Development of Electrolysis Process and Designing the Instrument with Energy Source of Solar Cell Module for the Production of Alkaline and Acidic Waters

Abstract

Electrolysis is a process of decomposing a substance or solution using an electric current. Electrolysis of pure water will create hydrogen gas on the cathode side and oxygen gas on the anode side. Mineral water electrolysis can produce alkaline water and acidic water, which is beneficial for improving public health. Alkaline water can use to drink-health, while acidic water can serve as an external medicine. The maximum pH standard for drinking water set by WHO (2006) and the Indonesian Ministry of Health (2010) are 9.5 and 8.5. Currently, the equipment for producing alkaline water and continuous acidic water is available on the market; however, has a weakness, which is that it is still quite expensive and not yet affordable to the general public. There is a batch type mineral water electrolysis device which is relatively inexpensive, but there are still many shortcomings, including a long reaction rate, large electrical energy. The composition of the water content of the production results from continuous and batch types has not been tested analytically both in quality and quantity, besides that the theory underlying the process has not been explained in the literature. This research intends to develop and modify a batch-type water electrolysis process with the energy source of the electrolysis instrument coming from the sun through the solar cell module stored in the battery; the voltage can be increased and regulated by a power electronic converter. The electrolysis instrument is designed to facilitate the formation or efficient production of acidic and alkaline water, so in such a way that not much hydrogen gas at the cathode side and oxygen gas at the anode side were generated simultantly. The results of the mineral water electrolysis experiment at an average voltage of 46 volts and an average volume of 1400 mL for one hour required an average current of 61 mA, the average current efficiency for alkaline and acid water formation of 3.35%, and 9.47 %, the average pH values for acids and bases are 3.8 and 9.0, the amount of water that becomes hydrogen and oxygen gas is only 0.021mL or about 0. 0015%. The test results on PDAM water in Cibenying Kaler, Bandung city of Indonesia, showed that the number of mineral ions Ca2+, Mg2+, Cl-, NO3 - , and SO4 2-before electrolysis were respectively: 24.03; 7.92; 23.8; 51.69; and 3.69 mg/L, after electrolysis at the anode side were respectively: 7.07; 5.15; 110; 97.39; and 10.39 mg/L, at the cathode side were: 25.75; 9,54; 10.7; 31.04; and 0.65 mg/L. These values indicate that the alkaline water content on the cathode side meets potable standards. The final result of this research is that a portable mineral water electrolysis instrument has been made, not only using solar energy sources but also using AC voltage from national electricity company so that it can be easily used by the community.