DFT study on the removal of polyacrylamide by titanium dioxide nanoparticles/polyacrylonitrile (rTiO₂@PAC) composite...

Due to its high solubility in water, polyacrylamide is one of the most widely used materials for removing environmental pollutants by coagulation and flocculation. It is worth noting that the excess amount of this polymer in the wastewater is considered a secondary pollutant, which causes the blocking of the membranes and filters used in the treatment plant. Polyacrylonitrile (PAN) is one of the practical polymers used to remove this pollutant, and its performance can be increased by using physical modification and hydrolysis of this polymer (poly-acrylic carboxylate (PAC)). This study evaluated and investigated structural and thermodynamic parameters of hydrolyzed polyacrylonitrile polymer containing rutile-titanium dioxide (rTiO₂) nanoparticles, and conversion of polyacrylamide to other products by computational methods. The obtained data show that titanium dioxide nanoparticles reduce the energy gap (E_g = 8.88 eV) and as a result increase the polarity and conductivity of the nanocomposite (rTiO₂@PAC). Gibbs free energy in the polyacrylamide conversion stage is equal to - 278.63 kJ mol ^-1. This decrease indicates the tendency of nanocomposite to transform the pollutant and reduce its blocking in the wastewater environment, and the obtained results show a good agreement with the experimental data.