The article presents the results of development of a roll-type electrobaromembrane apparatus for separation of technological solutions of chemical industries with differentiated removal of ions. A ...method is described for engineering calculation of the proposed promising design of a roll-type electrobaromembrane apparatus for separation of technological solutions of chemical and engineering industries, taking account of the hydrodynamics and direction of solution movement.
The paper presents a method for predicting the technological parameters of an electrodialysis apparatus using an improved mathematical model based on a friction mass transfer approach. The proposed ...method is presented on the example of the predicted separation of the aqueous solutions of CuSO
4
· 5H
2
O, Fe(NO
3
)
3
· 9H
2
O, and Ni(NO
3
)
2
· 6H
2
O. If necessary, the method can be applied in a modified form of calculation of other designs of electrodialysis apparatuses.
The article presents the results of a study of mass transfer in the process of electrochemical extraction of iron, magnesium and manganese ions from technological solutions. Mathematical expressions ...are obtained, and numerical values of empirical coefficients are determined for theoretical calculation of specific outflow, retention coefficient, and average mass transfer coefficients of the electrochemical membrane process of separation of technological solutions. The dependence of concentration polarization on solution flow rate, pressure gradient, and concentration is analyzed.
This paper presents an analytical overview of the study of the kinetic and physicochemical characteristics of composite membrane films. UAM-100, UAM-150, and MGA-95 composite films have been studied ...using thermogravimetry in the temperature range from 30 to 300°C. A kinetic analysis of experimental data by the Freeman–Carroll method is carried out. It was found that hydrated water for all the studied semi-permeable films evaporates in the temperature range from ~95 to ~180°C. Comparison of the ratios of the amount of removed water in the film samples correlates with the geometric parameters of the pores. The values of the activation energy and the pre-exponential factor (
E
= 26.9 kJ/mol and ln(
A
≈ 6.3 (min
–1
)) in the range 0.2 < α < 0.7 of the degree of dehydration indicate the same regularity in the distribution of water molecules in the polymolecular layer for all composite films. The high dehydration values, e.g., for a sample of a composite semipermeable film MGA-95 at the temperature of the maximum on the thermogravimetry curve (
T
max
= 169.6°C) indicate that water molecules form hydrogen bonds both with ionogenic groups of cellulose acetate and with each other.
A flat-chamber electrobaromembrane apparatus with improved design and technological characteristics for wastewater treatment and differentiated ion extraction from industrial water systems was ...developed. A method allowing the total working area of the anodic and cathodic membranes, the sizes of the anodic and cathodic outlet flows, and other parameters of the membrane process to be calculated was presented. The design and technological parameters of the chamber and electrobaromembrane apparatus as a whole were calculated.
Experimental data have been obtained, and the characteristics of the moisture content and permeability of cellulose acetate porous materials were analyzed via thermal action. Dynamic ...thermogravimetric analysis found that the destruction process in an air-dry sample of the membrane begins at 21°C. It is accompanied by a 2% weight loss and an endothermic effect. The destruction ends at 50°C. With a subsequent increase in temperature, the manifestation of endothermic effect continues a temperature of 120–175°C with the maximum rate of mass loss at 146°C. The weight loss ends at about 190°C and is 6.5%. The study of MGA-80 and MGA-95 porous cellulose acetate films at transmembrane pressure upon temperature exposure showed that the permeability and specific output flow to water increase as the temperature rises to 50°C. Analysis of dependences of the specific output flow on temperature revealed that the specific output flow to water increases by ~18% upon an initial temperature rise of 10°C. This is due to structural changes in the cellulose acetate layer. A further increase in temperature by 15°C leads to an increase in permeability by ~10%. These phenomena are associated with the process of structural transformation in the active layer and the polymer substrate of the MGA-95 and MGA-80P membranes, respectively.
A method for calculating a tubular electrobaromembrane apparatus with a nonuniform filtration area has been developed. Due to the addition of concentric cathode and anode membranes with protrusions ...of increased diameter, the tabular electrobaromembrane apparatus has an increased separation area per unit volume of the apparatus. The developed technique enables one to calculate the volume and weight of the apparatus and its environmental and economic efficiency in the separation of biologically active solutions.
The work is devoted to recovery of zinc, copper, nickel and cobalt from electroplating wastewater by electro-nanofiltration. The objects of study were the domestically produced nanofiltration ...membranes OPMN-K, OPMN-P (JSC Vladipor) and multicomponent technological solutions and wastewater from electroplating lines containing ions Cu
2+
, Zn
2+
, Co
2+
, Ni
2+
. The dependences of the retention coefficients of metal cations and the specific output flow on the applied pressure are obtained. The optimal current density for carrying out the electro-nanofiltration separation of electroplating wastewater has been determined. It was found that with an increase in the transmembrane pressure as the main driving force of the process, the retention coefficient rises, and at values exceeding the nominal working pressure by 25%, the retention coefficient begins to decrease for both types of membranes. The transfer numbers for the studied membranes were calculated for the retained cations. It is noted that the retention capacity of the OPMN-P membrane is higher than that of the OPMN-K membrane. The specific output flow increases with an increase in transmembrane pressure due to a rise in the driving force of the process on account of an increase in flow rate.
A mathematical description of heat transfer is presented and a procedure is developed for calculating the temperature characteristics of electro-ultrafiltration process for separating industrial ...solutions in flatchamber type of apparatuses. The permeate and retentate temperatures, solution heating temperature, heating power, and amount of heat liberated in the process of separation of industrial solutions and effluents containing anionic surfactants, proteins, and phosphatic and biochemical substances are calculated by the developed procedure.
The effect of temperature on the conformation changes of the structural and the thermophysical characteristics in the UAM-50, UAM-100, and MGA-95 composite films of cellulose acetate are studied. An ...interphase layer appears at the phase interface in the UAM-50 and the UAM-100 samples according to the data of differential scanning calorimetry. An exothermic effect appears in the calorimetry data curves for water-saturated samples in the temperature range of Δ
T
= 125–226°C with Δ
H
= 20.7 kJ/kg for the UAM-50 and 27.95 kJ/kg for the UAM-100; this indicates hydration of the polar groups of cellulose acetate and polyamide in the interphase layer of the composite films. When composite films in the air-dried and the water-saturated samples were studied with differential scanning, there was a redistribution of the ratio between the quantities of perfect crystalline structures in crystallites with different melting enthalpies. The melting enthalpy decreases from 6.06 to 0.99 kJ/kg for the MGA-95 low-temperature phase, from 1.99 to 1.72 kJ/kg for the high-temperature phase; from 3.04 to 1.38 kJ/kg for the UAM-50 low-temperature phase, from 8.12 to 1.76 kJ/kg for the high-temperature phase; from 4.99 to 1.5 kJ/kg for the UAM-100 low-temperature phase, and from 2.33 to 0.77 kJ/kg for the high-temperature phase. The total melting enthalpy of the endothermic peaks also decreases for all three samples; this is an indication of decreased crystallinity in the water-saturated samples of the composite films.
