Cellulose based hyper-crosslinked polymer for efficiently recovering valuable materials from PO/SM wastewater.

Herein, a TEMPO-oxidized cellulose-grafted-polystyrene hypercrosslinked polymer (TOC-PS-HCP) was synthesized facilely by TEMPO oxidation, grafting copolymerization and post crosslinking route. Based on the structural characterization, it was confirmed that TOC-PS-HCP mainly consisted of polystyrene chain on cellulose and rigid crosslinked bridge. Additionally, the as-prepared TOC-PS-HCP displayed appropriate hydrophobicity (water contact angle = 102.44°) and high specific surface area (SBET = 601.20 m2·g--1), which could efficiently recover ethylbenzene and styrene from PO/SM wastewater. The adsorption experiment was conducted to study the recovery performance for ethylbenzene and styrene in the aqueous phase. The results showed that TOC-PS-HCP could recover ethylbenzene and styrene quickly by adsorption process, and maintain a stable recovery rate both in different aqueous conditions and recycle experiments. The adsorption experiment in the simulated wastewater solution showed that TOC-PS-HCP exhibited the greater affinity for ethylbenzene and styrene than other substrates. Furthermore, a possible mechanism for the efficient recovery of ethylbenzene and styrene was suggested on the basis of experimental and theoretical results, which may be associated with van der Waals force and π-π stacking.

ß-Cyclodextrin functionalized SBA-15 via amide linkage as a super adsorbent for rapid removal of methyl blue.

To remove the bulky aqueous organic dye e.g. methyl blue (MB) from water, ordered mesoporous silica SBA-15 has been functionalized with ß-cyclodextrin (ß-CD) via amide linkage. The surface physical and chemical properties of the surface of the resulted ß-CD-functionalized adsorbents (abbrev. SBA15-A-CD) were characterized systematically. The results indicate that the channels of SBA-15 were uniformly modified with amine groups and were further ß-CD-terminated via amide linkages, without ruining its ordered mesoporous structure. The effects of contact time, pH, ionic strength, temperature and salt on the adsorption performance were explored. SBA15-A-CD showed maximum adsorption capacity for MB up to 1791 mg·g-1 combined with excellent recyclability. Besides, the adsorption behavior of MB onto SBA15-A-CD has been investigated by DFT calculation and two-dimensional NMR. Specifically, the enhanced adsorption capacity for MB stems from the tailored host-guest interaction between ß-CD cavity and aromatic moiety of MB in combination with the electrostatic attraction between amine groups and sulfonated group of MB. These findings offer good opportunities for improving the ability of mesoporous silica in adsorption of bulky anion dyes in wastewater.