Biosorption Phenomenon On A Porous Carbon Surface
BIOSORPTION PHENOMENON ON A POROUS CARBON SURFACE
S.K. Smolin, N.A. Klimenko
A.V. Dumansky Institute of Colloid Chemistry and Chemistry of Water, Ukrainian National Academy of Sciences,
Vernadsky avenue 42, 03680 Kiev, Ukraine
Biosorption processes are perspective ones for waste water purification. In this process both adsorption of organic substances and partial bioregeneration of activated carbon (AC) have place. In initial period of filtering through fixed AC beds biosorption process concedes to sorption process on efficiency and depth of cleaning. However the velocities of both adsorption and bioregeneration are equalized later.
It has a place on a finishing stage of adsorption process, when the large part of adsorption capacity is already exhausted. From this moment it is possible to speak about purely biosorption, when the efficiency of clearing is stabilized and does not depend on time of process. To our mind, biosorption is a complicated equilibrium dynamic process of desorption – bidegradation – adsorption of organic substances on a porous carbon surface.
The experimental researches of AC bioregeneration from biologically resistant surfactants by means of destructing bacteria have shown that the degree of AC regeneration does not exceed 20 – 30 % of the fresh AC equilibrium adsorption. If the activated carbon bed is exhausted under dynamic conditions, the degree of bioregeneration can reach 50 %.
The efficiency of surfactant removal by AC fixed beds with natural and special immobilized microflora under dynamic conditions is less than 20 %.
The AC vacant porosity at the stage of biosorption has been appreciated. The efficiency of biosorption is connected to the AC surface area, which can be regenerated owing to biofilm activity.
It should be the most kinetically favorable pores, immediately contiguous to a grain external surface.
The data concerning biosorption of surfactants from water solution treated by ozone and UV – radiation, specify that quality and efficiency of water cleaning depends on the water pretreatment, the concentration of organic compounds and their chemical nature.
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