air-drying on the topsoil of andosol did not show any substantial change before and after H2O2 treatment. Free oxides and hydroxides were found to have a great effect of air-drying on Hachirogata hedoro
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