Catalysts for iron, manganese and hydrogen sulfide removal.
Catalytic methods for iron, manganese and hydrogen sulfide catalysts.
Iron is an element that can be undesirable in water. Iron removal can be somewhat difficult because it can change its valence state from the water-soluble ferrous state (Fe2+) to the insoluble ferric state (Fe3+).
When we oxygenate or use an oxidizing agent, the ferrous states change to ferric, which is insoluble, and precipitate, giving an oxidized (red-brown) appearance in the water. This change can occur when iron-containing water from a deep well or covered site is pumped or passed into a pipe or other reservoir where it absorbs oxygen. The ferric iron can be treated by a filter or system containing catalysts that accelerate this process and the bed bed itself retains the precipitated iron.
Oxygen from the atmosphere that is introduced to the water during aeration is usually very effective in oxidizing iron. However, when the iron is organically complex, aeration alone is not sufficient.
The second point is that IRON OXIDATION is very slow at pH 7.0. When aeration and thus oxygenation does not meet expectations, alternative oxidants such as; chlorine or hydrogen peroxide can be used. Chemical oxidation is often used when iron and manganese must be removed simultaneously in a single filtration step and manganese oxygenation is very slow at pH 9.5;
The oxidation of iron with different oxidants can be described by the following chemical reactions:
Media of removal or elimination of Manganese from water.
If manganese is not removed from water it can cause health problems, staining or discoloration of water. Removal of dissolved manganese from water requires a strong catalyst to handle the pH and an oxidizer such as chlorine or hydrogen peroxide.
Manganese precipitates more rapidly at higher pH values and higher oxidant concentration.
2CO2 + Ca(OH)2 = Ca(HCO3)2
Mn(HCO3)2 + O + Ca(OH)2 = MnO2 + Ca(HCO3)2 + H2O
Waters containing hardness and some free carbon dioxide (CO2) have a pH of about 7.5 to 8.5 or higher.
Due to their adsorption properties, iron-manganese catalysts such as Katalox Ligth (MnO2) accelerate the removal of Mn from solution and cause the mixed oxide to form. The ratio of oxidized manganese dioxide along with a deep bed filter, which makes Mn removal during filtration with oxide coated media very effective.