Essay On Hardness Of Water

1617 Words 7 Pages
Water is an important resource needed for our subsistence & is required on a global level. The various hydrologic cycles are necessary in order to preserve the balance of our ecosystem. Thus, good quality water is necessary for our survival. Chemical & biological composition are two criteria for evaluating water quality. Water hardness can be defined by the presence of divalent cations dissolved in a water sample. The divalent cations usually present are Ca2+ & Mg2+ and these cations bestow chemical properties to water. Thus, hard water will have increased concentration of divalent cations when compared to soft water. Ca2+ & Mg2+ are the most commonly found divalent cations in hard water and are denoted by a +2 charge. But, polyvalent cations …show more content…
This method works on the principle that “the energy of the light incident on the atom must be equal to the energy separation (∆E) between two energy levels for the atom to be excited.” This principle is similarly used in atomic absorption spectrophotometry. A voltage is applied across the electrodes which causes the excitation of the specific divalent cation in the lamp. As the excited divalent cation returns to a similar energy level after excitation, the hollow cathode lamps produce the monochromatic light corresponding to the ∆E needed for the metal cation. This results in the absorption of the light by the metal cation. The sample is aspirated into the sample chamber where it is converted to an aerosol by an inefficient process since only 10% of the sample is converted & the rest is discarded from the chamber as waste. Then, the flame in the burner atomizes the aerosol sample since the flame is of an air-acetylene mixture at 23000C. Thus, the solvated metal ions are liberated of water. The monochromatic light is incident on the place of atomization where it is absorbed only if the energy separation of energy levels is the same. Then, a grating in the monochrometer is adjusted to make only the wavelength of light corresponding to ∆E pass through the slit. The light falls on the detector which consists of a photomultiplier tube (PMT). The …show more content…
The process of ionic exchange us executed as divalent cations are exchanged with monovalent cations present in the resin. The ion exchange material is a string of polymer beads attached to anionic groups covalently. The divalent cations are attracted to the anionic groups more than the divalent cations. This facilitates the removal of divalent cations & the monovalent cations in the water sample don’t cause hardness & scale formation.6 Regeneration of this resin is possible by reversing the

Related Documents

Related Topics