Preparation of Molecularly Imprinted Bacterial Cellulose Nanofiber Nonwovens for Selectively Removing Dye Molecule from Aqueous Solution

Abstract

In this study, a novel surface dye molecularly imprinted bacterial cellulose nanofiber nonwoven (DMIBC) has been successfully prepared using two-step process by surface molecule-imprinting method combined with electrospinning technique to improve the selective adsorption capacity using methylene blue (MB) dye molecule as the target pollutant. Scanning electron microscopy, surface area and Fourier transform infrared spectroscopy were used to characterize with the physico-chemical characteristics of the prepared DMIBC. The as-prepared DMIBC nanofiber nonwoven has small average nanofiber diameter of 172.6 ± 17 nm with large specific surface area of 233.64 ± 22.6 m²/g, which are favorable for adsorption. To systematically investigate the adsorption performances such as adsorption capacity and selectivity coefficient of the prepared DMIBC-MB nano-adsorbent for MB dye molecules, the effect of solution pH value, initial dye molecule concentrations, adsorption time, solution temperature and competitive dye molecules has been studied. The maximum adsorption capacity of 4250 mg/g can be reached at pH value of 6.0. The calculated adsorption selectivity coefficients and molecule imprinting factors suggest that DMIBC-MB nano-adsorbent possesses excellent adsorption selectivity for imprinted MB dye molecule. The dye adsorption isotherm models and kinetics models were also applied to analyze the adsorption mechanism of DMIBC nano-adsorbent for MB dye molecules. Durability test indicated that the adsorption capacity of DMIBC nano-adsorbent could remain 92.1% of the initial adsorption capacity after 10 consecutive regeneration cycles. In general, the DMIBC nano-adsorbent with highly selective removal of MB dye molecules could be applied for dye wastewater treatment.