A process for the chemical conversion of contaminated magnesium hydroxide to high purity solutions of magnesium bicarbonate include steps of providing an impure reagent including at least 40% and less than 95% by total weight of total metals of magnesium in a form of solid magnesium hydroxide and at least 10% by weight of total metals of calcium carbonate, combining the impure reagent containing the solid magnesium hydroxide with carbonic acid in water, thereby generating magnesium bicarbonate and water and then filtering out solid calcium carbonate leaving a solution of magnesium bicarbonate in water having a by weight ratio of Mg/(Mg+Ca) in the solution of greater than 95%. Heating and/or drying the magnesium bicarbonate solution produces correspondingly high purity magnesium carbonate.

Divalent ions are extracted from solids by leaching to form a divalent ion-containing solution. The divalent ion-containing solution is subjected to concentration to form a concentrated divalent ion-containing solution. Precipitation of a divalent ion hydroxide salt is induced from the concentrated divalent ion-containing solution. In other cases, the concentrated divalent ion-containing solution is exposed to carbon dioxide to induce precipitation of a divalent ion carbonate salt.

Divalent ions are extracted from solids by leaching to form a divalent ion-containing solution. The divalent ion-containing solution is subjected to concentration to form a concentrated divalent ion-containing solution. Precipitation of a divalent ion hydroxide salt is induced from the concentrated divalent ion-containing solution. In other cases, the concentrated divalent ion-containing solution is exposed to carbon dioxide to induce precipitation of a divalent ion carbonate salt.

A calcium and/or magnesium additive for membrane fouling control made up of particles for forming a dynamic protective layer on the membrane for fouling control of the membrane, when added in the liquid flowing through the membrane, wherein the particles are synthetic mineral precipitate particles based on calcium and/or magnesium selected from the group consisting of ultrafine synthetic mineral precipitate particles and microfine synthetic mineral precipitate particles, as well as a process and system for membrane fouling control.

A calcium and/or magnesium additive for membrane fouling control made up of particles for forming a dynamic protective layer on the membrane for fouling control of the membrane, when added in the liquid flowing through the membrane, wherein the particles are synthetic mineral precipitate particles based on calcium and/or magnesium selected from the group consisting of ultrafine synthetic mineral precipitate particles and microfine synthetic mineral precipitate particles, as well as a process and system for membrane fouling control.

Aspects of the invention include methods of removing carbon dioxide (CO.sub.2) from a CO.sub.2 containing gas. In some instances, the methods include contacting CO.sub.2 containing gas with a bicarbonate buffered aqueous medium under conditions sufficient to produce a bicarbonate rich product. Where desired, the resultant bicarbonate rich product or a component thereof may then be stored or further processed, e.g., combined with a divalent alkaline earth metal cation, under conditions sufficient to produce a solid carbonate composition. Aspects of the invention further include systems for practicing the methods, as well as products produced by the methods.

Aspects of the invention include methods of removing carbon dioxide (CO.sub.2) from a CO.sub.2 containing gas. In some instances, the methods include contacting CO.sub.2 containing gas with a bicarbonate buffered aqueous medium under conditions sufficient to produce a bicarbonate rich product. Where desired, the resultant bicarbonate rich product or a component thereof may then be stored or further processed, e.g., combined with a divalent alkaline earth metal cation, under conditions sufficient to produce a solid carbonate composition. Aspects of the invention further include systems for practicing the methods, as well as products produced by the methods.

Methods, systems, and apparatus, relate to a method for carbon capture from sea water. A first source of sea water into a reverse osmosis chamber. Reverse osmosis is performed on the sea water to produce fresh water and brine. The brine is provided to an electrolyzer. A current is passed through the brine and fresh water, thereby producing a hydroxide solution in a cathode chamber of the electrolyzer. The hydroxide solution is collected and placed into a contacting chamber and new sea water introduced. Precipitates are produced comprising at least calcium carbonate and magnesium carbonate.

A process is provided using a concentrated sodium bicarbonate solution as a solubilizer mixed with a calcium hydroxide to chemically produce an insoluble calcium carbonate and produce an alkaline liquid solution, then passing the alkaline liquid solution through detrimental gases in a scrubber to produce an enhanced sodium bicarbonate which regenerates the sodium bicarbonate thus creating a continuous closed loop. The process can also produce a sodium phosphate (trisodium phosphate) by mixing the alkaline liquid solution with a phosphoric acid.

A process is provided using a concentrated sodium bicarbonate solution as a solubilizer mixed with a calcium hydroxide to chemically produce an insoluble calcium carbonate and produce an alkaline liquid solution, then passing the alkaline liquid solution through detrimental gases in a scrubber to produce an enhanced sodium bicarbonate which regenerates the sodium bicarbonate thus creating a continuous closed loop. The process can also produce a sodium phosphate (trisodium phosphate) by mixing the alkaline liquid solution with a phosphoric acid.