Powder Technology, Vol.355, 183-190, 2019
A simple magnetite nanoparticle immobilized thermoresponsive polymer synthesis for heavy metal ion recovery
In order to develop environmentally friendly heavy metal ion recovery processes, a facile synthesis for magnetite nanoparticles with immobilized straight-chained thermoresponsive copolymers with high chelating group content was established by modifying the coprecipitation method. As the thermoresponsive copolymer, poly(N-isopropylacrylamide-co-acrylic acid) (poly(NIPAM-co-AA)) was used in this study. Cu(II) was used as a model heavy metal and the Cu(II) ion recovery performance based on temperature swing was evaluated. Generally, conventional methods for immobilizing polymers on nanoparticles have the disadvantages of being complex and time consuming. The results in this study show that the developed approach is not only simple and easy compared with the conventional method-4 steps can be reduced to 1 step-but also results in well dispersed magnetite nanoparticles, with high immobilized polymer loading; a maximum of 0.760 g/g-magnetite was achieved. The experimental results show the successful control of Cu(II) adsorption and desorption based on temperature swing between 60 degrees C and 20 degrees C, and the amount of recycled Cu(II) ions reached a maximum of 0.13 mmol/(g-adsorbent). Despite the simplicity of the procedure, the adsorbent prepared using our method shows higher recycled amounts than those for previously reported thermoresponsive adsorbents. In addition, waste generation throughout the process is also limited since the adsorbent preparation step does not require organic solvent, and the heavy metal ion recovery does not require acid. The developed process is therefore an environmentally friendly one. These findings demonstrate the effectiveness of our adsorbent and its synthesis. (C) 2019 Elsevier B.V. All rights reserved.