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Underwater superoleophobicity cellulose nanofibril aerogel through regioselective sulfonation for oil/water separation
Ist Teil von
Chemical engineering journal (Lausanne, Switzerland : 1996), 2017-12, Vol.330, p.774-782
Ort / Verlag
Elsevier B.V
Erscheinungsjahr
2017
Link zum Volltext
Quelle
Elsevier ScienceDirect Journals Complete
Beschreibungen/Notizen
•Modified cellulose via oxidation-sulfonation was fabricated into aerogel.•-SO3− groups introduced contributed aerogel enhanced hierarchical structure.•Resulting aerogel displayed superoleophobicity underwater.•Water phase penetrated while nonpolar oil was completely repelled from aerogel.•Sulfonated aerogel kept high separation efficiency and stable recyclability.
Cellulose nanofiber (CNF) aerogel regioselectively modified by sodium periodate oxidation and consecutive sodium sulfite sulfonation has been fabricated. The aerogel exhibits underwater superoleophobicity (θoil>150°) characteristic for various oils, which could be used as a filter for oil/water separation. Compared with originals, the charge density of sulfonated CNF increased from −39.8mmol/kg to −325mmol/kg, which prevented the aggregation in water suspension and resulted in better dispersion morphology of nanofibers in the final aerogel after freezing-drying. Therefore, modified aerogel with a good hierarchical structure and high charge density was able to trap more water molecules onto its voids once pre-wetted, which is energetically unfavorable for the oil to replace the water molecules. As a result, the sulfonated aerogel displayed superoleophobicity characteristic underwater thus nonpolar oil phase was completely repelled while the water easily penetrated the as-prepared aerogel. The sulfonated CNF aerogel maintained high oil-water separation efficiency by simply filtration. The oil content in filtrated water was always less than 300ppm (0.03%), and kept a stable recyclability even after 20 cycles, which could be practically used as a filter for oil/water.