Effect of surface chemistry of carbons from pine sawdust for the adsorption of acid, basic and reactive dyes and their bioregeneration using Pseudomona putida

The adsorption of acid blue 74 (AB74), basic green 1 (BG1) and reactive blue 4 (RB4) on carbons from pine sawdust (Ps) using single carbonization (C-Ps) and modification of Ps with a calcium chloride 1 M (C-Ps-Ca) was studied. Also the effects of the type of adsorbate (acid, basic and reactive dye) on the bioregeneration of exhausted carbons using Pseudomona putida were investigated. Characterization of the samples was performed using Nitrogen adsorption isotherms at 77 K, elemental analysis, FT-IR spectroscopy and SEM-EDX analysis. For this study, the maximum adsorption capacity obtained for the two types of carbons were for C-Ps: 12.8, 4.6 and 51.68 mg g−1, and for C-Ps-Ca: 38.3, 48.6 and 155.1 mg g−1, for AB74, RB4 and BG1 dyes respectively. The bioregeneration process showed that is possible to renovate 25% of original adsorption capacity of the carbon C-Ps-Ca, equivalent to the adsorption capacity of C-Ps carbon. Among the dye-loaded adsorbents, the bioregeneration efficiency of C-Ps-Ca using the bacteria Pseudomona putida showed a better capacity for the degradation of BG1 compared with AB74 and RB4. Modelling of the adsorption results using a non-linear regression approach and performing the global minimization showed that both Langmuir and Sips models showed an adequate description of the acid, basic and reactive dyes adsorption.