Synthesis, characterization and adsorption performance of a novel post-crosslinked adsorbent

In this paper a post-crosslinked polymeric adsorbent PDHT-2 with high specific surface area was prepared by Friedel–Crafts reaction of the pendant vinyl groups without an externally added crosslinking agent. It was obvious that both the specific surface area and the pore volume of starting copolymer PDHT-1 increased significantly after post-crosslinking. Batch adsorption runs of phenol from aqueous solution onto adsorbent PDHT-1 and PDHT-2 were researched, and commercial macroporous resin XAD-4 was chosen for comparison purpose. Experimental results showed that the adsorption isotherms could be fitted by Langmuir model and Freundlich model and the adsorption capacity onto PDHT-2 was much larger than that onto PDHT-1 and XAD-4 with respect to phenol and phenolic compound, which possibly resulted from its larger specific surface area. The adsorption process for phenol onto the three adsorbents was proved to be exothermic and spontaneous in nature. The thermodynamic parameters such as Gibb’s free energy (ΔG), change in enthalpy (ΔH) and change in entropy (ΔS) had been calculated. The adsorption kinetic curves obeyed the pseudo-second order model and the intraparticle diffusion process was the rate-controlling step.

The N2 adsorption capacity of the post-crosslinked resin PDHT-2 is much larger than the precursor PDHT-1, which resulted from its higher specific surface area after post-crosslinking reaction.Figure optionsDownload high-quality image (95 K)Download as PowerPoint slideResearch highlights
► Both the specific surface area and the pore volume of starting copolymer increased significantly after post-crosslinking reaction.
► Post-crosslinked adsorbent exhibited higher adsorption capacity of phenol than precursor and commercial resin XAD-4.
► The adsorption process for phenol onto the three adsorbents was proved to be exothermic and spontaneous in nature.
► Phenol uptake onto adsorbents followed the pseudo-second order model and the intraparticle diffusion process was the rate-controlling step.