Evaluation of CNT-COOH/MnO2/Fe3O4 nanocomposite for ibuprofen and paracetamol removal from aqueous solutions

Sensitive colorimetric detection of heparin using reverse modulation of peroxidase- and oxidase-mimetic activities in Fe3O4@PDA@MnO2 nanocomposites

Heparin, a widely studied glycosaminoglycan, plays crucial roles in the regulation of various physiological and pathological processes. Therefore, it's important to develop highly selective and sensitive methods for convenient monitoring of heparin levels in biological systems. We report the design and synthesis of Fe3O4@PDA@MnO2 nanoparticles (FPM-NPs), which exhibit dual enzymatic activities, enabling quantitative detection of heparin. The FPM-NPs feature a unique tri-layer spherical shell structure, possessing both peroxidase-like and oxidase-like activities, and catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence or absence of H2O2. Remarkably, upon co-incubated with heparin, the oxidase activity of FPM-NPs decreases, while the peroxidase activity increases. By leveraging these dual enzymatic properties of FPM-NPs, a highly sensitive and specific colorimetric detection of heparin is achieved, with a detection limit reaching 6.51 nM and a good linear response to quantify heparin ranging 10-800 nM. Additionally, the developed FPM-NPs are successfully applied to measure heparin in fetal bovine serum samples. We also extend this detection method to a paper-based chip, enabling portable detection of heparin through grayscale analysis of mobile phone photographs. The multi-nanozyme-based heparin detection approach provides a new perspective for future research on expanding the application of nanocomposite materials in biomedical detection and analysis.

Recent advances of piezo-catalysis and photocatalysis for efficient environmental remediation

The efficient degradation of organic pollutants in diverse environmental matrices can be achieved through the synergistic application of piezo-catalysis and photocatalysis. The focus of this study is on understanding the fundamental principles and mechanisms that govern the collaborative action of piezoelectric and photocatalytic materials. Piezoelectric nanomaterials, under mechanical stress, generate piezo-potential, which, when coupled with photocatalysts, enhances the generation and separation of charge carriers. The resulting cascade of redox reactions promotes the degradation of a wide spectrum of organic pollutants. The comprehensive investigation involves a variety of experimental techniques, including advanced spectroscopy and microscopy, to elucidate the intricate interplay between mechanical and photoinduced processes. The influence of key parameters, such as material composition, morphology, and external stimuli on the catalytic performance, is systematically explored. This study contributes to the increasing knowledge of environmental remediation and lays the foundation for the development of advanced technologies using piezo and photocatalysis for sustainable pollutant removal.

Effect of functionalization on the adsorption performance of carbon nanotube as a drug delivery system for imatinib: molecular simulation study

In this study, efficiency of functionalized carbon nanotube as a potential delivery system for imatinib anti-cancer drug was investigated. Accordingly, carboxyl and hydroxyl functionalized carbon nanotube were inspected as a notable candidate for the carriage of this drug in aqueous media. For this purpose, possible interactions of imatinib with pure and functionalized carbon nanotube were considered in aqueous media. The compounds were optimized in gas phase using density functional calculations. Solvation free energies and association free energies of the optimized structures were then studied by Monte Carlo simulation and perturbation method in water environment. Outcomes of quantum mechanical calculations presented that pure and functionalized carbon nanotubes can act as imatinib drug adsorbents in gas phase. However, results of association free energy calculations in aqueous solution indicated that only carboxyl and hydroxyl functionalized carbon nanotubes could interact with imatinib. Monte Carlo simulation results revealed that electrostatic interactions play a vital role in the intermolecular interaction energies after binding of drug and nanotube in aqueous solution. Computed solvation free energies in water showed that the interactions with functionalized carbon nanotubes significantly enhance the solubility of imatinib, which could improve its in vivo bioavailability.

Polyethyleneimine-functionalized magnetic sugarcane bagasse cellulose film for the efficient adsorption of ibuprofen

Polyethyleneimine-modified magnetic sugarcane bagasse cellulose film (P-SBC/Fe3O4 film) was simply fabricated for the removal of ibuprofen (IBP), a typical emerging organic contaminant. The P-SBC/Fe3O4 film exhibited an equilibrium adsorption amount of 370.52 mg/g for IBP and a corresponding removal efficiency of 92.63 % under following adsorption conditions: 318 K, pH 4, and 0.25 mg/mL dosage. Thermodynamic studies indicated that adsorption of IBP on the P-SBC/Fe3O4 film was spontaneous (∆G < 0) and endothermic (∆H > 0). The adsorption data conformed to the Freundlich isotherm model and multilayer adsorption model (two layers), and an average of 3-4 active sites on the P-SBC/Fe3O4 film share an IBP molecule. Both the EDR-IDR and AOAS models vividly described the dynamic characteristics of adsorption process. Model fitting results, theoretical calculations, and comprehensive characterization revealed that adsorption is driven by electrostatic interactions between the primary amine of P-SBC/Fe3O4 film and the carboxyl group of IBP molecule, while other weak interactions are also non-ignorable. Furthermore, quantitative calculations based on density functional theory (DFT) underscored the importance of PEI functionalization. In conclusion, P-SBC/Fe3O4 film is an environmentally friendly and cost-effective adsorbent with significant potential for effectively removing IBP, while maintaining its efficacy over multiple cycles.

An Updated Overview of Magnetic Composites for Water Decontamination

Water contamination by harmful organic and inorganic compounds seriously burdens human health and aquatic life. A series of conventional water purification methods can be employed, yet they come with certain disadvantages, including resulting sludge or solid waste, incomplete treatment process, and high costs. To overcome these limitations, attention has been drawn to nanotechnology for fabricating better-performing adsorbents for contaminant removal. In particular, magnetic nanostructures hold promise for water decontamination applications, benefiting from easy removal from aqueous solutions. In this respect, numerous researchers worldwide have reported incorporating magnetic particles into many composite materials. Therefore, this review aims to present the newest advancements in the field of magnetic composites for water decontamination, describing the appealing properties of a series of base materials and including the results of the most recent studies. In more detail, carbon-, polymer-, hydrogel-, aerogel-, silica-, clay-, biochar-, metal-organic framework-, and covalent organic framework-based magnetic composites are overviewed, which have displayed promising adsorption capacity for industrial pollutants.

Adsorption of uranium (VI) complexes with polymer-based spherical activated carbon

Adsorption processes with carbon-based adsorbents have received substantial attention as a solution to remove uranium from drinking water. This study investigated uranium adsorption by a polymer-based spherical activated carbon (PBSAC) characterised by a uniformly smooth exterior and an extended surface of internal cavities accessible via mesopores. The static adsorption of uranium was investigated applying varying PBSAC properties and relevant solution chemistry. Spatial time-of-flight secondary ion mass spectrometry (ToF-SIMS) was employed to visualise the distribution of the different uranium species in the PBSAC. The isotherms and thermodynamics calculations revealed monolayer adsorption capacities of 28-667 mg/g and physical adsorption energies of 13-21 kJ/mol. Increasing the surface oxygen content of the PBSAC to 10 % enhanced the adsorption and reduced the equilibrium time to 2 h, while the WHO drinking water guideline of 30 µgU/L could be achieved for an initial concentration of 250 µgU/L. Uranium adsorption with PBSAC was favourable at the pH 6-8. At this pH range, uranyl carbonate complexes (UO2CO3(aq), UO2(CO3)22-, (UO2)2CO3(OH)3-) predominated in the solution, and the ToF-SIMS analysis revealed that the adsorption of these complexes occurred on the surface and inside the PBSAC due to intra-particle diffusion. For the uranyl cations (UO22+, UO2OH+) at pH 2-4, only shallow adsorption in the outermost PBSAC layers was observed. The work demonstrated the effective removal of uranium from contaminated natural water (67 µgU/L) and meeting both German (10 µgU/L) and WHO guideline concentrations. These findings also open opportunities to consider PBSAC in hybrid treatment technologies for uranium removal, for instance, from high-level radioactive waste.

Highly effective degradation of ibuprofen by alkaline metal-doped copper oxides via peroxymonosulfate activation: Mechanisms, degradation pathway and toxicity assessments

Redox ratios of Cu2+/Cu+ and adsorbed oxygen species (Oads) have shown great activity toward radical generation by activating peroxymonosulfate (PMS). Herein, different alkaline metal oxides (CaO, MgO and BaO) and various amounts of CaO are incorporated into CuO, which could tune the main active sites of redox ratios of Cu2+/Cu+ and Oads. The results show that CaO-CuO-5% exhibits the outstanding performance of PMS activation toward ibuprofen (IBF) degradation with excellent kinetics (k = 0.812 min-1). The X-ray absorption spectroscopy (XAS) and density functional theory (DFT) calculation show that the CaO-CuO-5% has the higher electron density with superior electron transfer ability and lower PMS adsorption energy. Based on radical scavengers and electron paramagnetic resonance spectrometer (EPR), a nonradical process is proposed to play the dominant role. The degradation pathway and the corresponding toxicity of degraded intermediates with residue PMS after reaction is evaluated by LC-MS/MS and bioassay experiments, indicating the lower antagonistic influence on human hormone receptors after advanced oxidation process. Mitigation of the Cu leaching with cyclic stability can be achieved. This study provides a facile method to optimize high-performance catalysts to activate PMS and offer practical environmental applications in the remediation of emerging contaminants.

Thermally-activated gelatin-chitosan-MOF hybrid aerogels for efficient removal of ibuprofen and naproxen

Nonsteroidal anti-inflammatory drugs (NSAIDs) are one of the most frequently used drugs and have been frequently detected in aquatic environments. This paper demonstrates a thermally-activated gelatin-chitosan and amine-functionalized metal-organic framework (UiO-66-NH2) aerogel (CGC-MOF), which was successfully synthesized for the efficient removal of ibuprofen (IBP) and naproxen (NPX). Various characterization tools were used to systematically analyze the microstructure and physicochemical properties of the synthesized aerogel. In addition, the effect of key reaction parameters as well as batch and continuous-flow fixed-bed column experiments were carried out to elucidate the adsorption process. Several functional groups in the biopolymer network, combined with excellent MOF properties, synergistically couple to form an adsorbent with great performance. The mesoporous aerogel activated at 200 °C (CGC-MOF200) exhibited a high specific surface area (819.6 m2/g) that is valuable in providing abundant adsorption active sites that facilitate the efficient adsorption of IBP and NPX. CGC-MOF200 exhibited an excellent removal of IBP and NPX, accounting to 99.28 % and 96.39 %, respectively. The adsorption process followed the pseudo-second-order kinetics and the Freundlich isotherm models, suggesting heterogeneous and chemisorption adsorption processes. Overall, this work provides new and valuable insights into the development of a promising biopolymer-MOF composite aerogel for environmental remediation.

A novel hydrangea-like magnetic composite Fe3O4@MnO2@ZIF-67 for efficient selective adsorption of Pd(II) from metallurgical wastewater

The selective adsorption of palladium from wastewater is a feasible solution to solving palladium pollution and resource scarcity. Because traditional solvent extraction methods often involve the use of considerable amounts of organic solvents, research is focused on investigating adsorption techniques that can selectively remove palladium from wastewater. In this paper, the magnetic composite Fe3O4@MnO2@ZIF-67 was synthesized and its performance for the adsorption of Pd(II) in acidic water was investigated. Fe3O4@MnO2@ZIF-67 was characterized by various analytical methods such as TEM, SEM, EDS, BET, XRD, FTIR, zeta potential analysis, VSM, and TGA. The effects of palladium ion concentration, contact time, pH, and temperature on adsorption were evaluated. The kinetics were shown to follow the pseudo-second-order kinetic model and Elovich model, and the rate-limiting step was chemisorption. Thermodynamic studies showed that increasing the temperature promoted the adsorption of Pd(II), and the maximum uptake capacity of Fe3O4@MnO2@ZIF-67 for Pd(II) was 531.91 mg g-1. Interestingly, Fe3O4@MnO2@ZIF-67 exhibited superior selectivity for Pd(II) in the presence of Ir(IV), Pt(IV), and Rh(III). The adsorbent can be used repeatedly for selective adsorption of palladium. Even at the fifth cycle, the uptake rate of Pd(II) remained as high as 83.1%, and it showed a favorable adsorption capacity and selectivity for Pd(II) in real metallurgical wastewater. The adsorption mechanism was analyzed by SEM, FTIR, XRD, XPS, and DFT calculations, which indicated that electrostatic interactions and coordination with nitrogen-containing groups were involved. Fe3O4@MnO2@ZIF-67 is a promising adsorbent for the efficient adsorption and selective separation of palladium ions.

Correlation of Elemental Transfer, Bioactive Compounds and Antioxidant Activity on Lactuca sativa L. Grown in Soil with Functionalized CNT and HMs

While heavy metals (HM) have been considered in recent decades to be the most common and problematic pollutants, the expansion of the list of pollutants due to the active use of carbon nanotubes (CNT) raises new questions about the benefit and harm of HM released to nature individually or fixed on CNT walls. A pot experiment was conducted to compare the effect of two classes of potential pollutants-metal salts of Pb, Mn, Cu, Zn, Cd, and Ni; and functionalized CNTs with COOH, MnO2, Fe3O4, and MnO2-Fe3O4-applied in soil, on the elemental transfer, the bioactive compounds accumulation, and the antioxidant activity in lettuce. While CNTs mainly increased the elemental transfer from soil to leaves, HM salts strongly obstructed it. In the presence of CNTs, the antioxidant activity in lettuce leaves correlated with the transfer of elements from soil to root and from root to leaves. The excess of HMs in soil induced a greater variation of the polyphenols quantity and antioxidant activity than the excess of CNTs. It might be assumed that lettuce perceived HMs as a more aggressive stressor than CNTs and more strongly activated the defense mechanism, showing the reduction of the element transfer and enhancing of total polyphenol production and antioxidant activity.

Occurrence, toxicity, impact and removal of selected non-steroidal anti-inflammatory drugs (NSAIDs): A review

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most frequently used pharmaceuticals for human therapy, pet therapeutics, and veterinary feeds, enabling them to enter into water sources such as wastewater, soil and sediment, and seawater. The control of NSAIDs has led to the advent of the novel materials for treatment techniques. Herein, we review the occurrence, impact and toxicity of NSAIDs against aquatic microorganisms, plants and humans. Typical NSAIDs, e.g., ibuprofen, ketoprofen, diclofenac, naproxen and aspirin were detected at high concentrations in wastewater up to 2,747,000 ng L-1. NSAIDs in water could cause genotoxicity, endocrine disruption, locomotive disorders, body deformations, organs damage, and photosynthetic corruption. Considering treatment methods, among adsorbents for removal of NSAIDs from water, metal-organic frameworks (10.7-638 mg g-1) and advanced porous carbons (7.4-400 mg g-1) were the most robust. Therefore, these carbon-based adsorbents showed promise in efficiency for the treatment of NSAIDs.

The Effect of Functionalized Multiwall Carbon Nanotubes with Fe and Mn Oxides on Lactuca sativa L

The aim of this work was to evaluate the effect of six nanomaterials, namely CNT-COOH, CNT-MnO2, CNT-Fe3O4, CNT-MnO2-Fe3O4, MnO2, and Fe3O4 on lettuceTo determine the impact of nanomaterials on lettuce, the results obtained were compared with those for the control plant, grown in the same conditions of light, temperature, and humidity but without the addition of nanomaterial. The study found that the content of bioactive compounds and the antioxidant capacity varied in the treated plants compared to the control ones, depending on the nanomaterial. The use of CNTs functionalized with metal oxides increases the elemental concentration of lettuce leaves for the majority of the elements. On the contrary, metal oxide nanoparticles and CNT functionalized with carboxyl groups induce a decrease in the concentration of many elements. Soil amending with MnO2 affects the content of more than ten elements in leaves. Simultaneous application of CNT and MnO2 stimulates the elemental translocation of all elements from roots to leaves, but the simultaneous use of CNT and Fe3O4 leads to the most intense translocation compared to the control other than Mo.

Insight into the adsorptive removal of ibuprofen using porous carbonaceous materials: A review

Over the last decade, the removal of pharmaceuticals from aquatic bodies has garnered substantial attention from the scientific community. Ibuprofen (IBP), a non-steroidal anti-inflammatory drug, is released into the environment in pharmaceutical waste as well as medical, hospital, and household effluents. Adsorption technology is a highly efficient approach to reduce the IBP in the aquatic environment, particularly at low IBP concentrations. Due to the exceptional surface properties of carbonaceous materials, they are considered ideal adsorbents for the IBP removal of, with high binding capacity. Given the importance of the topic, the adsorptive removal of IBP from effluent using various carbonaceous adsorbents, including activated carbon, biochar, graphene-based materials, and carbon nanostructures, has been compiled and critically reviewed. Furthermore, the adsorption behavior, binding mechanisms, the most effective parameters, thermodynamics, and regeneration methods as well as the cost analysis were comprehensively reviewed for modified and unmodified carbonaceous adsorbents. The compiled studies on the IBP adsorption shows that the IBP uptake of some carbon-based adsorbents is significantly than that of commercial activated carbons. In the future, much attention is needed for practical utilization and upscaling of the research findings to aid the management and sustainability of water resource.

Evaluation of Fe3O4-MnO2@RGO magnetic nanocomposite as an effective persulfate activator and metal adsorbent in aqueous solution

A reduced graphene oxide (RGO) supported Fe₃O₄-MnO₂ nanocomposite (Fe₃O₄-MnO₂@RGO) was successfully prepared for catalytic degradation of oxytetracycline (20 mg/L) by potassium persulfate (PS) and adsorption removal of mixture of Pb²⁺, Cu²⁺, and Cd²⁺ ions (each 0.2 mM) in the synchronous scenario. The removal efficiencies of oxytetracycline, Pb²⁺, Cu²⁺, and Cd²⁺ ions were observed as high as 100%, 99.9%, 99.8%, and 99.8%, respectively, under the conditions of [PS]₀ = 4 mM, pH₀ = 7.0, Fe₃O₄-MnO₂@RGO dosage = 0.8 g/L, reaction time = 90 min. The ternary composite exhibited higher oxytetracycline degradation/mineralization efficiency, greater metal adsorption capacity (Cd²⁺ 104.1 mg/g, Pb²⁺ 206.8 mg/g, Cu²⁺ 70.2 mg/g), and better PS utilization (62.6%) than its unary and binary counterparts including RGO, Fe₃O₄, Fe₃O₄@RGO, and Fe₃O₄-MnO₂. More importantly, the ternary composite had good magnetic recoverability and excellent reusability. Notably, Fe, Mn, and RGO could play a synergistic role in the improvement of pollutant removal. Quenching results indicate that surface bounded SO₄^•- was the major contributor to oxytetracycline decomposition, and the -OH groups on the composite surface shouldered a significant role in PS activation. The results indicate that the magnetic Fe₃O₄-MnO₂@RGO nanocomposite has a good potential for removing organic-metal co-contaminants in waterbody.

Recent advances in new generation nanocomposite materials for adsorption of pharmaceuticals from aqueous environment

With rapid increase in the human population, a large amount of wastewater is generated every year. The availability of fresh water is decreasing at an alarming rate due to rapid industrialization and agricultural development. Pharmaceutical drugs which are credited for improving standards of life worldwide have emerged as major water contaminants, raising global concern about their potential risk to human health and environment. The presence of pharmaceutical compounds is detected in surface water (sea, river, lakes, etc.), groundwater, effluents from municipal, hospitals, and wastewater treatment plants, and even in drinking water. Efficient removal of pharmaceutical pollutants still remains a challenging task. Many techniques, including photodegradation, photocatalysis, oxidation, reverse osmosis, biodegradation, nanofiltration, adsorption, etc., have been used for the remediation of wastewater. Adsorption of pharmaceutical compounds on nanoadsorbents, as a low-cost and feasible technology, has gained immense popularity for wastewater treatment over the last decade. Adsorption techniques can be integrated with wastewater treatment plants to achieve efficient removal on an industrial level. Herein, we review the literature on the remediation techniques used for the pharmaceutical waste treatment using carbon nanotubes, metal oxides, nanoclay, and new-generation MXenes via adsorption. These materials show excellent adsorptive properties owing to their high surface area, low cost, high porosity, easy functionalization, and high surface reactivity. The adsorption mechanism of the nanoadsorbents and their reusability as a factor of sustainability have also been included in the review. The factors affecting the adsorption, including pH, the concentration of adsorbate, ionic strength, and adsorbate dose, have also been discussed.

Magnetite Nanoparticles as Solar Photo-Fenton Catalysts for the Degradation of the 5-Fluorouracil Cytostatic Drug

Heterogeneous catalysts based on magnetite nanoparticles, Fe3O4, were prepared by the chemical coprecipitation method using iron (III) chloride as a salt precursor. The physicochemical properties of the nanoparticles were determined by different techniques and the efficiency was evaluated for the degradation of the cytostatic drug, 5-fluorouracil (5-FU), in aqueous solution by photo-Fenton process under simulated solar radiation. The most influential parameters, namely pH of the solution, catalyst load, H2O2 dosage, and use of radiation, were studied and optimized in the degradation process. The optimal conditions to achieve a 100% degradation of 5-FU (10 mg L-1) and a high mineralization degree (76%) were established at the acidic pH of 3.0, 100 mg L-1 of catalyst loading, and 58 mM of H2O2 under simulated solar radiation. The contribution of iron leaching to the catalyst deactivation, the role of the dissolved iron ions on homogenous reactions, and the stability of the catalyst were assessed during consecutive reaction cycles.

Synthesis of metal-based functional nanocomposite material and its application for the elimination of paracetamol from synthetic wastewater

Non-steroidal anti-inflammatory medicines (NSAIDs) like paracetamol and other substances released into the water system pose serious environmental issues. The current work examines the synthesis of a nanocomposite combined with Moringa olifera aqueous leaf extract as a reducing and stabilizing agent for the green synthesis of nanocomposites. Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Thermogravimetric analysis (TGA), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) were used to investigate metal based functional nanocomposites. The absorption band centered at a wavelength of 243 nm, which corresponds to the surface plasmon resonances of the produced nanocomposite, is confirmed in UV-vis spectra. The distinctive band at this particular wavelength is attributed to a particular group of nanocomposites based on the result from the Fourier transform infrared spectroscopy spectra. The spherical with irregularly shaped aggregates was confirmed by transmission electron microscopy, and the average size of nanoparticles was found to be 1 nm. For the elimination of pharmaceutical contaminants such as paracetamol from aqueous solutions, the adsorptive characteristics of nanocomposites were examined. Temperature, pH, adsorbent dosage, and agitation speed were investigated as adsorption parameters using Box-Behnken Design (BBD). The best removal outcomes were found under the following circumstances: temperature at 303.15 K, pH = 7.5, 0.05 g of nanocomposites at 200 rpm. Based on the adsorption study, the kinetics was found to be pseudo first order (R² > 0.9481) which was validated and fitted by Langmuir isotherm (R² > 0.9973). The adsorption study confirms that it was adsorbed onto the synthesized nanocomposite and found to be present on the homogeneous surface.

Adsorptive removal of tetracycline and ciprofloxacin drugs from water by using a magnetic rod-like hydroxyapatite and MIL-101(Fe) metal-organic framework nanocomposite

A novel porous nanocomposite composed of hydroxyapatite nanorods (HAP), a MIL-101(Fe) metal-organic framework, and Fe₃O₄ nanoparticles was successfully fabricated in this work. The magnetic HAP/MIL-101(Fe)/Fe₃O₄ ternary nanocomposite was identified by various techniques, namely FT-IR spectroscopy, XRD, Raman spectroscopy, SEM, EDX, TEM, BET specific surface area, zeta potential, and VSM measurements. Tetracycline (TC) and ciprofloxacin (CIP) aqueous solutions were used to evaluate the adsorption performance of the resulting HAP/MIL-101(Fe)/Fe₃O₄ composite. The adsorption rate and capacity of HAP/MIL-101(Fe)/Fe₃O₄ were increased as compared with HAP, MIL-101(Fe), and HAP/MIL-101(Fe) samples due to the increased attraction. The influence of initial drug concentration, adsorbent dosage, temperature, and pH on the adsorption process was investigated. The results showed that the removal efficiencies of HAP/MIL-101(Fe)/Fe₃O₄ for TC and CIP were 95% and 93%, under the determined optimum conditions: pH of 7, drug concentration of 50 mg L^-1, adsorbent dosage of 30 mg, and temperature of 25 °C. The maximum adsorption capacities of HAP/MIL-101(Fe)/Fe₃O₄ for TC and CIP were 120.48 mg g^-1 and 112.35 mg g^-1, respectively. Reusability of the prepared nanocomposite was easily achieved up to three times without significant change in its structure. As a result, the synthesized magnetic nanocomposite can be reused as a suitable absorbent for TC and CIP removal from aqueous solutions.

The Antibacterial Properties of Nanocomposites Based on Carbon Nanotubes and Metal Oxides Functionalized with Azithromycin and Ciprofloxacin

Different microorganisms are present in nature, some of which are assumed to be hazardous to the human body. It is crucial to control their continuing growth to improve human life. Nanomaterial surface functionalization represents a current topic in continuous evolution that supports the development of new materials with multiple applications in biology, medicine, and the environment. This study focused on the antibacterial activity of different nanocomposites based on functionalized multi-walled carbon nanotubes against four common bacterial strains. Two metal oxides (CuO and NiO) and two antibiotics (azithromycin and ciprofloxacin) were selected for the present study to obtain the following nanocomposites: MWCNT-COOH/Antibiotic, MWCNT-COOH/Fe₃O₄/Antibiotic, and MWCNT-COOH/Fe₃O₄/MO/Antibiotic. The present study included two Gram-positive bacteria (Staphylococcus aureus and Enterococcus faecalis) and two Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). Ciprofloxacin (Cip) functionalized materials (MWCNT-COOH/Fe₃O₄/Cip) were most efficient against all tested bacterial strains; therefore, we conclude that Cu and Ni reduce the effects of Cip. The obtained results indicate that the nanocomposites functionalized with Cip are more effective against selected bacteria strains compared to azithromycin (Azi) functionalized nanocomposites. The current work determined the antibacterial activities of different nanocomposites and gave fresh insights into their manufacture for future research regarding environmental depollution.

Sequestration and toxicological assessment of emerging contaminants with polypyrrole modified carboxymethyl cellulose (CMC/PPY): Case of ibuprofen pharmaceutical drug

Ibuprofen (IBU) is a non-steroidal anti-inflammatory drug released into water bodies causing toxic biological effects on living organisms. The current study aims to eliminate IBU from aqueous solutions by a novel carboxymethylcellulose/polypyrrole (CMC/PPY) composite with high removal efficiency. Pyrrole was polymerized to polypyrrole whose average size was about 20 nm on the CMC surface. The maximum removal percentage of IBU by CMC/PPY composite was optimized at initial concentration 10 mg/L, dosage 0.02 g, and pH 7 with adsorption capacity of 72.30 (mg/g) and removal of 83.17 %. IBU adsorption onto CMC/PPY theoretically fits into the Langmuir isotherm and Elovich-kinetic models. Fish and Phytotoxicity assessment were performed with zebrafish and seeds of Vigna mungo (VM) and Vigna radiata (VR). The toxicity study reveals that before adsorption, IBU shows high toxicity towards the zebrafish mortality (33 %), growth inhibition (58.52 % for VM, 60.84 % for VR), and germination (86.66 % for VM and 90 % for VR). As CMC/PPY adsorbs IBU, toxicity drastically decreases. Before adsorption, LC₅₀ was 233.02 mg/L. After adsorption, the LC₅₀ increases to 2325.07 mg/L as IBU molecules get adsorbed by CMC/PPY. These findings show the feasibility of preparing CMC/PPY composite to effectively remove pharmaceutical pollutant IBU from aqueous solutions with their toxicological assessment.

Synthesis and Characterization of MWCNT-COOH/Fe3O4 and CNT-COOH/Fe3O4/NiO Nanocomposites: Assessment of Adsorption and Photocatalytic Performance

In this study the adsorption and photodegradation capabilities of modified multi-walled carbon nanotubes (MWCNTs), using tartrazine as a model pollutant, is demonstrated. MWCNT-COOH/Fe₃O₄ and MWCNT-COOH/Fe₃O₄/NiO nanocomposites were prepared by precipitation of metal oxides in the presence of MWCNTs. Their properties were examined by X-ray diffraction in powder (XRD), Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Raman spectroscopy, synchrotron-based Scanning PhotoElectron Microscopy (SPEM), and Brunauer-Emmett-Teller (BET) analysis. It was found that the optimal adsorption conditions were pH 4 for MWCNT-COOH/Fe₃O₄ and pH 3 for MWCNT-COOH/Fe₃O₄/NiO, temperature 25 °C, adsorbent dose 1 g L^-1, initial concentration of tartrazine 5 mg L^-1 for MWCNT-COOH/Fe₃O₄ and 10 mg L^-1 for MWCNT-COOH/Fe₃O₄/NiO and contact time 5 min for MWCNT-COOH/Fe₃O₄/NiO and 15 min for MWCNT-COOH/Fe₃O₄. Moreover, the predominant degradation process was elucidated simultaneously, with and without simulated sunlight irradiation, using thermal lens spectrometry (TLS) and UV-Vis absorption spectrophotometry. The results indicated the prevalence of the photodegradation mechanism over adsorption from the beginning of the degradation process.

Synthesis of a highly recoverable 3D MnO2/rGO hybrid aerogel for efficient adsorptive separation of pharmaceutical residue

Water contamination by non-steroidal anti-inflammatory drugs, such as acetaminophen, is an emerging ecological concern. In this study, a new three-dimensional manganese dioxide-engrafted reduced graphene oxide (3D MnO₂/rGO) hybrid aerogel was developed for acetaminophen sequestration. The synthesis involved firstly the self-assembly of GO aerogel, followed by thermal reduction and in-situ MnO₂ growth by redox-reaction. The aerogel demonstrated interlinked planes with smooth surfaces deposited with MnO₂ nanospheres and pores of 138.4 - 235.3 µm width. The influences of adsorbent dosage, initial pH, acetaminophen concentration, temperature and contact time were investigated. It was determined that the adsorption of acetaminophen occurred on uniform sorption sites in the aerogel, as suggested by the best fit of data to the Langmuir isotherm, yielding a maximum adsorption capacity of 252.87 mg/g. This highest adsorption performance of the 3D MnO₂/rGO aerogel was attained at a dosage of 0.6 g/L, initial pH of 6.2 and temperature of 40°C. The process kinetics were in-line with the pseudo-first-order and pseudo-second-order kinetics at 10 and 20 - 500 mg/L concentrations, respectively. Thermodynamic assay showed the spontaneity and endothermicity features of the 3D MnO₂/rGO-acetaminophen system. The acetaminophen adsorption mechanisms were mainly hydrogen bonding and pore entrapment. Moreover, the as-synthesised aerogel was effectively regenerated using acetone and re-utilised in four adsorption-desorption cycles. Overall, the results highly recommend the implementation of the 3D MnO₂/rGO hybrid aerogel for purification of wastewater polluted by acetaminophen residue.

Ecofriendly and sustainable Sargassum spp.-based system for the removal of highly used drugs during the COVID-19 pandemic

Analgesic consumption increased significantly during the COVID-19 pandemic. A high concentration of this kind of drug is discarded in the urine, reaching the effluents of rivers, lakes, and seas. These medicines have brought serious problems for the flora and, especially, the ecosystems’ fauna. This paper presents the results of removing diclofenac, ibuprofen, and paracetamol in an aqueous solution, using Sargassum spp. from the Caribbean coast. The study consisted of mixing each drug in an aqueous solution with functionalized Sargassum spp in a container under constant agitation. Therefore, this work represents an alternative to solve two of the biggest problems in recent years; first, the reduction of the overpopulation of sargassum through its use for the remediation of the environment. Second is the removal of drug waste used excessively during the COVID-19 pandemic. Liquid samples of the solution were taken at intervals of 10 min and analyzed by fluorescence to determine the concentration of the drug.

The sorption capacity for diclofenac, ibuprofen, and paracetamol was 2.46, 2.08, and 1.41 μg/g, corresponding to 98 %, 84 %, and 54 % of removal, respectively. The removal of the three drugs was notably favored by increasing the temperature to 30 and 40 °C, reaching efficiencies close to 100 %. Moreover, the system maintains its effectiveness at various pH values. In addition, the Sargassum used can be reused for up to three cycles without reducing its removal capacity. The wide diversity of organic compounds favors the biosorption of drugs, removing them through various kinetic mechanisms. On the other hand, the Sargassum used in the drugs removal was analyzed by X-ray diffraction, FTIR spectroscopy, TGA analysis, and scanning electron microscopy before and after removal. The results showed an evident modification in the structure and morphology of the algae and demonstrated the presence of the biosorbed drugs. Therefore, this system is sustainable, simple, economical, environmentally friendly, highly efficient, and scalable at a domestic and industrial level that can be used for aquatic remediation environments.

Sustainable Mitigation of Paracetamol with a Novel Dual-Functionalized Pullulan/Kaolin Hydrogel Nanocomposite from Simulated Wastewater

In the present investigation, a novel, green, and economical dual-functionalized pullulan/kaolin hydrogel nanocomposite (f-PKHN) was fabricated and subsequently applied for the liquid-phase decontamination of paracetamol (PCT), a pharmaceutical pollutant. Pullulan and kaolin were functionalized with l-asparagine and gallic acid, respectively. The physicochemical facets of the functionalized pullulan/kaolin hydrogel nanocomposite and its interactive behavior with PCT were elucidated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX), and elemental mapping. The process parameters along with the isotherm, kinetics, and thermodynamics were methodically appraised via a batch technique to unveil the adsorption performance of the as-fabricated hydrogel nanocomposite. The adsorption isotherm and kinetics of PCT uptake by f-PKHN conform well to Freundlich and pseudo-second-order models, respectively. Relying on hydrogen bonding, n-π, and van der Waals interactions, the maximum adsorption capacity was 332.54 mg g^-1, higher than for most of the previous adsorbents reported in the literature for PCT removal. Thermodynamic calculations corroborated endothermic, spontaneous, and feasible adsorption phenomena. The maintenance of a high uptake percentage (69.11%) in the fifth consecutive adsorption-desorption cycle implied the significant reusable potential of f-PKHN. Swelling studies exhibited 90% swelling within 200 min, indicating the successful fabrication of a cross-linked hydrogel network. The real water (distilled water, tap water, and river water) samples spiked with PCT specified a significant uptake of PCT (>85%), and the minor influence of ionic strength on the adsorptive potential of f-PKHN validated its potentiality for the decontamination of real effluents. In conclusion, f-PKHN with substantial adsorption capacity, green characteristics, and excellent reusability can be reckoned with as a promising adsorbent for the de-escalation of PCT from aquatic sources as well as at the industrial level.

Sustainable green nanoadsorbents for remediation of pharmaceuticals from water and wastewater: A critical review

In the last three decades, pharmaceutical research has increased tremendously to offer safe and healthy life. However, the high consumption of these harmful drugs has risen devastating impact on ecosystems. Therefore, it is worldwide paramount concern to effectively clean pharmaceuticals contaminated water streams to ensure safer environment and healthier life. Nanotechnology enables to produce new, high-technical material, such as membranes, adsorbent, nano-catalysts, functional surfaces, coverages and reagents for more effective water and wastewater cleanup processes. Nevertheless, nano-sorbent materials are regarded the most appropriate treatment technology for water and wastewater because of their facile application and a large number of adsorbents. Several conventional techniques have been operational for domestic wastewater treatment but are inefficient for pharmaceuticals removal. Alternatively, adsorption techniques have played a pivotal role in water and wastewater treatment for a long, but their rise in attraction is proportional with the continuous emergence of new micropollutants in the aquatic environment and new discoveries of sustainable and low-cost adsorbents. Recently, advancements in adsorption technique for wastewater treatment through nanoadsorbents has greatly increased due to its low production cost, sustainability, better physicochemical properties and high removal performance for pharmaceuticals. Herein, this review critically evaluates the performance of sustainable green nanoadsorbent for the remediation of pharmaceutical pollutants from water. The influential sorption parameters and interaction mechanism are also discussed. Moreover, the future prospects of nanoadsorbents for the remediation of pharmaceuticals are also presented.

Synthesis and characterization of Fe0@chitosan/cellulose biocompatible composites from natural resources as advanced carriers for ibuprofen drug: reaction kinetics and equilibrium

Fe0@chitosan/cellulose was synthesized as a carrier for Ibuprofen drug. It has achieved a loading capacity of 553 mg g−1 and a slow release profile for 260 h, which is controlled by complex diffusion and erosion mechanisms.

Understanding the factors affecting adsorption of pharmaceuticals on different adsorbents - A critical literature update

Remediation of emerging pharmaceutically active compounds (PhACs) as micropollutants in wastewater is of foremost importance as they can cause extremely detrimental effects on life upon bioaccumulation and generation of drug-resistance microorganisms. Presently used physicochemical treatments, such as electrochemical oxidation, nanofiltration and reverse osmosis, are not feasible owing to high operating costs, incomplete removal of contaminants along with toxic by-products formation. Adsorption with the utilization of facile and efficient nanoparticulate adsorbents having distinctive properties of high surface area, excellent adsorption capacity, ability to undergo surface engineering and good regeneration displays great potential in this aspect along with the incorporation of nanotechnology for effective treatment. The application of such nanosorbents provides optimal performance under a wide range of physicochemical conditions, decreased secondary pollution with reduced mechanical stress along with excellent organic compound sequestration capacity, which in turn improves the quality of potable water in a sustainable way compared to current treatments. The present review intends to consolidate the range of factors that affect the process of adsorption of different PhACs on to various nanosorbents and also highlights the adsorption mechanism aiding in the retrieval.

Metastable interface biomimetic synthesis of a smart nanosystem for enhanced starvation/gas therapy

Glucose oxidase (GOx)-mediated starvation therapy holds great promise in cancer treatment. However, the worse hypoxia conditions result into low therapeutic efficiency, and undegradability of carriers poses potential threats to living bodies. To address this, herein a bioinspired MnO2 nanosystem with controllable surface was developed for highly efficient starvation/gas synergistic enhanced therapy. Biomimetic design and further surface modification unprecedentedly endowed the nanosystem with ultrahigh loading capacity for GOx and l-Arginine (l-Arg) and special selectivity toward cancer cells. Especially, the dissipative O2 during starvation therapy was well replenished by a positive cycle formed by the nanosystem, which continuously reproduced O2 and accelerated glucose consumption. The abundant H2O2 was further used to oxidize l-Arg into nitric oxide to realize gas therapy. In vitro and in vivo testing confirmed that this new treatment effectively blocked the nutrition and energy sources of cells to obtain excellent therapeutic effect. We reported the first experimental item of this nanosystem for inhibiting cancer cell migration. Considering the novel design concept with facile biomimetic methods, effective co-loading of endogenous substances, and good anti-tumor and anti-migration effects, this work provided new theoretical and experimental basis for starvation therapy and inspired people to design more delicate platform for cancer treatment.

The selective adsorption performance and mechanism of multiwall magnetic carbon nanotubes for heavy metals in wastewater

The safe treatment of heavy metals in wastewater is directly related to human health and social development. In this paper, a new type of recyclable adsorbent is synthesized through the oxidation of enhancer and modification with magnetic nanoparticles. The new adsorbent not only inherits the advantages of multiwall carbon nanotubes (6O-MWCNTs), but also exhibits a new magnetic property and further improved adsorption capacity, which is conducive to the magnetic separation and recovery of heavy metals. The adsorption results indicate that multiwall magnetic carbon nanotubes (6O-MWCNTs@Fe₃O₄) have a good performance for Pb(II) selective adsorption, with a maximum adsorption capacity of 215.05 mg/g, much higher than the existing adsorption capacity of the same type of adsorbents. Under the action of an external magnetic field, 6O-MWCNTs@Fe₃O₄ that adsorbed metal ions can quickly achieve good separation from the solution. The joint characterization results of FTIR and XPS show that under the action of both coordination and electrostatic attraction, the C=O bond in the -COOH group is induced to open by the metal ions and transforms into an ionic bond, and the metal ions are stably adsorbed on the surface of 6O-MWCNTs@Fe₃O₄. Pb(II) has a stronger attraction than Cu(II) and Cd(II) to the lone pair of electrons in oxygen atoms to form complexes, due to the covalent index of Pb (6.41) is more larger than that of Cu (2.98) and Cd (2.71).These data provide a new type of recyclable adsorbent for the efficient treatment of heavy metal ions in wastewater and enrich relevant theoretical knowledge.

Degradation, solubility and chromatographic studies of Ibuprofen under high temperature water conditions

Ibuprofen (IBP) is an emerging environmental contaminant having low aqueous solubility which negatively affects the application of advanced oxidation and adsorption processes. It was determined that as the temperature increased to 473 K, the mole fraction solubility increased considerably from 0.02 × 10^-3 to 212.88 × 10^-3 (10600-fold). Calculation of the thermodynamic properties indicated an endothermic process, Δ_solH > 0, with relatively high Δ_solS values. Spectroscopic, thermal and chromatographic analyses established the IBP stability at subcritical conditions. In the second part of the study, the degradation of IBP in H₂O₂-modified subcritical was studied and the effect of each process variable was investigated. The optimum degradation of 88% was reached at an IBP concentration of 15 mg L^-1, temperature of 250 °C, 105 min treatment time and 250 mM H₂O₂. The process was optimized by response surface methodology and a mathematical model was proposed and validated. Temperature was determined as the most influential parameter, followed by H₂O₂ concentration. At temperatures higher than 230 °C, a small but noticeable reduction in degradation % suggested that the OH· radicals are consumed at a higher rate than they are produced, through side reactions with other radicals and/or IBP by-products. Finally, potential by-products were determined by gas chromatographic-mass spectrometric analysis and potential by-products were proposed.

Removal of ibuprofen from aqueous media by adsorption: A comprehensive review

Ibuprofen (IBP) is a non-steroidal anti-inflammatory drug released into the environment through hospital and medical effluents, pharmaceutical wastewater and veterinary use. The aim of this paper is to review the empirical findings on the adsorption of IBP from aqueous media. A preliminary ecotoxicological assessment confirmed the environmental risk of IBP in the aqueous environment. Open literature works considered in this review were for the past decade (2010-2020). Carbon-based adsorbents are the best class of adsorbent for the uptake of IBP and the highest reported maximum adsorption capacity (q_max) for IBP is 496.1 mg/g by SWCNTs. The range of adsorption capacities for IBP uptake in this review is between 0.0496 and 496.1 mg/g. The mechanism of uptake is majorly by hydrophobic interactions, π - π stacking, hydrogen bonds, electrostatic interactions and dipole-dipole interaction. IBP uptake was best fit to a wide variety of isotherm models but was well suited to the pseudo-second order kinetics model. The thermodynamics of IBP uptake depends majorly on the nature of the adsorbent and desorption from the solid phase is based on an appropriate choice of the eluent. Knowledge gaps were observed in used adsorbent disposal and process improvement. In the future, interest would increase in scale-up, industrial applications and practical utilisation of the research findings which would help in sustainable water resource management.

Effect of Grinding and the Mill Type on Magnetic Properties of Carboxylated Multiwall Carbon Nanotubes

The influence of the grinding process on the magnetic properties of as prepared and functionalized multiwall carbon nanotubes (MWCNTs) is presented. We have observed that 3 h mechanical grinding at 400 rpm in contrast to functionalization does not remove the iron contamination from MWCNTs. However, it changes the Fe chemical states. The magnetic properties of iron nanoparticles (Fe-NPs) embedded in the carbon matrix of MWCNTs have been analyzed in detail. We have proven that single-domain non-interacting Fe(C,O)-NPs enriched in the Fe3C phase (~10 nm) enclosed inside these nanotubes are responsible for their magnetic properties. Mechanical grinding revealed a unique impact of -COOH groups (compared to -COONH4 groups) on the magnetism of functionalized MWCNTs. In MWCNT-COOH ground in a steel mill, the contribution of the Fe2O3 and α-Fe phases increased while the content of the magnetically harder Fe3C phase decreased. This resulted in a 2-fold coercivity (Hc) decrease and saturation magnetization (MS) increase. A 2-fold remanence (Mr) decrease in MWCNT-COOH ground in an agate mill is related to the modified Fe(C,O)-NP magnetization dynamics. Comparison of the magnetostatic exchange and effective anisotropy length estimated for Fe(C,O)-NPs allows concluding that the anisotropy energy barrier is higher than the magnetostatic energy barrier. The enhanced contribution of surface anisotropy to the effective anisotropy constant and the unique effect of the -COOH groups on the magnetic properties of MWCNTs are discussed. The procedure for grinding carboxylated MWCNTs with embedded iron nanoparticles using a steel mill has a potential application for producing Fe-C nanocomposites with desired magnetic properties.

Ibuprofen elimination from water and wastewater using sonication/ultraviolet/hydrogen peroxide/zeolite-titanate photocatalyst system

The present investigation was designed to remove ibuprofen from aqueous solutions and wastewater by activating hydrogen peroxide using ultrasonication (US)/ultraviolet (UV) radiation/zeolite-titanium. The physical-chemical properties of the photocatalyst were determined using BET, FTIR, XRD, FESEM, and EDX-mapping techniques. The titanium oxide crystal size and the catalyst BET were determined to be 4.97 nm and 39.88 m²/g, respectively. Tests were performed in a reactor (with a volume of 316 mL) located in an ultrasonic bath to intensify reactions. The synergistic impact of the components of the UV/US/H₂O₂/Photocatalyst system was explored. The maximum efficiency (99.58%) was obtained at H₂O₂ concentration of 0.05 mM, pH 5, UV power of 6 W, photo-catalyst dose of 1 g/L, and contact time of 100 min. The pH variable was more effective than the other parameters. Ions of NO₃^-, Cl^-, and SO₄^2- had a slightly negative effect on contaminant removal efficiency. The ibuprofen removal (based on COD) from urban water and hospital wastewater was attained 77.82% and 66.24%, respectively. The ibuprofen removal by the developed system followed the first-order kinetic. The results show that the system has high efficiency and reasonable costs (with treatment cost of 6.25 €/m³) for ibuprofen decontamination.

Magnetite-Based Catalyst in the Catalytic Wet Peroxide Oxidation for Different Aqueous Matrices Spiked with Naproxen–Diclofenac Mixture

Magnetite supported on multiwalled carbon nanotubes catalysts were synthesized by co-precipitation and hydrothermal treatment. The magnetic catalysts were characterized by X-ray diffraction, Fourier-transform infrared spectrometry, thermogravimetric analysis and N2 physisorption. The catalysts were then tested for their ability to remove diclofenac (DCF) and naproxen (NAP) from an aqueous solution at different conditions (pH, temperature, and hydrogen peroxide) to determine the optimum conditions for chemical oxidation. The optimization of the process parameters was conducted using response surface methodology (RSM) coupled with Box–Behnken design (BBD). By RSM–BBD methodology, the optimal parameters (1.75 mM H2O2 dosage, 70 °C and pH 6.5) were determined, and the removal percentages of NAP and DCF were 19 and 54%, respectively. The NAP–DCF degradation by catalytic wet peroxide oxidation (CWPO) was caused by •OH radicals. In CWPO of mixed drug solutions, DCF and NAP showed competitive oxidation. Hydrophobic interactions played an important role during the CWPO process. On the other hand, the magnetic catalyst reduced its activity after the second cycle of reuse. In addition, proof of concept and disinfection tests performed at the operating conditions showed results following the complexity of the water matrices. In this sense, the magnetic catalyst in CWPO has adequate potential to treat water contaminated with NAP–DCF mixtures.

Iron Oxide Nanoparticles: Multiwall Carbon Nanotube Composite Materials for Batch or Chromatographic Biomolecule Separation

Carbon-based materials are the spearhead of research in multiple fields of nanotechnology. Moreover, their role as stationary phase in chromatography is gaining relevance. We investigate a material consisting of multiwall carbon nanotubes (CNTs) and superparamagnetic iron oxide nanoparticles towards its use as a mixed-mode chromatography material. The idea is to immobilize the ion exchange material iron oxide on CNTs as a stable matrix for chromatography processes without a significant pressure drop. Iron oxide nanoparticles are synthesized and used to decorate the CNTs via a co-precipitation route. They bind to the walls of oxidized CNTs, thereby enabling to magnetically separate the composite material. This hybrid material is investigated with transmission electron microscopy, magnetometry, X-ray diffraction, X-ray photoelectron and Raman spectroscopy. Moreover, we determine its specific surface area and its wetting behavior. We also demonstrate its applicability as chromatography material for amino acid retention, describing the adsorption and desorption of different amino acids in a complex porous system surrounded by aqueous media. Thus, this material can be used as chromatographic matrix and as a magnetic batch adsorbent material due to the iron oxide nanoparticles. Our work contributes to current research on composite materials. Such materials are necessary for developing novel industrial applications or improving the performance of established processes.

Selective and sensitive visible-light-prompt photoelectrochemical sensor of paracetamol based on Bi2WO6 modified with Bi and copper sulfide

Paracetamol (PA) is a ubiquitous non-steroidal anti-inflammatory drug, mainly used to treat headaches, arthritis and osteoarthritis and other diseases. In this work, a novel label free photoelectrochemical (PEC) sensor based on Bi-CuS/Bi2WO6 has been developed for the detection of PA, which was fabricated by a simple two-step hydrothermal process. It was found that Bi-CuS/Bi2WO6 with a CuS/Bi2WO6 heterojunction and surface plasmon resonance (SPR) effect of Bi possesses enhanced charge transfer and absorption wavelengths under visible light, particularly when compared to pristine Bi2WO6 films, thus producing an increase in the observed photocurrent. The photocurrent was increased after adding PA. And the photocurrent increment was linear with PA concentration in the range from 0.01-60 μM with a detection limit of 2.12 nM. Moreover, the PEC sensor also exhibited high anti-interference property and acceptable stability. In the present study, a Bi-CuS/Bi2WO6 photoelectrode is considered a promising candidate for carrying out PEC analysis.