Rapid removal of copper ions from aqueous media by hollow polymer nanoparticles

High-performance adsorbents are central to the effective removal of heavy metal ions from aqueous media by adsorption. In this study, novel carboxylate-functionalized hollow polymer nanoparticles (HPPs-COO-) were used to remove Cu(II) from aqueous media. The FT-IR, XPS and EDS results demonstrated that the complexation of Cu(II) with the carboxylate group was in a bidentate bridging form. The optimal pH for adsorption was 5.0, and the adsorption behavior could be described by the Langmuir isotherm and pseudo-second-order kinetics model. HPPs-COO- had a comparable adsorption capacity (145.14 mg/g) with other reported polymeric adsorbents. In addition, the adsorption equilibrium of Cu(II) onto HPPs-COO- could be achieved within 1 min. The superfast adsorption rate allowed the quick removal of Cu (II) from the wastewater, and definitely reduced the operating cost. The application of HPPs-COO- in the treatment of real wastewater showed that not only the main contaminant Cu(II), but other toxic heavy metal ions Ni(II) and Pb(II) in the wastewater could be effectively removed. Additionally, HPPs-COO- exhibited a good reusability in the treatment of the wastewater. The above results revealed that HPPs-COO- had a bright prospect in the application of the wastewater treatment.