A highly efficient adsorbent synthesized by reactive depositions of chitosan layers on fish scale collagen—Hydrodynamic swelling and dichlorophenol derivative sorption evaluated by continuous long-term solution microcalorimetry

In this work, a new adsorbent material (ADS) was synthesized by immobilization of chitosan layers on fish scale fibrillar collagen in sequential reactions. Characterization of ADS has performed by FTIR, surface-enhanced Raman spectroscopy, TG/DTG and solid-state UV–vis reflectance spectroscopy. The characterization results have pointed that the chemically immobilized chitosan layers present stable adhesion on the collagenous matrix. The interaction of ADS with a dichlorophenol derivative (DCP) was studied by long-term solution microcalorimetry under isothermal conditions. The exothermic low value of the heat of swelling of ADS has related to the low value of the swelling entropy caused by the chemically immobilized chitosan layers on ADS. The energies of DCP sorption were from −2.41 to −4.31 J g−1 and the DCP sorption enthalpies were slightly exothermic. The maximum sorption capacity observed for DCP on ADS (45.7 mmol g−1 or about 12,100 mg g−1) is highly superior in relation to literature reports. The calorimetric results have suggested that diffusional transport is the main interaction mechanism at ADS/DCP interfaces. The present work underlines the excellent features of the new chitosan-based adsorbent for use in phenol sorption applications.