Synthesis and characterization of PVDF/NaCI membrane for ammonia removal from aquaculture

Chiam , Chel Ken (2009) Synthesis and characterization of PVDF/NaCI membrane for ammonia removal from aquaculture. Masters thesis, Universiti Malaysia Sabah.

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Abstract

In this study, polyvinylidene fluoride (PVDF) flat membrane was fabricated to remove the total ammonia from saline water by direct contact membrane distillation (DCMD) at 50°C The effects of initial NH3 concentration from 0.03 to 0.47M, temperature from 30 to 50°C and salinity from 0 to 35ppt on ammonia-ammonium equilibrium, however, were initially investigated by using Law of Ostwald's Dissociation. The PVDF membranes were then fabricated from dimethylacetamide (DMAc) solvent and sodium chloride (NaCl) from concentration 0 to 6M as the dope additive by phase inversion in a distilled water coagulation bath. The membranes were dried and then characterized as well as applied in DCMD. Cocurrent configuration of DCMD was applied to study the mass transfer, water vapor flux and ammonia removal efficiency of the membranes. The experimental results showed the NH3 concentration in the water increases as the temperature and pH increased. The NH3 concentration, however, is relatively higher in pure water than that in saline water from temperature 30 to 50°C The drying process has improved the hydrophobicity of the membranes. The contact angles of the membranes with NaCI addition, however, were reduced from 165 to 156°. Graphically, the average ranges of membrane thickness and pore size were 71.5 to 111.5µm and 43.5 to 118.5nm, respectively. The addition of NaCI has reduced the average pore size from 81 to 66nm. Statistically, average ranges of the membrane thickness and pore size were 83 to 99µm and 82 to 103.3nm, respectively. The average membrane porosity with additives were increased from 78% to >82% compared to that of without the additives. The mass transfer coefficient of ammonia and the water vapor flux increase as the membrane porosity increased. The membrane porosity of 84% and effective membrane area of 56.40cm2 achieved the highest ammonia removal efficiency about 24% within 2 hours of DCMD.

Item Type:Thesis (Masters)
Uncontrolled Keywords:synthesis, polyvinylidene fluoride (PVDF), flat membrane, ammonia, aquaculture, saline water, direct contact membrane distillation (DCMD), characterization, temperature
Subjects:T Technology > TD Environmental technology. Sanitary engineering
Divisions:SCHOOL > School of Engineering and Information Technology
ID Code:6430
Deposited By:IR Admin
Deposited On:28 Jun 2013 10:15
Last Modified:28 Jun 2013 10:15

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