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Preparation of composite graphene hydrogels adsorbent with special-shaped ZnO and TiO2

Authors :
Xiaotong Sun
Mingyuan Xu
Luting Yan
Meng Wu
Runxiang Xu
Yanyun Zhu
Jingfa Yang
Yuting Li
Source :
Colloids and Surfaces A: Physicochemical and Engineering Aspects. 581:123783
Publication Year :
2019
Publisher :
Elsevier BV, 2019.

Abstract

Graphene-based hydrogels (GH) have exhibited prominent performances in wastewater treatment. Herein, Special-shaped ZnO tetrapods and TiO2 nanosheets were introduced to the preparation of GH via a one-step hydrothermal reduction method. The ZnO-GH and TiO2-GH composite hydrogel with a uniform 3D network structure and good mechanical properties can be used as an adsorbent for printing and dyeing wastewater. The optimum doping amount of ZnO and TiO2 in the composite hydrogel and the adsorption regularity to rhodamine B (RhB) with different concentrations were discussed. The cyclic adsorption performance and adsorption kinetics were briefly discussed. When the doping ratio of ZnO to graphene oxide (GO) is 5:8, ZnO-GH has the best adsorption rate, which is 71.7%. The best degradation rate appears at a ZnO doping ratio of 1:2, which also shows the best total removal rate of RhB of approximately 82.20%. When the doping ratio of TiO2 to GO is 3:4, the photocatalytic degradation rate is 30.3%, and the total removal rate of RhB reaches 99.1%, which indicates that RhB can be almost completely removed by TiO2-GH through adsorption and degradation. After five cycles, the adsorption capacity of ZnO-GH and TiO2-GH for the low RhB concentration is still good. The addition of ZnO and TiO2 improves not only the adsorption and degradation properties of the composite hydrogel but also its recycling performance as a result of the increase in mechanical stability.

Details

ISSN :
09277757
Volume :
581
Database :
OpenAIRE
Journal :
Colloids and Surfaces A: Physicochemical and Engineering Aspects
Accession number :
edsair.doi...........0afce610b3b38ed1107864f8960ba940
Full Text :
https://doi.org/10.1016/j.colsurfa.2019.123783