Nanomaterials

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26 pages, 7624 KiB

Open AccessArticle

Visible-Light Activation of Persulfate or H₂O₂ by Fe₂O₃/TiO₂ Immobilized on Glass Support for Photocatalytic Removal of Amoxicillin: Mechanism, Transformation Products, and Toxicity Assessment

by Francis M. dela Rosa, Marin Popović, Josipa Papac Zjačić, Gabrijela Radić, Marijana Kraljić Roković, Marin Kovačić, María José Farré, Boštjan Genorio, Urška Lavrenčič Štangar, Hrvoje Kušić, Ana Lončarić Božić and Mira Petrović

Nanomaterials 2022, 12(23), 4328; https://doi.org/10.3390/nano12234328 - 05 Dec 2022

Cited by 3 | Viewed by 2145

Abstract

Fe₂O₃/TiO₂ nanocomposites were fabricated via a facile impregnation/calcination technique employing different amounts iron (III) nitrate onto commercial TiO₂ (P25 Aeroxide). The as-prepared Fe₂O₃/TiO₂ nanocomposites were characterized by X-ray diffraction (XRD), Raman spectroscopy [...] Read more.

Fe₂O₃/TiO₂ nanocomposites were fabricated via a facile impregnation/calcination technique employing different amounts iron (III) nitrate onto commercial TiO₂ (P25 Aeroxide). The as-prepared Fe₂O₃/TiO₂ nanocomposites were characterized by X-ray diffraction (XRD), Raman spectroscopy (RS), scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDXS), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller analysis (BET), electron impedance spectroscopy (EIS), photoluminescence spectroscopy (PL), and diffuse reflectance spectroscopy (DRS). As a result, 5% (w/w) Fe₂O₃/TiO₂ achieved the highest photocatalytic activity in the slurry system and was successfully immobilized on glass support. Photocatalytic activity under visible-light irradiation was assessed by treating pharmaceutical amoxicillin (AMX) in the presence and absence of additional oxidants: hydrogen peroxide (H₂O₂) and persulfate salts (PS). The influence of pH and PS concentration on AMX conversion rate was established by means of statistical planning and response surface modeling. Results revealed optimum conditions of [S₂O₈²⁻] = 1.873 mM and pH = 4.808; these were also utilized in presence of H₂O₂ instead of PS in long-term tests. The fastest AMX conversion possessing a zero-order rate constant of 1.51 × 10⁻⁷ M·min⁻¹ was achieved with the photocatalysis + PS system. The AMX conversion pathway was established, and the evolution/conversion of formed intermediates was correlated with the changes in toxicity toward Vibrio fischeri. Reactive oxygen species (ROS) scavenging was also utilized to investigate the AMX conversion mechanism, revealing the major contribution of photogenerated h⁺ in all processes. Full article

(This article belongs to the Special Issue Recent Advances in Nanomaterials for Removal of New Emerging Pollutants from Water/Wastewater)

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22 pages, 5813 KiB

Open AccessArticle

Rapid Microwave-Assisted Synthesis of N/TiO₂/rGO Nanoparticles for the Photocatalytic Degradation of Pharmaceuticals

by Camilo Sanchez Tobon, Ivana Panžić, Arijeta Bafti, Gordana Matijašić, Davor Ljubas and Lidija Ćurković

Nanomaterials 2022, 12(22), 3975; https://doi.org/10.3390/nano12223975 - 11 Nov 2022

Cited by 6 | Viewed by 1402

Abstract

Nanocomposites comprising nitrogen-doped TiO₂ and reduced graphene oxide (N/TiO₂/rGO), with different rGO loading qualities, were prepared by a cost-effective microwave-assisted synthesis method. The synthesized materials were broadly characterized by Raman spectroscopy, X-ray diffraction (XRD), infrared spectroscopy (FTIR), photoelectron spectroscopy (XPS), [...] Read more.

Nanocomposites comprising nitrogen-doped TiO₂ and reduced graphene oxide (N/TiO₂/rGO), with different rGO loading qualities, were prepared by a cost-effective microwave-assisted synthesis method. The synthesized materials were broadly characterized by Raman spectroscopy, X-ray diffraction (XRD), infrared spectroscopy (FTIR), photoelectron spectroscopy (XPS), diffuse reflectance spectroscopy (DRS), electron microscopy (SEM-EDS), and nitrogen adsorption/desorption isotherms. Anatase was the only crystalline phase observed for all synthesized materials. The rGO loading did not affect the morphological properties, but it positively influenced the photocatalytic activity of the nanocomposite materials, especially at low rGO loading. Photocatalysts were evaluated via the degradation of specific organic micropollutant (OMP) pharmaceuticals: ciprofloxacin (CIP), diclofenac (DCF), and salicylic acid (SA), under different radiation sources: ultraviolet A (UVA), solar light simulator (SLS), blue visible light (BVL) and cold visible light (CVL). CIP and SA were removed effectively via the synergy of adsorption and photocatalysis, while DCF degradation was achieved solely by photocatalysis. After implementing scavenger agents, photocatalytic degradation processes mainly depended on the specific pollutant type, while irradiation sources barely defined the photocatalytic mechanism. On the other hand, changes in irradiation intensity significantly influenced the photolysis process, while photocatalysis was slightly affected, indicating that irradiation spectra are more relevant than intensity. Full article

(This article belongs to the Special Issue Recent Advances in Nanomaterials for Removal of New Emerging Pollutants from Water/Wastewater)

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19 pages, 4101 KiB

Open AccessArticle

Photocatalytic Activity of TiO₂ for the Degradation of Anticancer Drugs

by Kristina Tolić Čop, Dragana Mutavdžić Pavlović and Tatjana Gazivoda Kraljević

Nanomaterials 2022, 12(19), 3532; https://doi.org/10.3390/nano12193532 - 09 Oct 2022

Cited by 4 | Viewed by 1554

Abstract

To prevent water pollution, photocatalysis is often used to remove small molecules such as drugs by generating reactive species. This study aimed to determine the photocatalytic activity of two anticancer drugs, imatinib and crizotinib, and to investigate various influences that may alter the [...] Read more.

To prevent water pollution, photocatalysis is often used to remove small molecules such as drugs by generating reactive species. This study aimed to determine the photocatalytic activity of two anticancer drugs, imatinib and crizotinib, and to investigate various influences that may alter the kinetic degradation rate and ultimately the efficacy of the process. In order to obtain optimal parameters for the removal of drugs with immobilized TiO₂, the mutual influence of the initial concentration of the contaminant at environmentally relevant pH values was investigated using the response surface modeling approach. The faster kinetic rate of photocatalysis was obtained at pH 5 and at the smallest applied concentration of both drugs. The photocatalytic efficiency was mostly decreased by adding various inorganic salts and organic compounds to the drug mixture. Regarding the degradation mechanism of imatinib and crizotinib, hydroxyl radicals and singlet oxygen showed a major role in photochemical reactions. The formation of seven degradation products for imatinib and fifteen for crizotinib during the optimal photocatalytic process was monitored by high-resolution mass spectrometry (HPLC-QqTOF). Since the newly formed products may pose a hazard to the environment, their toxicity was studied using Vibrio fischeri, where the significant luminescence inhibition was assessed for the mixture of crizotinib degradants during the photocatalysis from 90 to 120 min. Full article

(This article belongs to the Special Issue Recent Advances in Nanomaterials for Removal of New Emerging Pollutants from Water/Wastewater)

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16 pages, 4225 KiB

Open AccessArticle

Microwave-Assisted Synthesis of N/TiO₂ Nanoparticles for Photocatalysis under Different Irradiation Spectra

by Camilo Sanchez Tobon, Davor Ljubas, Vilko Mandić, Ivana Panžić, Gordana Matijašić and Lidija Ćurković

Nanomaterials 2022, 12(9), 1473; https://doi.org/10.3390/nano12091473 - 26 Apr 2022

Cited by 7 | Viewed by 2264

Abstract

Nitrogen-doped TiO₂ (N/TiO₂) photocatalyst nanoparticles were derived by the environmentally friendly and cost-effective microwave-assisted synthesis method. The samples were prepared at different reaction parameters (temperature and time) and precursor ratio (amount of nitrogen source; urea). The obtained materials were characterized [...] Read more.

Nitrogen-doped TiO₂ (N/TiO₂) photocatalyst nanoparticles were derived by the environmentally friendly and cost-effective microwave-assisted synthesis method. The samples were prepared at different reaction parameters (temperature and time) and precursor ratio (amount of nitrogen source; urea). The obtained materials were characterized by X-ray diffraction (XRD), photoelectron spectroscopy (XPS), Raman spectroscopy (RS), infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS), electron microscopy (SEM-EDS), and nitrogen adsorption/desorption isotherms. Two cycles of optimizations were conducted to determine the best reaction temperature and time, as well as N content. The phase composition for all N/TiO₂ nanomaterials was identified as photoactive anatase. The reaction temperature was found to be the most relevant parameter for the course of the structural evolution of the samples. The nitrogen content was the least relevant for the development of the particle morphology, but it was important for photocatalytic performance. The photocatalytic activity of N/TiO₂ nanoparticle aqueous suspensions was evaluated by the degradation of antibiotic ciprofloxacin (CIP) under different irradiation spectra: ultraviolet A light (UVA), simulated solar light, and visible light. As expected, all prepared samples demonstrated efficient CIP degradation. For all irradiation sources, increasing synthesis temperature and increasing nitrogen content further improved the degradation efficiencies. Full article

(This article belongs to the Special Issue Recent Advances in Nanomaterials for Removal of New Emerging Pollutants from Water/Wastewater)

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23 pages, 18753 KiB

Open AccessFeature PaperArticle

Synthesis and Application of Cobalt Oxide (Co₃O₄)-Impregnated Olive Stones Biochar for the Removal of Rifampicin and Tigecycline: Multivariate Controlled Performance

by Ahmed S. El-Shafie, Insharah Ahsan, Mohamed Radhwani, Mohammed Ali Al-Khangi and Marwa El-Azazy

Nanomaterials 2022, 12(3), 379; https://doi.org/10.3390/nano12030379 - 24 Jan 2022

Cited by 19 | Viewed by 2710

Abstract

Cobalt oxide (Co₃O₄) nanoparticles supported on olive stone biochar (OSBC) was used as an efficient sorbent for rifampicin (RIFM) and tigecycline (TIGC) from wastewater. Thermal stabilities, morphologies, textures, and surface functionalities of two adsorbents; OSBC and Co-OSBC were compared. [...] Read more.

Cobalt oxide (Co₃O₄) nanoparticles supported on olive stone biochar (OSBC) was used as an efficient sorbent for rifampicin (RIFM) and tigecycline (TIGC) from wastewater. Thermal stabilities, morphologies, textures, and surface functionalities of two adsorbents; OSBC and Co-OSBC were compared. BET analysis indicated that Co-OSBC possesses a larger surface area (39.85 m²/g) and higher pore-volume compared to the pristine OSBC. FT-IR analysis showed the presence of critical functional groups on the surface of both adsorbents. SEM and EDX analyses showed the presence of both meso- and macropores and confirmed the presence of Co₃O₄ nanoparticles on the adsorbent surface. Batch adsorption studies were controlled using a two-level full-factorial design (2^k-FFD). Adsorption efficiency of Co-OSBC was evaluated in terms of the % removal (%R) and the sorption capacity (q_e, mg/g) as a function of four variables: pH, adsorbent dose (AD), drug concentration, and contact time (CT). A %R of 95.18% and 75.48% could be achieved for RIFM and TIGC, respectively. Equilibrium studies revealed that Langmuir model perfectly fit the adsorption of RIFM compared to Freundlich model for TIGC. Maximum adsorption capacity (q_max) for RIFM and TIGC was 61.10 and 25.94 mg/g, respectively. Adsorption kinetics of both drugs could be best represented using the pseudo-second order (PSO) model. Full article

(This article belongs to the Special Issue Recent Advances in Nanomaterials for Removal of New Emerging Pollutants from Water/Wastewater)

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25 pages, 3275 KiB

Open AccessArticle

Performance of TiO₂/UV-LED-Based Processes for Degradation of Pharmaceuticals: Effect of Matrix Composition and Process Variables

by Danilo Bertagna Silva, Gianluigi Buttiglieri, Bruna Babić, Danijela Ašperger and Sandra Babić

Nanomaterials 2022, 12(2), 295; https://doi.org/10.3390/nano12020295 - 17 Jan 2022

Cited by 5 | Viewed by 2141

Abstract

Ultra-violet light-emitting diode (UV-LED)-based processes for water treatment have shown the potential to surpass the hurdles that prevent the adoption of photocatalysis at a large scale due to UV-LEDs’ unique features and design flexibility. In this work, the degradation of five EU Watch [...] Read more.

Ultra-violet light-emitting diode (UV-LED)-based processes for water treatment have shown the potential to surpass the hurdles that prevent the adoption of photocatalysis at a large scale due to UV-LEDs’ unique features and design flexibility. In this work, the degradation of five EU Watch List 2020/1161 pharmaceutical compounds was comprehensively investigated. Initially, the UV-A and UV-C photolytic and photocatalytic degradation of individual compounds and their mixtures were explored. A design of experiments (DoE) approach was used to quantify the effects of numerous variables on the compounds’ degradation rate constant, total organic carbon abatement, and toxicity. The reaction mechanisms of UV-A photocatalysis were investigated by adding different radical scavengers to the mix. The influence of the initial pH was tested and a second DoE helped evaluate the impact of matrix constituents on degradation rates during UV-A photocatalysis. The results showed that each compound had widely different responses to each treatment/scenario, meaning that the optimized design will depend on matrix composition, target pollutant reactivity, and required effluent standards. Each situation should be analyzed individually with care. The levels of the electrical energy per order are still unfeasible for practical applications, but LEDs of lower wavelengths (UV-C) are now approaching UV-A performance levels. Full article

(This article belongs to the Special Issue Recent Advances in Nanomaterials for Removal of New Emerging Pollutants from Water/Wastewater)

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17 pages, 6517 KiB

Open AccessArticle

Kinetic Modeling for Photo-Assisted Penicillin G Degradation of (Mn_0.5Zn_0.5)[Cd_xFe_2-x]O₄ (x ≤ 0.05) Nanospinel Ferrites

by Omar Alagha, Noureddine Ouerfelli, Hafedh Kochkar, Munirah A. Almessiere, Yassine Slimani, Ayyar Manikandan, Abdulhadi Baykal, Ahmed Mostafa, Mukarram Zubair and Mohammad H. Barghouthi

Nanomaterials 2021, 11(4), 970; https://doi.org/10.3390/nano11040970 - 09 Apr 2021

Cited by 10 | Viewed by 1931

Abstract

Penicillin G is an old and widely used antibiotic. Its persistence in the environment started to appear in many environmental samples and food chains. The removal of these emerging pollutants has been a challenging task for scientists in the last decades. The photocatalytic [...] Read more.

Penicillin G is an old and widely used antibiotic. Its persistence in the environment started to appear in many environmental samples and food chains. The removal of these emerging pollutants has been a challenging task for scientists in the last decades. The photocatalytic properties of Cd²⁺ doped Manganese- Zinc NSFs with chemical formula (Mn_0.5Zn_0.5)[Cd_xFe_2−x]O₄ (0.0 ≤ x ≤ 0.05) NSFs are herein evaluated. The Manganese- Zinc N.S.F.s nanomaterials were deeply characterized, utilizing UV-Vis (reflectance) spectroscopy, X-ray diffraction, N₂ adsorption isotherm measurements, and S.E.M., SEM-EDX mapping, and T.E.M. The Kinetic model for the photodegradation of penicillin G (as a model molecule) is investigated using visible light as a source of energy. The kinetic study shows that our results fit well with the modified pseudo-first-order model. The Pen G degradation are 88.73%, 66.65%, 44.70%, 37.62% and 24.68% for x = 0.5, 0.4, 0.3, 0.2 and 0.1, respectively, against 14.68% for the free Cd spinel sample. The pseudo-rate constant is bandgap dependent. From the intra-diffusion rate constant (K_d), we developed an intra-diffusion time (τ) model, which decreases exponentially as a function of (x) and mainly shows the existence of three different domains versus cadmium coordination in spinel ferrite samples. Hence, Cadmium’s presence generates spontaneous polarization with a strong opportunity to monitor the charge separation and then open the route to a new generation of “assisted” photocatalysts under visible light. Full article

(This article belongs to the Special Issue Recent Advances in Nanomaterials for Removal of New Emerging Pollutants from Water/Wastewater)

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24 pages, 1830 KiB

Open AccessArticle

Adsorption Characteristics of Pristine and Magnetic Olive Stones Biochar with Respect to Clofazimine

by Marwa El-Azazy, Iman Nabil, Siham S. Hassan and Ahmed S. El-Shafie

Nanomaterials 2021, 11(4), 963; https://doi.org/10.3390/nano11040963 - 09 Apr 2021

Cited by 19 | Viewed by 2787

Abstract

Olive stone biochars (OSBC), both pristine and following magnetization (MAG–OSBC), were utilized as eco-friendly and cost-effective sorbents for the antituberculosis, clofazimine (CLOF). Morphologies, textures, surface functionalities, and thermal stabilities of both adsorbents were explored using SEM, EDX, TEM, BET, FT-IR, Raman, XRD and [...] Read more.

Olive stone biochars (OSBC), both pristine and following magnetization (MAG–OSBC), were utilized as eco-friendly and cost-effective sorbents for the antituberculosis, clofazimine (CLOF). Morphologies, textures, surface functionalities, and thermal stabilities of both adsorbents were explored using SEM, EDX, TEM, BET, FT-IR, Raman, XRD and TGA analyses. SEM analysis showed meso- and macroporous surfaces. BET data showed that the MAG–OSBC possesses a larger surface area (33.82 m²/g) and pore volume. Batch adsorption studies were conducted following the experimental scenario of Box–Behnken (BB) design. The adsorption efficiency of both adsorbents was evaluated in terms of the % removal (%R) and the sorption capacity (q_e, mg/g). Dependent variables (%R and q_e) were maximized as a function of four factors: pH, sorbent dose (AD), the concentration of CLOF ([CLOF]), and contact time (CT). A %R of 98.10% and 98.61% could be obtained using OSBC and MAG–OSBC, respectively. Equilibrium studies indicated that both Langmuir and Freundlich models were perfectly fit for adsorption of CLOF. Maximum adsorption capacity (q_max) of 174.03 mg/g was obtained using MAG–OSBC. Adsorption kinetics could be best illustrated using the pseudo-second-order (PSO) model. The adsorption–desorption studies showed that both adsorbents could be restored with the adsorption efficiency being conserved up to 92% after the sixth cycles. Full article

(This article belongs to the Special Issue Recent Advances in Nanomaterials for Removal of New Emerging Pollutants from Water/Wastewater)

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18 pages, 4351 KiB

Open AccessArticle

Reusable Fe₃O₄/SBA15 Nanocomposite as an Efficient Photo-Fenton Catalyst for the Removal of Sulfamethoxazole and Orange II

by Jorge González-Rodríguez, Lucía Fernández, Zulema Vargas-Osorio, Carlos Vázquez-Vázquez, Yolanda Piñeiro, José Rivas, Gumersindo Feijoo and Maria Teresa Moreira

Nanomaterials 2021, 11(2), 533; https://doi.org/10.3390/nano11020533 - 19 Feb 2021

Cited by 10 | Viewed by 2985

Abstract

Today, the presence of recalcitrant pollutants in wastewater, such as pharmaceuticals or other organic compounds, is one of the main obstacles to the widespread implementation of water reuse. In this context, the development of innovative processes for their removal becomes necessary to guarantee [...] Read more.

Today, the presence of recalcitrant pollutants in wastewater, such as pharmaceuticals or other organic compounds, is one of the main obstacles to the widespread implementation of water reuse. In this context, the development of innovative processes for their removal becomes necessary to guarantee effluent quality. This work presents the potentiality of magnetic nanoparticles immobilized on SBA-15 mesoporous silica as Fenton and photo-Fenton catalysts under visible light irradiation. The influence of the characteristics of the compounds and nanoparticles on the removal yield was investigated. Once the key aspects of the reaction mechanism were analyzed, to evaluate the feasibility of this process, an azo dye (Orange II) and an antibiotic (sulfamethoxazole) were selected as main target compounds. The concentration of Orange II decreased below the detection limit after two hours of reaction, with mineralization values of 60%. In addition, repeated sequential experiments revealed the recoverability and stability of the nanoparticles in a small-scale reactor. The benchmarking of the obtained results showed a significant improvement of the process using visible light in terms of kinetic performance, comparing the results to the Fenton process conducted at dark. Reusability, yield and easy separation of the catalyst are its main advantages for the industrial application of this process. Full article

(This article belongs to the Special Issue Recent Advances in Nanomaterials for Removal of New Emerging Pollutants from Water/Wastewater)

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18 pages, 3621 KiB

Open AccessArticle

Efficiency of Differently Processed Membranes Based on Cellulose as Cationic Dye Adsorbents

by Laura Maleš, Darinka Fakin, Matej Bračič and Selestina Gorgieva

Nanomaterials 2020, 10(4), 642; https://doi.org/10.3390/nano10040642 - 30 Mar 2020

Cited by 30 | Viewed by 3114

Abstract

In order to minimize the pollution caused by the reuse of textile dyes, technologies and materials have been developed that purify waste water in an efficient and cost-effective manner before it is discharged into a water body. In this context, the presented research [...] Read more.

In order to minimize the pollution caused by the reuse of textile dyes, technologies and materials have been developed that purify waste water in an efficient and cost-effective manner before it is discharged into a water body. In this context, the presented research investigates the potential of two types of fully cellulose-based membranes as adsorbents for cationic dyes used in the textile industry. The first type combines cellulose nanofibrils (CNFs) and carboxymethylated cellulose (CMC) using the solvent casting process and an esterification coupling reaction, while the second type uses commercial bacterial cellulose (BC) in a native and sodium periodate-treated form (BCox). The corresponding membranes were comprehensively evaluated by means of Fourier Transform Infrared (FTIR) Spectroscopy. Results confirm the esterification process within the CNF/CMC membranes, as well as BC oxidation after periodate treatment, as shown by bands at 1726.2 cm⁻¹ and 895 cm⁻¹, respectively. The Potentiometric Titration shows the highest total negative charge of 1.07 mmol/g for 4CNF/4CMC, which is assigned to the presence of COO⁻ within CMC polymers, and lowest (0.21 mmol/g) for BCox. The Contact Angle Goniometry data confirm the hydrophilicity of all membranes, and the angle increased from 0 ° (in pure BC) to 34.5 ° in CMC-rich and to 31.4 ° in BCox membranes due to the presence of CH₂COO⁻ and CHO groups, respectively. Confocal Fluorescent Microscopy (CFM) demonstrated the highest µ-roughness in 4CNF/4CMC, while Scanning Electron Microscopy (SEM) depicted diverse morphological features between the membranes, from ultrafine nanofiber networks (in BC and BCox) to larger fiber bundles connected within the polymer phase in CNF/CMC membranes. The adsorption experiment followed by UV–VIS spectroscopy, showed ~100% dye removal efficiency in both CNF/CMC-based membranes, while BC and BCox adsorbed only 24.3% and 23.6%, respectively, when anthraquinone dye was used. Azo dye was only adsorbed with an efficiency of 7–9% on CMC/CNF-based membranes, compared with 5.57% on BC and 7.33% on BCox membranes. The adsorption efficiency at equilibrium was highest for BC (1228 mg/g) and lowest for 7CNF/1CMC (419.24 mg/g) during anthraquinone dye adsorption. In the case of azo dye, the BCox was most effective, with 445.7 mg/g. Applicability of a pseudo second-order model was confirmed for both dyes and all membranes, except for BCox in combination with azo dye, showing the fastest adsorption rate in the case of the 7CNF/1CMC membrane. Full article

(This article belongs to the Special Issue Recent Advances in Nanomaterials for Removal of New Emerging Pollutants from Water/Wastewater)

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