查看更多>>摘要：The escalating impacts of climate change coupled with rapid population growth, and unsustainable consumption patterns, have created a global water crisis of unprecedented proportions. The availability of clean water is a fundamental human right, yet billions of people worldwide lack access to safe drinking water and basic sanitation. This necessitates the development of advanced wastewater treatment systems capable of producing high-quality effluent. In this study, we successfully synthesized highly efficient photocatalysts, specifically ZnS, bulk-g-C_3N_4, and bulk-g-C_3N_4/ ZnS composites, using microwave-assisted technique. These materials were designed to serve as effective photocatalysts driven by visible light for environmental applications. The synthesized materials included ZnS, bulk-g-C_3N_4, and their composites at a 1:1, 1:2, and 1:3 weight ratios. Comprehensive characterization of the prepared composites using various techniques, including XRD, UV-Vis, FTIR, FESEM, EDS, HRTEM, and XPS was conducted. The cubic zinc blend structure and layered stacking arrangement for the ZnS, and bulk-g-C_3N_4 compounds were revealed by the composite material's XRD analysis; the sizes of ZnS, pure bulk-g-C_3N_4, and their composites with various ratios of ZnS/bulk-g-C_3N_4 (1:1, 1:2, 1:3) were 2.72 nm, 5.62 nm, 3.02 nm, 2.74 nm, and 2.69 nm, respectively. FTIR analysis revealed that the stretching vibrations of C = N and C≡N bonds were located inside certain spectrum regions. Peaks in the 1600-1800 cm~(-1) range were seen for C = N bonds, while peaks in the 2350 cm~(-1) range were observed for C≡N bonds. Moreover, the noticeable peaks observed between 1300 and 1570 cm~(-1) are caused by the aromatic C-N stretching vibrations. The FESEM analysis showed that ZnS/bulk-g-C_3N_4 composites had a sheet-like nanohybrid morphology, whereas pure ZnS and bulk-g-C_3N_4 appeared as nanosheets and nanohybrids, respectively. The Zn, S, C, and N elements found in the produced materials were identified by EDS analysis, which also confirmed the lack of impurities. The HRTEM image of the ZnS/bulk-g-C_3N_4 (1:1) composite was used to quantify the interatomic distance between the ZnS atoms. The cubic zinc blend structure of ZnS was discovered to have a (111) plane that corresponds to a 0.31 nm lattice spacing. XPS revealed that Zn, S, C, and N were in the Zn 2p, S 2p, C 1 s, and N 1 s oxidation states. The pho-tocatalytic performance of the different composites (e.g., 30 mg) was evaluated for the degradation of malachite green dye (e.g., 3×10~5 M) in aqueous solution, utilizing a custom-built photocatalytic reactor equipped with a 250W halogen lamp under continuous magnetic stirring for 120 min. The findings indicated that the g-C_3N_4/ZnS composite pho-tocatalysts exhibited superior degradation efficiency compared to the individual components, showing a degradation rates of 2% and 28% for pure bulk-g-C_3N_4 and ZnS, respectively. Remarkably, under visible light irradiation, the g-C_3N_4/ZnS composite with a 1:3 weight ratio demonstrated the highest photocatalytic efficiency, achieving 33.50%. The 1:1, and 1:2 weight ratios exhibited photocatalytic efficiencies of 16.79%, and 25.57%, respectively. Ultimately, these findings indicate that ZnS/bulk-g-C_3N_4 (1:3) can be regarded as an exceptionally effective photocatalyst for the removal and degradation of malachite green dye from wastewater.
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