The use of halloysite for nutrient and moisture retention in soils
Liuskanto, Sonja (2015)
Liuskanto, Sonja
Tampereen ammattikorkeakoulu
2015
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-201505127465
https://urn.fi/URN:NBN:fi:amk-201505127465
Tiivistelmä
Halloysite is a clay mineral with interesting properties that are applicable in many fields, such as nanotechnology and environmental remediation. Halloysite is a kaolin subgroup mineral, which has the chemical formula Al2Si2O5(OH)2•4 H2O. Halloysite is an extremely interesting material due to its tubular nanoscale structure and its cation exchange capacity.
This study was done in order to determine whether halloysite, mixed in soil, would be helpful in retaining moisture or nutrients in the soil, and whether, through these properties, it would be useful for some practical application. The study was conducted by filtrating de-ionized water and chemical solution through peat samples containing different proportions of halloysite, and by using fast and slow flow rates. The parameters studied during the filtration test and analyses were pH, total dissolved solids (TDS), phosphate-phosphorus, nitrate-nitrogen and potassium, and the volume of water or nutrient solution retained.
The findings of this research showed that there is an increase in the retention of phosphate (57%), nitrate (14%) and potassium (16%) when halloysite is added in the peat. The reasons for the retention might be various, such as cation exchange, anion exchange and formation of precipitants, and this issue could be studied further. Out of the three elements, potassium was expected to be retained the best with halloysite in the soil, but in fact, it was phosphate retention that improved the most when halloysite was added, while the use of halloysite improved potassium and nitrogen retention approximately equally. Halloysite was also found to be helpful in moisture retention, especially when liquids are filtrating at a slow flow rate.
The ratio of halloysite in the soil is a very important variable, since halloysite easily forms an almost non-permeable layer in the soil.
This study was done in order to determine whether halloysite, mixed in soil, would be helpful in retaining moisture or nutrients in the soil, and whether, through these properties, it would be useful for some practical application. The study was conducted by filtrating de-ionized water and chemical solution through peat samples containing different proportions of halloysite, and by using fast and slow flow rates. The parameters studied during the filtration test and analyses were pH, total dissolved solids (TDS), phosphate-phosphorus, nitrate-nitrogen and potassium, and the volume of water or nutrient solution retained.
The findings of this research showed that there is an increase in the retention of phosphate (57%), nitrate (14%) and potassium (16%) when halloysite is added in the peat. The reasons for the retention might be various, such as cation exchange, anion exchange and formation of precipitants, and this issue could be studied further. Out of the three elements, potassium was expected to be retained the best with halloysite in the soil, but in fact, it was phosphate retention that improved the most when halloysite was added, while the use of halloysite improved potassium and nitrogen retention approximately equally. Halloysite was also found to be helpful in moisture retention, especially when liquids are filtrating at a slow flow rate.
The ratio of halloysite in the soil is a very important variable, since halloysite easily forms an almost non-permeable layer in the soil.