Ofloxacin Removal from Aqueous Media by Means of Magnetoactive Electrospun Fibrous Adsorbents

Functionalized electrospun polymer microfibrous membranes were fabricated by electrospinning and further surface-functionalized with magnetic iron oxide (Fe_xO_y) nanoparticles to yield magnetoactive nanocomposite fibrous adsorbents. The latter were characterized in respect to their morphology, mechanical properties and magnetic properties while they were further evaluated as substrates for removing Ofloxacin (OFL) from synthetic aqueous media and secondary urban wastewater (UWW) under varying physicochemical parameters, including the concentration of the pharmaceutical pollutant, the solution pH and the membranes' magnetic content. The magnetic-functionalized fibrous adsorbents demonstrated significantly enhanced adsorption efficacy in comparison to their non-functionalized fibrous analogues while their magnetic properties enabled their magnetic recovery and regeneration.

Preparation of polydopamine-modified zeolitic imidazolate framework-8 functionalized electrospun fibers for efficient removal of tetracycline

This work shows a simple and environmental friendly methodology to obtain a kind of polydopamine coating assisted preparation of zeolitic imidazolate framework-8 (ZIF-8) functionalized composite electrospun fiber (ZIF-8/PDA/PAN fibers) adsorbent. Characterization of the composite electrospun fiber was carried out and the tetracycline (TC) adsorption properties from water were also studied in detail. At the same time, principle adsorption mechanisms were thoroughly studied. The results show that the pseudo-second-order model can simulate sorption kinetics well, while sorption isotherms are able to significantly conform to the Freundlich model, and the adsorption capacity of the fibers can reach 478.18 mg/g at 298 K. In addition, the Weber-Morris model indicates that the processes of adsorption of ZIF-8/PDA/PAN fibers for TC involve surface adsorption as well as intraparticle diffusion, and the limit rate step is not only the intraparticle diffusion but also the binding of the sorbate to the sorbent. Moreover, the adsorption efficiency toward TC by ZIF-8/PDA/PAN fibers still reached over 85% of its initial adsorption capacity after five adsorption/desorption cycles, which signified that the adsorbents is stable and recyclable. This work indicates that the obtained ZIF-8/PDA/PAN fibers have practical application prospects in the field of antibiotic adsorption.

Disinfection of water with new chitosan-modified hybrid clay composite adsorbent

Hybrid clay composites were prepared from Kaolinite clay and Carica papaya seeds via modification with chitosan, Alum, NaOH, and ZnCl₂ in different ratios, using solvothermal and surface modification techniques. Several composite adsorbents were prepared, and the most efficient of them for the removal of gram negative enteric bacteria was the hybrid clay composite that was surface-modified with chitosan, Ch-nHYCA_1:5 (Chitosan: nHYCA = 1:5). This composite adsorbent had a maximum adsorption removal value of 4.07 × 10⁶ cfu/mL for V. cholerae after 120 min, 1.95 × 10⁶ cfu/mL for E. coli after ∼180 min and 3.25 × 10⁶ cfu/mL for S. typhi after 270 min. The Brouers-Sotolongo model was found to better predict the maximum adsorption capacity (q_max) of Ch-nHYCA_1:5 composite adsorbent for the removal of E. coli with a q_max of 103.07 mg/g (7.93 × 10⁷ cfu/mL) and V. cholerae with a q_max of 154.18 mg/g (1.19 × 10⁸ cfu/mL) while the Sips model best described S. typhi adsorption by Ch-nHYCA_1:5 composite with an estimated q_max of 83.65 mg/g (6.43 × 10⁷ cfu/mL). These efficiencies do far exceed the alert/action levels of ca. 500 cfu/mL in drinking water for these bacteria. The simplicity of the composite preparation process and the availability of raw materials used for its preparation underscore the potential of this low-cost chitosan-modified composite adsorbent (Ch-nHYCA_1:5) for water treatment.

Enhanced CO2 separation performance of P(PEGMA-co-DEAEMA-co-MMA) copolymer membrane through the synergistic effect of EO groups and amino groups

PEDM copolymer membrane showed excellent gas separation performance through synergistic effect of EO and amino.