Plasma-Induced Grafting of Cyclodextrin onto Multiwall Carbon Nanotube/Iron Oxides for Adsorbent Application

Designing carbon nanotube sponge/Au@MgO2 for surface-enhanced Raman scattering detection and fenton-like degradation of organic pollutants

With the acceleration of industry and agriculture process, the massive emission of organic pollutants is a major problem which seriously restricts the sustainable development of society. Rapid enrichment, efficient degradation and sensitive detection are three key steps to solve the problem of organic pollutants, while developing a simple method integrating the above three capabilities is still a challenge. Herein, a three-dimensional carbon nanotube sponge decorated with magnesium peroxide and gold nanoparticles (CNTs/Au@MgO2 sponge) was prepared for surface enhanced Raman scattering (SERS) detection and degradation of aromatic organics by advanced oxidation processes. The CNTs/Au@MgO2 sponge with porous structures adsorbed molecules rapidly through π-π and electrostatic interaction, thus more aromatic molecules were driven to the hot-spot areas for highly sensitive SERS detection. A detection of limit with 9.09 × 10-9 M was achieved for rhodamine B (RhB). The adsorbed molecules were degraded by an advanced oxidation process utilizing hydrogen peroxide produced by MgO2 nanoparticles under acidic condition with 99% efficiency. In addition, the CNTs/Au@MgO2 sponge exhibited high reproducibility with the relative standard deviation (RSD) at 1395 cm-1 of approximately 6.25%. The results showed the sponge can be used to effectively track the concentration of pollutants during the degradation process and maintain the SERS activity by re-modifying Au@MgO2 nanomaterials. Furthermore, the proposed CNTs/Au@MgO2 sponge demonstrated the simultaneous functions of enrichment, degradation, and detection for aromatic pollutants, thus significantly expanding the potential applications of nanomaterials in environmental analysis and treatment.

Surface Design of Liquid Separation Membrane through Graft Polymerization: A State of the Art Review

Surface modification of membranes is an effective approach for imparting unique characteristics and additional functionalities to the membranes. Chemical grafting is a commonly used membrane modification technique due to its versatility in tailoring and optimizing the membrane surface with desired functionalities. Various types of polymers can be precisely grafted onto the membrane surface and the operating conditions of grafting can be tailored to further fine-tune the membrane surface properties. This review focuses on the recent strategies in improving the surface design of liquid separation membranes through grafting-from technique, also known as graft polymerization, to improve membrane performance in wastewater treatment and desalination applications. An overview on membrane technology processes such as pressure-driven and osmotically driven membrane processes are first briefly presented. Grafting-from surface chemical modification approaches including chemical initiated, plasma initiated and UV initiated approaches are discussed in terms of their features, advantages and limitations. The innovations in membrane surface modification techniques based on grafting-from techniques are comprehensively reviewed followed by some highlights on the current challenges in this field. It is concluded that grafting-from is a versatile and effective technique to introduce various functional groups to enhance the surface properties and separation performances of liquid separation membranes.

Factorial Investigation of Cobalt Retention by Ti and Fe Oxides-Modified Carbon Nanotubes: Multivariate Against Univariate Analysis

Fe/Ti-oxides-modified-carbon nanotubes CNTs nanocomposites were prepared and tested toward Co removal from solution under different operational conditions. The final performance of the nanocomposites for Co was highly dependent on the type and loaded amount of the oxides. The nanocomposites were characterized by standard methods and the results evidenced that the presence of CNTs hampers the growth of Fe3O4 and TiO2 particles and forming smaller nano-particles leading to better Co removal from solution. Analysis of isotherms at different temperatures indicated that Co retention was two-fold increased upon adding Ti-oxides up to 90.2%. All isotherms were fairly presented using Langmuir-Freundlich isotherm and most surfaces have high heterogeneity particularly after deposition of oxides. The combined influence of the factors was investigated by running a multivariate analysis. An empirical equation was generated by principal component analysis (PCA) for predicting Co retention assuming different relationships and the binary-interaction behavior between factors was the most dominant: Co retention (mg/g) = 5.12 + 1.25Conc + 1.47Temp - 1.38CNT% - 6.03Ti% - 5.03Fe% - 0.01Conc2 + 0.12Temp2 - 0.55CNT%2 - 1.53Ti%2 - 3.44Fe%2 + 0.17Conc  ×  Temp + 0.07Conc × CNT% + 0.07Conc × Ti% + 0.10Conc × Fe% + 0.21Temp × CNT% + 0.10Temp × Ti% + 0.17Temp × Fe% - 1.67CNT% × Ti% - 1.45CNT% × Fe% - 4.11Ti% × Fe%. The most dominant factors on Co retention were temperature and concentration (positive linear correlation) and the positive interaction between temperature/concentration and temperature/CNTs mass. PCA indicated that the coefficient Temp × CNTs (+0.21) was higher than Temp × Ti% (+0.10). The negative coefficients of Ti/Fe with CNTs (1.45-4.11) indicated better Co retention at higher Ti/Fe loads and lower mass of CNTs. The results support that fact that incorporation of CNTs with Ti/Fe oxides may have a positive synergic impact on Co retention.

The "Lab4treat" Outreach Experience: Preparation of Sustainable Magnetic Nanomaterials for Remediation of Model Wastewater

The Lab4treat experience has been developed to demonstrate the use of magnetic materials in environmental applications. It was projected in the frame of the European project Mat4Treat, and it was tested several times in front of different audiences ranging from school students to the general public in training and/or divulgation events. The experience lends itself to discuss several aspects of actuality, physics and chemistry, which can be explained by modulating the discussion depth level, in order to meet the interests of younger or more experienced people and expand their knowledge. The topic is relevant, dealing with the recycling of urban waste and water depollution. The paper is placed within the field of water treatment for contaminant removal; therefore, a rich collection of recent (and less recent) papers dealing with magnetic materials and environmental issues is described in the Introduction section. In addition, the paper contains a detailed description of the experiment and a list of the possible topics which can be developed during the activity. The experimental approach makes the comprehension of scientific phenomena effective, and, from this perspective, the paper can be considered to be an example of interactive teaching.

Plasma-enhanced modification of polysaccharides for wastewater treatment: A review

In this work, novel polysaccharide-based sorbents modified with plasma technologies are discussed. Plasma selectively modifies the surface properties by generating specific moieties, enhancing adsorption performance, and the physical-chemical properties of the material without modifying its bulk properties. Among plasma technologies, cold plasma is more suitable and energy-efficient, since thermal-sensitive materials could be modified using this technology. Besides, atmospheric-pressure plasma systems possess the required features to scale-up plasma technologies for surface modification of sorbents. Moreover, a big challenge is the semi-continuous operation to modify sorbents as it would decrease overall process costs. Due to its low-cost and extensive availability, polysaccharide-based sorbents are promising substrates for plasma-enhanced modification to develop highly efficient adsorbents. The development of polysaccharide-based materials includes modified cellulose, chitosan, or lignocellulosic materials with functionalities that increase adsorption capacity and selectivity towards a specific organic or inorganic pollutant.

Green synthesis of a magnetic β-cyclodextrin polymer for rapid removal of organic micro-pollutants and heavy metals from dyeing wastewater

Adsorption is one of the most preferred techniques in the advanced treatment of dyeing wastewater. Magnetic porous materials with good adsorption performance, excellent reusability, and a green synthesis route are highly desirable adsorbents in commerce. In this study, we synthesized a magnetic β-cyclodextrin polymer (MNP-CM-CDP) containing many macro- and ultramicropores in aqueous phase. CO₂ adsorption-desorption isotherms and a dye adsorption method provided Langmuir specific surface areas for the MNP-CM-CDP of 114.4 m² g^-1 and 153 m² g^-1, respectively. Model pollutants (BPA, MB, BO₂, RhB, Cr(III), Pb(II), Zn(II), and Cu(II)) were rapidly and efficiently removed from the aqueous solution by the MNP-CM-CDP. In addition, the polymer could be easily separated from the solution under an external magnetic field. The adsorption of the contaminants was dependent on pH, while the effects of ionic strength and humic acid were slight in the concentration range studied. The polymer could be easily regenerated at room temperature and retained good adsorption performance. Moreover, the MNP-CM-CDP showed good feasibility for the removal of pollutants from actual dyeing wastewater samples.

Heterogeneous Fenton-like catalyst for treatment of rhamnolipid-solubilized hexadecane wastewater

The treatment of wastewater containing hydrophobic organic pollutants solubilized by surfactants is of great environmental importance. In this work, the removal of rhamnolipid-solubilized hexadecane via a salicylic acid-methanol-acetone modified steel converter slag (SMA-SCS) catalyzed Fenton-like process was studied. First, we investigated the adsorption of rhamnolipid and hexadecane onto SCS and SMA-modified SCS. Compared to that of SCS, SMA-SCS exhibited better adsorption performance with maximum adsorption capacities of 0.23 and 0.28 mg/g for hexadecane and rhamnolipid, respectively. Degradation experiments showed that hexadecane was more readily degraded by the Fenton-like process than rhamnolipid. Up to 81.1% of hexadecane removal was achieved over 20 g/L of SMA-SCS within 24 h, whereas only 36% of rhamnolipid was degraded. On the other hand, the results indicated that increased rhamnolipid concentration had a negative effect on the degradation of hexadecane. During the oxidation reaction, the pH value of solution remained between 6.0 and 6.72. All these results demonstrated that the SMA-SCS/H₂O₂ Fenton-like process could be a cost-effective and promising approach for the treatment of surfactant-solubilized hydrophobic organic compounds.

Effective Adsorption of Methylene Blue dye onto Magnetic Nanocomposites. Modeling and Reuse Studies

In the present study, new adsorbent beads of alginate (A)/maghemite nanoparticles (γ-Fe2O3)/functionalized multiwalled carbon nanotubes (f-CNT) were prepared and characterized by several techniques, e.g., N2 adsorption-desorption isotherms, Fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA/DTG), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM) and further tested for the adsorption of the dye methylene blue (MB) from water. The beads (A/γ-Fe2O3/f-CNT) presented a relatively low BET specific surface area value of 59 m2g−1. The magnetization saturation values of A/γ-Fe2O3/f-CNT beads determined at 295 K was equal to 27.16 emu g−1, indicating a magnetic character. The time needed to attain the equilibrium of MB adsorption onto the beads was estimated within 48 h. Thus, several kinetic and isotherm equation models were used to fit the kinetic and equilibrium experimental results. The number of adsorbed MB molecules per active site, the anchorage number, the receptor sites density, the adsorbed quantity at saturation, the concentration at half saturation and the molar adsorption energy were quantified using the monolayer model. The calculated negative ΔG0 and positive ΔH0 values suggested the spontaneous and endothermic nature of the adsorption process. In addition, A/γ-Fe2O3/f-CNT composites can be used at least for six times maintaining their significant adsorptive performance and could be easily separated by using a magnet from water after treatment.

Synthesis of mesoporous rebar MWCNT/alumina composite (RMAC) nodules for the effective removal of methylene blue and Cr (VI) from an aqueous medium

The distinctive and tuneable physical, chemical and configurational properties of carbon nanotubes (CNTs), has prompted their combination with metal oxides to contrive carbon composites showing entrancing adsorption property with incredible potential in water treatment. MWCNT/Alumina (RMAC) nodules with effective adsorption capacity were synthesized following aqueous sol-gel route. Batch sorption experiments examined the efficiency of removal of dyes and heavy metal ions from an aqueous solution on RMAC nodules. The factors affecting adsorption were studied for adsorption of methylene blue dye (MB) and hexavalent chromium by altering the MWCNT concentration from 1 wt.% to 5 wt.%. The adsorption experiment demonstrated an adsorption capacity of 187.5 and 597 mg g^-1 at 25 °C for MB and Cr (VI) respectively. Various characterization techniques such as XRD, BET, TEM, Raman, FTIR, TPD and CHN were employed to study the initial development of the material. Multiple adsorption interaction mechanisms (electrostatic interactions, hydrogen bonding, π-π electron-donor-acceptor interactions) may be credited for the remarkable adsorption capacity of these nodules. Results of this work are of great significance for environmental applications of Alumina/MWCNT composite as a promising adsorbent nanomaterial for organic pollutants from aqueous solutions. Apart from high sorption ability, these nodules offer ease of separation with splendid regeneration ability.

Open-tubular capillary electrochromatography with β-cyclodextrin-functionalized magnetic nanoparticles as stationary phase for enantioseparation of dansylated amino acids

Magnetic nanoparticles (MNPs) modified with β-cyclodextrin and mono-6-deoxy-6-(1-methylimidazolium)-β-cyclodextrin tosylate (an ionic liquid), which called MNP-β-CD and MNP-β-CD-IL, were coated into the capillary inner wall. Compared to an uncoated capillary, the new systems show good reproducibility and durability. The systems based on the use of MNP-β-CD or MNP-β-CD-IL as stationary phases were established for enantioseparation of Dns-modified amino acids. Improved resolutions were obtained for both CEC systems. Primary parameters such as running buffer pH value and applied voltage were systematically optimized in order to obtain optimal enantioseparations. Under the optimized conditions, the capillaries exhibited excellent chiral recognition ability for six Dns-amino acids (the DL-forms of alanine, leucine, lsoleucine, valine, methionine, glutamic acid) and provided a promising way for the preparation of chiral column. Graphical Abstract Schematic presentation of the open-tubular capillary electrochromatography systems with MNP-β-CD and MNP-β-CD-IL as stationary phases for enantioseparation of dansylated amino acids.

Surface grafting techniques on the improvement of membrane bioreactor: State-of-the-art advances

Membrane bioreactor (MBR) is regarded as the state-of-the-art technology in separation processes. Surface modification techniques play a critical role in improving the conventional membrane system which is mostly hydrophobic in nature. The hydrophobic nature of membranes is known to cause fouling, resulting in high maintenance costs and shorter lifespan of MBR. Thus, surface grafting aims to improve the hydrophilicity of bio-based membrane systems. This review describes the major surface grafting techniques currently used in membranes, including photo induced grafting, plasma treatment and plasma induced grafting, radiation induced grafting, thermal induced grafting and ozone induced grafting. The advantages and disadvantages of each method is discussed along with their parametric studies. The potential applications of MBR are very promising, but some integral membrane properties could be a major challenge that hinders its wider reach. The fouling issue could be resolved with the surface grafting techniques to achieve better performance of MBRs.

Synthesis of magnetic functionalized MWCNT nanocomposite through surface RAFT co-polymerization of acrylic acid and N-isopropyl acrylamide for removal of cationic dyes from aqueous solutions

In this study, magnetic multi-walled carbon nanotube (MMWCNT) composites were prepared via surface reversible addition fragmentation chain transfer (RAFT) co-polymerization of acrylic acid (AA) and N-isopropyl acrylamide (NIPAM) in the presence of Fe₃O₄ nanoparticles. First, a novel RAFT agent (RA) was prepared and then immobilized onto the surface of MWCNT to fabricate RA-g-MWCNT. Then, Fe₃O₄ nanoparticles were attached onto the surface of RA-g-MWCNT. Finally, RAFT co-polymerization of AA and NIPAM monomers was carried out via Fe₃O₄-g-RA-g-MWCNT RAFT agent. The structure and morphology of the prepared polymer-coated MWCNT was examined by FTIR, SEM, TEM, XRD, VSM, and TGA. The adsorption behaviours of the cationic dyes were studied. The equilibrium isotherm and kinetics of cationic dyes were investigated. Thermodynamics investigations also depicted that the adsorptions of cationic dyes were spontaneous and endothermic in nature. The synthesized dye adsorbent with high adsorption capacities, reusability, and easy recovery makes it as a good candidate for wastewater treatment.

Water-Soluble and Insoluble Polymers, Nanoparticles, Nanocomposites and Hybrids With Ability to Remove Hazardous Inorganic Pollutants in Water

The polymeric materials have presented a great development in adsorption processes for the treatment of polluted waters. The aim of the current review is to present the recent developments in this field of study by examining research of systems like functional water-soluble polymers and water-soluble polymer-metal complexes coupled to ultrafiltration membranes for decontamination processes in liquid-liquid phase. Noticing that a water-soluble polymer can be turned into insoluble compounds by setting a crosslinking point, connecting the polymer chains leading to polymer resins suitable for solid-liquid extraction processes. Moreover, these crosslinked polymers can be used to develop more complex systems such as (nano)composite and hybrid adsorbents, combining the polymers with inorganic moieties such as metal oxides. This combination results in novel materials that overcome some drawbacks of each separated components and enhance the sorption performance. In addition, new trends in hybrid methods combining of water-soluble polymers, membranes, and electrocatalysis/photocatalysis to remove inorganic pollutants have been discussed in this review.

Sustained antibacterial activity of berberine hydrochloride loaded supramolecular organoclay networks with hydrogen-bonding junctions

The environmental risk from antibiotics is an issue of increasing concern. So, carboxymethyl β-cyclodextrin-functionalized montmorillonite nanosheets were for the first time successfully synthesized through a cheap, environmentally friendly and scalable approach and confirmed by FTIR, XRD and TGA. FE-SEM investigation showed that the resulting functional material could be further self-assembled into dense supramolecular organoclay networks (D-networks). The antibacterial properties of the D-networks loaded with natural berberine hydrochloride (BBH) were investigated toward E. coli and S. aureus by using colony growth on agar plates, bacterial growth curves based on optical densities, and confocal and fluorescence microscopy. Our studies demonstrated that the BBH loaded D-network antibacterial activity was concentration dependent and significantly exceeded that of free BBH. FE-SEM observation confirmed that E. coli and S. aureus can directly contact the D-networks and confocal and fluorescence microscopy showed that free BBH was only very poorly internalized, while the BBH released from the BBH-loaded D-network could be internalized efficiently into bacterial cells, resulting in an increment of the intracellular BBH level compared with the free BBH group. Time-dependent antibacterial activity was observed and it was found that the BBH-loaded D-network dispersion at the BBH dosage of 600 μg mL^-1 almost completely suppressed the growth of E. coli, leading to a viability loss of up to 98.45 ± 1.22%, while the BBH-loaded D-network dispersion at the BBH concentration of 250 μg mL^-1 exhibited a growth inhibition of 97.81 ± 0.83% toward S. aureus over three days. Our results suggest that supramolecular organoclay networks, in the future, may function as promising antibacterial drug carrier systems to promote BBH delivery in E. coli and S. aureus, which can reduce the environmental risk of antibiotics.

Tailoring MWCNTs and β-Cyclodextrin for Sensitive Detection of Acetaminophen and Estrogen

Monitoring of trace amount of acetaminophen and estrogen in drinking water is of great importance because of their potential links to gastrointestinal diseases and breast and prostate cancers. The sensitive and accurate detection of acetaminophen and estrogen requires the development of advanced sensing materials that possess appropriate number of analyte-capturing sites and suitable signal conduction path. This can be achieved by implementing appropriate chemical attachment of multiwalled carbon nanotubes (MWCNTs) and β-cyclodextrin (βCD). Here, we report a systematic investigation of four types of modified MWCNT-βCD: (1) physical mixing, (2) "click reaction", (3) thionyl chloride esterification, and (4) Steglich esterification. The Steglich esterification is a one-step approach with shorter reaction time, lower reaction temperature, and eliminates handling of air/moisture-sensitive reagents. MWCNT-βCD prepared by Steglich esterification possessed moderate βCD loading (5-10 wt %), large effective surface area, and fast electron transfer. The host-guest interaction of βCD and redox properties of MWCNT enabled sensitive detection of acetaminophen and 17β-estradiol (E2 is a primary female sex hormone) in the range of 0.005-20 and 0.01-15 μM, with low detection limits of 3.3 and 2.5 nM, respectively. We demonstrated accurate detection results of pharmaceutical compositions in water and urine samples. These results indicate that Steglich esterification method may be applied in fabricating pharmaceutical contaminants sensors for health and environmental applications.

Insights into Metal Oxide and Zero-Valent Metal Nanocrystal Formation on Multiwalled Carbon Nanotube Surfaces during Sol-Gel Process

Carbon nanotubes are hybridized with metal crystals to impart multifunctionality into the nanohybrids (NHs). Simple but effective synthesis techniques are desired to form both zero-valent and oxides of different metal species on carbon nanotube surfaces. Sol-gel technique brings in significant advantages and is a viable technique for such synthesis. This study probes the efficacy of sol-gel process and aims to identify underlying mechanisms of crystal formation. Standard electron potential (SEP) is used as a guiding parameter to choose the metal species; i.e., highly negative SEP (e.g., Zn) with oxide crystal tendency, highly positive SEP (e.g., Ag) with zero-valent crystal-tendency, and intermediate range SEP (e.g., Cu) to probe the oxidation tendency in crystal formation are chosen. Transmission electron microscopy and X-ray diffraction are used to evaluate the synthesized NHs. Results indicate that SEP can be a reliable guide for the resulting crystalline phase of a certain metal species, particularly when the magnitude of this parameter is relatively high. However, for intermediate range SEP-metals, mix phase crystals can be expected. For example, Cu will form Cu₂O and zero-valent Cu crystals, unless the synthesis is performed in a reducing environment.

Designer carbon nanotubes for contaminant removal in water and wastewater: A critical review

The search for effective materials for environmental cleanup is a scientific and technological issue of paramount importance. Among various materials, carbon nanotubes (CNTs) possess unique physicochemical, electrical, and mechanical properties that make them suitable for potential applications as environmental adsorbents, sensors, membranes, and catalysts. Depending on the intended application and the chemical nature of the target contaminants, CNTs can be designed through specific functionalization or modification processes. Designer CNTs can remarkably enhance contaminant removal efficiency and facilitate nanomaterial recovery and regeneration. An increasing number of CNT-based materials have been used to treat diverse organic, inorganic, and biological contaminants. These success stories demonstrate their strong potential in practical applications, including wastewater purification and desalination. However, CNT-based technologies have not been broadly accepted for commercial use due to their prohibitive cost and the complex interactions of CNTs with other abiotic and biotic environmental components. This paper presents a critical review of the existing literature on the interaction of various contaminants with CNTs in water and soil environments. The preparation methods of various designer CNTs (surface functionalized and/or modified) and the functional relationships between their physicochemical characteristics and environmental uses are discussed. This review will also help to identify the research gaps that must be addressed for enhancing the commercial acceptance of CNTs in the environmental remediation industry.

Plasma-Facilitated Synthesis of Amidoxime/Carbon Nanofiber Hybrids for Effective Enrichment of 238U(VI) and 241Am(III)

Plasma- and chemical-grafted amidoxime/carbon nanofiber hybrids (p-AO/CNFs and c-AO/CNFs) were utilized to remove ²³⁸U(VI) and ²⁴¹Am(III) from aqueous solutions, seawater, and groundwater. Characteristic results indicated more nitrogen-containing groups in p-AO/CNFs compared to c-AO/CNFs. The maximum adsorption capacities of p-AO/CNFs at pH 3.5 and T = 293 K (588.24 mg of ²³⁸U(VI)/g and 40.79 mg of ²⁴¹Am(III)/g from aqueous solutions, respectively) were significantly higher than those of c-AO/CNFs (263.18 and 22.77 mg/g for ²³⁸U(VI) and ²⁴¹Am(III), respectively), which indicated that plasma-grafting was a highly effective, low-cost, and environmentally friendly method. Adsorption of ²³⁸U(VI) on AO/CNFs from aqueous solutions was significantly higher than that of ²³⁸U(VI) from seawater and groundwater; moreover, AO/CNFs displayed the highest effective selectivity for ²³⁸U(VI) compared to the other radionuclides. Adsorption of ²³⁸U(VI) onto AO/CNFs created inner-sphere complexes (e.g., U-C shells) as shown by X-ray absorption fine structure analysis, which was supported by surface complexation modeling. Three inner-sphere complexes gave excellent fits to pH-edge and isothermal adsorption of ²³⁸U(VI) on the AO/CNFs. These observations are crucial for the utilization of plasma-grafted, AO-based composites in the preconcentration and immobilization of lanthanides and actinides in environmental remediation.

Removal of tetracycline and oxytetracycline from water by magnetic Fe3O4@graphene

In this paper, Fe₃O₄@graphene (Fe₃O₄@G) magnetic nanocomposite was prepared via in situ precipitation method for the removal of oxytetracycline (OTC) and tetracycline (TC) from aqueous solution. The properties of the prepared nanocomposite were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and magnetic property measurement system (MPMS). Adsorption isotherm and kinetics of OTC and TC were studied in batch experiments. The influence of the dosage of Fe₃O₄@G, the solution pH, and ion strength on the adsorption process were also assessed. The results demonstrated that the Langmuir model fitted the adsorption equilibrium data better than did the Freundlich model, and the pseudo-first-order model was more suitable than the pseudo-second-order to describe the adsorption process, with a good adsorption rate constant (k = 0.974 and 0.834 g mg^-1 h^-1, respectively). The adsorption ability reached maximum at pH of 7 with no NaCl. The removal efficiency of Fe₃O₄@G in lake, tap, and pool water were 95.45, 96.68, and 89.82 % for OTC and 98.77, 98.23, and 89.09 % for TC, respectively. The π-π interaction and cation-π bonding of the adsorbent and analytes make it suitable for the removal of OTC and TC. The present study suggests that the prepared composite can be deemed as a promising material for the removal of tetracycline antibiotics from aqueous solution.

Novel highly stable β-cyclodextrin fullerene mixed valent Fe-metal framework for quick Fenton degradation of alizarin

Degradation of alizarin by β-cyclodextrin supported magnetic nanoscaled fullerene/Fe₃O₄ (CDFMNPs) catalyst in a heterogeneous Fenton reaction.