Photocatalytic Degradation of Single and Binary Mixture of Brilliant Green and Rhodamine B Dyes by Zinc Sulfide Quantum Dots

Abstract

We present the preparation of octadecylamine-capped ZnS quantum dots from bis(morpholinyldithiocarbamato)Zn(II) complex. The complex was thermolyzed at 130 °C in octadecylamine at different times, to study the effect of reaction time on the morphological and photocatalytic properties of the ZnS quantum dots. Powder X-ray diffraction patterns confirmed a hexagonal wurtzite crystalline phase of ZnS, while HRTEM images showed particle sizes of about 1–3 nm, and energy band gaps of 3.68 eV (ZnS–1), 3.87 eV (ZnS–2), and 4.16 eV (ZnS–3) were obtained from the Tauc plot for the ZnS nanoparticles. The as-prepared ZnS were used as photocatalysts for the degradation of brilliant green, rhodamine B, and binary dye consisting of a mixture of brilliant green-rhodamine B. The highest photocatalytic degradation efficiency of 94% was obtained from ZnS–3 with low photoluminescence intensity. The effect of catalytic dosage and pH of the dyes solution on the photocatalytic process shows that pH 8 is optimal for the degradation of brilliant green, while pH 6.5 is the best for photocatalytic degradation of rhodamine B. The degradation of the binary dyes followed the same trends. The effect of catalytic dosage shows that 1 mg mL−1 of the ZnS nano-photocatalyst is the optimum dosage for the degradation of organic dyes. Reusability studies show that the ZnS quantum dots can be reused five times without a significant reduction in degradation efficiency.

Multiwalled Carbon Nanotube/Fe-Doped ZnO-Based Sensors for Droplet Electrochemical Detection and Degradation Monitoring of Brilliant Green

“…Ragupathy et al reported that Sn-doped ZnO loaded CSAC (Sn–ZnO/CSAC) NPs photocatalytically degrades 96.52% BG in 120 min . Similarly, octadecylamine-capped ZnS quantum dots were reported to degrade 94.61% BG in 180 min . Our work involves the synthesis of Fe–ZnO that photocatalytically degrades BG up to 99% in just 30 min.…”

Synthesis and Crystal Structures of Bis(diallydithiocarbamato)zinc(II) and Silver(I) Complexes: Precursors for Zinc Sulfide and Silver Sulfide Nanophotocatalysts

“…All the diffraction peaks of ZnS nanoparticles correspond with the standard values of hexagonal wurtzite zinc sulfide (JCPDS card no. 39–1363). , The differences in the diffraction patterns and the number of peaks could be ascribed to the different capping agents used to prepare the nanoparticles. The broad diffraction peaks observed could be attributed to the small particle sizes of the as-prepared zinc sulfide nanoparticles …”

Hydrothermal synthesis and photocatalytic performance of visible light responsive ZnS microspheres for azo dyes

“…This could be attributed to the incomplete recovery of catalysts, material agglomeration or accumulation of a small amount of the RhB on the surface of catalysts. 6,18,23 The XRD results of Z-L-ZnS-180 before and after cyclic experiments are shown in Fig. 15(b).…”

“…[3][4][5] Among them, photocatalytic technology has been evaluated as an ideal method with huge economic and social benefits due to its advantages of low energy consumption, high efficiency, and being environment friendly. 6,7 The key problem of this method is the selection of suitable photocatalysts. Currently, scholars are struggling to explore efficient photocatalysts, including oxides, 8 sulfides, 9 carbides, 10 and metal-organic frameworks (MOFs).…”