EURO-ECO 2006 Hanover 1 - 2 December 2006	Environmental and Engineering Aspects for sustainable living
	European Academy of Natural Sciences, Hanover European Scientific Society, Hanover Russian Academy of Natural Sciences, Moscow

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Abstracts EURO-ECO 2006

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S.V. Sverguzova

Summary: the opportunity of obtaining carbon sorbents from vegetative raw materias, such as pine raspings and shells of walnuts is under investigation. It is shown that active coals obtained have high adsorptive activity and can find application in technology of waste water clearing from nickel ions.

The studies of porous timber structure and structure of walnut shells, their sorbate capacity and possibility of deriving fissile coals from vegetative raw materials are carried out. Heat treatment of the granulated raw was carried out under laboratory conditions in the hermetic container manufactured of steel at 400, 450 and 500 ºC with the purpose of clearing raw materials from volatile substances, moisture and partially gum. Besides walnut shells worked up at 600 and 700 ºC.

The time of treatment of given patterns at given temperatures amounted to 15, 25 and 35 min. The speed of raw materials heating at carbonization should be low, otherwise the exit of coal and acetic acid decreases and the exit of gum increases. The problem of obtaining lace microporous structure is solved in the process of activation. For this purpose before feeding raw materials in the container it was treated by chloride of zinc with coefficient of impregnation equal to 1:2. The chloride of zinc transfers cellulose in the solution, which emits at the temperature rise the highly dispersive amorphous carbon forming a microporous structure. The fissile coal obtained by the method of chemical activation, varies by the large uniformity of the texture as a whole from the pattern of coal of steam-gaseous activation. Besides, the identity of structure at chemical activation is saved in pellets: their peripheral and internal leases are one-type. The agent of steam-gaseous activation was steam. The criterium of carbon materials quality is the sorbate tankage (mg/g of ions Ni²⁺, absorbed 1 g of sorbent). Concentration of nickel was determined by the photometric method on the spectrophotometer.

Estimating quality of fissile coals it is necessary to consider complicity of their physicochemical properties. In operation some differentiating tests were applied which described the physicochemical properties of the initial raw materials and obtained carbon sorbents. At the process of activation measurings of weight of the booted and obtained products (M_I and M_A, g), volume of the booted and obtained products (V_I and V_A, cm³) were conducted. The criteria of quality estimation of fissile coals were the following parameters: methylene number, I_M, %; bulk and true density (ρN and ρT, g/cm³), volume of sorbate pores (by exixated method) on benzol (WS, cm³/g), exit of fissile coal on mass R_M, %; exit of fissile coal on volume R_V, %; an extent of hardening of the material obtained, w, %; a ratio of the exit on weight to the exit on volume RM/Rv; a volumetric index of porosity Ws• ρN, cm³/cm³; specific surface, S, m²/g. The properties of fissile coals obtained from raspings are represented in tab. 1, in tab. 2 – from walnut shells.

Table 1. The physical properties of fissile coals from pine raspings

T of pyrolysis, ºC	Time of pyrolysis, t, min	ρN, g/cm³	ρT, g/cm³	RM, %	RV, %	RM /RV	IM, %	WS, cm³/g	w, %	Ws•ρN, cm³/cm³	S, m²/g
400	15	0,273	1,95	96,6	64	1,51	15	0,063	0,09	0,017	428
	25	0,218	1,91	74,9	60	1,25	17	0,062	25,1	0,013	595
	35	0,196	1,79	65,9	58	1,14	20	0,059	34,1	0,012	689
450	15	0,266	1,90	91,6	60	1,53	20	0,078	8,3	0,021	798
	25	0,209	1,75	69,9	57	1,23	30	0,079	31,1	0,017	1126
	35	0,202	1,56	64,8	56	1,16	22	0,063	35,2	0,013	960
500	15	0,246	1,80	79,2	56	1,41	10	0,072	21,0	0,018	780
	25	0,194	1,36	59,7	54	1,11	15	0,042	40,3	0,008	852
	35	0,192	1,35	57,3	52	1,10	5	0,045	42,7	0,009	838

Table 2. Physical properties of fissile coals from walnut shells

T of pyrolysis, ºC	Time of pyrolysis, t, min	ρN, g/cm³	ρT, g/cm³	RM, %	RV, %	RM /RV	IM, %	WS, cm³/g	w, %	Ws•ρN, cm³/cm³	S, m²/g
400	15	0,369	2,11	69,1	68	1,02	10	0,011	30,9	0,004	404
	25	0,336	1,98	60,9	65	0,94	10	0,014	39,3	0,004	425
	35	0,321	1,95	49,1	60	0,82	15	0,020	46,7	0,006	445
450	15	0,340	2,04	67,4	64	1,05	10	0,027	32,6	0,009	470
	25	0,326	1,95	58,4	62	0,94	15	0,031	41,6	0,010	496
	35	0,310	1,90	51,6	60	0,86	15	0,039	48,4	0,012	520
500	15	0,302	1,97	49,8	55	0,91	20	0,027	50,2	0,008	535
	25	0,305	1,87	46,7	55	0,85	20	0,033	53,3	0,010	571
	35	0,289	1,81	42,9	54	0,79	25	0,041	57,1	0,012	590
600	15	0,298	1,81	41,65	53,7	0,78	25	0,059	51,5	0,017	600
	25	0,295	1,70	41,44	53,3	0,77	25	0,073	55	0,022	630
	35	0,279	1,79	40,23	53,23	0,76	35	0,089	59,08	0,025	650
700	15	0,290	1,75	39,9	53,5	0,75	35	0,068	53	0,019	667
	25	0,285	1,73	39,3	53	0,74	35	0,084	57	0,024	685
	35	0,272	1,71	39,26	52,91	0,74	40	0,098	60,74	0,027	700

As it can be observed from Tab. 1 and 2 the exit of fissile coal on weight and volume decreases with the increase of time and temperature of pyrolysis, and the extent of hardening increases.

The loss of weight is bound up with the process of pore formation and the process of level-by-level combustion of the material. By the results of experiments the sorbent capacitance on an ions of nickel is established, which lays within the limits 80,1–97,7 mg/g (pine raspings) and 91,0–97,5 mg/g (walnut shells). The optimum regime of the process of pyrolysis of pine raspings is bound with the temperature 450 ºC at the time of carbonization 25 min, walnut shells – 700 ºC at the time of carbonization 30 min; at the same time the increase of specific surface, volume of sorbate pores and sorbate capacitance is marked.

Conclusions

1. The fissile coals from vegetative raw materials, such as pine raspings and walnut shells at the temperatures of pyrolyses 400–700 ºC are obtained.
2. Carried out analysis of physicochemical properties of sorbents after activation.
3. The estimation of sorbate activity of several patterns of fissile coal in a ratio of sorption of ions of nickel from the model solution was carried out. The value amounts to 80,1–97,7 mg/g (pine raspings) and 91,0–99,5 mg/g (walnut shells).
4. The optimal conditions for obtaining fissile coals from pine raspings are calculated: temperature equal to 450 ºC, the time of carbonization equal to 25 min; pine raspings – temperature 700 ºC, the time of carbonization equal to 30 min.