A sustainable cationic chitosan/E. coli fiber biosorbent for Pt(IV) removal and recovery in batch and column systems

• Published in: Separation and purification technology Vol. 143; pp. 32 - 39
• Main Authors: Mao, Juan, Kim, Sok, Wu, Xiao Hui, Kwak, In-Soeb, Zhou, Tao, Yun, Yeoung-Sang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 25.03.2015
• Subjects: Bacteria; Batch system; Cationic; Chitosan; Chitosan fiber; Coefficients; Column system; E. coli; Escherichia coli; Fibers; Mathematical models; Pt(IV); Recovery; Sustainability; Pt(IV); Column system; Batch system; Chitosan fiber; E. coli
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2015.01.023

•We presented a sustainable biosorbent for removal and recovery of Pt(IV) from acidic aqueous solution.•Powder form of poly(allylamine hydrochloride)-modified E. coli was immobilized as the fiber form.•The mechanical strength of biosorbent was good even in a strong acidic solution in both batch and column systems.•The sorption performance was best comparing other three kinds of ion exchange resin.•The column was successfully eluted with high desorption efficiency of 99.7%, opening up the possibility of regeneration. In this study, the cationic bacterial biosorbent, poly(allylamine hydrochloride) (PAA/HCl)-modified Escherichia coli, was successfully immobilized as a chitosan fiber, which was proved to be a sustainable biosorbent for platinum removal and recovery from aqueous solutions in batch and column systems. Compared to the commercial ion exchange resins, PAA/HCl-modified E. coli chitosan fiber showed a quite good performance for Pt(IV) removal. Two-parameter (Langmuir and Freundlich) and three-parameter (Sips and Redlich–Peterson) models were employed to describe the batch isotherm experimental data. Among these four models, the Redlich–Peterson model fit best, with higher coefficient of determination, chi-square and average percentage error values. Thermodynamic parameters (ΔG0<0 and ΔH0>0) showed the spontaneity and endothermic nature of biosorption process. The kinetics of Pt(IV) biosorption with different initial concentrations were better fit by the pseudo-second-order model, with higher coefficient of determinations and more closely predicted qe values. An acidified 0.005M thiourea was used to regenerate platinum from exhausted biosorbent maintaining desorption efficiencies over 90.2% until five cycles. In the column studies, the breakthrough curve showed a typical S-shaped curve, with breakthrough and exhaustion times appearing at 36.0h and 52.5h, respectively, which was opened up a possibility of column regeneration.