A method for the determination of selenium, tellurium and arsenic in commercial copper

The elimination of selenium(IV) from aqueous solution by precipitation with sodium sulfide

“…As noted earlier several other reagents have been found to reduce selenious ions to elemental state. Sodium dithionite is one of them that has found industrial application as described elsewhere [13] albeit with its own drawbacks, such as relatively poor efficiency, high cost, and subsequent redissolution of the selenium [17]. In this work the removal of selenium(IV) by sodium sulfide is described.…”

“…On the other hand, separation techniques such as bacterial reduction, ion exchange membranes, electrocoagulation, and sorption have been investigated but proven either too costly or only suitable for solutions containing low levels of soluble selenium (<5 mg/L) [6,10,11]. For solutions with higher concentrations of selenium use of reductive techniques taking advantage of the favorable Se(IV)/Se reduction potential are employed [12][13][14].…”

Volumetric Determination of Selenium

“…They apparently undergo partial or complete oxidation by the oxygen in solution which is produced concurrently with hydrogen ion at the anode. THE value of coulometry as a method for the determination of small amounts of materials has been amply demonstrated in recent years (2). DeFord (4) has applied this method for the titration of acids and bases in aqueous systems.…”

Stannous chloride—an effective reducing agent for the removal of selenium(IV) from acidic solution

“…For industrial applications involving more concentrated solutions, techniques that involve the precipitation of selenium seem to achieve the best results 9. Because of the high Se(IV)/Se reduction potential, various reagents have been evaluated and found to reduce selenium(IV) species in different types of aqueous solutions 10–12. In industrial applications, sulfur dioxide is apparently by far the preferred reactant to reduce selenium(IV) to the elemental state.…”