Recycling of soya (Glycine max) vegetable waste to obtain a carbon-containing sorption material

Belgorod State Technological University named after V.G. Shukhov, Kostyukov St., 46, Belgorod, 308012, Russia

^* Corresponding author: Land-VNA78@list.ru

Abstract

The analysis of research literature indicates that certain innovations are required in managing vegetable carbon-containing waste. A method of obtaining a new sorption material from vegetable waste of soya Glycine max (leaves, stalks, pod shucks), carbonized at the temperature from 200 to 400 °С in the anaerobic environment in an airtight steel container for 1 hour, is suggested. The criteria for evaluating the quality of a thermally activated sorption material were presented with the following parameters: bulk density; mass yield and volume yield of the sorption material; combustion loss degree. The elemental analysis has demonstrated that with the increase in the treatment temperature the increase of the carbon content from 58 % (Т = 200 °С) to 65.6 % (Т = 400 °С) is registered; and the oxygen content is reduced from 37 to 24 %. The heat-treated samples were researched by means of a scanning electron microscope. The porosity type of all the obtained sorption materials is a macroporous body with a pore radius of over 100–200 nm. The general view of the carbon-containing materials has the following morphological characteristics: bulges on the outer surface, and the channel structure of macropores, typical of carbonized materials. The amount of functional groups was determined by the Boehm method. With increase in the treatment temperature, the amount of carboxyl groups on the surface of carbon-containing materials is increased, while the amount of lactone groups is decreased, which is due to the burning-off of organic matter. The sorption capacity for methylene blue dye (from 35.0 to 81.85 mg/g) was determined during heat treatment in the mentioned temperature range.