ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 10, pp. 1680!1682. + Pleiades Publishing, Ltd., 2007.
Original Russian Text + Yu.P. Osadchii, T.E. Nikiforova, 2007, published in Zhurnal Prikladnoi Khimii, 2007, Vol. 80, No. 10, pp. 1651!1653.
PROCESSES AND EQUIPMENT
OF CHEMICAL INDUSTRY
A Model of Separation of Wastewater
Containing Vat Dyes
Yu. P. Osadchii and T. E. Nikiforova
Ivanovo State University of Architecture and Building, Ivanovo, Russia
Ivanovo State University of Chemical Engineering, Ivanovo, Russia
Received November 14, 2006; in final form, April 2007
Abstract-Mechanism of fluid separation with capillary-porous polymeric membranes was studied and
a mathematical model of separation by ultrafiltration of vat-dye-containing wastewater from finishing shops
of textile plants was suggested. The model takes into account the effect of physical parameters on the mech-
anism and kinetics of the cross-membrane transfer of ingredients, in which a gel layer is formed.
The process of baromembrane separation of indus-
trial wastewater containing dye vats, in which a gel
layer is formed on the membrane, is nonstationary.
The reason is that changes in the thickness of the gel
layer affect the hydrodynamics and mass exchange
because of the changing permeability and selectivity
of this layer.
The objective in developing a mathematical model
of separation of industrial wastewater containing vat
dyes (Brilliant Green ZhD, Blue OD, Reddish 2ZhD)
used in yarn dyeing in AKDU-6-02 apparatus is to de-
scribe the effect of physical parameters on the mech-
anism and kinetics of the cross-membrane transfer of
ingredients, in which a gel layer is formed.
The ultrafiltration process was performed under
a pressure of 0.330.4 MPa, created within membranes
by a centrifugal pump, flow velocity of 43 6m
pH 1312, and temperature of the solution being sep-
arated in the range 153 90oC. The tubular membranes
have the form of a multilayer tubular fiberglass frame
covered from within with a semipermeable polymeric
film. The input wastewater is concentrated via perma-
nent circulation through BTU-0.5/2 membrane units
comprising a set of tubular membranes , with con-
tinuous removal of the permeate. The resulting con-
centrate is delivered at regular intervals of time to
a receiver tank for subsequent recirculation.
Apparatus with tubular membranes operate in
the piston-flow mode. In the case in question, we have
low concentrations of a vat dye (0.23 0.3 g l
water and weak effect of gelation on the permeability
and selectivity of membrane durian a certain time. It
is assumed that wastewater is separated at a constant
pressure along the entire length of membrane units
and constant temperature. A schematic of the baro-
membrane separation process is shown in Fig. 1.
The material balance equation for the flow rates
of water and dye has the form
is the flow rate a substance (water and dye)
before a cross-section under consideration (kg s
Fig. 1. Schematic of the ultrafiltration separation with
a tubular membrane. (1) Arbitrary longitudinal cross-sec-
tion of the flow being separated in the range from l to
l + ,l, where l is an arbitrary coordinate along the tube
length and (2) separating layer of a polymeric membrane,
deposited onto the inner surface of the tube.