Flux Decline and Fouling Analysis in Reverse Osmosis of Watermelon Juice

In this paper, the concentration of watermelon juice by HR98PP membrane was investigated at 30 and 40 bar of operating pressure. The semi-empirical model of permeate flux was determined. The predominant fouling mechanism in the concentration was found to be complete blocking by Hermia’s model. Recovery yield and content of total solid, lycopene and antioxidant capacity in concentrate was analyzed. Results indicated that, concentration of watermelon juice by HR98PP at 40 bar exhibited the higher effectiveness than that at 30 bar. At 40 bar and 2.25 of CF, contents of total sugar (TS), lycopene and antioxidant capacity in concentrate were 171.31 g/L, 83.9 mg/L and 124.74 mg TEAC/L, respectively. Recovery yields of TS, lycopene and antioxidant capacity in concentrate were 98.67. 90.03 and 82.39%, respectively. Maximum CF value of concentration at 40 bar of operating pressure was 2.64. The mathematical model was built for estimation of the change in the contents of lycopene and TS versus time. Maximum theoretical content of lycopene and TS at 40 bar were estimated as 185 mg/L and 341 g/L, respectively. The cleaning procedure with NaOH solution at pH10 could fully recovery permeate flux after the concentration. Results imply that, concentration of watermelon juice by HR98PP was feasible.