Ag2CO3 anchored on BiOI/CoFe2O4 composites with p-n-p heterojunctions: Highly enhanced activity for photocatalytic oxidation of Hg0 under fluorescent light irradiation

Construction lamellar BaFe12O19/Bi3.64Mo0.36O6.55 photocatalyst for enhanced photocatalytic activity via a photo-Fenton-like Mo6+/Mo4+redox cycle

The novel BaFe₁₂O₁₉/Bi_3.64Mo_0.36O_6.55 composite materials were constructed as magnetically recyclable photo-Fenton-like degradation systems. The composite catalyst not only promoted the effective transfer of photo-generated electrons and improved the Mo⁶⁺/Mo⁴⁺ cycle consequent, but also activated hydrogen peroxide to generate oxidizing free radicals. BaFe₁₂O₁₉/Bi_3.64Mo_0.36O_6.55-0.25 exhibited an outstanding degradation performance for tetracycline hydrochloride it is 1.3 times to Bi_3.64Mo_0.36O_6.55. The thermal catalytic performance of the Bi_3.64Mo_0.36O_6.55 monomer is similar to that of the BaFe₁₂O₁₉/Bi_3.64Mo_0.36O_6.55 material without light. However, the removal rate of BaFe₁₂O₁₉/Bi_3.64Mo_0.36O_6.55 material reaches 84.5% after 60 min with light, far exceeding that of Bi_3.64Mo_0.36O_6.55 material. By way of the contrast experiment with light and without light, it is further demonstrated that interfacial interaction between BaFe₁₂O₁₉ and Bi_3.64Mo_0.36O_6.55 acted a key role in the photocatalytic reaction system. It is also a good advantage that pollutants can be efficiently degraded without adjusting the pH. The characterization of photocurrent and X-ray photoelectron spectroscopy (XPS) also further proved the synergy between the two materials, which is useful to the separation of electrons and holes. The synergy ultimately improves the degradation performance. Besides, BaFe₁₂O₁₉/Bi_3.64Mo_0.36O_6.55 can be easily separated by an external magnetic field after the photocatalytic activity reaction owing to BaFe₁₂O₁₉'s magnetic properties. It provides a new research idea for the construction and iron-based heterogeneous Fenton-like system for magnetic degradation of antibiotics.

Highly efficient, bioactive, and bifunctional sorbent p-n-p visible light heterogeneous photocatalyst utilizing ultra-fine ZnS nanoparticles embedded in a polymeric nanocomposite

This study reports the successful synthesis of a ZnS@GO@Pani polymeric nanocomposite (NC) via chemical polymerization. The product was used for simultaneous photocatalytic degradation-adsorption of malachite green (MG), a carcinogenic and widely used dye. The physicochemical properties of the prepared NC were characterized by various techniques. Morphological and XRD results confirmed the fine size of ZnS nanoparticles (NPs) with an approximate mean size of 5 nm, uniformly distributed within the polymeric matrix. For comparative purposes, photocatalytic dye degradation-adsorption of this nanohybrid was explored both in the dark and under natural light. It was observed that 0.1 g of the ternary NC in MG aqueous solution (20 ppm) leads to dye adsorption within 15 minutes with an efficiency of 70% under dark conditions. Also, MG removal efficiency of up to 90% was achieved in 15 minutes under natural light owing to integrated photocatalytic degradation-adsorption mechanisms. Adsorption isotherm studies were performed considering Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich (D-R) models. The results showed that the Freundlich isotherm with R 2 = 0.988 is well consistent with the experimental data. Integrated photocatalytic degradation-adsorption kinetics were modeled with pseudo-first-order (PFO) and pseudo-second-order (PSO) models where PSO with R 2 = 0.999 best fitted the data, implying the predominant role of chemical adsorption in the dye removal process. Antibacterial tests revealed superior antibacterial activity of the prepared ZnS@GO@Pani NC against both Gram-negative and Gram-positive bacteria, demonstrating the remarkable synergistic effect of ZnS NPs embedded in the GO@Pani matrix. Accordingly, the prepared NC could be regarded as a promising candidate for wastewater treatment applications. The leaching and regeneration studies also confirmed that the prepared NC is a non-toxic dye removal agent with good reusability.