Graphitic carbon nitride (g-C3N4) is considered a promising metal-free photocatalyst for solar applications; however, its practical efficiency is limited by rapid charge recombination, low surface reactivity, and restricted light absorption. In this work, we report the design of a ternary P-doped g-C3N4/ZnO/Ag2MoO4 nanocomposite aimed at improving photocatalytic performance specifically under natural solar irradiation, addressing a key gap between laboratory studies and real-world applications. The photocatalyst was synthesized via a simple co-precipitation route and characterized using XRD, FTIR, SEM/EDS, TEM, and XPS. Its photocatalytic activity was evaluated under genuine sunlight for the degradation of malachite green dye and the pharmaceutical contaminant indomethacin, selected as representative emerging pollutants in water. Compared with pristine g-C3N4 and binary systems, the ternary composite exhibited a reduced band gap, enhanced charge carrier separation, and significantly higher degradation rate constants under fluctuating solar irradiation conditions. The photocatalyst also showed good stability and reusability over five successive solar photocatalytic cycles. Monte Carlo simulations revealed stronger adsorption of malachite green compared to indomethacin, supported by more negative adsorption energies and favorable thermodynamics. Based on UV-vis diffuse reflectance spectroscopy and active species trapping experiments, a dual Z-scheme charge transfer mechanism was proposed, explaining the improved utilization of the solar spectrum and enhanced redox capability. This study highlights the effectiveness of heterostructure engineering and elemental doping for developing efficient and stable photocatalysts operating under real sunlight, offering practical insights for scalable solar photocatalytic water treatment.

This paper investigates the synthesis of g-C3N4/BiOCl/Ag2WO4 nanocomposites for application in solar energydriven photodegradation of Methylene Blue dye (MB) and Amoxicillin antibiotic (AMOX). The as-prepared precursor photocatalysts (Ag2WO4, BiOCl, and g-C3N4) and nanocomposite photocatalyst g-C3N4/BiOCl/ Ag2WO4 were investigated using a full characterization process to determine their oxidation states (XPS), composition (EDX), morphology (SEM & TEM), structure (FTIR), and crystallinity (XRD). Examination of these characteristics attests to successful synthesis of g-C3N4/BiOCl/Ag2WO4 nanoparticles with enhanced crystallinity. Photocatalysis experiments proved that ternary nanocomposite is highly active towards degrading contaminating molecules, with 98 % for MB and 95 % for AMOX, through redox processes driven by sunlight. Monte Carlo simulation studies reveal that the g-C3N4/BiOCl/Ag2WO4 composite is readily formed, and MB molecules are adsorbed onto its surface in multiple layers, driven by favorable negative adsorption energies. In addition, the recyclability of g-C3N4/BiOCl/Ag2WO4 demonstrates its ability to retain photocatalytic activity across four consecutive cycles. According to active species trapping experiment and UV-vis diffuse reflectance spectroscopy (DRS), a proposed photocatalytic mechanism elucidates the observed enhancement in performance of the g-C3N4/BiOCl/Ag2WO4 system. According to the mechanism, the newly designed dual Zscheme heterojunction, which promotes the synergistic interaction among the photocatalysts, further accelerates the effective separation and transfer of e_/h+ and accordingly greatly improves the photocatalytic degradation efficiency.

The transformation of seafood processing residues into advanced functional materials offers a dual solution to environmental pollution: mitigating waste streams while addressing water contamination. In this study, shrimp exoskeletons were valorized into a chitin-protein composite (SE-CP) through acid demineralization and thermal activation and evaluated as a biosorbent for the removal of anionic textile dyes Sellacid Red (SR) and Sellaset Blue (SB). The material was characterized using SEM, EDX, FTIR, XRD, BET, DLS, XPS, and PZC analyses, confirming a mesoporous structure (specific surface area = 51.4914 m(2) g(-1)) enriched with amino and hydroxyl groups that favor electrostatic and hydrogen-bonding interactions. Batch adsorption studies showed maximum removal efficiencies of 99.2% for SR at pH = 3 and 98.7% for SB at pH = 4 both around 20 degrees C and an initial dye concentration of 100 mg L-1. Kinetic data fitted the pseudo-second-order model (R-2 > 0.96), and equilibrium was best described by the Freundlich isotherm, with adsorption capacities of 158.43 mg g(-1) (SR) and 63.81 mg g(-1) (SB). SE-CP retained over 76% of its adsorption capacity after five regeneration cycles, indicating strong stability and reusability. This work demonstrates a low-cost and sustainable biosorbent derived from shrimp waste, with high efficiency, reusability, and green synthesis, positioning SE-CP as a promising candidate for industrial dye wastewater treatment within circular economy principles.

This study investigates the use of CoxFe3-xO4 with different cobalt ratios (x = 1, 1.2, and 1.5) for the electrocatalytic water splitting process. Experimental measurements showed that the electrocatalytic performance of cobalt ferrite toward both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) was systematically enhanced by cobalt enrichment. In particular, the Co1.5Fe1.5O4 catalyst showed a lower OER overpotential compared to the CoFe2O4 composition (341 mV vs. RHE at 10 mA/cm2 compared to 467 mV), while the HER overpotential decreased from 370 to 331 mV at -10 mA/cm2. These enhancements are attributed to an increase in the electrochemically active surface area (ECSA) from 11.72 to 20.03 cm2 and an improvement in the OER turnover frequency (TOF) from 1.9 to 2.8 s-1. Additionally, Co1.5Fe1.5O4 showed excellent stability, maintaining over 96% of its activity during 48 h of continuous operation. The HER and OER processes appear to be favored by the presence of cationic metal sites and oxygen vacancies, which are particularly promoted by the oxidation of Co2+ to Co3+. This study reports a strong correlation between the Co/Fe ratio and electrocatalytic efficiency of water splitting, thus providing valuable insights for the design of robust and cost-effective catalysts for sustainable hydrogen and oxygen production.

The main challenge for sustainability and green environmental is developing efficient advanced materials for photocatalytic applications. In this study, we designed a new ternary hybrid photocatalyst based on BiOBr, g-C3N4, and kaolinite. This nanocomposite was employed for degrading toxic RhB dye through photocatalysis under sunlight exposure. This materials were thoroughly characterized using advanced techniques including XRD, FTIR, SEM, TEM, EDS, DRS, and XPS to investigate their structural, microstructural, optical, and spectroscopic properties. Photocatalytic performance studies revealed that RhB dye was completely removed within 20 min of irradiation. The degradation efficiency was 8.44 and 5.60 times higher than that of g-C3N4 and BiOBr, respectively. A direct Z-Scheme charge transfer pathway is proposed, supported by DRS, and further confirmed by radical scavenging experiments. Furthermore, the composite exhibited excellent stability, maintaining its performance over five reuse cycles. This work highlights a promising strategy for practical large-scale wastewater treatment using sunlight-driven photocatalysis.

This study reports the development of a novel Ag3PO4/g-C3N4/Bi2WO6 photocatalyst featuring a ternary heterostructure and a dual Z-scheme pathway mechanism. SEM and TEM analyzes confirmed the intimate contact between Ag3PO4, Bi2WO6, and g-C3N4, and hence the successful formation of the ternary heterojunction. Further, under natural solar light irradiation, the Ag3PO4/g-C3N4/Bi2WO6 photocatalyst, in comparison to single Ag3PO4, g-C3N4 and Bi2WO6 component, achieved an improved and remarkable CIP antibiotic photodegradation efficiency of 94 % within 90 min. Reactive Oxygen Species (ROS) center dot OH and center dot O2- played the dominant roles in the photocatalytic reaction. The overall data suggest that the dual Z-scheme carrier transfer pathways are responsible for the superior photocatalytic activity as resulting from the efficient separation of photogenerated charge carriers while maintaining their strong redox capabilities. The Ag3PO4/g-C3N4/Bi2WO6 photocatalyst demonstrates promising potential for wastewater treatment applications due to its high efficiency, efficient charge separation, and generation of potent oxidizing species. Additionally, Monte Carlo simulation was used to calculate the interactions of Ag3PO4, Bi2WO6, and CIP, occurring on, respectively, g-C3N4, Ag3PO4/g-C3N4, and Ag3PO4/g-C3N4/ Bi2WO6, in order to investigate their configurations and adsorption energies. The most stable geometries and pollutant remove were assessed from the negative adsorption energies (Ead) values.

In this study, natural clay (NC) was composited with 3-aminopropyltriethoxysilane (APTES)-modified Phoenix dactylifera date stone (DS) for the development of an efficient adsorbent, named APTES-DS@NC, capable of removing mercury ions from aqueous solution. At optimal conditions (pH 5.1 +/- 0.01, DS-APTES@NC dosage: 2.4 +/- 0.0001 g L-1, Hg(II) ion concentration: 175 mg L-1 +/- 1, and temperature: 25 +/- 1 degrees C), the removal efficiency at 120 +/- 0.1 min was 81.60%. The experimental results of Hg(II) adsorption by APTES-DS@NC agree with the Langmuir and PSO models. The maximum adsorption capacity was found to be 59.88 mg g(-1). The thermodynamic calculations confirmed that adsorption is exothermic and a feasible process. These may be explained by the high affinity of the Hg(II) ions due to electrostatic interactions with the APTES-DS@NC surface and ion exchange mechanisms. After 5 cycles, the Hg(II) removal efficiency was 41.32%. The study also emphasizes how the synthesis method and environmental conditions enhance the adsorption capabilities of APTES-DS@NC, demonstrating their effectiveness in removing heavy metals such as mercury from water.

Herein, an innovative methodology aimed at the valorization of sewage sludge through advanced treatment and utilization strategies, thereby fostering a circular economy while attaining both ecological and economic advantages. The research involved a two-step process: an initial Fenton-like chemical pretreatment to enhance sludge biodegradability, followed by anaerobic digestion (AD) to yield methane as an energy source. Subsequently, the iron-rich digestate generated from this process was subjected to pyrolysis, resulting in iron-rich biochar (FBC-600). As a catalyst, FBC-600 accelerated the degradation of Orange G (OG) via persulfate (PS) activation. Under optimized conditions (0.5 g/L FBC-600, 10 mM PS, 50 mg/L OG), 100 % of OG removal was achieved within 60 min. Notably, FBC-600/PS system exhibited remarkable stability and robustness against variations in pH (from 3 to 11), coexisting anions, tap water, and using other common organic pollutants. The FBC-600/PS system exhibited an activation energy of 14.88 kJ/mol and retained 88.9 % OG removal efficiency after five reuse cycles. ensuring consistent performance. Furthermore, mechanistic investigations revealed that the synergistic interaction of oxygen-containing groups (OFGs), iron and nitrogen species, and structural defects synergistically promoted PS activation and enhanced reactive oxygen species (ROS) production. Quenching experiments and electron paramagnetic resonance (EPR) confirmed the predominant role of radical species, particularly O2●-, in the degradation of OG. In the context of the circular economy, the as-developed FBC-600, estimated at $3210 US$/t. Hence, this work highlights a sustainable "waste-to-resource" approach for water treatment, offering both ecological and economic benefits.

The present work deals with the design via a facile co-precipitation method, and the comprehensive characterization of a novel ternary photocatalyst, Ag3PO4/g-C3N4/CuO. Further, by employing various methods such as XRD, FTIR, XPS, SEM, TEM, BET, and UV-visible DRS, we elucidate its structural, morphological, and optical properties. This innovative ternary catalyst demonstrates exceptional photocatalytic efficiency in the sunlight-driven degradation of Orange G dye, achieving a final removal rate of approximately 93.73 % in 60 min, and in the reduction of hexavalent chromium Cr(VI), reaching a 92.7 % reduction in the same time, as facilitated by a sacrificial electron donor, EDTA, at a concentration of 100 ppm. Further, the Ag3PO4/g-C3N4/CuO composite, as compared to its individual constituents, Ag3PO4, g-C3N4, and CuO, exhibits superior photo-degradation and photo-reduction efficiency. The influences of the critical parameters, including photocatalyst dosage, initial polluant concentration, solution pH and EDTA concentration on the photoreduction of Cr(VI), were systematically investigated. Furthermore, the composite showed satisfactory photostability over four cycles. Mechanistic insights from trapping experiments demonstrate the crucial roles of electrons (e-) and superoxide radicals (center dot O2-) in Cr(VI) reduction, while holes (h+) and (center dot O2-) are primarily responsible for the degradation of OG dye. The remarkable photocatalytic performance of the ternary photocatalyst, Ag3PO4/g-C3N4/CuO, is attributed to the synergistic effects occurring between the three components in the designed double Z-scheme heterojunction structure, leading to enhanced electron-hole pair separation.

This study highlights the potential of anaerobically treated sewage sludge, a by-product of anaerobic digestion (AD) produced in large quantities by wastewater treatment plants (WWTPs), which is further thermally activated to yield biochar. This biochar serves as a template for HNO3 modification, enabling efficient pollutant remediation. Herein, we investigated the removal efficiency of methylene blue (MB) using modified biochars under different HNO3 concentrations. The BC-HN9 exhibited the best MB sorption performance and was selected for further investigations, including characterization, evaluation of adsorption parameters, and investigations of kinetic and isotherm models. It was determined that chemical and physical interactions contribute to MB sorption, with the maximum adsorption capacity of 176.05 mg.g-1. Additionally, thermodynamic investigations confirmed that the process is endothermic and occurs spontaneously. The adsorption mechanism of MB was analyzed using DFT, radial distribution function (RDF), Monte Carlo (MC) and molecular dynamics (MD) calculations in combination with advanced techniques. The findings indicate that adsorption is facilitated by electrostatic interactions, pore filling, H-bonding, as well as n-it and it-it interactions. This method demonstrates a scalable approach to producing activated biochars, providing both an effective pathway for fabricating high-value carbon materials and a practical means of mitigating environmental pollution associated with biomass waste.

Three ZIF-8 nanomaterials with different Zn : 2-methylimidazole molar ratios (1 : 30, 1 : 50, and 1 : 70) were synthesized at room temperature in aqueous medium within 30 minutes without surfactants. Structural analyses confirmed the formation of mesoporous ZIF-8 with distinct morphologies, ranging from spherical assemblies to rhombic dodecahedra. Response Surface Methodology using a Box-Behnken design (RSM-BBD) was applied to optimize five parameters (pH, contact time, pollutant dose, linker amount, and catalyst weight) governing rhodamine B (RhB) removal. Under optimized conditions (pH 7, 70 mg catalyst, 10 ppm RhB, 60 min contact), ZIF-8 with a 1 : 70 ratio achieved a maximum adsorption capacity of 91.7 mg g-1 and a removal efficiency of ∼91%, fitting well with the Langmuir model (R 2 = 0.97). Photodegradation studies revealed high activity under UV irradiation, with rate constants of 0.00812, 0.00215, and 0.0014 min-1 for ZIF-8 (1 : 30, 1 : 50, and 1 : 70), respectively. The materials also demonstrated excellent recyclability, retaining over 92% efficiency after five cycles. The novelty of this work lies in the systematic evaluation of the Zn : 2-Hmim molar ratio on the morphology and performance of ZIF-8, combined with the first application of RSM-BBD to optimize the dual adsorption-photodegradation process for RhB removal. These findings provide new insights into tailoring ZIF-8 synthesis for efficient wastewater treatment applications.

This review article critically evaluates recent developments in removing thorium (Th) ions from wastewater and discusses future perspectives. Moreover, it is imperative to develop effective and sustainable techniques for removing Th due to the significant environmental and health risks its contamination produces. This review is done to understand the recent technologies and strategies developed for the removal of Th ions from wastewater and to evaluate their efficiency, feasibility, and environmental friendliness. Removal of Th ions from wastewater is an urgent issue due to the radiotoxicity and chemical toxicity of Th. This review may facilitate a broad understanding of the advances in various methods used for the removal of thorium ions through adsorption, ion exchange, membrane technologies, and bioremediation. Again, the article tries to spotlight the problems or gray areas associated with the different techniques developed so far, thereby suggesting scopes for future research and improvement. It is hoped that this review can successfully guide the development of new and more powerful approaches to mitigating Th contamination in wastewater by synthesizing leading-edge research findings and advances for better environmental protection and public health safety. It is of critical importance to protect the environment and human health from the toxic effects of radioactive thorium mixed into life-threatening wastewater. Because a clean environment means a more livable world left to future generations.

The ubiquitous presence of sulfamethoxazole (SMX) within aquatic ecosystems coupled with the increasing production of solid waste digestate has emerged as a critical environmental challenge. This necessitates the development of efficient decontamination strategies and sustainable waste management approaches. This study introduces iron-doped biochar (FBC-600), synthesized via pyrolysis of sewage sludge digestate (SSD), as an effective catalyst for peroxymonosulfate (PMS) activation to degrade SMX in aqueous media, thereby transforming this waste byproduct into a valuable material for environmental remediation. The FBC-600/PMS system exhibited efficient SMX removal nearly complete within 90 min under optimized conditions. Notably, the system demonstrated robustness against pH variations and the presence of inorganic ions. Mechanistic investigations implicated singlet oxygen (1O2) and electron transfer as predominant reactive oxygen species (ROS). The catalytic performance was attributed to the synergistic interplay of C--O, embedded iron, structural defects active sites on the FBC-600 surface. Moreover, the catalyst exhibited exceptional reusability and minimal iron leaching. The transformed products of SMX were examined through density functional theory (DFT) calculations and Liquid Chromatography-Mass Spectrometry (LC-MS). Concomitantly, the estimated toxicity of the identified intermediates was determined to be lower than that of SMX. This study highlights the potential of FBC-600 as a sustainable catalyst for SMX degradation by valorizing industrial bio-digestate according to zero-waste principles, which aim to minimize waste through strategies such as, reusing, reducing, recycling, refusing and composting.

This work presents a novel approach for the design and the stabilization of cobalt oxide nanoparticles supported on g-C 3 N 4 (CoCN- x ) catalyst to efficiently degrade various organic pollutants through peroxymonosulfate (PMS) activation.

In this study, a chemical precipitation approach was adopted to produce a photocatalyst based on bismuth tungstate Bi2WO6 for enhanced and environmentally friendly organic pollutant degradation. Various tools such as X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), optical spectroscopy and X-ray photoelectron spectroscopy, were employed to assess the structural and morphological properties. Hence, the XRD profiles showed a well crystallized Bi2WO6 orthorhombic phase. The photocatalytic performance of the resulting photocatalyst was assessed by the decomposition of Rhodamine B (RhB) and methyl orange (MO) with a decomposition efficiency of 97 and 92%, along with the highest chemical oxygen demand of 82 and 79% during 120 min of illumination, respectively. The principal novelty of the present work is to focus on the changes in the crystalline structure, the morphology, and the optical and the photoelectrochemical characteristics of the Bi2WO6, by tuning the annealing temperature of the designed photocatalyst. Such physicochemical property changes in the as-prepared photocatalyst will affect in turn its photocatalytic activity toward the organic pollutant decomposition. The photocatalytic mechanism was elaborated based on electrochemical impedance spectroscopy, photocurrent analysis, photoluminescence spectroscopy, and radical trapping measurements. The overall data indicate that the superoxide O2•− and holes h+ are the principal species responsible for the pollutant photodegradation.