Abstract

Disinfecting of water is an obligatory stage of water treatment, the widespread disinfecting agent is gaseous chlorine. Availability, reliability, cheapness are related to its advantages as oxidizer. As it was established earlier, gaseous chlorine can be obtained in the course of self-diffusion interaction at system of peroxide compounds of salt of sodium, containing chlorine. Some oxygen containing compounds of sodium, for example, peroxide, chlorate are able to interact with salts of heavy metals, by that it is possible the presence of reaction in the mode of self-diffusion with extracting of large amount of heat, and as result of such reaction the extracting of oxygen takes place. However if investigated salt contains ions of chlorine, then one of the gaseous products can be free chlorine. Special interest has studying of interaction at three components systems, in which each initial substance can react each other and two of which contain chlorine. The purpose of this investigation is studying of exothermal processes of interaction at system CoCl 2 – NaClO 3 – NaO 2 with extracting as gaseous phase – chlorine, which can be used further.

Earlier the interaction were studied at systems NaClO 3 – NaO 2, CoCl 2 – NaClO 3, CoCl 2 – NaO 2, by that chlorine can be one of the products of interaction at the second and the third systems. Ratio Cl 2:O 2 at gaseous products depends on initial composition of mixture, theoretical optimal mole ratio of chloride of cobalt to superoxide of sodium is 3:2. In this case it is possible obtaining of gaseous mixture with maximal containing of chlorine in the conformity with equation of reaction

3CoCl 2 + 2NaO2 = Co3O4+ 2NaCl + 2Cl 2 H = -210,8 к J

It is experimentally established, that as result of self-diffusion interaction at this system gaseous chlorine is extracted, however in very small amount. Entering of chlorate of sodium, presumably, will allow to increase extracting of gaseous chlorine. Therefore interaction was studied at mixtures CoCl 2 : NaO 2 : NaClO 3 at mole ratio of initial components 3:2: х, where х was changed from 1 mol to 6 mols.

Mass of mixture for experiments was unchangeable and it was 5 g . Course of experiment was as follows : 1) preparation of mixture from reagents at definite ratios , 2) pressing of mixture , 3) burning of obtained tablet with simultaneous collecting of extracting gas . Definition of chlorine was conducted by iodine metrical method , for that collected gas was pumped through acidified solution of potassium iodide .

Theoretically the largest amount of chlorine is extracted at mole ratio of components CoCl 2:NaClO 3:NaO 2=3:2:2. In such case containing of chlorine at gas phase after conducting of reaction:

3CoCl 2 + 2NaClO 3 + 2NaO 2 = Co 3O 4 + 4NaCl + 3O 2 + 2Cl 2, H = 559,4к J

must be 40% of amount. As result of conducted experiments it was established, that as result of conducting of SRV at mole ratio of components CoCl 2:NaClO 3:NaO 2=3:2:2 the gas mixture is extracted, containing 0,0568g of chlorine, that relates to 3,24 % at gas mixture. This maximal containing of chlorine at gaseous products of reaction, can be coped to obtain at system CoCl 2:NaClO 3:NaO 2 (fig.1, table1). By that 2,85 % of chlorine is transformed to gas phase, which contained at initial mixture at chloride- and chlorate-ions.

Figure 1 – Dependence of chlorine contain at gaseous products on amount of chlorate of sodium at initial system

Data, shown at table 1, witness, that only small part of chlorine is transferred to gas phase, the main part is left as product of reaction: chloride of sodium.

So, conducted experiments show the possibility of obtaining of chlorine as result of self-diffusion interaction at system CoCl 2 – NaClO 3 – NaO 2. The advantages of such obtaining method are 1) absence of additional power expenditures, 2) usage of salts of heavy metals, which are the wastes of some productions and are not a subject to utilization, and therefore process, taking place at investigated system, can be put to base of further working out of compact resources of gaseous disinfecting agents.