Studies On Extraction And Separation Of P-Aminobenzoic Acid From Water Using Emulsion Liquid Membranes

The separation and extraction of p-aminobenzoic acid using liquid emulsion membranes was studied. First, the existing states of p-aminobenzoic acid in water and the mechanism of mass transfer of p-aminobenzoic acid in the membrane process were discussed; also, a system of liquid emulsion membrane which can be used to extract p-aminobenzoic acid from water was created. The experimental results showed that, the system of liquid emulsion membrane can successfully separate and extract p-aminobenzoic acid from water. The extraction ratio of p-aminobenzoic acid were affected by several factors, including the pH of external phase, the dosage of mobile carrier TBP and the dosage of surfactant Span-80 in oil membrane phase and the concentration of sodium hydroxide in the internal phase.Then, the effects of the surfactant structure and dosage on membranes stability and extraction ratio of p-aminobenzoic acid were investigated especially. Three different type surfactants, L-113A,L-113B and Span-80, were selected to discuss how the structure and dosage of surfactant affect the stability of membranes and extraction ratio of p-aminobenzoic acid. The experimental results showed that, L-113A was more suitable to extract p-aminobenzoic acid from water than L-113B and Span-80.Finally, the effects of the type and dosage of mobile carrier on membranes stability and extraction ratio of p-aminobenzoic acid were investigated. The experimental result indicated that TRPO was more suitable for extracting p-aminobenzoic acid form water than TBP, N235 and N503. The maximum membrane phase stability and p-aminobenzoic acid extraction ratio were obtained using TRPO as mobile carrier.