Striking the balance: Unveiling the interplay between photocatalytic efficiency and toxicity of La-incorporated Ag3PO4

Persistent molecules, such as pesticides, herbicides, and pharmaceuticals, pose significant threats to both the environment and human health. Advancements in developing efficient photocatalysts for degrading these substances can play a fundamental role in remediating contaminated environments, thereby enhancing safety for all forms of life. This study investigates the enhancement of photocatalytic efficiency achieved by incorporating La3+ into Ag3PO4, using the co-precipitation method in an aqueous medium. These materials were utilized in the photocatalytic degradation of Rhodamine B (RhB) and Ciprofloxacin (CIP) under visible light irradiation, with monitoring conducted through high-performance liquid chromatography (HPLC). The synthesized materials exhibited improved stability and photodegradation levels for RhB. Particularly noteworthy was the 2% La3+-incorporated sample (APL2), which achieved a 32.6% mineralization of CIP, nearly three times higher than pure Ag3PO4. Toxicological analysis of the residue from CIP photodegradation using the microalga Raphidocelis subcapitata revealed high toxicity due to the leaching of Ag + ions from the catalyst. This underscores the necessity for cautious wastewater disposal after using the photocatalyst. The toxicity of the APL2 photocatalysts was thoroughly assessed through comprehensive toxicological tests involving embryo development in Danio rerio, revealing its potential to induce death and malformations in zebrafish embryos, even at low concentrations. This emphasizes the importance of meticulous management. Essentially, this study adeptly delineated a thorough toxicological profile intricately intertwined with the photocatalytic efficacy of newly developed catalysts and the resultant waste produced, prompting deliberations on the disposal of degraded materials post-exposure to photocatalysts.

In situ fabrication of Ag decorated porous ZnO photocatalyst via inorganic-organic hybrid transformation for degradation of organic pollutant and bacterial inactivation

In this study, in situ silver (Ag) - porous ZnO photocatalysts were synthesized via solvothermal and post-annealing treatment. The formation of the porous ZnO structure due to the removal of organic moieties from the inorganic-organic hybrids Ag-ZnS(en)0.5 during the annealing process. The optimal Ag-ZnO photocatalyst showed excellent photocatalytic degradation activity, with 95.5% orange II dye and 97.2% bisphenol A (BPA) degradation under visible light conditions. Additionally, the photocatalytic inactivation of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) led to a 97% inactivation rate after 2 h under dark conditions. Trapping experiments suggest that the superoxide anion (O2-) radicals are the main active species to degrade the organic dye. The improved photocatalytic dye degradation activity and inactivation of bacteria were attributed to the synergistic effect of Ag and porous ZnO structure, increased surface area, and efficiently separated the photoexcited charge carriers. This work could provide an effective strategy for the synthesis of porous structures toward organic pollutant degradation and bacterial inactivation in wastewater.

Understanding systematic growth mechanism of porous Zn1-xCdxSe/TiO2 nanorod heterojunction from ZnSe(en)0.5/TiO2 photoanodes for bias-free solar hydrogen evolution

Herein, a porous Zn_1-xCd_xSe structure was developed on TiO₂ nanorod (NR) array for photoelectrochemical (PEC) application. Firstly, TiO₂ NR and ZnO/TiO₂ NR photoanode were synthesized via a series of hydrothermal methods on FTO. Next, the solvothermal synthesis method was adopted to develop inorganic-organic hybrid ZnSe(en)_0.5 on ZnO /TiO₂ NR-based electrode using different concentrations of the selenium (Se). We found that the ZnO NR acts as a mother material for the formation of inorganic-organic hybrid ZnSe(en)_0.5, whereas TiO₂ NR acts as a building block. In order to further improve the PEC charge transfer performance, inorganic-organic hybrid ZnSe(en)_0.5/TiO₂ NR electrode was transferred into a porous Zn_1-xCd_xSe/TiO₂ NR photoanode using the Cd²⁺ ion-exchange method. The optimized porous Zn_1-xCd_xSe/TiO₂ NR -(2) photoanode converted from ZnSe(en)_0.5 -(2) electrode (optimized Se concentration) showed a higher photocurrent density of 6.6 mA·cm^-2 at applied potential 0 V vs. Ag/AgCl. The enhanced photocurrent density was owing to the effective light absorption, enhanced charge separation, delay the charge recombination, and porous structure of Zn_1-xCd_xSe. This work highlights the promising strategy for the synthesis of porous Zn_1-xCd_xSe/TiO₂ NR from inorganic-organic ZnSe(en)_0.5/TiO₂ NR for effective charge separation and prolonging the lifetime during the photoelectrochemical reaction.

Application of Mesoporous Silica Nanoparticles in Cancer Therapy and Delivery of Repurposed Anthelmintics for Cancer Therapy

This review focuses on the biomedical application of mesoporous silica nanoparticles (MSNs), mainly focusing on the therapeutic application of MSNs for cancer treatment and specifically on overcoming the challenges of currently available anthelmintics (e.g., low water solubility) as repurposed drugs for cancer treatment. MSNs, due to their promising features, such as tunable pore size and volume, ability to control the drug release, and ability to convert the crystalline state of drugs to an amorphous state, are appropriate carriers for drug delivery with the improved solubility of hydrophobic drugs. The biomedical applications of MSNs can be further improved by the development of MSN-based multimodal anticancer therapeutics (e.g., photosensitizer-, photothermal-, and chemotherapeutics-modified MSNs) and chemical modifications, such as poly ethyleneglycol (PEG)ylation. In this review, various applications of MSNs (photodynamic and sonodynamic therapies, chemotherapy, radiation therapy, gene therapy, immunotherapy) and, in particular, as the carrier of anthelmintics for cancer therapy have been discussed. Additionally, the issues related to the safety of these nanoparticles have been deeply discussed. According to the findings of this literature review, the applications of MSN nanosystems for cancer therapy are a promising approach to improving the efficacy of the diagnostic and chemotherapeutic agents. Moreover, the MSN systems seem to be an efficient strategy to further help to decrease treatment costs by reducing the drug dose.

Comparative photocatalytic dye and drug degradation study using efficient visible light-induced silver phosphate nanoparticles

The industrialization, growing population, and human activities (e.g., liquid waste of households, industrial units, and agricultural lands) are the main causes to contaminate fresh water sources. To overcome this issue, many techniques have been applied for water purification and chemical oxidation is one of the effective ways to treat the wastewater called as advanced oxidation process (AOPs). In the present study, synthesized silver phosphate nanoparticles were employed as catalysts in the photocatalytic advanced oxidation process for the degradation of various dyes (RhB, MB, MO, and OG) and drug (SMZ). The photocatalyst was characterized through different analytical tools, e.g., PXRD, FTIR, UV-Vis DRS, DLS, FESEM, and HRTEM. The chemical behavior or interaction of dye molecule with catalyst surface has also been explored to understand the mechanism of photodegradation reaction. All the organic dyes and drugs showed pseudo first-order rate kinetics and it was found that RhB dye and SMZ drug degraded so fast by the photocatalyst. The maximum observed photodegradation rate was 0.0744 min^-1 for SMZ drug and 0.0532 min^-1 for RhB dye, respectively. The minimum dye degradation was observed ~ 0.0036 min^-1 for OG, which is ~ 15 times lesser than the degradation rate of RhB dye. From the comparative dye degradation study, it was found that the photodegradation efficiency of organic pollutants depends on the surface charge of the photocatalyst. The role of photogenerated reactive species (holes, superoxides, and hydroxyl free radicals) was also studied using different types of scavengers which helped to understand the photochemical reactions and mechanism by photocatalyst. The real sample analysis of textile effluent was also performed using the best photocatalyst in the presence of light.

An Update on Mesoporous Silica Nanoparticle Applications in Nanomedicine

The efficient and safe delivery of therapeutic drugs, proteins, and nucleic acids are essential for meaningful therapeutic benefits. The field of nanomedicine shows promising implications in the development of therapeutics by delivering diagnostic and therapeutic compounds. Nanomedicine development has led to significant advances in the design and engineering of nanocarrier systems with supra-molecular structures. Smart mesoporous silica nanoparticles (MSNs), with excellent biocompatibility, tunable physicochemical properties, and site-specific functionalization, offer efficient and high loading capacity as well as robust and targeted delivery of a variety of payloads in a controlled fashion. Such unique nanocarriers should have great potential for challenging biomedical applications, such as tissue engineering, bioimaging techniques, stem cell research, and cancer therapies. However, in vivo applications of these nanocarriers should be further validated before clinical translation. To this end, this review begins with a brief introduction of MSNs properties, targeted drug delivery, and controlled release with a particular emphasis on their most recent diagnostic and therapeutic applications.

Photocatalytic degradation of ketoconazole by Z-scheme Ag3PO4/graphene oxide: response surface modeling and optimization

Ketoconazole is an imidazole fungicide which is commonly used as pharmaceutical and healthcare products. Residual amount of this compound can cause adverse ecological health problems. The present study investigated ketoconazole photocatalytic degradation using Ag₃PO₄/graphene oxide (GO). Ag₃PO₄/GO and Ag₃PO₄ as visible light-driven photocatalysts was synthesized using the in situ growth method. Degradation of ketoconazole at the concentration of 1-20 mg/L in aqueous solutions was optimized in the presence of Ag₃PO₄/GO nanocomposite with the dosage of 0.5-2 g/L, contact time of 15-20 min, and pH of 5-9 using response surface methodology. A second-order model was selected as the best fitted model with R² value and lack of fit as 0.935 and 0.06, respectively. Under the optimized conditions, the Ag₃PO₄/GO catalyst achieved a photocatalytic efficiency of 96.53% after 93.34 min. The photocatalytic activity, reaction kinetics, and stability were also investigated. The results indicated that the Ag₃PO₄/GO nanocomposite exhibited higher photocatalytic activity for ketoconazole degradation, which was 2.4 times that of pure Ag₃PO₄. Finally, a direct Z-scheme mechanism was found to be responsible for enhanced photocatalytic activity in the Ag₃PO₄/GO nanocomposite. The high photocatalytic activity, acceptable reusability, and good aqueous stability make the Ag₃PO₄/GO nanocomposite a promising nanophotocatalyst for photocatalytic degradation of azoles contaminants.

Pt nanoparticles decorated heterostructured g-C3N4/Bi2MoO6 microplates with highly enhanced photocatalytic activities under visible light

Exploring an efficient and photostable heterostructured photocatalyst is a pivotal scientific topic for worldwide energy and environmental concerns. Herein, we reported that Pt decorated g-C₃N₄/Bi₂MoO₆ heterostructured composites with enhanced photocatalytic performance under visible light were simply synthesized by one-step hydrothermal method for methylene blue (MB) dye degradation. Results revealed that the synthetic Pt decorated g-C₃N₄/Bi₂MoO₆ composites with Bi₂MoO₆ contents of 20 wt.% (Pt@CN/20%BMO) presented the highest photocatalytic activity, exhibiting 7 and 18 times higher reactivity than the pure g-C₃N₄ and Bi₂MoO₆, respectively. Structural analyses showed that Bi₂MoO₆ microplates were anchored on the wrinkled flower-like g-C₃N₄ matrix with Pt decoration, leading to a large expansion of specific surface area from 10.79 m²/g for pure Bi₂MoO₆ to 46.09 m²/g for Pt@CN/20%BMO. In addition, the Pt@CN/20%BMO composites exhibited an improved absorption ability in the visible light region, presenting a promoted photocatalytic MB degradation. Quenching experiments were also conducted to provide solid evidences for the production of hydroxyl radicals (^•OH), electrons (e⁻), holes (h⁺) and superoxide radicals (^•O²⁻) during dye degradation. The findings in this critical work provide insights into the synthesis of heterostructured photocatalysts with the optimization of band gaps, light response and photocatalytic performance in wastewater remediation.

Ultrasound-assisted Synthesis of Ag-ZnS/rGO and its Utilization in Photocatalytic Degradation of Tetracycline Under Visible Light Irradiation

Recent improvements based on heterojunction nanocomposites have opened new possibilities in photocatalysis. In this research, an ultrasound-assisted coprecipitation method was used to fabricate silver, zinc sulfide and reduced graphene oxide (Ag-ZnS/rGO) nanocomposite, and characterization results indicated that 3% Ag-ZnS spherical nanoparticles are successfully embedded in rGO matrix. The potential of the Ag-ZnS/rGO, as a visible light active photocatalyst, was assessed through optimizing degradation of Tetracycline (TC) by response surface methodology. It was found that the photocatalytic degradation of TC increased with an increase in the amount of nanocomposite and irradiation time, whereas it decreased with increasing the initial TC concentration. Under the optimal conditions (10 mg L^-1 of TC, 1.25 g L^-1 of Ag-ZnS/rGO, at pH = 7, and irradiation duration 110 min), more than 90% of the TC was degraded. The study of the mechanism of the photocatalytic process disclosed that the synergistic role of surface plasmon resonance (SPR) induced by Ag nanoparticles and p-type semiconductor feature of rGO leads to ZnS semiconductor stimulation in the visible light region. Eventually, a pseudo-first order kinetics model was developed based on the proposed mechanism. The obtained results highlight the role of Ag-ZnS/rGO nanophotocatalyst toward degradation of some antibiotics under visible light.

Enhanced visible-light photocatalytic activity and photostability of Ag3PO4/Bi2WO6 heterostructures toward organic pollutant degradation and plasmonic Z-scheme mechanism

Novel Ag3PO4/Bi2WO6 heterostructured materials with enhanced visible-light catalytic performance were successfully synthesized by assembly combined with a hydrothermal treatment. The microstructures, morphologies, and optical properties of the prepared samples were characterized by multiple techniques. The irregular Ag3PO4 nanospheres dispersed on the surface of Bi2WO6 nanoflakes, and their catalytic performances were evaluated via the degradation of organic pollutants including rhodamine B (RB), methylene blue (MB), crystal violet (CV), methyl orange (MO), and phenol (Phen) under visible-light irradiation. The resulting Ag3PO4/Bi2WO6 heterostructured materials displayed higher photocatalytic activity than that of either pure Bi2WO6 or Ag3PO4. The enhanced photocatalytic activity was due to the good formation of heterostructures, which could not only broaden the spectral response range to visible light but also effectively promoted the charge separation. Meanwhile, the reasonable photoreactive plasmonic Z-scheme mechanism was carefully investigated on the basic of the reactive species scavenging tests, photoelectrochemical experiments, and photoluminescence (PL) spectrum. In addition, the excellent photostability of Ag3PO4/Bi2WO6 was obtained, which Ag formed at the early photocatalytic reaction acted as the charge transmission-bridge to restrain the further photoreduction of Ag3PO4.