Enhanced adsorption of tetracycline antibiotics from pharmaceutical wastewater on expanded graphite composites modified by metal oxide (original) (raw)
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Journal of Advanced Scientific Research
The gradual increase of antibiotics in aquatic environments poses a serious threat to human health and ecosystems, and removal technology for antibiotics has attracted great interest in recent years. An adsorption method using an adsorbent MNC was designed for the rapid removal of tetracycline (TC) antibiotics from water. The results showed that TCs sorption on adsorbent was highly pH-dependent, and the optimal pH was found to be 4.5-5.6 for tetracycline (TC). The adsorption efficiency could reach 99.8%, suggesting that MNC is an excellent adsorbent for TC removal from water. The adsorption kinetics fitted the pseudo-second-order model perfectly. The adsorption isotherms study showed the maximum sorption capacity. The differences in the removal trends of the three TCs may be attributed to their different pKa values. Moreover, the thermodynamic parameters for the adsorption were estimated, and the ΔH° and ΔG° values indicated the endothermic and spontaneous nature of the sorption pro...
Graphene oxide as a new generation adsorbent for the removal of antibiotics from waters
Separation Science and Technology, 2020
The presence of antibiotic molecules in the natural water sources is currently a huge problem due to the development of bacterial resistance. Graphene oxide (GO) has a large potential as a candidate for the applications of water treatment. In this paper, graphene oxide was tested as a new generation adsorbent for the removal of two antibiotics: trimethoprim (TMP) and isoniazid (INH). Both adsorption processes reached the equilibrium in less than one hour. Maximum adsorption capacities were found to be 204.08 mg g-1 for TMP and 13.89 mg g-1 for INH. TMP adsorption on GO was favoured in alkaline medium while the performance of GO for INH adsorption was better in acidic conditions.
Process Safety and Environmental Protection, 2021
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In this study, reduced graphene oxide (rGO) was successfully produced from graphite precursor by chemical oxidation and exfoliation processes which were followed by a reduction process in mild conditions. rGO was then applied in the adsorption of tetracycline (TC) in water. SEM/EDX, XRD, FT-IR, BET, pHpzc were conducted to characterize the synthesized materials. The adsorption efficiency of TC from water was evaluated by changes in several factors such as contact time, temperature, pH of the solution, adsorbent load, and tetracycline concentration. Furthermore, adsorption kinetics, thermodynamics, and isotherms were also investigated. As the result, the adsorption process of TC onto rGO was spontaneous, endothermic, and governed by both physisorption and chemisorption. The maximum uptake calculated from Langmuir isotherm model was 58.03 mg/g. rGO material could be regenerated by using methanol and diluted NaOH solutions. The findings in this work provides a complete data on the TC a...
Materials, 2019
Recently, many methods have been developed to efficiently eliminate oil spills due to its long-term harmful effects on marine life and human health. Expanded graphite (EG) has been considered as an excellent platform to remove contaminated oil from aqueous solution through a facile adsorption route. As an innovative approach, the decoration of magnetic components, namely, MnFe2O4, into graphite layers was taken into account for facilitating phase separation under magnetic field which resulted into an easy collection of the used adsorbents in a large scale. The expanded graphite/manganese ferrite composites were prepared from Vietnamese graphite flakes via a two-stage process. Characterization was performed using Scanning Electron Microscope (SEM), Fourier-Transform Infrared Spectroscopy (FTIR), X-Ray Powder Diffraction (XRD), Vibrating Sample Magnetometer (VSM), Energy-Dispersive X-ray (EDS), and nitrogen adsorption/desorption analysis. The adsorption behavior of EG-MnFe2O4 for wide...
ADSORPTIVE REMOVAL OF DOXYCYCLINE FROM AQUEOUS SOLUTION USING GRAPHENE OXIDE/HYDROGEL COMPOSITE
International Journal of Applied pharmaceutics, 2020
Objective: Preparation of novel, safe, and low-cost composite by addition of graphene oxide (GO) to polyvinylpyrrolidone-acrylic acid composite (PVP-AAc) to remove the doxycycline hydrochloride (D) from polluted aquatic environment. Methods: Different concentrations of D were used to study the adsorption process of the antibiotic on the surface of GO/(PVP-AAc) hydrogel composite. The aquatic solution of D was used for studying the adsorption process through a series of different experiments to determine the contact time, adsorbate amount, appropriate temperature, the preferred pH, ionic strength, adsorption kinetics and isotherms on the adsorbent surface of GO/PVP-AAc composite. Fourier transform infrared (FT-IR) spectroscopy and Field-emission scanning electron microscopy (FE-SEM) were used to detect the structure, functional groups and surface morphology of the composite before and after D adsorption. Results: Doxycycline is adsorb on the surface of GO/PVP-AAc hydrogel composite through by physical interactions. The adsorption kinetics correlated to the pseudo-second-order model, contact time studies of D equal to 180 min and the high R 2 value of 0.98 indicates that Langmuir isotherm model better fitted to the data for the removal of D at 15 °C. The results of thermodynamic parameters show that the nature of the adsorption process is physical, exothermic, orderly and spontaneous. The adsorption capacity of D favors the acidic media. When NaCl is added to the solution, the adsorption capacity of D will increase. Conclusion: Graphene oxide/PVP-AAc composite is a novel, worthy and efficient adsorbent for the removal of the doxycycline polluted the water because of its low cost, hydrophilic properties, large surface area and special structure that give impressive dispersible activity in aquatic solutions.
Scientific Reports, 2022
In this work, the synthesis of an rGO/nZVI composite was achieved for the first time using a simple and green procedure via Atriplex halimus leaves extract as a reducing and stabilizing agent to uphold the green chemistry principles such as less hazardous chemical synthesis. Several tools have been used to confirm the successful synthesis of the composite such as SEM, EDX, XPS, XRD, FTIR, and zeta potential which indicated the successful fabrication of the composite. The novel composite was compared with pristine nZVI for the removal aptitude of a doxycycline antibiotic with different initial concentrations to study the synergistic effect between rGO and nZVI. The adsorptive removal of bare nZVI was 90% using the removal conditions of 25 mg L −1 , 25 °C, and 0.05 g, whereas the adsorptive removal of doxycycline by the rGO/nZVI composite reached 94.6% confirming the synergistic effect between nZVI and rGO. The adsorption process followed the pseudo-second order and was wellfitted to Freundlich models with a maximum adsorption capacity of 31.61 mg g −1 at 25 °C and pH 7. A plausible mechanism for the removal of DC was suggested. Besides, the reusability of the rGO/nZVI composite was confirmed by having an efficacy of 60% after six successive cycles of regeneration. Water scarcity and pollution are now serious threats to all nations. Pollution of water, specifically, with antibiotics has increased in recent years because of the increased production and consumption during the COVID-19 pandemic 1-3. Thus, developing an effective technique to eliminate antibiotics from wastewater is of great concern. One of the resistant semisynthetic antibiotics that is derived from the tetracycline group is Doxycycline (DC) 4,5. The remains of DC have been reported in ground and surface water as it cannot be metabolized, only 20-50% is metabolized, and the remaining is discharged into the environment causing serious environmental and health problems 6. Low levels contact of with DC can kill aquatic photosynthetic microbes, pose a threat to the transmission of antimicrobial bacteria, and increase antimicrobial resistance; therefore, it is a necessity to remove this pollutant from the water effluent. The natural degradation of DC in water is a very slow process. Physio-chemical processes, such as photolysis, biodegradation, and adsorption can degrade only in small concentrations and at a very slow rate 7,8. However, adsorption is the most cost-effective, simple, environmentally friendly, facile in handling, and highly efficient approach 9,10. Nano-zero valent iron (nZVI) is a very effective material in the elimination of many antibiotics from water including metronidazole diazepam, ciprofloxacin, chloramphenicol, and tetracycline. This ability comes from the astonishing properties that nZVI possesses such as great reactivity, large surface area, and numerous exterior binding sites 11. However, nZVI tends to agglomerate in aqueous media because of the Van der Wales forces and
Adsorption of Lead and Nickel on to Expanded Graphite Decorated with Manganese Oxide Nanoparticles
Applied Sciences, 2019
In this study, expanded graphite (EG) was decorated with manganese oxide nanoparticles (MONPs) by the hydrothermal method, and the newly formed composite (MONPs-EG) was applied as adsorbent for the removal of heavy metals from aqueous solutions. The comparative and competitive adsorption of Pb 2+ and Ni 2+ (0.01-1.00 mM) on MONPs-EG was investigated. Data from isothermal adsorption of single and binary systems suggested that both Pb 2+ and Ni 2+ were well described by the Langmuir isotherm, and the maximum adsorption capacities at 298 K were calculated at 0.278 and 0.113 mmol/g for Pb 2+ and Ni 2+ , respectively. In binary systems, a dramatic decrease in adsorption capacity of Ni 2+ was observed, while the adsorption capacity of Pb 2+ was almost stable, indicating the favorable adsorption of Pb 2+ over Ni 2+ onto the prepared adsorbent. Kinetics studies of single and binary systems showed that a pseudo-second order model could explain the adsorption processes well. Thermodynamic analysis results demonstrated that the adsorption of these metal ions on the prepared adsorbent is spontaneous and exothermic in nature. The adsorption capacity of MONPs-EG increased significantly in the presence of humic acids. Overall, the results of this study suggest that MONPs-EG can be used effectively as an adsorbent for heavy metals removal from aqueous solutions.