title: A novel adsorbent obtained by inserting carbon nanotubes into cavities of diatomite and applications for organic dye elimination from contaminated water.
abstract: A novel approach is described for establishing adsorbents for elimination of water-soluble organic dyes by using multi-walled carbon nanotubes (MWCNTs) as the adsorptive sites. Agglomerates of MWCNTs were dispersed into individual tubes (dispersed-MWCNTs) using sodium n-dodecyl itaconate mixed with 3-(N,N-dimethylmyristylammonio)-propanesulfonate as the dispersants. The resultant dispersed-MWCNTs were inserted into cavities of diatomite to form composites of diatomite/MWCNTs. These composites were finally immobilized onto the cell walls of flexible polyurethane foams (PUF) through an in situ PUF formation process to produce the foam-like CNT-based adsorbent. Ethidium bromide, acridine orange, methylene blue, eosin B, and eosin Y were chosen to represent typical water-soluble organic dyes for studying the adsorptive capabilities of the foam-like CNT-based adsorbent. For comparisons, adsorptive experiments were also carried out by using agglomerates of the sole MWCNTs as adsorbents. The foam-like CNT-based adsorbents were found to have higher adsorptive capacities than the CNT agglomerates for all five dyes; in addition, they are macro-sized, durable, flexible, hydrophilic and easy to use. Adsorption isotherms plotted based on the Langmuir equation gave linear results, suggesting that the foam-like CNT-based adsorbent functioned in the Langmuir adsorption manner. The foam-like CNT-based adsorbents are reusable after regeneration with aqueous ethanol solution.
authors.affiliation: Laboratory of Environmental Remediation, Graduate School of Environmental Science, Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: Hongwen
authors.initials: H
authors.lastname: Yu
authors.forename: Bunshi
authors.initials: B
authors.lastname: Fugetsu
mesh_terms: D000327:Adsorption; D004396:Coloring Agents / Q000302:isolation & purification*; D003247:Conservation of Natural Resources / Q000379:methods; D007692:Diatomaceous Earth; D037742:Nanotubes, Carbon; D011140:Polyurethanes; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D004396:Coloring Agents; D037742:Nanotubes, Carbon; D011140:Polyurethanes; D014874:Water Pollutants, Chemical; D007692:Diatomaceous Earth; C033787:diatomite; C028279:polyurethane foam