Polymer particles templated by O/W emulsions and application as PdNPs carrier for the reduction of 4-NP

The polymerizable monomer ETPTA as the inner phase and Tween 80 as the emulsifier to construct O/W emulsions, which could be polymerized to solid polymers by UV-irradiation with the advantages of environmentally friendly and easy preparation. The stirring speed is an important factor affecting the mean size of emulison droplets and solid particles. Increasing the stirring speed is beneficial for the emulsion stabilization due to the small emulison droplets, which can construct smaller solid particles as the carriers of the catalytic active centers. PdNPs as functional metal nanomaterials are selected as the active centers attributed to the peroxidase activity, which can adsorb on the polymer surface (PdNPs@polymer) because of the electrostatic interactions. The analysis of PdNPs@polymer confirm the PdNPs are well-distributed at the polymer surface and have no noticeable aggregation. PdNPs@polymer can reduce 4-NP to 4-AP in the aqueous solution showing remarkable catalytic activity. The carrier polymer particles prepared with the largest stirring speed loaded with PdNPs has the best catalytic activity compared with the low stirring speeds. PdNPs@polymer with higher stirring speed has outstanding catalytic activity due to the numerous emulsion droplets and corresponding solid particles, which are contributed to the loading of PdNPs and improve the catalytic performance. Our findings of the novel catalyst composites are instructive in providing technical guidance for environmental remediation applications with better catalytic activity and being environmentally friendly.