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Main Title: Grafting and stabilization of ordered mesoporous silica COK-12 with graphene oxide for enhanced removal of methylene blue
Author(s): Henning, Laura M.
Simon, Ulla
Gurlo, Aleksander
Smales, Glen J.
Bekheet, Maged F.
Type: Article
Language Code: en
Abstract: Large-pore ordered mesoporous silica (OMS) COK-12, analogous to the well-known SBA-15, but synthesized in a more environmentally friendly way and exhibiting a shorter plate-like structure, was grafted with different amounts of graphene oxide (GO) for the first time in an inexpensive and rapid process, that was successfully upscaled. Samples were examined with nitrogen sorption analysis, SAXS, Raman spectroscopy, XPS, and zeta potential analysis. Adsorption experiments with the cationic dye methylene blue (MB) were conducted on the grafted materials and on pure COK-12, taking into account the influence of initial dye concentration (30–600 mg L−1), adsorbent dosage (0.2–14 g L−1), contact time (0.3–300 min), solution pH (4–10), and influence of salts and temperature (0–1 M NaCl, 80 °C) to simulate industrial dye effluent. The adsorption process was found to be represented best by the Langmuir isotherm model, i.e., adsorption is a monolayer process. The calculated maximum adsorption capacities were found to be 20.2 and 197.5 mg g−1 at dosages of 5 and 0.5 g L−1 for pure COK-12 and COK-12 grafted with 50 wt% GO, respectively, at pH 5.65 and MB concentration of 100 mg L−1. Adsorption kinetics were found to follow the pseudo-second order model, i.e., chemisorption is the rate controlling step. The adsorption performances could be well preserved at simulated dye effluent. Desorption was found to be most effective with hydrochloric acid. The COK-12 grafted with GO presented in this work shows superior adsorption properties in comparison to other grafted OMS materials. In addition, grafting with GO remarkably improved the stability of COK-12 in aqueous solution.
Issue Date: 7-Nov-2019
Date Available: 26-Nov-2019
DDC Class: 540 Chemie und zugeordnete Wissenschaften
Subject(s): mesoporous silica
graphene oxide
methylene blue
Sponsor/Funder: TU Berlin, Open-Access-Mittel - 2019
Journal Title: RSC Advances
Publisher: Royal Society of Chemistry
Publisher Place: Cambridge
Volume: 9
Issue: 62
Publisher DOI: 10.1039/C9RA05541J
Page Start: 36271
Page End: 36284
EISSN: 2046-2069
Appears in Collections:FG Keramische Werkstoffe » Publications

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