On the adsorption mechanisms of diethylamine by medically-certified activated carbons: Investigation of critical parameters controlling sorption properties

International audienceThis study investigates the adsorption mechanisms and reaction pathways involved in the adsorption ofdiethylamine (DEA) by medically-certified activated carbons (ACs). DEA is used as a model of aminessecreted during healing process of chronic wounds. DEA adsorption kinetics/isotherms were performedin liquid phase. Based on a preliminary assumption of a sorption favoured by surface chemical functions,it was found that the sorption kinetics followed accurately a pseudo-second order model. In addition, ouranalysis revealed that surface diffusion strongly influenced DEA sorption. If Langmuir and Redlich–Peterson models provided the most accurate fit of the adsorption isotherms, the Freundlich isothermgave a fair representation of experimental data as well. L-type isotherms supported the occurrence ofstrong surface interactions. Also, a negative correlation was drawn between the micropore volumepercentage and adsorption capacity at equilibrium. Further, acid/base reactions were believed to occur,along with the establishment of numerous H-bonds between the sorbent and DEA. This study is ended bya discussion of the effect of AC entrapment within a polymeric matrix on the adsorption properties. IfDEA removal was still observed, a serious decrease of sorption properties was measured. We concludedthat AC must be treated during the activation process in order to possess a high BET surface, an importantmesopore/macropore content and a high content of acidic surface functions, in order to balance thedecreasing of adsorption properties owed to its entrapment