ALEXANDRIA, Va., Sept. 30 -- United States Patent no. 12,428,590, issued on Sept. 30, was assigned to KING FAHD UNIVERSITY OF PETROLEUM AND MINERALS (Dhahran, Saudi Arabia).

"Method of removing hydrogen sulfide from a subterranean geological formation with a zeolitic imidazolate framework in waste cooking oil-based drilling fluids" was invented by Sagheer A. Onaizi (Dhahran, Saudi Arabia) and Mustapha Iddrisu (Dhahran, Saudi Arabia).

According to the abstract* released by the U.S. Patent & Trademark Office: "A method of removing hydrogen sulfide from a subterranean geological formation includes mixing a zinc-imidazolate material, ZIF-8, in an amount of 0.1 to 2.5 percent by weight with an organic liquid containing one or more unsaturated ...