Chemical treatment of water

Summary

Data on the treatment of contaminated waste water with chromium (VI) ions using industrial wastes have been studied. Was used iron and relatively aluminum residues which are only industrial wastes for the treatment of waste water containing chrome ions. In fact, this method has advantages over many other methods:

1. Dewatering method does not require any electrical energy, reagents or complex equipment.

4. The most important is to find the remnants of the iron found in experiments anywhere.

And these advantages, how much will this method cost and how much it will benefit. That is why this method can be considered as a very effective, very convenient method in difficult economic conditions.

Keywords: iron residues, chromium (VI) compounds, treatment, purification, oxidation.

GOAL RESEARCH

Iron is very popular in the human society for a long time. It is a common olive oil in nature. This iron accounts for 4.2 percent of the Earth's crust. Among all the metals, iron has a huge role in the national economy. Production of ferrous metals, ie cast iron and steel, is one of the leading positions in the national economy development plan. In this regard, the abundance of iron residues is being developed. Currently, one of the most simple, effective and efficient methods of waste removal is to use other waste products [1-2]. Nowadays, in the era of science and technology in the revolution, when production growth rates are high, pollution of the external environment is global and causes great environmental problems. Pollution of the environment: pollution of air, soil and water, as well as the effects of water-industry. The main component of the water-human body is 80-90%, and cleaning of clean water and contaminated water is a big environmental problem. contaminated waste water of the industry, including the drainage water containing the valley ions (VI), has a great impact on the environment [3-4]. .

The toxicity of iron compounds in the water depends on its pH. In an alkaline environment, toxic fats immediately rise to the fish, ie, formed iron hydroxide is deposited into the fish groove, clogging them and breathing difficult.

Iron (II) compounds are extremely toxic: they cause death by entering the stomach in various organs of the mouse, causing various diseases. Iron (III) compounds are not too toxic but have a strong effect on the pathway to the digestive tract. Iron (III) sulfate and chloride, in the event of poisoning, first of all, at the microcirculation level, that is, heart failure. Iron-colored aerosols (dusts, smoke) and oxides, other compounds, accumulate in the lungs for a long time, and cause pneumoconiosis.

At the same time, iron (II) easily passes into iron (III) state and binds dissolved oxygen in the water and leads to mass death of fishes and other hydraulic biscuits. Water that contains iron can not be used for incubation of fish caviar, in which case hydroxides are deposited in fish groats and the aforementioned condition occurs. Iron (II) is very sensitive to hydroxide. The optimal concentration of Fe (OH) 2 for algae is 0.14-1.4 mg / l.

Iron can exist in aquatic systems (natural waters and their sediments) in several oxidation states: metallic iron (iron metal), ferrous iron (Fe II), and ferric iron (Fe III). The oxidation state in which iron exists in a particular aquatic system, and the redox reactions (chemical oxidation- reduction reactions) in which it participates, depends on the presence or absence of dissolved oxygen (DO). The sediments of many, if not most, aquatic systems are anoxic (without oxygen) as a result of the bacterial oxidation of particulate organic matter. Sediment organic matter includes dead and decomposing aquatic plants, algae and other organisms that settle to and become part of the sediments. In some waters, anthropogenic oxygen-demanding material (particulate biochemical oxygen demand, such as from wastewater treatment plant effluents) also accumulates in sediments. In such an anoxic environment, iron exists in the sediment in the reduced form, ferrous iron (FeII). In that form, it is often associated with sulfide, as black, iron sulfide.

BATCH EXPERIMENTS

Dewatering waters include the study of the properties of chromium (VI) ions by means of iron residues, the processing of various methods, time, water pH and so on. Let's explore the effects of parameterization. At the beginning of the experiment, we divided the powder residues into several fractions by passing the powders in different sieves, which was washed off by dust from the dust, oxide layer, and drying the powder with hydrochloric acid. In the course of the experiment, a photocoupleter was used to detect metal ions, the powder weight was measured using an analytical scale of 0.001g measuring accuracy "Shumadzu". At the end of the experiment, the solution was treated with alkali, and chromium (III) oxides were sulphated.

RESULTS AND DISCUSSION

Conducting research with the use of fine powders, because of the high degree of purification properties of fine metal than large powders. It is based on the properties of the two valence ions of iron, which are studied by the method of reducing the chromium six valence ions to three valents.

Fe2 + ions are capable of reducing the Cr6 + ion to the Cr3 + ion in chromate and dichromate solution and deposition of Fe(CrO2) 2 precipitate:

Cr2O7-2 + 6Fe 2 ++ 14H + ^ 6Fe3 ++ 2Cr3 ++ 7H2O (1)

2Fe2 ++ nH2O + Cr2O7-2 + 4OH- + 4e >-2Fe (CrO2) 2 + 2 (n + 1) H2O + 4O2 (3)

Iron and aluminum powder were obtained to investigate the effect of drain water on the level of chromium (VI) ions. The greatest degree of purification was detected in iron powders in 10 minutes, as the concentration of iron (II) in the solution increased, the degree of purification from chromium (VI) ions increased to 98%. The degree of purification of contaminated water from chromium (VI) ions in aluminum powder reached 65% in 10 minutes

Table 1 - Influence of the time of the experiment on degree of cleansing of chromium (VI) ions

Table 2 - Influence of waste weight on degree of purification of chromium (VI) ions

CONCLUSIONS

Data on the treatment of contaminated waste water with chromium (VI) ions using industrial wastes have been studied little. We used iron and relatively aluminum residues which are only industrial wastes for the treatment of waste water containing chrome ions. That is why we do not think that this work has practical value.

In fact, this method has advantages over many other methods:

1. Dewatering method does not require any electrical energy, reagents or complex equipment.

1. The most important is to find the remnants of the iron found in experiments anywhere.

And these advantages, how much will this method cost and how much it will benefit. That is why this method can be considered as a very effective, very convenient method in difficult economic conditions.

REFERENCES

1. A.S. USSR N 1785519 Method for purification of chrome-containing wastewater. Opubl. 30.12.92. Bullet No. 48
2. Vorobyova OM, Ippolitova EA, Nemkova OG, Dunaev KM Workshop on Inorganic Chemistry, Moscow, 1976, 298c
3. Patent of the Russian Federation No. 2023670, Method for purification of waste water from heavy metals, Opobl. 30.11.94, Bul # 22
4. Holleman, Arnold F.; Wiberg, Egon; Wiberg, Nils; (1985). "Chromium" (in German). Lehrbuch der Anorganischen Chemie(91-100 ed.). Walter de Gruyter. pp. 1081-1095. ISBN 3110075113.
5. Aber S., Amani-Ghadim A.R. and Mirzajani V. (2009) Removal of Cr (VI) from polluted solutions by electrocoagulation: Modeling of experimental results using artificial neural network, J. Hazard Mater, 171(1-3), 484-490.
6. Akbal F. and Camci S. (2012) Treatment of metal plating wastewater by electrocoagulation, Environ Prog Sustain Energy, 31(3), 340-350. 502
7. Arroyo M.G., Perez-Herranz V., Montanes M.T., Garcia-Anton J. and Guinon J.L. (2009) Effect of pH and chloride concentration on the removal of hexavalent chromium in a batch electrocoagulation reactor, J. Hazard Mater, 169(1-3), 1127-1133.
8. Arsand D.R., Kummerer K. and Martins A.F. (2012) Removal of dexamethasone from aqueous solution and hospital wastewater by electrocoagulation, Sci Total Environ, 443(C), 351-357.