Synthesis of Thermosensitive Polymer and Its Application for Ni Nanoparticle Removal

The removal of hazardous materials and toxic agents (such as heavy metals), from wastewater in different industries attracted much attention in recent years. There are variousprocesses for treating polluted water, among these separation techniques, flocculation of suspended particles has beenwidely used because of consuming less energy and having a minimum impact on the environment [1]. Nowadays thermosensitive polymers are used asflocculant polymers and their application in water treatment is developing. Temperature-responsive polymers, such as poly (N-isopropylacrylamide) (PNIPAAm), exhibit a volume phasetransition at a critical temperature, which causes a sudden change in the solvation state. Such polymers, which becomeinsoluble and hydrophobic upon heating, have a lower critical solution temperature (LCST). The LCST behavior of polymers can be explained as a balance between the entropic effects of the dissolution and the ordered state of water molecules in the vicinity of the polymer and the enthalpic effects due tohydrogen bonding and hydrophobic interactions [2, 3]. PNIPAAm is hydrophilic below the LCST (about 32C) andthere is no considerable interaction between polymer and the suspended particles, but above LCST hydrophobichydrophobic interactions occur between polymer andparticles, which lead to shrinkage of the polymer and sorption of suspended particles. Nickel and its derivatives are believedto be toxic, carcinogenic, and allergic. In this paper, poly PNIPAAm was synthesized via free radical polymerization and the nanoparticle sorption ability ofpolymer was evaluated in nickel nanoparticle-water suspension mixture. The nanoparticle sorption ability of the polymer is considered as a potential capability for removing polluting agents. Results of examinations showed a well sorption capacity of PNIPAAm and the usage in water treatment.