Flocculation of Ferric Laurate Suspension Using Cationized Pyrodextrins

Commercial pyrodextrins (PDs) British gum (BG), Dexy-84 (D84), and Dexy-86 (D86) were cationized using 3-chloro-2-hydroxypropyl trimethyl ammonium chloride solution and used as flocculating agents for ferric laurate suspension. Results indicate that: a) optimal dose of flocculation at pH 6 using different cationized PDs having approximately the same % N (0.372%, 0.365%, and 0.354% and designated as BG-2, D84–2 and D86–2, respectively) follows the descending order: D84–2 > D86–2 > BG-2; b) optimal dose of flocculation using BG-2 is higher at pH 8 than that at pH 6; and c) practically complete flocculation occurs at pH 6 using cationized BG of three different % N (namely 0.21%, 0.372%, and 0.481% and designated as BG-1, BG-2, and BG-3, respectively) and the optimal dose decreases upon increasing the % N. Comparing BG-3 with a commercially available cationic polymer shows that: a) the optimal dose of the latter is 15% of that of BG-3 at pH 6; however, BG-3 achieves complete flocculation, which is not the case regarding to the commercial polymer; and b) at pH 8 the optimal dose of the polymer is 5% that of BG-3 and the extent of flocculation is slightly higher in case BG-3 than the polymer. Combination of BG-3 with aluminum sulfate co-flocculants shows that their effect is higher than that of any of them separately. Adsorption dynamic using Lagergren's equation showed that ferric laurate suspension is combined with BG-3 through a first-order reaction. Moreover, the same process obeys Freundlich type adsorption isotherm.

Keywords:

• Pyrodextrins
• Cationization
• Ferric laurate
• Flocculation

Notes

50-g PD sample was incubated in NaOH solution in ethanol/H₂O (114 mL/29 mL) at 50°C/15 min, followed by CHPTAC addition and continuing incubation for extra 8 h with continuous shaking.

Temperature, 25°C.

Temperature, 25°C.

Temperature, 25°C; pH, 6.