Editing Magnesium oxide (section)

===Waste treatment===
Magnesium oxide is used extensively in the soil and [[groundwater remediation]], wastewater treatment, drinking water treatment, air emissions treatment, and waste treatment industries for its acid buffering capacity and related effectiveness in stabilizing dissolved heavy metal species.{{according to whom|date=December 2016}}

Many heavy metals species, such as [[lead]] and [[cadmium]], are least soluble in water at mildly basic conditions (pH in the range 8–11). Solubility of metals increases their undesired bioavailability and mobility in soil and groundwater. Granular MgO is often blended into metals-contaminating soil or waste material, which is also commonly of a low pH (acidic), in order to drive the [[pH]] into the 8–10 range. Metal-hydroxide complexes tend to [[Precipitation (chemistry)|precipitate]] out of aqueous solution in the pH range of 8–10.

MgO is packed in bags around [[transuranic waste]] in the disposal cells (panels) at the [[Waste Isolation Pilot Plant]], as a {{CO2}} getter to minimize the complexation of [[uranium]] and other [[actinide]]s by [[carbonate]] ions and so to limit the [[solubility]] of [[radionuclide]]s. The use of MgO is preferred over [[CaO]] since the resulting [[hydrate|hydration product]] ({{chem|Mg|(OH)|2}}) is less soluble and releases less [[hydration enthalpy|hydration heat]]. Another advantage is to impose a lower [[pH]] value (about 10.5) in case of accidental water ingress into the dry salt layers, in contast to the more soluble {{chem|Ca|(OH)|2}} which would create a higher pH of 12.5 (strongly [[alkaline]] conditions). The {{chem|Mg|2+}} [[cation]] being the second most abundant cation in [[seawater]] and in [[rocksalt]], the potential release of magnesium ions dissolving in [[brine]]s intruding the [[deep geological repository]] is also expected to minimize the [[geochemistry|geochemical]] disruption.<ref>[http://www.wipp.energy.gov/fctshts/wastehandling.pdf wipp.energy.gov Step-By-Step Guide for Waste Handling at WIPP]. Waste Isolation Pilot Plant. wipp.energy.gov</ref>