A New Porphyrin-Porous Organic Polymer for Effective Adsorption of Mercury Ions

Herein, we synthesized a new type of porphyrin-based porous organic polymer (PPOP) as an effective bio-inspired adsorbent capable of rapidly separating and measuring Hg(II) ions from the water. The synthesized bio-based adsorbent was analyzed by several techniques including PXRD (presented an amorphous network), FT-IR, SEM (spherical 250–1000 nm nanoparticles), EDS, BET, and TG/DTG (high thermal stability up to 500 °C). The experimental parameters in the procedure of adsorption including pH of the samples, times for adsorption and desorption, the sorbent mass, and also, the type and volume of eluent were examined and optimized. The experimental data were evaluated by Freundlich and Langmuir isotherm model equations and the results showed that the Langmuir model exhibited a better fit for mercury ions adsorption. PPOP exhibited the highest capacity for adsorption at 384.6 mg/g within only five minutes. The enhanced efficiency for adsorption can be mainly attributed to the combination effect of the electrostatic and coordination interactions between PPOP and Hg(II) ions. In addition, PPOP showed an excellent limit of detection (LOD) value of 2.1 ng L^− 1. Finally, the prepared adsorbent was employed for the extraction of Hg(II) ions in various water samples from the environment, achieving recoveries up to 91%.