Synthesis of Alginate-synthetic and Chitosan-synthetic polymer Semi-IPN Xerogels for the removal of As(V) and Cu(II) ions

In this work, the removal of As(V) using poly[2-(acryloyloxy)ethyl]trimethylammonium chloride/chitosan (PClAETA/chitosan) and of Cu(II) using polyitaconic acid/alginate (PIA/alginate) xerogels has been reported. In this system cationic (PClAETA/chitosan) -N+(CH3)3 Cl- groups have been proposed to be involved in the adsorption of As(V), and anionic (PIA/alginate) OH and –COOH groups have been proposed for Cu(II) ion adsorption. These xerogels were characterized by FTIR and TGA-DGA. FTIR showed the presence of –OH and –COOH groups possibly involved in Cu(II) ion adsorption and NH₂ and N⁺(CH₃)₃ groups involved in As(V) adsorption. TGA-DGA demonstrated good thermal stability for all xerogel systems. Adsorption studies were performed using a batch adsorption technique. The As(V) adsorption capacity of PClAETA/chitosan at room temperature and pH 9 at lower concentrations was 82.3 mg/g and reached fast adsorption around 45 minutes. At the same time, the adsorption study for PClAETA/chitosan yielded 76% removal efficiency and an adsorption capacity of 30 mg/g of arsenic at 60ºC for a solution concentration of 100 mg/L. Meanwhile, the Cu(II) adsorption capacity of PIA/alginate at pH 4.5 and lower concentrations reached 93 mg/g, with a faster adsorption of around 5 minutes. This work reports the synthesis and characterization of novel semi-IPN xerogels, which demonstrated tunable adsorption properties by controlling their surface moieties and nanoscale structure, which is useful for wastewater treatment systems.