Clean light oriented ultrafast Pt/Bi2S3 nanoflakes for the photocatalytic destruction of gemifloxacin mesylate drug and methylene blue

Metal sulphides and their heterojunctions for photocatalytic degradation of organic dyes-A comprehensive review

Water pollution caused by organic dyes is one of the greatest threats to the ecosystem. The removal of dyes from water has remained a challenge for scientists. Recently, metal sulphides have emerged as a potential candidate for water remediation applications. The efficient charge transportation, greater surface-active sites, and low bandgap of metal sulphides make them an excellent choice of semiconductor photocatalysts for degradation of dyes. This review summarises the potential application of metal sulphides and their heterojunctions for the photocatalytic degradation of organic dyes from wastewater. A detailed study has been presented on the synthesis, basics of photodegradation and heterojunctions and photocatalytic activity. The effect of the use of templates, doping agents, synthesis route, and various other factors affecting the photocatalytic activity of metal sulphides have been summarised in this review. The synthesis techniques, characterisation techniques, mechanism of degradation of organic dyes by Z-scheme heterojunction photocatalyst, reusability and stability of metal sulphides, and the scope of future research are also discussed. This study indicates that Scopus-based core gathered data could be used to give an objective overview of the global dye degradation research from 2008 to 2023 (15 years). All data (articles, authors, keywords, and publications) is compiled in the Scopus database. For the bibliometric study, 1962 papers relevant to dye photodegradation by sulfide-based photocatalysts were found, and this number rises yearly. A bibliometric analysis provides a 15-year evaluation of the state-of-the-art research on the impact of metal sulfide-based photocatalysts on the photodegradation of dyes.

CaTiO3/g-C3N4 heterojunction-based composite photocatalyst: Part I: Experimental design, kinetics, and scavenging agents' effects in photocatalytic degradation of gemifloxacin

A critical, challenging environmental issue is explored pollution of water supplies by discharging industrial/pharmaceutical/hospital/urban wastewaters into the aquatic environment. These needs introducing/developing novel photocatalysts/adsorbents/procedures for removing or mineralizing various pollutants in wastewater before discharging them into marine environments. Further, optimizing conditions to achieve the highest removal efficiency is an important issue. In this study, CaTiO₃/g-C₃N₄ (CTCN) heterostructure was synthesized and characterized by some identification techniques. The simultaneous interaction effects of the experimental variables on the boosted photocatalytic activity of CTCN in the degradation of gemifloxcacin (GMF) were studied in RSM design. The optimal values for four parameters were: catalyst dosage: 0.63 g L^-1, pH: 6.7, C_GMF: 1 mg L^-1, and irradiation time: 27.5 min, with approximately 78.2% of degradation efficiency. The quenching effects of the scavenging agents were studied to show the reactive species' relative importance in GMF photodegradation. The results illustrate that the reactive ^•OH plays a significant role, and the electron plays a minor role in the degradation process. The direct Z-scheme mechanism better described the photodegradation mechanism due to the great oxidative and reductive abilities of prepared composite photocatalysts. This mechanism is an approach to efficiently separating photogenerated charge carriers and improving the CaTiO₃/g-C₃N₄ composite photocatalyst activity. The COD has been performed to study the details of the mineralization of GMF. The pseudo-first-order rat (from the Hinshelwood model) constants of 0.046 min^-1 (t_1/2 = 15.1 min) and 0.048 min^-1 (t_1/2 = 14.4 min) were respectively obtained from the GMF photodegradation data and COD results. The prepared photocatalyst retained its activity after five reusing runs.

Tumor microenvironment-responsive artesunate loaded Z-scheme heterostructures for synergistic photo-chemodynamic therapy of hypoxic tumor

Tumor microenvironment (TME) with the particular features of severe hypoxia, insufficient endogenous H₂O₂, and overexpression of glutathione (GSH) markedly reduced the antitumor efficacy of monotherapy. Herein, a TME-responsive multifunctional nanoplatform (Bi₂S₃@Bi@PDA-HA/Art NRs) was presented for synergistic photothermal therapy (PTT), chemodynamic therapy (CDT), and photodynamic therapy (PDT) to achieve better therapeutic outcomes. The Z-scheme heterostructured bismuth sulfide@bismuth nanorods (Bi₂S₃@Bi NRs) guaranteed excellent photothermal performance of the nanoplatform. Moreover, its ability to produce O₂ and reactive oxygen species (ROS) synchronously could relieve tumor hypoxia and improve PDT outcomes. The densely coated polydopamine/ammonium bicarbonate (PDA/ABC) and hyaluronic acid (HA) layers on the surface of the nanoplatform enhanced the cancer-targeting capacity and induced the acidic TME-triggered in situ "bomb-like" release of Art. The CDT treatment was achieved by activating the released Art through intracellular Fe²⁺ ions in an H₂O₂-independent manner. Furthermore, decreasing the glutathione peroxidase 4 (GPX4) levels by Art could also increase the PDT efficiency of Bi₂S₃@Bi NRs. Owing to the synergistic effect, this nanoplatform displayed improved antitumor efficacy with minimal toxicity both in vitro and in vivo. Our design sheds light on the application of phototherapy combined with the traditional Chinese medicine monomer-artesunate in treating the hypoxic tumor.

Rapid elimination of antibiotic gemifloxacin mesylate and methylene blue over Pt nanoparticles dispersed chitosan/g-C3N4 ternary visible light photocatalyst

Appropriate material selection and proper understanding of bandgap modification are key factors for the development of efficient photocatalysts. Herein, we developed an efficient, well-organized visible light oriented photocatalyst based on g-C₃N₄ in association with polymeric network of chitosan (CTSN) and platinum (Pt) nanoparticles utilizing a straightforward chemical approach. Modern techniques like XRD, XPS, TEM, FESEM, UV-Vis, and FTIR spectroscopy were exploited for characterization of synthesized materials. XRD results confirmed the involvement of α-polymorphic form of CTSN in graphitic carbon nitride. XPS investigation confirmed the establishment of trio photocatalytic structure among Pt, CTSN, and g-C₃N₄. TEM examination showed that the synthesized g-C₃N₄ possesses fine fluffy sheets like structure (100 to 500 nm in size) intermingled with a dense layered framework of CTSN with good dispersion of Pt nanoparticles on g-C₃N₄ and CTSN composite structure. The bandgap energies for g-C₃N₄, CTSN/g-C₃N₄, and Pt@ CTSN/g-C₃N₄ photocatalysts were found to be 2.94, 2.73, and 2.72 eV, respectively. The photodegradation skills of each created structure have been examined on antibiotic gemifloxacin mesylate and methylene blue (MB) dye. The newly developed Pt@CTSN/g-C₃N₄ ternary photocatalyst was found to be efficacious for the elimination of gemifloxacin mesylate (93.3%) in 25 min and MB (95.2%) just in 18 min under visible light. Designed Pt@CTSN/g-C₃N₄ ternary photocatalytic framework exhibited ⁓ 2.20 times more effective than bare g-C₃N₄ for the destruction of antibiotic drug. This study provides a simple route towards the designing of rapid, effective visible light oriented photocatalyts for the existing environmental issues.

Olive mill wastewater from a liquid biological waste to a carbon/oxocalcium composite for selective and efficient removal of methylene blue and paracetamol from aqueous solution

In this study, a Carbon/Oxocalcium was prepared from olive mill wastewater and successfully applied to the removal of paracetamol and methylene blue (MB) from an aqueous medium. The optimized composite (0.3 % CaO) is rich in anionic sites, porous and has a specific surface area of about 1383 m².g^-1. Adsorption tests showed significant adsorption capacities up to 1141 mg.g^-1. The adsorption of MB and paracetamol is well described by the Redlich-Peterson and Dubinin-Radushkevich isotherm, respectively. Moreover, the adsorption kinetics fitted to pseudo-second order. The π -π interactions, hydrogen bonds and electrostatic interactions were responsible for the adsorption of paracetamol and MB substrates. This work develops by a single, easy and simple action a new effective and selective material for the removal of emerging pollutants, a new method for the development of more stable carbon composites and a cost-effective method for the valorization of olive mill wastewater.