2002 年 9 巻 297 号 p. 91-98
An effluent standard is becoming severe from a viewpoint of environmental conservation in recent years. Perceiving to reduce selenium (Se (VI)) that it is said to be difficulty, the examination was conducted for removal of selenium in solution with the high concentration of chloride ions which made the removal more difficult. Moreover, the experiment was carried out to remove selenium and fluorine which behaved as anion. The results can be summarized as follows :
1) SeO32- (IV) ions could be removed easily even in the solution with the high concentration of chloride ions. In the case of SeO42- (VI), it was needed to be reduced to SeO32-. The quantity of reducing agent for solution including much amount of chloride ions was required as much as thousand times of amount of SeO42-.2) FeSO4·7H2O was desirable for a reducing agent for the solution of high chloride concentration. FeCl3 was needed to decrease the concentration of Fe. Furthermore, Ca (OH) 2 was suited to adjust pH rather than NaOH. Ca (OH) 2 improved the efficiency of both filtration and removal of SeO42-.
3) It was possible to remove fluorine by using H3PO4 and to remove selenium with FeSO4 continuously. Furthermore, the reaction of both was carried out under the same condition, pH 10. Therefore, it was found that it is an easy processing method to control pH.