Effective sorption material based on red mud
О. V. Shvorak, Т. А. Dontsova
Химия и современные технологии
Every year waste of production, both in Ukraine and in the world, is growing significantly. Mining and metallurgical enterprises accumulate the largest amount of waste. As a result of their accumulation leads to the ecological balance in nature is disturbed; they are a significant factor in pollution of the environment. One of this hazardous waste is red mud. It is a by-product of the aluminum oxide production, which contains various oxides of metals in its composition. About 95% of aluminum production is formed by Baer's process; 1-1.5 tons of red mud are obtained from every ton of aluminum oxide. The annual growth of red mud from only one enterprise is approximately 800 thousand tons. At this stage due to the economic disadvantage of the problem of its remaking is not solved in full .
In this paper, effective sorption material by processing of red mud in relation to anionic dyes (Congo Red) is proposed.
The treatment of red mud was carried out by heating at 200, 400, 600 and 800ºС for 1 hour (samples TR200, TR400, TR600, TR800). Additionally, a magnetic sample was obtained by treated at a temperature of 600ºC in the presence of starch (TS600).
The samples were tested on the sorption capacity of anionic dyes on an example of the Congo Red. Also, for comparison, sorbent activity was investigated of the initial red mud.
Sorption experiments were carried out as follows: a sorbent with a dose of 10 g/dm3 was added to the Congo Red solution with concentration of 20 mg/dm3. The contact time of the sorbent with the dye solution was 4 hours. The sorbent was then separated, and the obtained solutions were analyzed by spectrophotometric method. The calculated degree of removal of dye for each sorbent is shown in Figure 1.
Consequently, from Figure 1, we see that the dye removal for the primary sludge and the TS600 simple was 21% and 67%, accordingly. For samples TR200, TR400, TR600, TR800, the degree of Congo Red removal is 25%, 70%, 90% and 95%, respectively. Thus, according to the obtained results more rational is the TR600 simple.
Next, the rational duration of the contact between the choose sorbent TR600 and the solution of the Congo Red was established. For this purpose, the following times were chosen: 30 minutes, 1 hour, 2 hours, 3 hours and 4 hours. The results obtained are shown in Figure 2.
Figure 1 – Removal (%) of Congo Red from solution by different samples.
Based on the data obtained, we can see that the adsorption equilibrium is set in 2 hours.
Figure 2 – Dependence of the degree of Congo red removal on the contact duration.
Consequently, it can be concluded that the simple heat treatment of red mud results in the formation of an effective sorption material for the removal of anionic dyes from water.
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