Search Results (1,656)

This study investigates the bio-inspired photocatalytic degradation of humic acids using TiO₂-functionalized clinoptilolite (C–TiO₂) and Ag-doped TiO₂ (C–TiO₂/Ag) under UV irradiation. TiO₂ acts as an artificial analogue of naturally occurring photoactive mineral phases, while clinoptilolite provides a biomimetic scaffold mimicking mineral–organic interfaces. Ag doping enhances charge separation and promotes reactive oxygen species formation, accelerating degradation. The effects of pH and catalyst composition were evaluated over a range of conditions, including the native pH of the humic solution. Degradation was monitored via changes in UV₂₅₄ absorbance, VIS₄₃₆ absorbance, and COD values, revealing a multistage pathway: rapid decolorization of chromophoric groups, slower breakdown of aromatic structures, and final mineralization. Acidic conditions further enhanced performance through increased adsorption and ROS (reactive oxygen species) generation, while measurable activity persisted at near-natural pH values. Kinetic analysis indicated pseudo-first-order behavior, with the highest apparent rate constants obtained for VIS436 removal under C–TiO₂/Ag at pH 3 (k = 0.0166 min⁻¹), followed by COD₁ (k = 0.0190 min⁻¹), confirming faster oxidation of labile fractions and slower mineralization of recalcitrant intermediates. Therefore, the results demonstrate that semiconductor–mineral hybrid systems can serve as biomimetic platforms that reproduce and accelerate natural self-purification processes, providing mechanistic insights into nature-inspired pathways for water treatment. Full article

This study investigates the TiO₂ photocatalytic degradation of naproxen (NPX), a nonsteroidal anti-inflammatory drug, and spiramycin (SPM), a macrolide antibiotic, in aqueous solution. Experiments were conducted using a closed-loop falling thin-film photoreactor equipped with external UV lamps, with particular focus on the competitive degradation behavior when both pharmaceuticals are present simultaneously. Under optimized conditions such as natural pH, UV light intensity of 38 Wm⁻², and a recirculation flow rate of 25 L h⁻¹, the TiO₂-UV process achieved near-complete degradation of the parent compound (≥99%) for both compounds, whether treated individually or in combination. The degradation kinetics followed a pseudo-first-order model, consistent with heterogeneous photocatalytic systems at low pollutant concentrations. The apparent pseudo-first-order rate constants (k_app) were 0.025 min⁻¹ for NPX and 0.087 min⁻¹ for SPM in single-component systems. In competitive degradation, k_app ranged from 0.005 to 0.007 min⁻¹ for NPX and from 0.003 to 0.031 min⁻¹ for SPM, highlighting the influence of competitive adsorption and reactive-site interaction during simultaneous treatment. Mineralization efficiency differed between the compounds, reaching up to 67% for SPM and 41% for NPX when treated individually, suggesting the formation of more persistent by-products during naproxen degradation. Under competitive conditions, total mineralization rates ranged from 51% to 67% depending on the SPM/NPX molar ratio. Full article

This study explored the influence of high silver (Ag) loading (5–10 mol%) on the photocatalytic performance of zirconium (Zr) co-doped TiO₂ (AZT) with a low Zr content. Although various Ag/Zr ratios have been reported, the effect of high Ag loading combined with low Zr content remains largely unrevealed, particularly in low-temperature synthesis where the role of Zr as a phase inhibitor is less critical. To address this gap, the AZT photocatalyst was fabricated via a solvothermal method combined with organic-free peroxy route. Characterization indicated Zr⁴⁺ incorporated into the TiO₂ lattice, inducing structural distortions and promoting Ti³⁺ defect states. Simultaneously, silver existed as ternary Ag species, which functioned as visible light responsive co-catalysts that enhanced light absorption via Surface Plasmon Resonance (SPR) and facilitated efficient charge separation. Photocatalytic performance was evaluated through Methylene Blue (MB) decolorization under household LED lamp. The optimized 7% Ag loaded catalyst achieved 99.4% removal efficiency within 6 h, with a reaction rate ten times higher than the Zr-doped sample. This superior activity was attributed to a p-n heterojunction and the SPR effect, narrowing the optical band gap to 2.60 eV. Radical scavenger experiments confirmed that the process was primarily driven by photogenerated holes. Full article

This work reports the synthesis, characterization, and photocatalytic performance of multifunctional spheres based on AgNP-doped TiO₂-Fe₃O₄ embedded in an alginate–chitosan biopolymeric matrix for the removal of organic contaminants from water. The composite powders exhibited a nanocrystalline structure composed of anatase TiO₂ (~20 nm) and magnetite (~25 nm), with homogeneously dispersed Ag nanoparticles, as observed by SEM. The spheres presented a mainly submicrometric particle size distribution (0.55–0.92 µm), favoring high surface area and colloidal stability. Under simulated solar irradiation, the material achieved efficient photocatalytic degradation of methylene blue, with a pseudo-first-order rate constant of 0.112 h⁻¹ and ~46% decolorization after 5 h. UV-Vis spectra showed progressive attenuation of the dye absorption band without accumulation of intermediates. Magnetic recovery tests confirmed rapid separation and reuse without performance loss. The enhanced activity is attributed to the synergistic interaction among plasmonic Ag, photocatalytic TiO₂, redox-active Fe₃O₄, and the adsorptive carbon–biopolymer matrix. The material exhibited strong antibacterial activity, achieving over 90% removal of fecal coliforms after 5 h of irradiation. Therefore, the developed AgNP-doped TiO₂-Fe₃O₄ spheres represent a sustainable, reusable, and efficient material for solar-assisted water sanitation. Full article

Extracellular polymeric substances (EPSs) are high-molecular-weight biopolymers secreted by microorganisms, showing great potential for bioremediation. However, comprehensive analyses of the development context and quantitative research on the overall trends of EPSs in bioremediation are lacking. This study conducted a systematic bibliometric analysis of microbial EPS research using VOSviewer and CiteSpace. Keyword burst and thematic evolution analysis indicate a distinct thematic shift: early research focused on “structural characterization and adsorption mechanisms of EPSs”, whereas current hotspots highlight interactions with emerging pollutants (e.g., microplastics, antibiotics, and antibiotic resistance genes (ARGs)). EPSs significantly influence the environmental fate and removal efficiency of emerging pollutants through multiple pathways, including physical adsorption, chemical complexation, photocatalytic degradation, and electron transfer. For microplastic remediation, EPSs mediate hetero-aggregation, surface modification, and biodegradation processes. In antibiotic removal, EPSs function through biosorption, biodegradation, and photosensitized degradation. Regarding the mitigation of ARGs, EPSs can either suppress or facilitate their horizontal gene transfer, depending on their composition and environmental conditions. Additionally, as electroactive medium, EPSs play a crucial role in facilitating electron transfer, enhancing nitrogen removal, and promoting heavy metals reduction. This study systematically reviewed the current status and research hotspots of EPSs in bioremediation. However, practical applicability remains constrained by challenges such as low production yield and high costs. Future directions to address these limitations are also outlined to guide further development. Full article

This work investigates the conditions for obtaining 3D matrix films for wound dressings based on a copolymer of cod collagen (CC), pectin, and methyl methacrylate (MMA). The synthesis was carried out under photocatalytic conditions using the RbTe_1.5W_0.5O₆ oxide, with glycerol as a plasticizer. The development was based on CC-PMMA-pectin hydrogels synthesized in an aqueous dispersion via photocatalysis in the presence of the complex oxide RbTe_1.5W_0.5O₆. The hydrogels were characterized by elemental analysis and electron microscopy. By mixing the hydrogel and glycerol in a 5:1 ratio, plasticized films (CC-PMMA-pectin-glycerol films) were obtained. These films were transparent, homogeneous, elastic, and easily removed from the polymer substrate. In order to assess the stability of the obtained films, their physical and mechanical characteristics were investigated. An increase in the initial polymer content in the solution from 5% to 12% led to a simultaneous increase in tensile strength (from 0.6 MPa to 0.9 MPa) and elongation at break (from 61% to 76%). It was shown that these films are resistant to bacterial action, which is of great importance for the practical use of such wound dressings in non-sterile conditions. In vivo wound healing tests on rats showed complete wound closure (area reduced to 0 cm² by day 28). Tests of wound healing in rats using new coverings demonstrated high efficiency, providing a rationale for further clinical trials. Full article

Pure Bi₂O₃ is a favorable photocatalyst for visible-light-driven processes; however, the rapid recombination of photogenerated charge carriers limits its practical performance. In this work, Co-doped Bi₂O₃ nanoparticles, Co_xBi_2−xO₃ (x = 0–0.1), were produced through a sol–gel combustion route to enhance their visible-light photocatalytic activity. As demonstrated by XRD analysis, Co was successfully incorporated into the Bi₂O₃ lattice, along with changes to the crystal structure, crystallite size (up to ~88 nm), and lattice strain. Optical measurements revealed that Co-doping induces a clear absorption edge’s red shift, resulting in a systematic reduction of the optical band gap from 3.9 eV for pure Bi₂O₃ to approximately 3.1 eV for the doped samples. This band gap narrowing enhances visible-light absorption and improves photocatalytic efficiency. Photocatalytic activity was assessed by measuring the degradation of MB under visible-light irradiation. Incorporation of Co consistently enhanced the performance across all doped samples compared to the pristine oxide counterpart. The Co_0.1Bi_1.9O₃ composition demonstrated the best performance, achieving a removal efficiency of 94.5% within 120 min, compared with 73.0% for pure Bi₂O₃. Kinetic analysis indicated pseudo-first-order behavior, with the optimal sample showing a rate constant of 0.0240 min⁻¹—more than twice that of the undoped material (0.0105 min⁻¹). These results validate that Co-doping is an actual approach for engineering the electronic structure of Bi₂O₃, leading to enhanced visible-light absorption, improved charge-carrier separation, and significantly higher photocatalytic efficiency for environmental remediation applications. Full article

The development of sustainable technologies capable of simultaneously addressing environmental pollution and renewable energy production remains a major scientific challenge. In this work, titanium dioxide nanoparticles (GTiO₂) were synthesized through a plant-extract-assisted route using Punica granatum (pomegranate) peel extract and subsequently modified with platinum nanoparticles (Pt NPs) to obtain an efficient photocatalyst for the photoreforming of organic pollutants. The resulting Pt-GTiO₂ material exhibited an anatase crystal structure with an average crystallite size of approximately 12 nm and a specific surface area of about 140 m² g⁻¹. Comprehensive characterization using XRD, BET, TEM, FTIR, Raman, and photoluminescence spectroscopy (PL) revealed favorable structural and optoelectronic properties that promote efficient charge separation. The photocatalytic performance of Pt-GTiO₂ was evaluated through the simultaneous degradation of 2-naphthol, a priority aromatic pollutant, and hydrogen evolution under simulated solar irradiation in anaerobic conditions. Under the investigated conditions, Pt-GTiO₂ effectively promoted 2-naphthol degradation, with substantial but incomplete mineralization, as confirmed by TOC removal. The synthesized catalyst showed degradation efficiency higher than Pt-UV100 and comparable to Pt-P25, while exhibiting superior hydrogen evolution when compared with Pt-P25. Mechanistic investigations combining scavenger experiments, electron paramagnetic resonance (EPR) spectroscopy, and the identification of reaction intermediates suggest that photogenerated holes play a major role in the initial oxidation step under the mechanistic test conditions. The detected intermediates indicate that photoreforming proceeds via multiple pathways, including hydroxylation, ring-opening, reduction, and fragmentation. These findings highlight the potential of biogenic TiO₂-based photocatalysts for converting hazardous organic pollutants into clean hydrogen fuel while simultaneously achieving wastewater purification, offering a promising route toward sustainable environmental and energy technologies. Full article

Increasing volumes of dye-containing wastewater generated by the textile industry have become a serious environmental issue, particularly in Indonesia, where textile production contributes substantially to industrial activity. Among synthetic dyes, methylene blue (MB) is widely used because of its low cost and high solubility in water; however, its persistence, toxicity, and potential carcinogenicity make its removal from wastewater highly important. Conventional treatment methods are often limited by incomplete degradation and secondary waste generation. In this study, iron oxide nanoparticles (IONPs) were synthesized through a green route using Psidium guajava leaf extract as both a reducing and stabilizing agent. Characterization by PSA, UV-Vis, SEM-EDX, and XRD confirmed the formation of magnetite-like iron oxide particles with sizes ranging from 209.2 to 291.4 nm. Photocatalytic experiments showed high MB degradation efficiency (94.7–99.0%) under UV irradiation, highlighting the potential of guava leaf-mediated IONPs as low-cost, sustainable photocatalysts for wastewater treatment. Full article

Industrial modernization has generated a wide range of toxic contaminants in industrial wastewater and domestic effluents. The increasing presence of emerging contaminants and endocrine disruptors in aquatic environments poses serious threats to ecosystems and human health. Accordingly, effective strategies are urgently needed for the removal of emerging organic pollutants, including dyes and antibiotics in pharmaceutical wastewater. Photocatalysis has attracted considerable interest as a versatile and sustainable remediation approach because photocatalysts are often cost-effective, earth-abundant, and capable of utilizing solar energy. This review summarizes recent advances in ZnO-based photocatalysts, focusing on compositional tuning and heterostructure engineering to enhance pollutant degradation. The major photocatalytic degradation mechanisms are also discussed. Despite significant progress, challenges remain, including limited light absorption, poor catalytic stability, and obstacles to practical application in wastewater treatment. This review provides an updated perspective on the development of ZnO-based photocatalysts for emerging pollutant removal. Full article

With the rapid development of the edible fungus industry, the environmental pressure and resource waste caused by the massive generation of fungal residue have become increasingly prominent. Meanwhile, heavy metal wastewater pollution and the growing demand for clean energy pose dual challenges to sustainable development. This study focuses on Auricularia cornea var. Li. fungal residue, exploring the establishment of a multi-level resource utilization pathway integrating “porous carbon material preparation—heavy metal adsorption—photocatalytic hydrogen evolution.” Firstly, the Auricularia cornea var. Li. residue-based porous carbon material was examined by combining hydrothermal carbonization, activation and slow pyrolysis. In optimal conditions, the porous carbon obtained yielded a surface area of 675.56 m²/g and formed a composite pore structure consisting of micropores with coexisting micropore and mesopore. Secondly, we performed batch adsorption experiments to study the effects of solution pH, adsorbent dosage and contact time and the adsorption behavior via fitting adsorbing kinetic models. Under optimal conditions, Cd(II) removal efficiency reached 92.36% and an equilibrium adsorption capacity of 92.47 mg/g. We used Cd(II) adsorbed porous carbon as a cadmium source and converted into a CdS photocatalyst using a hydrothermal sulfidation process. The CdS prepared using sodium sulfide as a sulfur source gave an average hydrogen evolution rate of 668.01 μmol·g⁻¹·h⁻¹ and showed higher photocatalytic performance for water splitting to produce hydrogen. Full article

The development of durable and practical polymer-supported photocatalytic materials that are suitable for use in continuous-flow systems has become an increasingly pressing issue in the field of water treatment. In this study, FeTiO₃/BiOCl heterojunction structures were synthesized at different ratios and integrated into a poly(vinylidene fluoride) (PVDF) matrix to develop photocatalytic thin-film systems. The resulting materials were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and UV–visible diffuse reflectance spectroscopy (UV-DRS) analyses. In photocatalytic experiments conducted under visible light, a 66.3% removal of doxycycline was achieved for pristine FeTiO₃ within 180 min, whilst the FTO@BiOCl(III) composite reached 74.4%. In the PVDF-based thin-film system, the film catalyst demonstrated a removal efficiency of 68.9%. When the pH effect was investigated, the highest total removal of 90.3% was achieved under pH 6.0 conditions. Radical scavenging experiments revealed that superoxide radicals were the predominant active species (a decrease to 30.5% in the presence of benzoquinone (BQ). In experiments conducted in the air-lift reactor system, the P-FTO@BiOCl(III) film achieved approximately 65% removal after 9 h and maintained its structural stability. The PVDF-supported FeTiO₃/BiOCl heterojunction thin-film system offers a noteworthy alternative for environmental applications due to its suitability for continuous systems, structural stability and effective photocatalytic performance. Full article

Zeolite-based composite nanomaterials represent a versatile and mechanistically rich platform for the removal of organic micropollutants (OMPs)—including pharmaceuticals, endocrine-disrupting compounds, pesticides, and per- and polyfluoroalkyl substances (PFAS)—from contaminated water systems. Although pristine zeolite frameworks provide well-defined microporous architectures, tunable Si/Al ratios, and ion-exchange capacity, their intrinsic hydrophilicity restricts interaction diversity and limits performance toward the structurally heterogeneous OMPs prevalent in real aquatic environments. Composite integration with carbonaceous nanophases, functional polymers and surfactants, and catalytically active metal oxide nanoparticles substantially extends this interaction repertoire, yielding multifunctional materials whose adsorption performance exceeds that of the individual components. Drawing on a systematic survey of peer-reviewed literature published between 2016 and 2026, this review develops a mechanism-oriented, structure–property–performance framework examining five dominant adsorption mechanisms—electrostatic attraction, π–π stacking, hydrogen bonding, hydrophobic partitioning, and micropore confinement—in relation to composite nanoarchitecture, surface chemistry, and structural parameters. The modulating influence of realistic water matrix conditions on adsorption efficiency is critically assessed, alongside challenges of regeneration, long-term stability, metal leaching, and the persistent gap between laboratory-scale synthesis and scalable deployment. Priority research directions are identified, including standardized performance evaluation under environmentally representative conditions and rational design of hierarchical multifunctional nanocomposites from earth-abundant and waste-derived precursors. Full article

Polycyclic aromatic hydrocarbons (PAHs) are highly toxic pollutants in marine ecosystems, necessitating efficient remediation. This study synthesized magnesium phthalocyanine (MgPc) and its modified derivatives, magnesium azaphthalocyanine (NMgPc) and methyl-substituted magnesium azaphthalocyanine (MeNMgPc), as visible-light-driven photocatalysts for PAH degradation. To enhance efficiency and recoverability, these photosensitizers were immobilized onto coconut shell activated carbon (AC) via multiple ultrasonic impregnation. Characterizations (UV-Vis, SEM, EDAX, BET) confirmed successful active component deposition; nitrogen substitution and peripheral methyl groups synergistically tuned the electronic structure and suppressed aggregation. Under xenon lamp irradiation, the MeNMgPc/C composite exhibited superior activity, degrading 90.55% of naphthalene. Box-Behnken response surface optimization identified optimal conditions (13.18 g/L dosage, 20 A, 2.28 h), yielding 96.67% experimental removal and adhering to pseudo-first-order kinetics. Mechanistic studies via electron spin resonance identified hydroxyl (•OH) and superoxide radicals (O₂^•−) as primary reactive species. GC-MS analysis elucidated a sequential phenanthrene ring-opening pathway, progressing to ultimate mineralization into CO₂. Consequently, MeNMgPc/C presents a highly efficient, recoverable photocatalytic platform for marine PAH remediation. Full article

This study focuses on the application of photocatalysis for air pollution, targeting both chemical and biological contaminants. The selected target compounds were 3-methylbutan-1-ol (C₅H₁₂O), a volatile organic compound abundantly generated in the food industry, and Escherichia coli, representing a relevant bacterial indicator commonly encountered in such industrial environments and effectively embodying a biological threat. In this work, a series of experiments was conducted in a batch reactor using a novel TiO₂-based photocatalytic system integrating metal wires, namely copper (Cu) and silver (Ag), woven into an optical fiber support. A comparative evaluation of photocatalytic performance across different media was carried out for the removal of 3-methylbutan-1-ol, as well as for E. coli deactivation. The results demonstrated notable performance of the TiO₂-Cu medium for chemical treatment, achieving 97% removal efficiency after 85 min at an inlet concentration of 28 mg·m⁻³. Similarly, significant antibacterial activity was observed with 5.50 log reduction in colony-forming units (CFU) after 2.5 h. The photocatalytic performance of TiO₂-Cu supports was further validated under different operating conditions, including relative humidity levels ranging from 20% to 60% and concentration range from 5–30 mg·m⁻³. Finally, this study also includes a comparison between the TiO₂-Cu support and conventional photocatalytic systems based on TiO₂, particularly for simultaneous (combined) treatment of chemical and biological contaminants, with promising and encouraging outcomes. Full article