Influence of Modified Alumina Nanoparticles on the Performance of Polymeric Membrane in Reduction of Water Hardness

Innovative nanofiller produced by poly(acrylic acid) attachment onto alumina nanoparticles was embedded into the polysulfone membrane. The efficiency of the nanofiltration membrane was investigated for hardness removal from water. Considering the feed concentration and pH as well as nanoparticle content, the optimization of process variables was performed using response surface methodology (RSM). The negative charge of the membrane surface caused by carboxyl functional groups on alumina nanoparticles elevated the cation removal efficiency from water. Statistical analysis revealed that 0.5 wt.% nanoparticles in the membrane matrix along with a high concentration of Mg2+ ions in water at pH 6.84 were the optimum condition to achieve the highest water softening efficiency. The predicted model well matched with experimental results suggesting a practical preparation and process conditions for achieving a water-softener membrane. Furthermore, the membrane permeability of prepared nanocomposite membranes was improved to higher amounts due to the induced changes in membrane bulk structure and surface hydrophilicity.