Search Results (211)

This study investigated the impact of cobalt/nickel-silicate loadings on graphitic carbon nitride at 10% and 20% doses, designated (CoNiSi-10) and (CoNiSi-20), for the removal of ciprofloxacin (CPF), a hazardous, bioaccumulative antibiotic. The synthesized composites were characterized in detail using SEM, EDX, TEM, N₂ adsorption–desorption, XRD, and FTIR techniques. The CoNiSi-10 and CoNiSi-20 exhibited CPF q_t values of 64 and 107 mg g⁻¹, respectively, which were consistent with the surface area results. Adsorption kinetics indicated that CPF uptake on CoNiSi-10 and CoNiSi-20 fitted the Lagergren model, with the liquid-film and intraparticle-diffusion mechanisms co-governing CPF sorption. The isotherm investigations indicated CPF adsorption on CoNiSi-10 and CoNiSi-20 aligned with the Langmuir model, suggesting a homogeneous surface, while the Dubinin-Radushkevich results primarily indicated physisorption-based CPF removal. The thermodynamic analyses supported the physisorption outcome and indicated that CPF sorption onto CoNiSi-10 and CoNiSi-20 was endothermic. A five-cycle reusability test yielded average efficiencies of 94% and 96% for CoNiSi-10 and CoNiSi-20, respectively, and an after-sorption analysis indicated their stability and robustness. The ease of synthesis and excellent sorption performance may nominate CoNiSi-10 and CoNiSi-20 as promising adsorbents for treating pharmaceutically contaminated wastewater. Full article

Background/Objectives: The widespread presence of antimicrobial-resistant pharmaceutical contaminants in wastewater poses serious ecological and public health risks and remains difficult to address using conventional treatment technologies. Moreover, remediation strategies often involve overlooked environmental burdens, highlighting the need for technologies that are both efficient and environmentally sustainable. This study developed a novel GO/ZIF-60/CoNiAl -LTH (GO/ZIF-60/LTH) ternary nanocomposite adsorbent for removal of ciprofloxacin (CIP) from water matrixes while evaluating its environmental implications using Life cycle assessment (LCA). Methods: The adsorbent was synthesized by integrating graphene oxide (GO) and Ni–Al–Co layered triple hydroxide (LTH) into a ZIF-60 framework. Structural and surface characterization was conducted using XRD, FTIR, SEM–EDX, BET, and UV–Vis analyses. The adsorbent’s CIP aqueous uptake was evaluated through batch experiments supported by kinetic, isotherm, thermodynamic, and response surface methodology (RSM) analyses. Environmental performance was assessed through life cycle-based evaluation. Results: The composite achieved a maximum adsorption capacity of 291 mg g⁻¹ and 91.6% removal efficiency with adsorption following pseudo-first-order kinetics and the Freundlich isotherm. The process was spontaneous and exothermic, with 75% efficiency retained after three regeneration cycles. The LCA revealed an overall global warming impact of 0.953 kg CO₂ eq per functional unit, with the NiAlCo-LTH synthesis stage (1.04 kg CO₂ eq) as the dominant hotspot, followed by final composite formation stage (0.66 kg CO₂ eq). Adsorption and regeneration provided credits (−0.336 and −0.513 kg CO₂ eq), offsetting the upstream impacts. Conclusions: The study demonstrates a new MOF–GO–LTH hybrid adsorbent with high CIP removal efficiency combined with its environmental sustainability assessment, providing a more comprehensive basis for adsorbent evaluation. Although the NiAlCo-LTH component was primarily responsible for the enhanced adsorption performance, yet, it also constituted the major environmental hotspot during its synthesis. These findings highlight the relevance of trade-off between functionality and environmental burden for process optimization, cleaner production, and the sustainable development of advanced adsorbents for pharmaceutical-contaminated water treatment. Full article

A multilayer gradient composite membrane was fabricated on a PES ultrafiltration substrate through layer-by-layer assembly of chitosan (CS) and montmorillonite (MMT), followed by Ca²⁺ crosslinking. The designed architecture forms a multi-layer gradient composite membrane through successive self-assembly, aiming to balance adsorption, interfacial transport and structural stability. SEM observations showed a clear stratified configuration with relatively uniform thickness distribution, including a relatively dense MMT-rich surface layer and a porous PES support that preserved mass-transfer channels. FTIR confirmed the introduction of hydroxyl/amino-containing CS and aluminosilicate-related MMT species onto the membrane surface, indicating successful incorporation of both organic and inorganic components. TG–DTG results further suggested enhanced thermal stability arising from the cooperative effect of the inorganic lamellae and the polymer framework. In dynamic tests, the membrane displayed concentration-responsive adsorption behavior toward gatifloxacin, ciprofloxacin and ofloxacin, and different pollutants reached equilibrium or quasi-steady states at different rates. Comparative kinetic results at the same initial concentration showed that diclofenac, gatifloxacin and ciprofloxacin approached stable plateaus much faster, whereas ofloxacin increased slowly and did not reach an obvious plateau within the tested period. These results indicate that pollutant removal was jointly governed by interfacial interactions, gradient-layer diffusion resistance and overall transport behavior rather than by concentration alone. Overall, the layer-by-layer strategy provided a controllable route for constructing gradient functional layers on PES membranes, demonstrating potential for advanced treatment of antibiotic-containing wastewater and related pharmaceutical effluents. Full article

Ciprofloxacin (CIP) is a persistent fluoroquinolone antibiotic frequently detected in water bodies, and its efficient mineralization remains a challenge in wastewater treatment. In this work, iron oxide–chitosan macroporous nanocomposite hydrogels were developed as heterogeneous catalysts for the electro-Fenton degradation of CIP. The materials were synthesized via Pickering high internal phase emulsion templating, yielding monoliths with a three-dimensional interconnected porous structure, an average pore size of 18.9 ± 0.7 µm, a window size of 8.1 ± 0.7 µm, an openness degree of 39.6%, a specific surface area of 1.77 m² g⁻¹, an iron content of 64.2 mg g⁻¹, and a crosslinking degree of 92.1%. The monoliths exhibited controlled swelling in aqueous medium at pH 3, with a gravimetric water uptake of 142.1 ± 2.3% and a volumetric swelling of 39.3 ± 1.2% at equilibrium. Iron oxide particles remained exposed on the porous surface, providing accessible catalytic sites, while the interconnected porosity favored reactant diffusion. Compared with direct anodic oxidation, which achieved 32% total organic carbon removal after 20 min, the heterogeneous electro-Fenton process using the synthesized monoliths as catalysts showed superior performance, reaching nearly 95% removal within 2 min and complete mineralization within 15 min. This enhanced performance was associated with higher hydroxyl radical generation (~3.5 µM) than that observed for anodic oxidation alone (~1.5 µM). These findings highlight the potential of biodegradable iron oxide–chitosan macroporous hydrogels as sustainable catalysts for antibiotic removal from water. Full article

The persistent accumulation of antibiotic pollutants in aquatic environments poses potential threats to ecological safety and human health, highlighting the importance of developing low-cost, high-performance adsorbents for their efficient removal. In this study, a hydrothermal method was employed to prepare highly dispersed coal gangue-based calcium silicate hydrate (CSH) adsorbents. The structural characteristics, adsorption performance, and adsorption mechanisms of the material were systematically investigated. The as-prepared CSH exhibited an interwoven nanorod/nanosheet composite morphology with a more developed pore structure and a higher specific surface area. Kinetic analysis indicated that the adsorption process followed a pseudo-second-order model and involved both Boyd diffusion and intraparticle diffusion, with liquid-film diffusion likely serving as the primary rate-limiting step. Isotherm analysis revealed that the adsorption behavior was well described by the Langmuir model, suggesting monolayer adsorption, with a theoretical adsorption capacity (Q_m) of 129.29 mg/g. Thermodynamic analysis further demonstrated that the adsorption of CIP onto CSH was a spontaneous and endothermic process. Combined characterization results and theoretical calculations suggested that the adsorption of CIP by CSH was mainly governed by surface oxygen containing active sites, accompanied by electrostatic interactions, hydrogen bonding, and possible surface coordination effects. In addition, CSH maintained excellent adsorption performance and structural stability in the presence of coexisting ions, in tap water systems, and after repeated adsorption–desorption cycles. This study not only enables the high-value utilization of coal gangue but also provides new insights into the development of low-cost adsorbent materials for antibiotic removal. Full article

The overuse of antibiotics has led to their widespread environmental residues, posing a significant threat to the ecological environment. In this study, a flower-like spherical CoFe-layered double hydroxide (CoFe-LDH) catalyst was prepared using a hydrothermal method. The degradation performance of the CoFe-LDH/peroxymonosulfate (PMS) system was systematically investigated using tetracycline (TC) as a model pollutant. The CoFe-LDH exhibited a three-dimensional nanoflower-like spherical structure formed by interlaced nanosheets, featuring smooth surfaces and well-defined edges. This hierarchical porous structure facilitates the exposure of active sites. The CoFe-LDH/PMS system demonstrated remarkable degradation efficiency, achieving over 90.17% TC removal within 10 min. As the dosage of CoFe-LDH and PMS increases, the degradation rate of TC improves significantly, but the marginal improvement effect decreases. TC degradation efficiency increased with pH up to an optimum at pH 5.0, beyond which it declined. The anions—Cl⁻, $\mathrm{N}{\mathrm{O}}_3^{-}$, and $\mathrm{S}{\mathrm{O}}_4^{2-}$—all exhibited inhibitory effects on TC degradation; the TC removal rates decreased to 77.88%, 80.58%, and 82.78%, respectively. The removal experiments of different organic pollutants, such as oxytetracycline (88.91%), methylene blue (98.36%), and ciprofloxacin (84.52%), as well as actual water experiments, such as lake water (92.48%) and tap water (80.86%), have demonstrated the good universality of the CoFe-LDH/PMS system. Radical quenching experiments confirmed that ^•OH and $\mathrm{S}{\mathrm{O}}_4^{•-}$ were the dominant reactive species. Full article

The widespread presence of ciprofloxacin (CIP) in aquatic environments threatens ecological and public health, yet conventional treatment processes fail to remove such persistent contaminants. Conventional solvothermal synthesis of Bi-doped g-C₃N₄ photocatalysts involves complicated procedures and low productivity. Herein, we employ a single-step, template-free and solvent-free green calcination method to construct Bi³⁺-modified g-C₃N₄ with strong Bi-N coordination interactions. A series of Bi/g-C₃N₄ photocatalysts with Bi-doping mass ratios of 0.09–0.34 wt% was prepared, and the structure–performance relationship as well as the surface–interface reaction mechanism for ciprofloxacin (CIP) degradation were systematically elucidated. Experimental results confirm that Bi³⁺ incorporates into the lattice via Bi-N coordination bonds with nitrogen in the g-C₃N₄ framework, which narrows the band gap, suppresses photogenerated carrier recombination, and constructs a loose porous morphology beneficial for increasing specific surface area and active sites. Under optimal conditions, 15Bi/g-C₃N₄ achieves 97.6% degradation of 15 mg L⁻¹ CIP within 90 min, which is 13.7% higher than that of pristine g-C₃N₄. The effects of catalyst dosage, initial pH, CIP concentration, common coexisting ions, and different real water matrices on the degradation performance were systematically investigated. Radical quenching experiments combined with ESR characterization confirm that h⁺ is the dominant reactive species responsible for CIP degradation. This green, simple and scalable method yields uniform products, and the resulting materials exhibit high efficiency, economic feasibility and environmental safety, demonstrating promising potential for antibiotic wastewater treatment. Full article

CaFe₂O₄ is a p-type ferrite semiconductor of interest for photo-assisted environmental remediation due to its narrow band gap and high chemical stability. In this work, CaFe₂O₄ powders were synthesized via the Pechini polymeric precursor method and calcined between 550 and 850 °C to investigate the influence of calcination temperature on structural order and material properties. X-ray diffraction combined with Rietveld refinement revealed the progressive stabilization of the orthorhombic Pnma phase, accompanied by relaxation of the FeO₆ octahedral framework. Raman and FT-IR spectroscopies confirmed a significant increase in vibrational coherence with increasing calcination temperature, quantified by a nearly three-fold increase in the global Raman order parameter and phonon lifetimes. Nitrogen physisorption showed a modest specific surface area and a pore system dominated by interparticle meso–macroporosity, typical of thermally treated ferrites. Removal tests using ciprofloxacin under UV-A irradiation showed limited photo-assisted activity, while agar diffusion assays against Escherichia coli and Staphylococcus aureus revealed no inhibition halos, indicating the absence of detectable antibacterial activity under the experimental conditions employed. Overall, CaFe₂O₄ combines photo-assisted response with good structural stability, highlighting its potential as a chemically stable ceramic material with no detectable antibacterial activity under the tested conditions. Full article

Background/Objectives: Although triple antibiotic paste is effective in managing infected primary teeth, its incomplete removability from tooth structure remains a major limitation, prompting the search for alternative drug-delivery systems. The aim of this study was to obtain a multi-antibiotic porous composite system for tailored drug delivery, to develop a formulation strategy, and to characterize the physicochemical properties and drug release. Methods: The developed composites consisted of a porous composite matrix (PCM; chitosan/bioactive filler) and two or three antibiotics (ciprofloxacin [CIP], metronidazole [MET], clindamycin [CLI]). Three methods of incorporating antibiotics were used: applying an antibiotic solution to the stabilized PCM; introducing an antibiotic solution into the polymer matrix; and introducing an antibiotic into the polymer matrix as nanoparticles. The physicochemical properties of the composites, including microstructure, compressive strength, and swelling, were assessed. The antibiotic release profile was assessed for up to 168 h. Results: The most advantageous method for introducing MET and CLI, in terms of release profile, was applying them to the PCM surface, whereas ciprofloxacin exhibited stable release when incorporated directly into the polymer matrix and entrapped during the stabilization process. The composites with nanoparticles, including MET or CIP, did not release any active substances during the experimental period. Conclusions: The results demonstrate that the developed formulation strategy enables the production of composites that rapidly release substantial amounts of the active substances within a short time frame and maintain their concentration for an extended period, which may be beneficial for the treatment of bacterial infections. Full article

Contamination of water bodies caused by increasing human and industrial activities poses a serious threat to human health and environmental sustainability, highlighting the need for green and efficient remediation strategies. In this study, a facile hydrothermal synthesis followed by controlled calcination was developed to fabricate phase-pure α- and β-Bi₂O₃ with a unique coral-like hierarchical morphology as visible-light-active photocatalysts. Phase selectivity was achieved by tuning the calcination temperature, yielding pure β-Bi₂O₃ while preserving the hierarchical structure. Optical characterization revealed a narrower bandgap for β-Bi₂O₃ (2.24 eV) compared to α-Bi₂O₃ (2.75 eV), favoring visible-light absorption. Photocatalytic performance was evaluated using Rhodamine B as a model pollutant, where β-Bi₂O₃ achieved complete degradation within 240 min, significantly outperforming α-Bi₂O₃. The degradation followed pseudo-first-order kinetics, and the catalyst exhibited excellent robustness and reusability. To further demonstrate applicability toward persistent contaminants, Methyl Orange (MO) and the antibiotic ciprofloxacin (CIP) were employed as additional model pollutants. The coral-like β-Bi₂O₃ showed high visible-light activity toward MO, including complete removal under acidic conditions. Moreover, efficient degradation of CIP was achieved at neutral pH, with 90% removal within 150 min and complete degradation after 240 min. Overall, these results highlight coral-like β-Bi₂O₃ as an efficient standalone photocatalyst for visible-light-driven degradation of dye and pharmaceutical pollutants. Full article

The use of adsorbents based on naturally occurring materials to eliminate antibiotics from industrial effluents has attracted remarkable interest owing to the abundance of raw materials and the sustainability of this method. The ciprofloxacin (CIP) removal capacity of a previously synthesized antimicrobial hydrogel based on carboxymethyl chitosan (CMCs)/xanthan gum (XG) was investigated for the first time in this study. CMCs and XG were blended in an equivalent-weight ratio and crosslinked using trimellitic anhydride isothiocyanate (TAI) to synthesize an eco-friendly, low-cost hydrogel, which was characterized using FTIR, SEM, and XRD analyses. The pseudo-second-order model fitted the experimental data well: the experimental q_e (49.59 mg g⁻¹) was close to the theoretical value (51.81 mg g⁻¹). The Langmuir isotherm best fitted the adsorption results (R² = 0.999), with a maximum adsorption capacity of 147.06 mg g⁻¹. The thermodynamic results indicate that adsorption is spontaneous, favorable, and exothermic in nature. The percentages of desorption obtained were 95.72, 94.34, 89.52, 88, and 86.28% after five consecutive cycles. Thus, this hydrogel possesses potential for further testing and application in wastewater remediation. Full article

The presence of antibiotics in aquatic systems presents significant ecological and health risks. Herein, Fe₃O₄/MgAl₂O₄ (MgFeAl-1), 2.5%NiO@Fe₃O₄/MgAl₂O₄ (MgFeAl-2), 5%NiO@Fe₃O₄/MgAl₂O₄ (MgFeAl-3), and 10%NiO@Fe₃O₄/MgAl₂O₄ (MgFeAl-4) were synthesized, selecting glucose as a capping agent, and 600 °C as calcination temperature. The TEM, EDX, BET, XRD, and FTIR techniques were employed to characterize the preidentified sorbents. The average size of MgFeAl-1, MgFeAl-2, MgFeAl-3, and MgFeAl-4 was about 6.53, 5.0, 7.61, and 10.52 nm, respectively, and they exhibited surface areas of 114.15, 154.02, 153.36, and 128.54 m² g⁻¹, respectively. The sorbents were tested for the removal of ciprofloxacin (CFCN) from aqueous solutions using the batch protocol. The MgFeAl-2 exhibited the highest performance, achieving an adsorption capacity of 99.45 mg g⁻¹, and the sorption equilibrium was reached within 60 min. The pseudo-second-order model best described CFCN sorption onto MgFeAl-2, and liquid-film diffusion influenced CFCN sorption. The CFCN adsorption onto MgFeAl-2 was well represented by the Langmuir isotherm model (R² = 0.93), indicating a monolayer adsorption. The thermodynamic results indicated a spontaneous, endothermic sorption process. A four-cycle MgFeAl-2 reusability study showed an average efficiency of 90%. Notably, MgFeAl-2 was effective in treating natural-water matrices, with a slight reduction in seawater due to ionic interference. The findings highlight the potential of MgFeAl-2 as an affordable and reusable adsorbent for removing antibiotics from contaminated water. Full article

Background: Enterococcus species are involved in urinary tract infections (UTIs), and they are known to be intrinsically resistant to certain antibiotics. We aimed to investigate the clinical characteristics and treatment outcomes of enterococcal UTIs in three hospitals in Saudi Arabia and Oman. Methods: A retrospective cohort study was conducted on adults with clinically and microbiologically confirmed enterococcal UTI based on urinary symptoms and a urine culture of ≥100,000 CFU/mL, who received an antibiotic active against the pathogen. The primary endpoint was clinical cure. Secondary endpoints included microbiological cure, length of stay (LOS), in-hospital mortality, and recurrence. Results: E. faecalis and E. faecium were isolated from 188 (67.1%) and 92 (32.9%), respectively, of 280 included patients. Ampicillin/amoxicillin (25%) and vancomycin (22.1%) were the most-used antibiotics. Compared with E. faecium, E. faecalis was associated with higher clinical cure rates (75% vs. 57.6%; p = 0.003), lower in-hospital mortality (15.7% vs. 38.5%; p < 0.0001), and shorter LOS (12.5 vs. 25 days; p < 0.0001). No difference in recurrence was observed. Ciprofloxacin was associated with high odds of clinical cure (OR, 4.28; 95% CI, 1.18–15.56). Conversely, the recent cancer chemotherapy and growth of Enterococcus at another site were associated with lower odds of clinical cure. Urinary catheter removal was associated with lower recurrence odds (OR, 0.48; 95% CI, 0.24–0.98). Conclusions: This study highlights the clinical challenges posed by enterococcal UTIs, particularly by E. faecium. Ciprofloxacin remains an effective option, particularly against E. faecalis. Patients with advanced age, critical illness, complicated infections, and liver disease, as well as patients on hemodialysis, require close monitoring to improve outcomes. Full article

One of the many applications of metal–organic frameworks (MOFs) is their use as adsorbents for removing emerging contaminants, such as ciprofloxacin (CIP), a fluoroquinolone-class antibiotic, from aqueous environments. We selected the copper-based MOF HKUST-1 and coupled it with TiO₂, then immobilized the composite on glass beads (TiO₂/HKUST-1@GB) to produce a reusable photocatalyst. The immobilization of the composite on glass beads improved the structural strength as well as the reusability of the photocatalyst. Together, these properties pave the way for scale-up for commercial applications in continuous-flow water treatment systems. Herein, we used XRD, FTIR, and SEM to characterize the immobilized catalyst and assess its structural, morphological, and optical properties. Photocatalytic experiments showed 98% degradation in 45 min under UV irradiation at pH 6 and a CIP concentration of 200 μgL⁻¹. The TiO₂/HKUST-1@GB composite showed higher degradation compared to pristine TiO₂ and HKUST-1 due to enhanced charge–carrier separation and synergistic interfacial effects. The reusability of the composite over five cycles was observed, with high stability and negligible Cu and Ti leaching, indicating promising environmental performance. Thus, TiO₂/HKUST-1@GB provides an efficient and sustainable approach for removing ciprofloxacin from aqueous solutions. The degradation performance, reusability, and ability to work simultaneously in adsorption and photocatalytic processes make TiO₂/HKUST-1@GB a promising candidate for the advanced treatment of aqueous-phase antimicrobial compounds such as ciprofloxacin. Full article

This study investigates how graphitic carbon nitride (g-C₃N₄), derived from melamine, urea, and thiourea, degrades recalcitrant pharmaceuticals. Among the materials used, g-C₃N₄ derived from urea showed the highest degradation of methyl orange (60.25%). When calcined with biochar derived from onion flower seed-cover biomass via pyrolysis and further activated with potassium hydroxide (KOH), it showed better adsorption and photodegradation results of 92.59%, 84.44%, 68.11%, and 61.11% for tetracycline, cefixime, ciprofloxacin, and carbamazepine, respectively. These results emphasize the potential of biochar-g-C₃N₄ composites as sustainable photocatalysts for water treatment focused on removing recalcitrant pharmaceutical contaminants. Full article