Evaluation of Single and Mixed Draw Solutions on Forward Osmosis Process Performance
摘要
The current study focuses on the efficiency of the fertilizer-drawn forward osmosis process to produce a nutrient solution for hydroponic use. Instead of separating the draw solution from desalinated water, this study explores the potential of using the diluted fertilizer draw solution directly for fertigation. To achieve this, different fertilizers were tested as draw solutions. The study tested eight single inorganic and one organic salt separately and mixtures of these salts. Two parameters, water flux and reverse salt flux, were used to evaluate the forward osmosis process. The results indicate that mixed salts have a higher water flux than single salts due to increased draw solution osmotic pressure. In contrast, mixed salts have a lower reverse salt flux than single salts. The reverse salt flux varied from 17.42 g/m2.h for KCl to 5.15 g/m2.h for Mg(C2H3O2)2·4H2O. The water flux of the single salts ranged from 2.44 L/m2.h for Mg(C2H3O2)2·4H2O to 4.47 L/m2.h for MgCl2·6H2O. The mixture of NaNO3 and Mg(C2H3O2)2·4H2O gave the highest water flux at 5.92 L/m2.h; while, the mixture of MgCl2·6H2O and Mg(C2H3O2)2·4H2O produced the lowest reverse salt flux.