Ultra-Highly Efficient Removal of Methylene Blue Based on Graphene Oxide/TiO2/Bentonite Sponge

Abstract

An ultra-highly efficient Graphene Oxide/TiO2/Bentonite (GO/TiO2/Bent) sponge was synthesized using an in situ hydrothermal method. GO/TiO2/Bent sponge with a GO mass concentration of 10% exhibited the highest treatment efficiency of methylene blue (MB), combining adsorption and photocatalytic degradation, and achieved a maximum removal efficiency of 100% within about 70 min. To further prove the ultra-high removal capacity of the sponge, the concentration of MB in water increased to ten times the original concentration. At so high a MB concentration, the removal rate was still as high as 80% in 90 min. The photocatalytic mechanism of GO/TiO2/Bent sponge was discussed through XPS, PL and radicals quenching experiments. Here Bent can immobilize TiO2 and react with a photo-generated hole to increase the amount of hydroxyl radical; effectively enhancing the degradation of MB.GO sponge enlarges the sensitivity range of TiO2 to visible light by increasing the charge separation of TiO2 and reducing the recombination of photo-generated electron–hole pairs. Additionally, GO sponge with an interconnected porous structure provides an effective platform to immobilize TiO2/bent and makes them be easily recovered. The as-prepared sponge develops a simple and cost-effective strategy to realize the ultra-highly efficient treatment of dyes in wastewater.

Kaolin-graphene carboxyl incorporated TiO2 as efficient visible light active photocatalyst for the degradation of cefuroxime sodium

“…6. TiO 2 displayed an absorption edge at 393 nm which is in good agreement with the previous reports [54,55]. From the figure, it is evident that the absorption edges were extended to visible light range with the incorporation of KG into TiO 2 matrix.…”

“…Pollutant molecules initially gets adsorbed to TiO 2 /kaolin-graphene carboxyl surface and later undergo degradation in situ from its surface. Graphene carboxyl possess outstanding electronic transmission ability, which can effectually hinder the electron-hole pairing of TiO 2 and progress the photocatalytic efficiency [54]. Kaolin having good adsorption property makes available a large number of hydroxyl groups on its surface, which leads to the increased production of •OH via its reaction with holes.…”

A Comparative Study of Cerium- and Ytterbium-Based GO/g-C3N4/Fe2O3 Composites for Electrochemical and Photocatalytic Applications

“…The time interval was set to 5 min for every reading in order to measure the percentage of degradation of RhB and MB repeatedly. Nearly 3 mL for each reading was used and showed a noticeable decrease in absorbance values, thus confirming the degradation of dyes [41,42]. Nearly 3 mL for each reading was used and showed a noticeable decrease in absorbance values, thus confirming the degradation of dyes [41,42].…”

“…Nearly 3 mL for each reading was used and showed a noticeable decrease in absorbance values, thus confirming the degradation of dyes [41,42]. Nearly 3 mL for each reading was used and showed a noticeable decrease in absorbance values, thus confirming the degradation of dyes [41,42]. The photocatalytic efficiency of the nanocomposites used has been worked out by using Equation (3) [43,44] as…”

Luminescence, Paramagnetic, and Electrochemical Properties of Copper Oxides-Decorated TiO2/Graphene Oxide Nanocomposites

“…This finding is in good agreement with the data reported by M. Janczarek and E. Kowalska in their comprehensive review that presents the Cu 2 O and CuO as active species in TiO 2 photocatalytic system being efficient electron trappers to prevent the recombination of the photogenerated electron–hole pairs [ 19 ]. This trend is more pronounced after graphene oxide addition, confirming that GO reduces the recombination process in TiO 2 by immediate electron transfer from excited TiO 2 to GO sheets [ 20 , 21 ].…”