MoS 2 -modified In 2 S 3 ( x wt.%MoS 2 -In 2 S 3 ) samples (0 ≤ x ≤ 20) were fabricated through a facile one-pot hydrothermal process. All In 2 S 3 samples modified by MoS 2 deliver an excellent Cr 6+ removal ability under visible-NIR-light-driven, and 5% MoS 2 -In 2 S 3 can reduce 20 mg/L Cr 6+ solution completely within 30 min with a trace photocatalyst concentration (0.27 mg/mL) which is 3.2-hold higher than that of single In 2 S 3 . Further investigations demonstrate that the loaded MoS 2 can not only enhance the absorption of light scope but also promote the interfacial electron transfer from In 2 S 3 to MoS 2 and then to Cr 6+ , thus greatly improving the Cr 6+ removal ability. ESR shows that the modifying of MoS 2 can accelerate the transformation of electrons from the In 2 S 3 to MoS 2 which results in that the intensity of O 2 − • significantly increased. PL, photocurrent, and EIS further identified that the modification of MoS 2 can greatly improve the charge carrier separation efficiency. The fabricated MoS 2 -In 2 S 3 samples also exhibit characteristic features such as stable and reducing Cr 6+ in the weak alkaline environment for the first time, which could always be a great challenge for wastewater purification in alkaline condition.
Wang Dadao,Li Jian,Xu Zhifeng,Zhu Yeran,Chen Guoxin,Cui Zheng
A novel three-dimensional ball-flower-like g-C 3 N 4 /NiO (GN) photocatalyst was firstly fabricated by a simple two-step calcination method for enhanced degradation capability. Our investigation focuses on the construction of p–n heterojunction and specific ball-flower-like structure to overcome limitations of single-component semiconductors, such as low surface area, poor light response and fast recombination of the photogenerated electrons and holes. Detailed photocatalytic experiments revealed that the novel ball-flower-like GN (50%) exhibited much higher activity for the removal of TC and Cr 6+ than single g-C 3 N 4 , NiO and traditional layered GN. The trapping experiments proved that the superoxide radicals ( \( ^{ \cdot } {\text{O}}_{2}^{ - } \) ), holes (h + ) and electrons (e − )were the main active species in the photodegradation process. Moreover, three different degradation pathways and fourteen intermediate products of TC were also determined by the LC/MS analysis and these intermediates could be further degraded completely into CO 2 , H 2 O, \( {\text{NH}}_{4}^{ + } \) , carboxylic acids and any other inorganic intermediates. These results will benefit the fabrication of other 3D p–n heterojunction photocatalysts and their potential application in treatment of organic pollutants.
Considerable interest has been devoted to developing nanoscale biomass materials as adsorbents for wastewater treatment. A facile route was proposed to prepare cellulose-based composite nanofibers via electrospinning of cellulose acetate with organically modified montmorillonite , followed by deacetylation. The composite nanofibers are suitable for metal adsorption given their reasonably high selectivity in removing Cr 6+ ions from aqueous solution. The effects of experimental parameters, including solution pH, temperature, and contact time, on the removal of Cr 6+ ions were determined in a batch system to optimize the adsorption conditions. Results from this study may provide a promising biosorbent that can be used as an emerging material in large-scale adsorption of heavy metal ions.
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