Investigation of the Efficiency of Water Purification from Phenol by Means of Incomplete Freezing
N. L. Lavrik, V. V. Boriskin, K. L. Danilov, V. A. Brednev
Keywords: : freezing - melting procedures, efficiency of water purification, phenol, distorting factor, polluting factor, purification factor
Pages: 341-350
Abstract
With the help of freezing - melting procedure, the efficiency kpur of water purification from phenol is investigated as a dependence on the fraction of frozen solution (g) and freezing temperature T (freezing rate). The following kinds of dependencies are established: 1) a monotonous increase in kpur with an increase in g at T = -3.5, -6.5, -10, -15 oC; 2) an increase in kpur with an increase in the fraction of frozen aqueous solution to g ≈0.2, followed by a decrease, at freezing temperatures -20 and -25 oC (non-monotonous dependence). The influence of reasons preventing high kpur (veiling the purification factor) is discussed. These reasons include the impossibility to separate the solution adhered to the ice surface from ice itself due to the sampling procedure (distorting factor) and trapping the impurities into the interdendritic cavities on the surface of the crystallization front (polluting factor). It is concluded that the most optimal technological conditions for the use of freezing for water purification is freezing at the crystallization front rate about 0.2 cm/h until the value of g ~ 0.5 is achieved.
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