Студент Разиньков Д.Ю., студент Будыкина Д.В., к.х.н. Пожидаева С.Д.

Юго-Западный государственный университет

The use of agrowaste as the absorbing agent for different classes of industrial dyes

Creating effective ways of toxic waste treatment and disposal, including different technological wastewater is an important environmental problem. Sorbents that could be used to solve this problem, more often than not, are expensive or ineffective. Therefore, special attention should be paid to finding new innovative materials with high sorption properties including industrial waste and natural materials.

It was interesting to investigate the sorption ability of corn's residues not used as fodder to purify water from organic dyes. Specially provided for this purpose sorption capacity and sorption percent of corn was determined.

To determine the sorption capacity and sorption percent of corncobs it was necessary to prepare solutions with four classes of dyes: acid ( acid dye bright blue), cationic ( cationic dye red), chromium (chromium dye blue 2 K) and active ( active dye orange) concentration of 0.005 to 0.1 g/l. The sorption of dye solutions was carried out under the same conditions (m_sorbent=2g, t_contact=30 min, v_solution=50 ml). To determine the residual concentration after sorption the photometric method, the method of calibration curve A=F(due) was used. The results of this research are shown in Tables 1-4. The data in Tables 1-4 show that complete sorption was achieved within 30 minutes only for active orange dye and acid bright blue dye with concentration 0.005 g/l.

Tables 1 – Sorption cationic dye red

С source, g/l	С residual, g/l	А	G,10^-3	G,%
0,100	0,009	0,238	2,275	91
0,050	0,014	0,375	0,900	72
0,010	0,004	0,109	0,150	60
0,005	0,004	0,041	0,025	20

Tables 2 – Sorption active dye orange

С source, g/l	С residual, g/l	А	G,10^-3	G,%
0,100	0,086	1,886	0,350	14
0,050	0,006	0,138	0,100	40
0,010	0,003	0,071	0,050	40
0,005	0	0,110	0,025	100

Tables 3 – Sorption acid dye bright blue

С source, g/l	С residual, g/l	А	G,10^-3	G,%
0,100	0,006	0,121	2,350	94
0,050	0,003	0,056	1,175	94
0,010	0,002	0,041	0,200	80
0,005	0	0	0,125	100

Tables 4 – Sorption chromium dye blue

С source, g/l	С residual, g/l	А	G,10^-3	G,%
0,100	0,021	0,501	1,980	79
0,050	0,007	0,169	1,075	86
0,010	0,003	0,059	0,180	75
0,005	0,003	0,102	0,040	32

Sorption isotherm of active orange dye is similar to isotherm of the 4th type according to the classification of the Brunauer, Emmet and Teller. This S - shaped isotherm refers to the isotherm transition-porous sorbents . Convex portions of sorption isotherms specify the presence of micropores in the sorbents, concave portions indicate the presence of macropores.

Sorption isotherms of acid dye bright blue, chromium dye blue, cationic dye red are similar to the isotherm of the 3rd type and describe strong intermolecular interaction in the sorbate's substance.

The research has shown that corncobs have good sorption capacity. During a short period of contact maximal level of sorption is achieved for almost all dyes used in the experiment, which indicates their high sorption capacity.