A treatment composition for remediating for remediating H.sub.2S and other contaminant(s) in contaminated liquids, comprising: 0.1-10.0 weight % collectively of at least one hydroxide compound; 0.01-3.0 weight % collectively of at least one organic acid selected from a group consisting of fulvic acid and humic acid; 0.01-10.0 wt % of a chelating agent; and at least 75% weight of water.

A treatment composition for remediating for remediating H.sub.2S and other contaminant(s) in contaminated liquids, comprising: 0.1-10.0 weight % collectively of at least one hydroxide compound; 0.01-3.0 weight % collectively of at least one organic acid selected from a group consisting of fulvic acid and humic acid; 0.01-10.0 wt % of a chelating agent; and at least 75% weight of water.

A treatment process for remediating H.sub.2S and other contaminants in liquids includes: partially filling a closed vessel with a contaminated liquid containing ≥5 ppm H.sub.2S with a head space above the liquid within the vessel where gasses released from the liquid from the liquid collect; separately providing a treatment composition in the head space so that the gasses from the liquid may contact the treatment composition; and permitting the contact between the vapors from the liquid and the treatment composition to continue until a collective concentration of H.sub.2S in the liquid and in the head space is <5 ppm. The treatment composition includes an aqueous solution containing at least one hydroxide compound, a collective concentration of the at least one hydroxide compound in the aqueous solution is in a range of 35-55 weight %, and the aqueous solution constitutes at least 80 weight % of the treatment composition.

A treatment process for remediating H.sub.2S and other contaminants in liquids includes: partially filling a closed vessel with a contaminated liquid containing ≥5 ppm H.sub.2S with a head space above the liquid within the vessel where gasses released from the liquid from the liquid collect; separately providing a treatment composition in the head space so that the gasses from the liquid may contact the treatment composition; and permitting the contact between the vapors from the liquid and the treatment composition to continue until a collective concentration of H.sub.2S in the liquid and in the head space is <5 ppm. The treatment composition includes an aqueous solution containing at least one hydroxide compound, a collective concentration of the at least one hydroxide compound in the aqueous solution is in a range of 35-55 weight %, and the aqueous solution constitutes at least 80 weight % of the treatment composition.

A liquid treatment composition for remediating and removing mercaptans, H.sub.2S and other sulfur based contaminants from contaminated hydrocarbon liquids, the treatment composition consisting essentially of a carrier solvent and at least one alkoxide compound. The liquid treatment composition may contain no terpene. Further, the liquid treatment composition may include water. The at least one alkoxide compound includes at least one of sodium methoxide and sodium ethoxide.

A liquid treatment composition for remediating and removing mercaptans, H.sub.2S and other sulfur based contaminants from contaminated hydrocarbon liquids, the treatment composition consisting essentially of a carrier solvent and at least one alkoxide compound. The liquid treatment composition may contain no terpene. Further, the liquid treatment composition may include water. The at least one alkoxide compound includes at least one of sodium methoxide and sodium ethoxide.

A reaction system and method for removing heteroatoms from oxidized-heteroatom-containing hydrocarbon streams and products derived therefrom are disclosed. An oxidized-heteroatom-containing hydrocarbon feed is reacted in a reaction system thereby forming non-ionic hydrocarbon products. The products derived therefrom are useful as transportation fuels, lubricants, refinery intermediates, or refinery feeds.

A reaction system and method for removing heteroatoms from oxidized-heteroatom-containing hydrocarbon streams and products derived therefrom are disclosed. An oxidized-heteroatom-containing hydrocarbon feed is reacted in a reaction system thereby forming non-ionic hydrocarbon products. The products derived therefrom are useful as transportation fuels, lubricants, refinery intermediates, or refinery feeds.

Methods and systems for reducing sulfur content in crude oil are provided. The methods and systems apply a first alkaline aqueous solution to crude oil to produce alkaline-treated crude oil, apply an acid aqueous solution to the alkaline-treated crude oil to produce acid-treated crude oil, apply a second alkaline aqueous solution to the acid-treated crude oil to produce neutralized crude oil; and separate residual water that contains sulfur from the neutralized crude oil to produce treated crude oil that has less sulfur content than the crude oil before the treatment.

In an aspect, a method is disclosed that includes contacting a composition with an aqueous solution to yield a mixture, where the composition includes one or more of animal fats, animal oils, plant fats, plant oils, vegetable fats, vegetable oils, greases, and used cooking oil, about 5 wt. % or more of free fatty acids, about 10 wppm or more of total metals, about 8 wppm or more phosphorus, about 20 wppm or more of nitrogen, and the aqueous solution includes ((NH.sub.4).sub.2H.sub.2EDTA, (NH.sub.4).sub.4EDTA, a monoammonium salt of diethylenetriaminepentaacetic acid, a diammonium salt of diethylenetriaminepentaacetic acid, a triammonium salt of diethylenetriaminepentaacetic acid, a tetraammonium salt of diethylenetriaminepentaacetic acid, (NH.sub.4).sub.5DTPA, a combination of citric acid and Na.sub.4EDTA, a combination of citric acid and Na.sub.2H.sub.2EDTA, a combination of citric acid and a monosodium salt of diethylenetriaminepentaacetic acid, a combination of citric acid and a disodium salt of diethylenetriaminepentaacetic acid, a combination of citric acid and a trisodium salt of diethylenetriaminepentaacetic acid, a combination of citric acid and a tetrasodium salt of diethylenetriaminepentaacetic acid, a combination of citric acid and Na.sub.5DTPA, or a combination of any two or more thereof, where the method further includes centrifuging the mixture to yield a first treated composition, wherein the first treated composition has less total metals and less phosphorus than the composition.