Studies of Nutrients Speciation in the Solid Substrate Polystyrene Nutrients Anchored Material Using pH-Metric Method

Abstract

Studies of relationship between pH variation and the nutrients distribution in the substrate/water mixture provides information about the concentration of the nutrients anchored in the substrate and the efficiency in which they are availed and controlled for plant relative growth. The technique for determining this relationship was based on measurement of changes in peak current (ip) by DPASV method, following different concentration of HNO3 added to a fixed amount of solid substrate polystyrene nutrients anchored material (M+). The total nutrients in the substrate residual (MLn-1) after several stripping experiments is determined by AAS method, the difference between the initial total nutrients concentration before stripping (MLn) and (M+ + MLn-1), gives the concentration of the nutrients in the transition state. The method is advantageous in that the relationship can be measured under conditions where nutrients in the solution controlled directly the current. The results were then modeled so as to make an estimation of the availability of plants nutrients anchored in the substrate. The results shows that at pH 5.5, 5.02×10-1µmol l-1of the nutrients had solubilized, 3.98×10-1µmol l-1was complexed and 15.23×10-1µmol l-1was in the transition state. This balance is enough to support plant growth without chemical burn.