Polyacrylonitrile and Hybrid SBA-15: A Robust Composite Material for Use as Copper (II) Adsorbent in Flow Conditions

Novel processes for treating industrial wastewater containing metals are needed nowadays in order to meet environmentally safe water treatment standards. Attention has been paid to innovative adsorbents that permit to trap and subsequently desorb ions, permitting their selective recovery. In this work, we design a robust porous exchange matrix able to adsorb Cu (II) (often found in industrial wastewater), that meets the following requirements: (a) to perform copper desorption with a minimum condition modification, (b) to preconcentrate already desorbed ions, (c) to be reusable, and (d) to be able to work in flow condition. A hybrid mesoporous material matrix (HMM) composed of a hybrid mesoporous filler embedded into a highly accessible polymer was chosen as adsorbent. The mesoporous filler is mesoporous silica (SBA-15) chemically modified through post-grafting with amino groups. The composite material was prepared by combining the adsorbent material and polyacrylonitrile (PAN). The system could be easily processed in columns of fixed bed in order to perform copper adsorption-desorption. Under these conditions, a Cu (II) loading of 1.2 x 10(-3) mol per gram of adsorbent material was obtained. Copper desorption was performed in HCl 0.1 M, achieving a final concentration at least 5 times higher than the initial one. The material was reused 10 times without losing its adsorption capacity, demonstrating its potentiality for water treatment.