Ciprofloxacin desorption from gel type ion exchange resin: Desorption modeling in batch system and fixed bed column

Highly Adsorptive Removal of Ciprofloxacin and E.coli inactivation using Amino acid Tryptophan Modified Nano-gibbsite

Adsorption of essential amino acid, Tryptophan (Tryp) on synthesized gibbsite nanoparticles and their applications in eliminating of antibiotic ciprofloxacin (CFX) and bacteria Escherichia coli (E.coli) in aqueous solution. Nano-gibbsite which was successfully fabricated, was characterized by XRD, TEM-SAED, FT-IR, SEM-EDX and zeta potential measurements. The selected parameters for Tryp adsorption on nano-gibbsite to form biomaterial, Tryp/gibbsite were pH 11, gibbsite dosage 20 mg/mL and 1400 mg/L Tryp. The optimum conditions for CFX removal using Tryp/gibbsite were adsorption time 60 min, pH 5, and 20 mg/mL Tryp/gibbsite dosage. The CFX removal significantly raised from 63 to 90% when using Tryp/gibbsite. The Freundlich and pseudo-second-order models achieved the best fits for CFX adsorption isotherm and kinetic on Tryp/gibbsite, respectively. The amount of CFX increased with increasing ionic strength, suggesting that both electrostatic and non-electrostatic interactions were important. After four reused time, CFX removal was greater than 66%, demonstrating that Tryp/gibbsite is reusable with high performance in removing CFX. The application in bacterial activity in term of E.coli reached greater than 98% that was the best material for bacteria inactivation. The present study reveals that Tryp/gibbsite is an excellent bio-material for removing CFX and E.coli.

Design and fabrication of magnetic Fe3O4-QSM nanoparticles loaded with ciprofloxacin as a potential antibacterial agent

In this investigation, we have synthesized magnetite nanoparticles (Fe₃O₄ NPs) coated with quince seed mucilage (QSM) as a natural, biocompatible, and biodegradable component and loaded them with ciprofloxacin (CIP) to act as an antibacterial agent. The structural, magnetic, physicochemical, colloidal, and antibacterial properties of the samples were tested using various characterization tools such as XRD, TEM, FE-SEM, VSM, FT-IR, UV-Vis, DLS, BET, and disk diffusion for testing the antibacterial properties. XRD and VSM results confirmed the fabrication of a highly pure cubic spinel phase for Fe₃O₄. The results of FE-SEM and TEM analyses indicate a spherical morphology of the magnetite NPs with a mean diameter of about 13 nm, and the results of DLS show a hydrodynamic diameter of 81.9 to 119.2 nm. The zeta potential value for the magnetic Fe₃O₄ NPs was as high as -55.2 mV, indicating suitable colloidal stability of the NPs for biological applications. The VSM results indicate a high saturation magnetization of the samples as well as a small coercivity and Remanence of the samples, which indicate the superparamagnetic property of the NPs. It was also indicated that the amount of drug adsorbed on the magnetic nanoparticles at different pH values (5.5 to 6.5) is about 85 %. It was likewise detected that the synthesized Fe₃O₄@QSM-CIP NPs possess antibacterial activity against standard strains of both Gram positive and Gram-negative bacteria (minimum inhibitory concentration = 100 ppm). The overall findings imply that the proposed magnetic NPs with antibacterial activity are promising for biomedical applications.

Critical review on adsorptive removal of antibiotics: Present situation, challenges and future perspective

This review gives a proper dedicated understanding of the contamination level, sources, and biological dangers related with different classes of antibiotics in consumable water. The literature on the adsorption of antibiotics is relatively uncommon and developments are still under progression, especially for adsorbents other than activated carbon. Also, adsorption technique has already been applied vastly for water treatment. Notwithstanding significant progressions, designed natural wastewater treatment frameworks are just bearably effective (48-77%) in the expulsion of antibiotics. Hence, the compilation of available literature especially for antibiotic adsorption was much needed. Moreover, the conventional adsorbents have some limitations of their own. In this study, the main focus was laid on unconventional adsorbents such as Biochar, Biopolymers, Carbon Nanotubes, Clays, Metal-Organic Frameworks, Microalgae and some miscellaneous adsorbents. The mechanism of adsorption by the unconventional adsorbents includes electrostatic interactions, π-π bonding, weak Van der Waal forces, H-bonding and surface complexation, which was similar to that of conventional adsorbents and hence these unconventional adsorbents can easily replace the costlier conventional adsorbents with even better adsorption efficiency. This paper also briefly discussed the thermodynamics, adsorption equilibrium; isotherm and kinetics of adsorption. This review paper seizes the critical advances of adsorption phenomenon at various interfaces and lays the foundation for current scenario associated with further progress. Besides, this study would help in understanding the antibiotic adsorption, cost estimation and future goals that will attract the young the researchers of this field.

Adsorption and Desorption Behavior of Ectoine Using Dowex® HCR-S Ion-Exchange Resin

Dowex® HCR-S ion-exchange resin was used to adsorb ectoine in a batch system under varying operation conditions in terms of contact time, temperature, pH value, initial concentration of ectoine, and type of salt. Six adsorption isotherm models (Langmuir, Freundlich, Temkin, Dubinin–Radushkevich, Sips, and Redlich–Peterson) and three kinetic models (pseudo-first-order, pseudo-second-order, and intraparticle diffusion) were used to investigate the ectoine adsorption mechanism of ion-exchange resin. According to the experimental results, the mechanism of ectoine adsorption using an ion exchanger includes the ion-exchange reaction and physisorption. Both the Langmuir and Freundlich models were found to have a high fitting. For the kinetic analysis, the pseudo-second-order and intraparticle diffusion models were suitable to describe the ectoine adsorption. Dowex® HCR-S resin has an average saturated adsorption capacity of 0.57 g/g and 93.6% of ectoine adsorption at 25~65 °C, with an initial concentration of 125 g/L. By changing the pH of the environment using NaOH solution, the adsorbed ectoine on the ion-exchange resin can be desorbed to 87.7%.

Utilization of gel-type polystyrene host for immobilization of nano-sized hydrated zirconium oxides: A new strategy for enhanced phosphate removal

The urgent need for eutrophication control motivated the development of many novel adsorbents for enhanced phosphate polishing removal. Among these, zirconium-based nanomaterial was regarded as an effective kind because of its ability to bind phosphate specifically via inner-sphere complexation. In this study, we proposed a new strategy to improve the efficiency of zirconium oxides (HZO) nanoparticles by immobilizing them onto a gel-type anion exchange resin covalently attached with ammonium groups, denoted as HZO@N201. A previously developed macro-porous polymeric nanocomposite HZO@D201 was used for comparison. The immobilized nanoparticles in HZO@N201 were well dispersed in the gel matrix, manifesting smaller particle size and richer surface hydroxyl groups in comparison to HZO@D201. As a result of the structural merits in collective, HZO@N201 not only exhibited superior phosphate adsorptive capacity and affinity towards phosphate to HZO@D201, but also facilitate phosphate diffusion, based on isotherm, pH and kinetic tests. Mechanistic study by XPS and ³¹P SS-NMR substantiated the selective phosphate adsorption pathway as the formation of inner-sphere complexes by HZO@N201, which exhibited enhanced reactivity than HZO@D201. Lastly, fixed-bed runs of HZO@N201 was conducted, achieving an effective treatable volume of 2000 BV, which was 600 BV more than HZO@D201. Additional adsorption-regeneration cycle confirmed its reusability and potential for practical application. We believe the gel-type polymeric host could facilitate the formation and dispersion of smaller sized nanoparticles, exposing more surface hydroxyl groups highly accessible to phosphate. The results of this paper offer insights to a new strategy for immobilization of functional nanoparticles aiming at enhanced adsorptive removal of phosphate.