In-situ functionalization of poly(m-phenylenediamine) nanoparticles on bacterial cellulose for chromium removal

A novel efficient adsorbent of bacterial cellulose/poly(m-phenylenediamine (BC/PmPD) was prepared for Cr(VI) removal by combining the advantages of high adsorption capacity of PmPD and easy reclamation of BC. Through monomer (mPD) pre-adsorption on BC, the stable hybrid structure of PmPD nanoparticles functionalization on BC fibril was successfully realized by in-situ oxidative polymerization of adsorbed mPD. The morphology and structure of the adsorbents were analyzed by SEM, TEM, XRD, FTIR, and XPS techniques. The interaction between BC and PmPD and adsorption mechanism were also analyzed. The optimized BC/PmPD has Langmuir Cr(VI) adsorption capacity of 434.78 mg/g, much higher than many reported adsorbents. The Cr(VI) adsorption on BC/PmPD was ascribed to the Cr(VI) adsorption on protonated NH and NH2 groups and the redox reaction of Cr(VI) to Cr(III) by the reduction of amine, followed by Cr(III) chelation on imino groups of PmPD. The recycling test indicated that the BC/PmPD has good regeneration and reusability capacity with its fast-reversible macroscopic assembly and disassembly features, and high stabilization of PmPD on BC. Findings in the present study demonstrated that the BC/PmPD can be considered as a promising adsorbent for Cr(VI) removal due to its high adsorption capacity, efficient reclamation, good regeneration performance.