Process for simultaneous removal of hydrogen sulfide and heavy metals

A process for simultaneous removal of hydrogen sulfide (H2S) and heavy metals from mixture, comprising:

• charging a contaminated aqueous composition containing heavy metal ions to a reactor;
• passing a H2S-containing gas composition via a plurality of gas spargers through the contaminated aqueous composition present in the reactor to form a H2S-containing contaminated aqueous composition and a purified gas composition;
• reacting the H2S from the H2S-containing contaminated aqueous composition with the heavy metal ions in the H2S-containing contaminated aqueous composition to form a metal sulfide precipitate in a metal-sulfide-containing contaminated aqueous composition;
• at least partially introducing the metal-sulfide-containing contaminated aqueous composition to a solid-liquid separator;
• removing the metal sulfide precipitate from the metal-sulfide-containing contaminated aqueous composition to form a purified aqueous composition;
• wherein the plurality of gas spargers is within the body of the contaminated aqueous composition to distribute the gas composition in the form of bubbles and is adjacent to a lower end of the reactor;
• wherein the reactor is in fluid communication with the solid-liquid separator;
• and
• wherein the H2S-containing gas composition is introduced to the reactor at a rate of 4 to 120 milliliters per minute (mL/min) per milligram of the heavy metal ions in the contaminated aqueous composition.