Synergistic Adsorption for Parabens by an Amphiphilic Functionalized Polypropylene Fiber with Tunable Surface Microenvironment

A series of novel amphiphilic functionalized fibers with polarity tunable surface microenvironment were constructed by introducing hydrophilic polyamines and hydrophobic linear alkyl chain groups, aiming to selectively remove parabens from water. In addition, Fourier-transform infrared spectroscopy, X-ray powder diffraction, scanning electron microscopy, etc. were employed to determine the successful preparation of amphiphilic functionalized fibers. The adsorption experimental data indicated that the amphiphilic fibers showed excellent selectivity for parabens. In the amphiphilic fibers, hydrogen bonding and hydrophobic interaction existing in one molecular unit can effectively act together to enhance the interaction between substrate and fibers. Kinetic studies illustrated that the adsorption process was a physical adsorption with chemical characteristics. The overall initial adsorption rate together with the stepwise adsorption rate was quantified, and it is inferred that the hydrophobic interaction plays a leading role in the first step of the adsorption process. Moreover, the Freundlich model well described the sorption process with a maximum adsorption of 138.4 mg/g. What's more, the fiber still keeps excellent adsorption capacity (>90%) even after 10 adsorption/desorption cycles, which certifies it is an excellent adsorbent and can be utilized to remove paraben in practice.