Electro-galvanic alkalization and treatment of rainwater to obtain drinking water

Abstract

ABSTRACT Rainwater Electro-Galvanic Alkalization (EGA) was performed using copper and magnesium (1:1) electrode. Efficiently removal of pollutants without external energy consumption was carried out, in addition essential ions were dosed for alkalization of rainwater. The optimal system conditions were obtained using response surface methodology (RSM) by considering the following operating variables: flow rate and concentration of the supporting electrolyte (NaCl and CaCl2). Furthermore, the maximum efficiency of nitrate, ammoniacal nitrogen, colour, and turbidity removal was evaluated. The results showed that the response variables were mainly sensitive to the type of supporting electrolyte used and the flow rate. Under experimental conditions of 0.009 M (NaCl) and 20 mL min−1, the removal rate was 74.19%, 72.49%, and 81.43% for nitrates, colour, and turbidity, respectively, and the lowest concentration of ammoniacal nitrogen ( 0.99 mg L − 1 ) was obtained. The kinetic models for nitrate and colour were fitted to zero-order models with k = 0.33 mg L − 1 mi n − 1 and k = 0.933 Pt − Co , respectively. In addition, turbidity was fitted to a first-order model ( k = 0.1661 mi n − 1 ) , and ammoniacal nitrogen was fitted to a second-order model ( k = 0.0217 L m g − 1 mi n − 1 ) . The concentration increases of minerals such as Ca and Mg, which rises the rainwater alkalinity after treatment (pH shift from 6.1 to 8.91), was determined by inductively coupled plasma (ICP) analysis.