The study of the physic-chemical properties of bentonite-based composite sorbents modified with carbon under the conditions of catalytic carbonization

Abstract

The structural and sorption properties of composite sorbents based on natural bentonite modified with carbon compounds have been investigated. Modification of the initial bentonite by low-temperature (650°C) pyrolysis of sucrose in the presence of metal salts of the iron subgroup leads to a significant increase in the specific surface area of composite sorbents (up to 275 m2/g), this is due to low-temperature catalytic graphitization of the carbon fraction formed during pyrolysis. The sorption capacity of the investigated nanostructured composite sorbents with respect to nickel (II) and lead (II) ions has been studied. The highest values of the limiting adsorption of nickel (II) and lead (II) ions in neutral solutions (30–86 mg/g) were obtained on composite sorbents in which the introduced carbon underwent a stage of low-temperature catalytic graphitization. The pyrolytic method of introducing carbon with its simultaneous catalytic graphitization into composite sorbents based on bentonite is promising for the further improvement of sorbents based on natural aluminosilicates.

Keywords

• bentonite
• composite sorbent
• adsorption
• specifi c surface area
• catalytic graphitization