Determination of reaction rate constant for increasing pH level in geothermal hot spring

Abstract

Geothermal hot spring can be used as source of hot bath. It contains mineral elements such as Cl−, K+, Na+, and SO4 2−. One of geothermal hot springs in Leilem, Sulawesi Utara, is categorized as Acid Sulfate Water. Leilem geothermal hot spring contains high acid sulfate and causing the pH level reach to 1. Leilem hot bath is categorized into acidic type. In order to reach mildly acidic type, the pH level should be up to 4. The method research to increase the pH level is to flow the hot water to the stack of CaCO3. To design the system, the reaction rate constant should be known. These constants are assumed to follow the Arrhenius’ equation, k = A e^((-Ea )/RT).The value of frequency factor (A) and activation energy (Ea ) are collected through a laboratory scale experiment of H2SO4 with CaCO3 (powder) by using variant variables of the temperature of water and the mass of CaCO3. Based on the result of the experiment the value of A is 1.8 and Ea 18.515 J(gmol)−1 and the research successfully increases the pH up to 4 or even higher.