Soil dehydration apparatus

A versatile soil dehydration apparatus has been carried out. It consists of a variable number of specimen vats in parallel, two desiccating filters, a centrifugal pump for flammable fluids and two acetone reservoirs. Circuit allows continuous replacement of the water-acetone solution with dehydrated acetone filtered through cylinders containing grains of synthetic zeolite. This latter is a crystalline aluminosilicate capable of adsorbing water dissolved in acetone up to 15 % of its weight (the presence of a lattice having nominal diameter 3Å allows to capture water molecule and not acetone molecule which are very larger). System functions continuously as filters can alternately regenerated by drying in oven at 300 °C for few hours. Moreover it is possible to filter only acetone contained in the tanks and to draw samples of the solution in several points in the circuit to check the water concentration. Water content in acetone is measured by an enhalpimetric method based on the heat of dilution at different initial solute concentration. The change in temperature after mixing a 1.5 ml aliquot of distilled water with 50 ml of water/acetone mixture alters the resistance of the thermistor thereby changing the circuit current, which is read with the amp meter. The water concentration is then read from a standard curve drown with a set of solutions of given concentration.