Methods of producing ferrihydrite nanoparticle slurries, and systems and products employing the same

A method for treating a H2S-containing fluid stream, the method comprising:

• (a) contacting a H2S -containing fluid stream with a ferrihydrite slurry, wherein the ferrihydrite slurry includes ferrihydrite nanoparticles and a 2LI promotor wherein the contacting step results in
• (i) a treated fluid stream comprising less H2S than the H2S -containing stream and
• (ii) a used slurry including ferrous sulfide, a 2LI promotor, and a first sulfur concentration of sulfur obtained from the H2S -containing stream;
• (b) regenerating the used slurry to obtain elemental sulfur and a regenerated ferrihydrite slurry, wherein regenerating includes:
• (i) contacting the used slurry with an oxidizing agent thereby converting at least some of the sulfur in the used slurry into elemental sulfur and converting at least some of the ferrous sulfide in the used slurry into regenerated ferrihydrite thereby forming regenerated ferrihydrite slurry;
• and
• (ii) separating the elemental sulfur from the regenerated ferrihydrite slurry, wherein the regenerated ferrihydrite slurry includes ferrihydrite nanoparticles and a 2LI promotor and a second sulfur concentration less than the first sulfur concentration of the used slurry;
• wherein the 2LI promotor is selected from the group consisting of D-sorbitol, alkali metasilicates and combinations thereof.