Study of the influence of crystallisation companions on the oxidation - precipitation of Fe2+ applied to the synthetic water of Dan Daji -Illela (Tahoua -Niger)

Abstract

The elimination of iron by the oxidation-precipitation technique applied to Dan Daji water requires the study of the influence of certain parameters that frequently coexist with iron in water, such as Ca2+, Mg2+, Na+ , K+, SO42-, HCO3-, CO32- and NO3-. The use of natural water does not make this study possible. To overcome this limitation, synthetic water was adopted to study the influence of these parameters on iron precipitation. For the needs of this study, the physico-chemical characteristics of the synthetic groundwater are identical to those of the Dan Daji drilling. All the experiments were carried out in a 1000 mL beaker with stirring to allow contact with atmospheric oxygen for a precipitation time of 60 minutes. Among the ions that accompany Fe2+ precipitation, certain ions such as HCO3-, Ca2+, K+ and Mn2+ promote the precipitation of iron to Fe(OH)3. On the contrary, other ions such as Mg2+, SO42- and NO3- inhibit the formation of Fe(OH)3.