Coprecipitation-An Efficient Method for Removal of Polymer Nanoparticles from Water

Abstract

Increasing concentrations of micro- and nanoparticles of common polymers are beginning to cause significant damage to our environment. Techniques such as coagulation and flocculation are commonly used for the removal of particles from water. As a proof of concept, here we investigate the removal of synthetic poly(methyl methacrylate) (PMMA) and poly(vinyl acetate) (PVAc) nanoparticles from aqueous solution through the calcium carbonate (CaCO3) coprecipitation method. The physical entrapment and negative surface charges of the polymer particles play a significant role toward the efficient removal during coprecipitation. Critical parameters, such as the amount of solid precipitated, contact time, interfering ions, and initial concentrations of sodium carbonate and calcium chloride solutions were optimized for maximum removal of polymeric nanoparticles. Our study shows that equilibrium was established within 30 min for the complete removal (99%) of both PMMA and PVAc nanoparticles, using relatively low concentrations of Na2CO3 and CaCl2 solutions. The results also imply that such a simple and efficient coprecipitation method using natural and nontoxic materials could be used as an alternative method for the removal of plastic nanoparticles and other pollutants from water.