Porosity Regulation of Surfactant-Assisted Glycerol Organosolv Lignin Modified Hyper-Cross-Linked Polymers and Their Efficient Adsorption for Dyes From Water

Here, we tried to use the natural biomass resources (lignin) to modify porous organic polymers (POPs) and expected to reduce the preparation cost and enhance the adsorption performance. Specifically, the surfactant-assisted glycerol organosolv lignin (saGO lignin) was used as the modified agents to prepare lignin modified hyper-cross-linked polymers (LHCPs) by the copolymerization and Friedel-Crafts reaction. We investigated the effect of synthesis conditions (the types and dosages of crosslinkers, the feeding amount of lignin, and so on) on the structure and adsorption performance of LHCPs. The results showed that divinyl benzene (DVB) crosslinked LHCP-D (1041.3 m 2 /g) showed higher specific areas ( S BET ) than N,N′-methylene diacrylamide (MBA) crosslinked LHCP-M (183.1 m 2 /g), and the S BET had a certain increase with increasing the amount of DVB. Intriguingly, the S BET and micropore volume ( V micro ) of LHCPs appeared a linear decrease with the increase of lignin dosage, meanwhile, their morphology had a change from irregular block to agglomerated spherical particles, indicated their porosity and morphology can be well controlled. The Rhodamine B (RhB) adsorption experiments indicated that these LHCPs possessed fast adsorption rate (equilibrium time < 240 min) and good recycling performance, especially, LHCP-D (lignin of 0.5 g, DVB of 1.0 g, catalyst of 3.0 g, reaction time of 10 h) showed the ultrahigh adsorption capacity, up to 743.7 mg/g. The adsorption mechanism was preliminarily investigated by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and adsorption models analysis, we found that the physical adsorption played the dominated roles by the π–π interaction, hydrogen bonding, and electrostatic interaction. This work not only offered an important reference for the high-value utilization of lignin, but also provided an effective sustainable adsorbent for environmental remediation. Graphical