RU2422187C2 - Sorption filter - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to sorption filter and may be used for water treatment in industrial water supply systems. Sorption filter comprises housing with sorbent, and electrodes to separate layers of said sorbent. Said electrodes make electrochemical current sources and are made up of aluminium perforated plates with negative potential and graphite perforated plates with positive potential. Activated carbon is arranged between said electrodes. Quantity of electrochemical current sources exceeds unity. Filtration is carried out at 5-11 m/h rate. Quantity of consecutively arranged current sources makes 2 to 5 and distance between aforesaid electrodes equals 187-241 mm.

EFFECT: reduced power consumption.

4 cl, 2 dwg, 1 ex, 3 tbl

Description

The invention relates to the field of public utilities in centralized and decentralized water supply systems, and can also be used in water treatment for water supply to industrial enterprises.

Known sorption filter loaded with activated carbon (Zhurba MG Water supply. - M.: Publishing house of architectural and construction universities, 2004, p.146-151). The disadvantages of the device are the large dimensions of the filter, as well as a low cleaning effect.

The closest technical solution of the same purpose to the claimed device according to the set of essential features and the maximum achievable positive effect is a sorption filter (RF Patent 2315647, B01D 25/00, C02F 1/46, published 2005.03.11).

The device contains a sorbent from zeolite placed in a cylindrical body, and electrodes delimiting the layers of the sorbent, where the positive pole is connected to the first electrode from the body, to the third, etc., to all electrodes odd in numbers, and the negative pole is connected to the second, fourth, etc., to all electrodes even in numbers. The device contains one or several parallel-connected identical housings with a mixture of activated carbon or sulfonated coal and zeolite and connected to them one or more parallel-connected identical identical housings with electrodes, where the first half of the gap between the housing wall and the first electrode is filled with a sorbent layer of zeolite, followed by a dividing wall in the form of a grid of dielectric material, and the second half of this gap is filled with a layer of sorbent from amphoteric materials. Further, the layers of these sorbents from zeolite and amphoteric materials alternate, starting with amphoteric materials, while the layers between the electrodes have a thickness of 0.02-0.2 m, and the electrodes are connected to a rectifier with a constant voltage of 5-220 V.

The disadvantage of this device is that water purification occurs at high energy costs. In addition, with the polarization of the electrodes, dissolution of the anode and its passivation, deposition of hardness salts on the cathode occur.

The objective of the invention is to reduce energy consumption during water treatment.

The problem is solved in that the sorption filter, comprising a housing filled with a sorbent, and electrodes that delimit the layers of sorbent in the housing, according to the invention, contains electrodes that create electrochemical current sources made of perforated aluminum disks having a negative potential and perforated graphite disks, having a positive potential, between which a granular sorbent is located, and the number of electrochemical current sources is more than one. Filtering is carried out at a speed of 5-11 m / h. As the sorbent, activated carbon of the AG-3 brand is used. The number of successive current sources is 2-5, and the distance between the electrodes of the electrochemical current source is 187-241 mm.

Figure 1 presents a sketch of the sorption filter, figure 2 is a graph of the dependence of the power of the electrochemical current source on the interelectrode distance and the concentration of an aqueous solution of sodium chloride.

The sorption filter (figure 1) consists of a cylindrical body 1, closed at the top and bottom with elliptical covers 2. Water is supplied to the filter through a pipe 3 located in the upper part of the filter housing. The purified water is discharged through a pipe 4 located in the lower part of the filter housing. In the filter housing 1, electrochemical current sources are arranged sequentially in the direction of water flow, consisting of an aluminum disk 5 and a graphite disk 6, separated by a granular sorbent, for example, activated carbon 7.

Sorption filter operates as follows. The purified water is filtered in the filter loading in the direction from top to bottom. In electrochemical current sources consisting of disks 5 having a negative value of electrode potential and disks 6 having a positive value of electrode potential, an electromotive force and, accordingly, an electric current arise. The sorbent located in the electric field between the two electrodes is polarized, and the adhesion forces increase. In addition, the electronegative aluminum electrode dissolves. Aluminum ions in water are hydrolyzed to form an insoluble salt of Al (OH) ₃ , which is a coagulant. The process of aluminum hydroxide formation intensively proceeds on the surface of the sorbent, due to which the sorption capacity increases significantly.

It was experimentally established that the power of the electrochemical current source has an extreme dependence on the interelectrode distance in a wide range of solution concentrations. Figure 2 shows graphs of the dependence of the power of the electrochemical current source on the distance in sodium chloride solutions with a concentration of from 1 to 100 g / l.

As follows from figure 2, on the graph there are two maximum values of the power of the electrochemical filter. The distance between the electrodes corresponding to the first and second maximum is determined by differentiating the corresponding regression equations (Table 1).

Table 1 The distance between the electrodes corresponding to the first, second maximum power of the electrochemical filter The concentration of the solution, g / l First high Second high The equation Distance mm The equation Distance mm one hundred y = -0.0353x ² + 0.9426x-3.4118 13.35 y = -0.00006x ² + 0.027x + 0.7966 225 fifty y = -0.0458x ² + 1.3143x-7.0771 14.34 y = -0.00002x ² + 0.0095x-0.112 237 10 y = -0.0321x ² + 0.9245x-5.2906 14.40 y = -0.000006x ² + 0.0029x + 0.0428 241 5 y = -0.0246x ² + 0.7107x-4.0992 14.44 y = -0.000004x ² + 0.0016x + 0.0384 200 one y = -0.0257x ² + 0.7512x-4.538 14.61 y = -0.00000008x ² + 0.00003x + 0.0753 187 Average value 14.23 Average value 218

From the obtained results it follows that in a wide range of solution concentrations the position of the first and second maximum changes insignificantly and can be determined by the average value of the interelectrode distance, namely 14 and 218 mm. Since the height of the filter layer must be at least 1 m, the electrochemical filter must be converted to a multi-electrode, and the number of current sources, respectively, should be 71 and 5 pcs. It follows that in practice it is irrational to use the first maximum due to the complexity of the filter design. Thus, the optimal value of the interelectrode distance should be considered 187-241 mm, and the number of sequentially located current sources is 5.

There are no energy costs in the electrochemical filter.

The regeneration of filter materials is carried out by a reverse flow of water. The shape of the case and its geometric size do not play a role, so the case can be cylindrical, rectangular or other shape.

Example 1. Water was filtered in a sorption filter in the direction from top to bottom. An aluminum perforated disk was located in the upper part of the filter, and a graphite perforated disk in the lower part. The space between the disks was filled with activated carbon of the AG-3 grade.

The filtration rate was varied in the range from 1 to 20 m / h.

Table 2 and 3 show the data on the degree of water purification in comparison with the purification of the same water on the prototype device at various filtration rates, as well as various initial concentrations of pollution. An organic pollutant, chromogen black, was artificially introduced into the water. The degree of water pollution was determined by the optical density D. The initial value of the optical density of water was D = 0.08 (Table 2) and D = 2.0 (Table 3).

table 2 Optical density of water after purification Filtration rate, m / h Optical density of water after purification one 3 5 8 eleven fifteen twenty Prototype device 0,037 0,038 0,038 0,039 0,043 0,047 0,055 Sorption filter with 1 current source 0,038 0,038 0,038 0,038 0,039 0,042 0,045 Sorption filter with 5 power sources 0,030 0,030 0,031 0,031 0,032 0,034 0,035

Table 3 Optical density of water after purification Filtration rate, m / h Optical density of water after purification one 3 5 8 eleven fifteen twenty Prototype device 0.50 0.50 0.51 0.67 0.81 1.30 1.70 Sorption filter with 1 current source 0.48 0.48 0.48 0.48 0.55 0.73 0.89 Sorption filter with 5 power sources 0.18 0.18 0.20 0.20 0.25 0.30 0.37

From the results of the experiments it follows that at a filtration rate of 1-8 m / h, the optical density of water purified by a sorption filter according to the prototype and a filter with one current source is almost the same, but with an increase in the filtering speed to 20 m / h, the filter with one current source gives greater effect of water purification.

A sorption filter with five current sources gives a significantly better water quality in a wide speed range from 1 to 20 m / h. Obviously, for practical purposes, a high filtration rate is of greater interest, since the dimensions of the structures are reduced.

Claims (4)

1. A sorption filter, comprising a housing filled with a sorbent, and electrodes that delimit the layers of sorbent in the housing, characterized in that the electrodes create electrochemical current sources made of perforated aluminum disks having a negative potential and perforated graphite disks having a positive potential between which activated carbon is located, and the number of electrochemical current sources is more than one. 2. The device according to claim 1, characterized in that the filtering is carried out at a speed of 5-11 m / h. 3. The device according to claim 1, characterized in that as activated carbon use activated carbon brand AG-3. 4. The device according to claim 1, characterized in that the number of sequentially located current sources is 2-5, and the distance between the electrodes of the electrochemical current source is 187-241 mm.

Images