Chemistry of water -Part 8-

Water hardness treatment:

Station for complex water treatment SKO-10K

Matt lime, which changes bicarbonate into carbonate, is used in the chemical treatment of hard water. And sodium carbonate, which also turns calcium chloride or sulfate into carbonate:

Ca(HCO3)2 + Ca(OH)2 === 2CaCO3 + 2H2O

CaSO4 + NaCO3 === CaCO3 + Na2SO4

CaCl2 + Na2CO3 === CaCO3 + 2NaCl

The lime method to reduce water hardness is built around this process.

In addition, the zeolite method, which was developed since 1910, is a good way to soften water.

Synthetic zeolite
Zeolite is a large-molecule aluminosilicate compound, these molecules have what appear to be pores where sodium ions are weakly bound to the rest of the molecule due to the atoms' steric structure, ion exchange happens when hard water flows through these pores, calcium and magnesium ions are left behind by the water while it takes the sodium ions. After passing through the zeolite layer, the water emerges almost completely free of its hardness. If we use the symbol "Ze" to represent the zeolite, we can write the equation for this reaction in the manner shown below:

Na2Ze + Ca++ ==== CaZe + 2Na+

Zeolite can be restored to its original state once it has been saturated with lime by being treated with a table salt solution, which is then discarded along with the calcium ions it carries:

CaZe + 2Na+ === Na2Ze + Ca++

Today, zeolite is produced on a large scale. In 1935, it was discovered that it was possible to sulfonate synthetic resins to produce resins with better qualities than either natural or synthetic zeolite.

• The conventional method of distillation is used to purify water, and pure tin tubes and containers are frequently used to store distilled water. Because the alkaline compounds in regular glass dissolve slowly in water, it is not appropriate for this use. Additionally, silica-based containers are used to obtain water that is of a high purity.

Since water is a necessary component of all life, man must discover a way to access it from the sea, which serves as the world's largest reservoir. In reality, desalinating sea water is not a technological challenge because it is practiced in many countries; the challenge is to do so at a reasonable cost.

References:

• Kada, Imene- Double ionisation de la molécule d’eau par impact d’électrons- Phd thesis

• Pezzella, Marco. Molecular dynamics at water interfaces: from astrophysical to biochemical applications. 2020, Phd Thesis no:13717, University of Basel, Faculty of Science.

• [General and inorganic chemistry book- M. Shkhashirou- H. Birqdad- Y. Qodsi- University publications. Algeria]

• Berend Ensing; geboren te Delfzijl- Chemistry in Water. Phd Thesis. University of Amsterdam- 2003

• [AQUAPROX- Livre: Traitement des eaux de refroidissement. Imprimé en France par EMD S.A.S- 53110 Lassay-les-Chateaux. N° d'imprimeur: 15566- Dépot légal: juin 2006. N° 842- Cyclus print 90°]