Destabilization potential of Fe3+ and Al3+ chloride salts and af-PFCl of Mg(OH)2 during the treatment of AMD

Ntwampe I O; Mootha K

Destabilization potential of Fe3+ and Al3+ chloride salts and af-PFCl of Mg(OH)2 during the treatment of AMD

Joint Event on 4^th International Conference on Pollution Control & Sustainable Environment & 6^th Edition of International Conference on Water Pollution & Sewage Management
July 26-27, 2018 Rome, Italy

Ntwampe I O and Mootha K

University of Johannesburg, South Africa

Posters & Accepted Abstracts: J Environ Res

Abstract

The treated acid mine drainage (AMD) was collected from the western decant in Krugersdorp, South Africa and was investigated in a series of small-scale laboratory tests using 200 mL of AMD dosed with FeCl3, AlCl3 and a synthetic acid free (af) flocculent prepared by a mixture of FeCl3 and Mg(OH)2 (af-PFClMg) respectively, the latter being to reduce the negative effect of the reagents (FeCl3 and Mg(OH)2) when dosed in pure form. Three treatment methods were employed such as a jar test, no mixing and a shaker. The speed of the equipment used for mixing and shaking was at 250 rpm for 2 mins and allowed to settle for 1 hour after which the pH, conductivity and turbidity were measured. The experimental results show that turbidity removal in the samples with AlCl3 and a synthetic af-PFClMg is similarly identical but slightly higher than that of the samples with FeCl3. The results showed that conductivity has an impact on the rate of hydrolysis. Comparative turbidity removal of the AMD sample between AlCl3, FeCl3 and af-PFCl indicates that the latter is an ideal replacement of a corrosive FeCl3 and Alzheimer-associated AlCl3. On the other hand, the optimal turbidity removal of the samples without mixing shows that destabilization-hydrolysis depends on the valence and electronegativity of the metal ions, which also indicates the insignificant effect of the pH adjustment. The SEM images show that the sludge in the samples with af-PFClMg dosage consists of a large cake-like structure, which is typical of optimal adsorption. The formation of the precipitates was found to be influenced by the ionic strength of the metal ion rather than by the pH of the solution.