Facile in-situ synthesis of PEI-Pt modified bacterial cellulose bio-adsorbent and its distinctly selective adsorption of anionic dyes

Abstract

With the continuous civilization and industrialization, the problem of dye wastewater treatment has been drawn widespread attention. This study focuses on in-situ reduction of cationic polyethylenimine (PEI) caged platinum nanomaterials (PEI-Pt) onto the bacterial cellulose (BC) substrate to fabricate a versatile bio-adsorbent (PEI-Pt@BC membrane). Scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) were employed to confirm that PEI-Pt composite could anchor onto BC without any damage of its original three-dimensional porous structure. Thereafter, the distinguishing adsorption behaviors of PEI-Pt@BC membrane were studied choosing acid black ATT as a target and methylene blue (MB) as a control group. The maximum amount of acid black ATT adsorption reaches to 1157.9 mg/g, which conforms to the quasi-second-order kinetic model and Freundlich isothermal model. Whereas, the adsorption capacity of MB is only 13.5 mg/g. Obviously, the PEI-Pt@BC membrane has a preferential adsorbability of anionic dye than cationic analogue mainly attributed to the interaction between positive-charged PEI and dye molecules. Thus, this PEI-Pt@BC adsorbent exhibits eco-friendly and highly-efficient merits, showing a promising potential in treatment of anionic dyes especially from the textile printing and dyeing effluent.