(419n) Sulfuric Acid Concentration By Vacuum Equipped Direct Contact Membrane Distillation

Production of every ton of titanic oxide (TiO₂) will generate around 8 tons of sulfuric acid (~20wt.%) with various inorganic salts (e.g. FeSO₄, TiOSO₄, Al₂(SO₄)₃). Recovery of the above sulfuric acid will lead to both environmental and economic benefits. In current work, vacuum equipped direct membrane distillation (VEDCMD) was used to concentrate the simulated sulfuric acid. The inorganic salt in the solution is FeSO₄. The process delivered purified water that can be recycled and iron vitriol crystals were formed during the cooling crystallization step. The experiments were carried out keeping the warm feed temperatures at 323 to 343, while cold solution 290 K, respectively. Effects of feed temperature, feed flow rate and distillate flow rate on the separation performance were investigated. Surface contamination and membrane wetting were studied by SEM, XPS, XRD etc. Chemical cleaning and the recovery of the membrane separation properties were also investigated.