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Removal of methylene blue from aqueous solution by electrophoretically deposited titania‐halloysite nanotubes coatings
Author(s) -
FarrokhiRad Morteza,
Mohammadalipour Mehrdad,
Shahrabi Taghi
Publication year - 2018
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.15757
Subject(s) - halloysite , adsorption , photocatalysis , chemical engineering , coating , methylene blue , electrophoretic deposition , composite number , aqueous solution , materials science , dispersion (optics) , catalysis , chemistry , composite material , organic chemistry , physics , optics , engineering
Abstract Two‐component suspensions of titania and halloysite nanotubes ( HNT s) were prepared in ethanol with 0.5 g/L (optimum concentration) of polyethyleneimine ( PEI ) and different wt% of HNT s. Kinetics of Electrophoretic deposition ( EPD ) decreased with increasing the HNT s content in suspensions due to their less mobility compared with titania particles. HNT s reinforced the microstructure of coatings and reduced or completely prevented from cracking during drying and heat‐treatment steps. Removal of methylene blue ( MB ) via adsorption by HNT s coatings was faster than its photocatalytic degradation by titania coating. Dispersion of HNT s (up to ≈30 wt%) in the matrix of titania resulted in the synergistic catalytic effect in MB removal. The synergistic effect was because of the shorter traveling distance of MB molecules adsorbed on HNT s toward the photocatalytic active site of titania particles in composite coatings. However, the synergistic effect was destroyed with increasing the HNT s content in coating. Difference between the amount of MB removed by titania and composite coatings increased at longer times (≥60 minutes). Mass transfer of MB adsorbed on HNT s toward the photocatalytic active sites of adjacent titania particles can compensate the decline in the mass transfer from solution at longer times.