Preparation and characterization of forward osmosis cellulose acetate butyrate/OH‐functionalized multiwalled carbon nanotube membrane for the concentration of bitter orange juice

Abstract

AbstractAs an essential process in food industry, fruit dewatering should have the least impact on the nutritional values of the product. In this research, bitter orange juice was concentrated via the forward osmosis (FO) process for the first time. For this purpose, cellulose acetate butyrate (CAB)/OH‐functionalized multiwalled carbon nanotubes (FMWCNTs) membranes were prepared using various nanofiller concentrations. The obtained membranes were characterized in terms of their morphology, porosity, water contact angle, chemical structure, tensile properties, and pure water flux. During the FO process, NaCl solution was applied as the draw solution (DS), and the concentration of NaCl was varied (1.2, 2.2, and 4.2 M) to assess its effect on the process performance. Increasing FMWCNTs loading in the casting solution up to 0.3 wt% boosted the membrane porosity, hydrophilicity, elastic modulus, and pure water flux. The CAB membrane incorporated with 0.3 wt% nanofiller and the DS with 4.2 M NaCl concentration represented the highest water flux (29.93 L/m2h) in the FO experiment and provided the maximum turbidity (1545 NTU) and viscosity (4.64 cP) of the treated feed. According to the obtained results, the developed CAB/FMWCNTs membrane proved promising in the FO concentration of fruit juice.Practical ApplicationsBitter orange juice was concentrated via the FO process using the developed CAB/OH‐FMWCNTs membranes. According to the results, water flux, and thus the dewatering efficiency increased and reached its highest value using the CAB membrane incorporated with 0.3% FMWCNTs. Since membrane processes operate at low temperatures and do not deteriorate the concentrate quality, FO concentration of bitter orange juice using the membrane modified in this study can be a superior alternative to the conventional thermal methods.