Investigation of Crystal Size Distribution in Purification of Terephthalic Acid from Polyester Textile Industry Waste by Reactive Crystallization

The purification of terephthalic acid recovered from an alkali-reduction wastewater by reactive crystallization was investigated. crude reacted with sodium hydroxide solution to form a salt disodium terephthalate, then acidified sulfuric get the higher purity. Effects time, pH, concentration, and flow rate secondary feed solutions, temperature, stirring on Crystal Size Distribution (CSD) precipitate were results showed that CSD influenced concentration reactants pH solution. On other hand, solution, had no significant effects CSD, which mean size crystals ±3 μm. at 5, 4, 3 6.03, 9.42, 10.34 μm, respectively; meanwhile, concentrations 0.5, 0.3, 0.1 M, 7.57, 3.24, 3.09 respectively. semi-batch double-feeding constant temperature produced monodispersed crystals. However, this method needs be carried out more than once for purification, is intended polyethylene terephthalate (PET) polymerization.