Novel Magnetite Nanocomposites (Fe3O4/C) for Efficient Immobilization of Ciprofloxacin from Aqueous Solutions through Adsorption Pretreatment and Membrane Processes

Enhancing the efficiency of magnetically driven carbon nitride-based nanocomposites with magnetic nanoflowers for the removal of methylene blue dye at neutral pH

The present study focuses on the elaboration of magnetic nanocomposites by the in situ incorporation of magnetite (Fe3O4) nanoparticles (NPs) with spherical and nanoflower-like morphologies in graphitic carbon nitride (g-C3N4) sheets using two different synthetic routes. Nanomaterials are characterized by TEM, SEM, XRD, FTIR, BET, zetametry, vibrating sample magnetometry, and UV-vis absorption spectroscopy. The decoration of the carbon nitride matrix with the magnetic NPs enhanced optical and textural properties. The influence of the morphology of the magnetic NPs on the adsorptive and photocatalytic properties of the nanocomposites under different pH conditions (4.5, 6.9, and 10.6) was assessed from batch tests to remove methylene blue (MB) from aqueous solutions. In extreme pH conditions, the nanocomposites exhibited lower or equivalent MB removal capacity compared to the pure g-C3N4. However, at neutral medium, the nanocomposite with incorporated Fe3O4 nanoflowers showed a significantly higher removal efficiency (80.7%) due to the combination of a high adsorption capacity and a good photocatalytic activity in this pH region. The proposed nanocomposite is a promising alternative to remove cationic dyes from water by magnetic assistance, since no pH adjustment of the polluted effluent is required, reducing costs and environmental impact in the dyeing industry.

Remediation of acetamiprid pesticide from contaminated water by antibacterial biosorbent based on carboxymethyl tragacanth-grafted-poly(3-aminophenol) decorated with ZnO@Fe3O4

Pesticides can have harmful impacts on the environment and living organisms. Thus, removing them from polluted water is crucial. In this study, a bionanocomposite of carboxymethyl tragacanth-grafted-poly(3-aminophenol)/zinc oxide@iron oxide (CMT-g-P3AP/ZnO@Fe3O4) synthesized by in situ copolymerization as an efficient adsorbent to eliminate the acetamiprid pesticide from polluted water. The CMT-g-P3AP/ZnO@Fe3O4 magnetic nanocomposite was analyzed utilizing various techniques including FTIR, EDX, FESEM, XRD, BET, CHNSO, and TGA. The results displayed that the resulting nanocomposite with maximum adsorption capacity (Qmax) successfully removed the acetamiprid pesticide from polluted water under optimal conditions such as pH of 7.00, 5.00 mg of adsorbent, 20.0 min duration, and 400 mg/L acetamiprid concentration. According to the linear Langmuir isotherm, the Qmax of the biosorbent was 833 mg/g. The experimental adsorption data fitted well with Temkin's nonlinear isotherm model. The adsorption kinetic data were closely related to the Weber-Morris intraparticle diffusion nonlinear model. After three repetitive cycles, CMT-g-P3AP/ZnO@Fe3O4 can be outstandingly renewed and recycled without significant reduction in its adsorption efficacy, as evidenced by the adsorption-desorption experiments. In addition, the CMT-g-P3AP/ZnO@Fe3O4 displayed the good antibacterial activity against E. coli and S. aureus.

Magnetic carboxymethyl gond katira-grafted-poly(3-aminobenzoic acid) as an antibacterial biosorbent for purification of acetamiprid-contaminated water

The elimination of pesticides from polluted water is critical due to their harmful environmental and biological impacts. Recently, there has been interest in utilizing natural polymer-based adsorbents as an eco-friendly approach to eliminate or reduce the levels of water pollutants. In this work, we synthesized an antimicrobial and magnetic bionanocomposite consisting of carboxymethyl gond katira-grafted- poly(3-aminobenzoic acid) with iron oxide and zinc oxide NPs (CMT-g-P3ABA/ZnO/Fe3O4) through an in situ polymerization reaction and examined for its ability to adsorb the pesticide acetamiprid (AP). The bionanocomposite was characterized using several analytical techniques, including spectroscopy; XRD presented the crystalline structure of ZnO/Fe3O4 in the CMT-g-P3ABA amorphous matrix. The ZnO/Fe3O4 partially aggregated formation and exhibited polyhedral crystal shapes was depicted by electron microscopy images, vibrating sample magnetometer (45.06 emu/g), porosimetry (5.52 m2/g), and thermal (Chair yield of approximately 43.83 %) and elemental analyses. Under various conditions, including solution pH (4-9), adsorbent dosage (0.005-0.025 g), time of contact (10-30 min), and pesticide preliminary concentration (200-400 mg/L) in 10 mL of the solution. Based on this research, Adsorption data were perfectly fitted by the Freundlich isotherm model with RAP2= 0.99038, while the pseudo-second-order (PSO) model well-explained adsorption kinetics with RAP2= 0.99847. AP adsorption to the CMT-g-P3ABA/ZnO/Fe3O4 bionanocomposite was successful due to hydrophobic interactions, hydrogen bonding, and π-π stacking. Furthermore, adsorption-desorption experiments demonstrated that the bionanocomposite could be regenerated after three reuse cycles without considerable loss of pesticide removal performance. The bionanocomposite also exhibited promising antimicrobial activity in contradiction to test bacteria.

A feasible approach for azo-dye (methyl orange) degradation by textile effluent isolate Serratia marcescens ED1 strain for water sustainability: AST identification, degradation optimization and pathway hypothesis

Methyl orange (MO) is a dye commonly used in the textile industry that harms aquatic life, soil and human health due to its potential as an environmental pollutant. The present study describes the dye degradation ability of Serratia marcescens strain ED1 isolated from textile effluent and characterized by 16S rRNA gene sequence analysis. The laccase property of bacterial isolate was confirmed qualitatively. The effects of various factors (pH, temperature, incubation time, and dye concentration) were evaluated using Response Surface Methodology (RSM). The maximum dye (MO) degradation was 81.02 % achieved at 37 °C temperature and 7.0 pH with 200 mg/L dye concentration after 48 h of incubation. The beef extract, ammonium nitrate and fructose supplementation showed better response during bioremediation among the different carbon and nitrogen sources. The degree of pathogenicity was confirmed through the simple plate-based method, and an antibiotic resistance profile was used to check the low-risk rate of antibiotic resistance. However, the fate and extinct of degraded MO products were analysed through UV-Vis spectroscopy, FT-IR, and GC-MS analysis to confirm the biodegradation potential of the bacterial strain ED1 and intermediate metabolites were identified to propose metabolic pathway. The phytotoxicity study on Vigna radiata L. seeds confirmed nontoxic effect of degraded MO metabolites and indicates promising degradation potential of S. marcescens strain ED1 to successfully remediate MO dye ecologically sustainably.

Bioinspired Stevia rebaudiana Green Zinc Oxide Nanoparticles for the Adsorptive Removal of Antibiotics from Water

Green zinc oxide nanoparticles (ZnO NPs) synthesized using Stevia rebaudiana as a reducing agent were investigated as ecofriendly adsorbents for the removal of the antibiotics ciprofloxacin (CIP) and tetracycline (TET) from water. Green ZnO NPs were synthesized using a rapid novel approach that did not require annealing or calcination at high temperatures to produce mesoporous NPs with a size range of 37.36-71.33 nm, a specific surface area of 15.28 m2/g, and a negative surface charge of -15 mV at pH 5. The green ZnO NPs exhibited an antioxidant activity of 85.57% at 250 μg/mL and an antibacterial activity with MIC and MBC of 50 and 100 mg/mL, respectively, against both Escherichia coli and Staphylococcus aureus. The best adsorption performance was achieved using a 4 g/L dose and pH 5, yielding, respectively, 86.77 ± 0.82% removal and 27.07 ± 0.26 mg/g adsorption capacity for CIP at 10 mg/L and 67.86 ± 3.41% and 15.88 ± 0.37 mg/g for TET at 25 mg/L. The green ZnO NPs achieved 79.71% ± 0.28 and 61.55% ± 0.53 removal of 10 mg/L CIP and 25 mg/L TET, respectively, in a spiked tap water binary system of the two contaminants. Adsorption of CIP and TET occurred mainly via electrostatic interactions, whereby CIP was bound more strongly than TET by virtue of its charge and size. The synthesis and adsorption processes were evaluated by a stepwise regression statistical model to optimize their parameters. Lastly, the green ZnO NPs were regenerated and reused for 5 cycles, indicating their functionality as simple, reusable, and low-cost adsorbents for the removal of CIP and TET from wastewater, in accordance with SDGs #6 and 12 for the sustainable management of water.

Synthesis and Characterization of Supermagnetic Nanocomposites Coated with Pluronic F127 as a Contrast Agent for Biomedical Applications

Nanomedicine has garnered significant interest owing to advances in drug delivery, effectively demonstrated in the treatment of certain diseases. Here, smart supermagnetic nanocomposites based on iron oxide nanoparticles (MNPs) coated with Pluronic F127 (F127) were developed for the delivery of doxorubicin (DOX) to tumor tissues. The XRD patterns for all samples revealed peaks consistent with Fe3O4, as shown by their indices (220), (311), (400), (422), (511), and (440), demonstrating that the structure of Fe3O4 did not change after the coating process. After loading with DOX, the as-prepared smart nanocomposites demonstrated drug-loading efficiency and drug-loading capacity percentages of 45 ± 0.10 and 17 ± 0.58% for MNP-F127-2-DOX and 65 ± 0.12 and 13 ± 0.79% for MNP-F127-3-DOX, respectively. Moreover, a better DOX release rate was observed under acidic conditions, which may be credited to the pH sensitivity of the polymer. In vitro analysis demonstrated the survival rate of approximately 90% in HepG2 cells treated with PBS and MNP-F127-3 nanocomposites. Furthermore, after treatment with MNP-F127-3-DOX, the survival rate decreased, confirming cellular inhibition. Hence, the synthesized smart nanocomposites showed great promise for drug delivery in liver cancer treatment, overcoming the limitations of traditional therapies.

Optimization, Nature, and Mechanism Investigations for the Adsorption of Ciprofloxacin and Malachite Green onto Carbon Nanoparticles Derived from Low-Cost Precursor via a Green Route

The spread of organic pollutants in water spoils the environment, and among the best-known sorbents for removing organic compounds are carbonaceous materials. Sunflower seed waste (SFSW) was employed as a green and low-cost precursor to prepare carbon nanoparticles (CNPs) via pyrolysis, followed by a ball-milling process. The CNPs were treated with a nitric–sulfuric acid mixture (1:1) at 100 °C. The scanning electron microscopy (SEM) showed a particle size range of 38 to 45 nm, and the Brunauer–Emmett–Teller (BET) surface area was 162.9 m2 g−1. The elemental analysis was performed using energy-dispersive X-ray spectroscopy, and the functional groups on the CNPs were examined with Fourier transform infrared spectroscopy. Additionally, an X-ray diffractometer was employed to test the phase crystallinity of the prepared CNPs. The fabricated CNPs were used to adsorb ciprofloxacin (CFXN) and malachite green (MLG) from water. The experimentally obtained adsorption capacities for CFXN and MLG were 103.6 and 182.4 mg g−1, respectively. The kinetic investigation implied that the adsorption of both pollutants fitted the pseudo-first-order model, and the intraparticle diffusion step controlled the process. The equilibrium findings for CFXN and MLG sorption on the CNPs followed the Langmuir and the Fredulich isotherm models, respectively. It was concluded that both pollutants spontaneously adsorbed on the CNPs, with physisorption being the likely mechanism. Additionally, the FTIR analysis of the adsorbed CFXN showed the disappearance of some functional groups, suggesting a chemisorption contribution. The CNPs showed an excellent performance in removing CFXN and MLG from groundwater and seawater samples and possessed consistent efficiency during the recycle–reuse study. The application of CNPs to treat synthetically contaminated natural water samples indicated the complete remediation of polluted water using the ball-mill-fabricated CNPs.

High-Efficiency Adsorption of Hexavalent Chromium from Aqueous Solution by Samanea saman Activated Carbon

Heavy metal wastewater pollution has become an environmental and industrial challenge worldwide. Hexavalent chromium (Cr(VI)) is one of the most common forms of chromium metal. Hexavalent chromium pollution is a concern because it was hazardous and can accumulate in the tissues of living organisms and the environment. The adsorption method using activated carbon can be one of the methods to treat hexavalent chromium waste. This study selected Samanea saman as the activated carbon because it contains hemicellulose, lignocellulose, and lignin, which are the requirements for an excellent activated carbon. The study’s objective is to analyze Samanea saman activated carbon (SSAC) to remove hexavalent chromium, measure the adsorption capacity, and determine the appropriate type of adsorption isotherm layer based on the maximum $R^2$ and minimum ${\chi }^2$ values. The process of making activated carbon was activated using K2CO3 through a pyrolysis process and using batch adsorption. The SEM results as characterization of SSAC depicted that the high pore was well developed. The optimal conditions for Samanea saman indicated high efficiency toward hexavalent chromium ions within the following process parameters; pH value 5, adsorbent dosage 5 g, and initial concentration 20 mg/L. The findings demonstrate that SSAC leads to the removal efficiency of hexavalent chromium being 99.90%, with the greatest adsorption capacity of 0.8949 mg/g. Based on the maximum $R^2$ and minimum ${\chi }^2$ values, the most suitable adsorption isotherm model in SSAC was the Freundlich isotherm existing in the monolayer ( $R^2=0.999$ ). The experimental results demonstrated that adsorption of Cr(VI) was well performed by SSAC. Thus, the SSAC material is an appropriate adsorbent for the removal of hexavalent chromium in the water and has the potential to be industrial applied.

Removal of Safranin-T and Toluidine from Water through Gum Arabic/Acrylamide Hydrogel

Hydrogels as “smart sorbents” for wastewater treatment have attracted much attention due to their facile fabrication, rapid regeneration, environment friendly nature, and strong interaction with pollutants. In this study, gum arabic/acrylamide (GA/AM) hydrogel was developed via the free radical polymerization method by employing acrylamide (AM) (monomer), gum arabic (GA) (grafting backbone), N,N-methylenebisacrylamide (MBA) (chemical crosslinker), and tetramethylethylenediamine (TEMED) (accelerator). The fabricated adsorbent was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and surface area analyzer. The adsorption properties of the subject hydrogel were explored against cationic safranin and toluidine dyes in aqueous media. The point of zero charge (PZC) for the GA/AM sorbent was found to be $\text{p}{\text{H}}_{\text{PZC}}=7.1$ whereas maximum sorption occurred at pH 11. Different kinetic and isotherm models were applied to evaluate the adsorption mechanism and estimate values of different adsorption parameters. The adsorption isotherm and kinetics were better explained by the Langmuir isotherm and pseudo-second-order kinetic model whereas the adsorption thermodynamics depicted the endothermic, spontaneous, and favorable nature of the process. The adsorbent was regenerated with acetone and reused for the selected dyes for many cycles. After the 5th cycle, the hydrogel retained safranin/toluidine removal $\text{capacity}\ge 60\%$ which pointed toward the reusability of the prepared adsorbent for cycles without appreciable reduction in its adsorption capacity. Hence, the GA/AM sorbent can be applied as an alternative of activated carbon to treat dye-contaminated waters.