The usage potential of activated carbon in sugar beet molasses purification: Influence on colour and turbidity

Abstract
Sugar beet molasses represents valuable sugar industry by-product due to the diversity of present
compounds. Constrains towards molasses complete exploitation through present compounds
valorisation initiated numerous investigations. The primary aim of the corresponding
investigations was to identify an effective treatment for sugar and non-sugars separation.
Separation of sugar and non-sugars concentrated in the sugar beet molasses could be achieved by
various adsorption based treatments under appropriate conditions.
Considering successful application of activated carbon as an adsorbent of non-sugars in juice
purification, the presented study aims to investigate its usage potential in molasses purification.
In this regard, granulated activated carbon adsorption performance was determined through sugar
beet molasses colour and turbidity assessment.
According to the applied Box-Behnken experimental design, the influence of 3 independent
parameters: pH (3, 5 and 7), temperature (40, 60 and 80°C) and activated carbon concentration
(1, 3 and 5 g/L) on molasses colour and turbidity were examined. The molasses dry substance
(10° Brix) was kept constant in all conducted experiments. Response surface methodology was
used for determination of applied parameters significance.
Molasses colour and turbidity reduction extent was greatly dependent on pH. Applied strongly
acidic conditions (pH 3) were adequate for reaching maximal molasses colour reduction while the
opposite effect was observed in molasses turbidity reduction. Furthermore, an increase in the
activated carbon concentration contributed to the molasses colour reduction. The influence of
treatment temperature was not established as significant in terms of molasses colour and turbidity
reduction.
The obtained positive results regarding molasses colour and turbidity reduction upon activated
carbon application confirm its adsorption potential towards non-sugars present in molasses.
Nevertheless, to accomplish balance between satisfactory molasses colour and turbidity
reduction, determination of adequate treatment conditions is crucial and requires further research.
Key words: molasses, colourants, adsorbent, purification
Acknowledgements: Presented study was financially supported through bilateral project between the
countries of Hungary and Serbia (HU project no. TÉT-16-1-2016-0138 financed under the NKFIH-1557-
1/2017; SRB project number 451-03-02294/2015-09/4).