Adsorption studies of lignin model compounds on activated charcoal particles

Abstract

In this work we have investigated possibilities for immobilization of lignin model compounds (LMCs) as potential antimicrobial agents on activated charcoal particles aimed for applications in wound dressings. LMC adsorption kinetics was determined for different initial LMC concentrations (0.1, 0.5 and 1.1 mg ml-1) by using UV-visible spectroscopy over 24 h when the equilibrium was reached. LMC adsorption on charcoal particles was confirmed by Fourier-transform infrared spectroscopy (FTIR). Adsorption kinetics was successfully modeled by the pseudo-second order Lagergren model while the adsorption isotherm at room temperature could be described by both Freundlich and Langmuir models showing satisfactory agreements. The maximal capacity of activated charcoal particles for LMCs according to the Langmuir model was 312.5 mg g-1. However, the immobilizates did not exhibit antibacterial activity against Pseudomonas aeruginosa indicating the need for further studies of LMC adsorption mechanism with the specific aim to elucidate exact compounds or functional groups responsible for antimicrobial action and their conformation on activated charcoal.