Equilibrium and kinetic studies on the adsorption process with liquid sugar production from carob

The objective of this research is to conduct liquid sugar production from carob fruit in addition to the examination of its adsorbtion kinetics and mechanism. Within this framework, 22 brix concentrate extracts were obtained by the seedfree and chopped parts of the carob fruits. The extracts possess a great deal of turbidity. Therefore, gelatine, bentonite and kieselsol agents were applied for clear fruit juice production. The bleached carob extracts were first treated with powder activated charcoal prior to the removal of impurities by an ion-exchange resin. In this study, three different concentrates of carob extracts were used. Thus, the Brix value of the 22 brix carob extracts was adjusted to three different concentrates of 5, 10 and 15 brix which will be analyzed in the following part of the research. In order to bleach the extracts whose brix values were adjusted for the working conditions, three different concentrations (5,10 and 15 g/L) of powder activated charcoal at 20, 25 and 30⁰C were used. Powder activated charcoal provided the decolorization of the samples but led to a reduction in the lightness of the extracts. Having treated with powder activated charcoal, 25 g of Dowex Marathon MR-3 resin per 100 ml extract was added in order to increase the lightness and remove the impurities. After the treatment with the resin, the problems and impurities caused by the powder activated charcoal were eliminated. The goal of this study is to obtain higher L* and lower a* and b* values for the final products in comparison with the control groups after the treatment with ion exchange resin. Following this, Hunter Lab color analysis were performed which revealed higher L* values of 15 Brix concentrates and lower values of a* and b* compared to the control group. The most effective application was carried out with the 15 brix concentrates of carob extracts. The studies in relation to the adsorbtion kinetics and mechanism were conducted by the Dowex Marathon MR-3 resin. The highest removal was yielded by treating with the resin of 20 g/L at 40⁰C under the working conditions with the resin concentrations of 10 g/L and 20 g/L at 30, 40 and 50⁰C. The adsorbtion process was described by the Langmuir isoterm model. The process was determined as a pseudo first order reaction and it was observed that pore diffusion is the rate determining step. This process occurs spontaneously by physical adsorbtion and it is also an exothermic reaction. Key words: Carob, liquid sugar, powder activated charcoal, ion exchange resin, adsorbtion