Adsorption Of Lead (ii) Ions On Transcarpathian Clinoptilolite
ADSORPTION OF LEAD (II) IONS ON TRANSCARPATHIAN CLINOPTILOLITE
V. I. Gomonay1, N. P. Golub1, K. Yu. Sekeresh1,
P. V. Gomonay1, R. Leboda2
1Uzhhorod State University, Ukraine
2Maria Curie-Sklodowska University, Lublin, Poland Introduction
The large crashes on getting mines of Romania have reduced in pollution of the river Tissa and major squares of cultivated grounds along its coast (more than 5000 hectare). By the purpose of the present research was the development of a method of deleting of bonds of a lead (II) with the help of the modified forms of Transcarpathian clinoptilolite.
The adsorption of ions lead (II) was conducted in static and dynamic conditions. The concentration of ions Pb2+ in solution before and after adsorption was analyzed by spectrophotometric method.
The value of a limiting adsorption of ions Pb2+on initial natural clinoptilolite is insignificant and achieves only 0,5 mg Pb2+/g. Processing the initial zeolite by 1 N solutions of sodium chloride or ammonium nitrate it was possible considerably to increase an adsorption capacity till 6 mg/g sorbent.
However taking into account major dimension of ions of a lead (II) even in a unhydrated state (12,2Å), it is possible to assume, that the large part of canals in zeolite remains unavailable to them.
With the purpose of augmentation of a diameter of pores and specific surface area was conducted dealumination of clinoptilolite by solution of hydrochloric acid (1 N). After processing zeolite by hydrochloric acid during 5 hours the specific
surface area is magnified in 5 times (from 15 up to 97 м2/g), surface of micropores - in 30 times (from 2,5 up to 66 м2/g), volume of pores approximately in 2 times (from 0,030 up to 0,075 см3/g), and volume of micropores was magnified in 20 times (from 0,0011 up to 0,02884 см3/g), that in the total results in augmentation of an adsorption of ions Pb2+ till 10 mg/g. The linear increase of an adsorption with augmentation of an amount of the extracted aluminum oxide from a crystal lattice of zeolite (fig.1) is watched practically.
Dimension of beads of sorbent plays a major role on its adsorption capacity. The cleavage of zeolite up to a powder of dimension is less 0,1 mm results in destruction of its frame and decrease of getter ability in relation to ions Pb2+ more than twice. The finely divided powder of zeolite can be successfully utilised in a fluidized layer.
The absorption rate in dynamic conditions is much higher, than in static: in dynamic conditions the maximum of an adsorption is achieved in 45 minutes, whereas in static conditions only in 24 hours. Optimum aggregate size of sorbent in dynamic conditions - 2÷5 mm.
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