SU1664750A1 - Method of cleaning water from impurities - Google Patents

Abstract

This invention relates to a process for the purification of water from pollution, in particular, to electrochemical methods for purifying water. The purpose of the invention is to reduce energy consumption and increase the degree of purification. The goal is achieved by initial adjustment of the PH to a value of 6.7 - 6.9, by electrical treatment using a soluble anode containing ingredients in the following ratio, wt.%: AI 12.5 - 18.0, C 0.1 - 0.25, FE - the rest, changing the polarity of the current on the electrodes and settling. Moreover, the electric treatment process is carried out at a current density of 200 - 3000 A / m ² . 1 tab.

Description

This invention relates to a process for the purification of water from pollution, in particular, to electrochemical methods for purifying water.

The purpose of the invention is to reduce energy consumption and increase the degree of cleaning.

The method is implemented as follows.

Sewage water before being fed into the electrotreatment apparatus is corrected by the reaction of the medium to a pH of 6.7-6.9, after which it is fed into the electrotreatment apparatus. Electrical treatment is carried out in a direct current electrolytic cell with operating anode current densities in the range of 200-3000 A / m2. The anodes of the electrolyzer are made of iron-aluminum alloys with a content of components,%: A 12,5-18,0: C 0.1-0.25; Fe rest. To reduce the passivation effects, reversing the operating current, i.e. switching the polarity of the working electrodes after 3.5–4 h of operation for 15–20 s. The treated water stream is sent to a horizontal sump with a period of settling of 20 minutes.

Example. The electrocoagulator for cleaning contains two electrodes with a diameter of 40 mm at an initial current density of 100-4000 A / m2. The water supply is carried out from the bottom up, which provides a water flow rate of 5-6 m / s. The anodes are made of alloys of aluminum, carbon and iron, and the cathode is made of steel 3. Before processing, the pH of the waste water is set to 6.7-6.9 by adding hydrochloric acid. After electrotreatment, the pH of the purified water is 6.9-7.3.

An electrocoagulant for cleaning in a known manner contains two electrodes made of hot water iron-22 iron in the form of plates with dimensions of 83x180 mm. The cathode is made of chrome-nickel steel.

In all cases, the current is reversed — a change of polarity every 4 hours for 15–20 s. The residence time of the treated water in the sump 20 minutes

J

ABOUT

about

B

VJ eaten about

The results on finding the optimal alloy composition used to make anodes for wastewater treatment are shown in Table 1 (at a current density of 500 A / m).

As can be seen from Table 1, the positive effect of wastewater treatment compared with the known effect is achieved using an anode containing aluminum, carbon and iron in the following ratio, wt%: AI 12.5-18.0; From 0.1-0.25; Fe rest.

By reducing the carbon concentration to less than 0.1%, the current efficiency Fe + decreases. resulting in a reduced cleaning effect.

With an increase in the carbon concentration of more than 0.25%, the alloy loses its thermodynamic stability, the lattice parameters sharply decrease, which causes a decrease in the alloy dissolution rate and, as a result, a decrease in the cleaning effect.

The results of the comparison of the cost of electricity for processing 1 m3 of liquid and the efficiency of water purification by the proposed and known methods are presented in Table 2.

As can be seen from Table 2, in all cases of water treatment by the proposed method, a decrease in power consumption by an average of 0.22-0.03 kWh / m3 (17-20%) and an increase in the effect of water purification on suspended substances (HE) is observed by 3-5%. The optimum range of current densities is in the range of 200-3000 A / m2.

This is due to the fact that the ionization rate of the components and the alloy as a whole in the concentration range of 12.5–18.0 wt.% AI is characterized by abnormally high ionization rates at which the amount of metal for the same electrolysis conditions is greater than for alloys. other composition. This is due to the fact that the selected area is characterized by the presence of a stable, ordered ResA superstructure with a n. type B grill For such a crystal lattice, the period is twice as long as for the a-phase, which contributes

an increase in the rate of anodic dissolution, as well as all the deformation of the crystal lattice.

FORUMAWLAH AND ISLANDS

Claims (2)

1. A method of purifying water from contamination, including adjusting the pH to a value of 6.7-6.9, electrical treatment with a soluble anode containing iron, aluminum and carbon, changing the polarity of the current on the electrodes and settling, are also different in that , in order to reduce energy consumption and increase the degree of purification, during electrotreatment an anode is used containing the ingredients in the following ratio, wt.%: Aluminum 12,5-18,0 Carbon 0.1-0.25 IronErest 2. A method according to claim 1, characterized in that the electrical treatment is carried out at a current density of 200-3000 A / m2. Table 1 15.6 91 92 91 88 93 95 93 88 88  Iron up to 100% - the rest a j Proportional to the period of the crystal lattice. table 2