Humic coated polybenzoxazine xerogel for copper removal

Abstract

A polybenzoxazine xerogel was synthesized from bisphenol-A, formaldehyde, and aromatic diamine. FTIR, DSC, TGA, measurements were used to characterize the properties of the polybenzoxazine xerogel. SEM micrograph showed the interconnected structure of the organic xerogel derived from 25 wt% of polybenzoxazine. Humic acid 0.1 w% was coated on polybenzoxazine xerogel at room temperature via the layer-by-layer polyelectrolyte multilayer (PEM) surface modification method using poly(diallyldimethylammonium chloride) (PDADMAC) and poly(sodium 4-styrenesulfonate) (PSS) as primer coating for 4 layers. The PEM layers were investigated using UV-VIS measurements. The results showed that the absorbance of the prepared samples increased when the number of PEM layers increased. Finally, copper(II)acetate at pH7, was added to the coated xerogel to study the ability of humic acid to remove copper. The UV-VIS results indicated that copper was adsorbed on the humic surface. When the injection time of copper was increased, the absorbance of copper after the adsorption was decreased.