Organic and inorganic matter removal using high polymeric Al13 containing polyaluminium chloride

Abstract

The ability of locally laboratory-synthesized polyaluminium chloride (PAC) with high Al13 content (PAC-Al13) to remove organic, inorganic matter and colour from potable water, agricultural and electroplating wastewaters was evaluated relative to commercial PAC (PACI). PAC-Al13 used in this study was prepared using batch titration of NaOH into AlCl3·6H2O solution under vigorous stirring as opposed to the conventional slow-base titration method. The highly pure PAC-Al13 (containing 79% polymeric Al13 species) with high basicity (87%) was isolated and extracted using the sulphate displacement method and metathesis reaction. PAC-Al13 showed higher COD (85–96%), metals (95–100%), TDS (86–90%) and colour (90–95%) removal compared with PACI, i.e. COD (57–74%), metals (71–99%), TDS (58–80%) and colour (85–92%). The dominance of polymeric Al13 species in PAC-Al13 was supported from the scanning electron microscopy images (presence of Keggin structure of Al13) and the 27Al nuclear magnetic resonance analysis that showed the appearance of a single peak at 62.1 ppm. This study demonstrated the potential of using a new type of PAC, produced using simple preparation technique and contain high polymeric Al13 species, that has the ability to remove contaminants from water and wastewater systems more efficiently.