Enhanced surface modification of Fe-metal organic gel with cold plasma as an eco-friendly alternative for the separation of antibiotics.

As an effective and widely used technique for removing antibiotics from water, the adsorption process is limited by hazardous issues encountered with the chemicals used for the surface chemistry enhancement, low adsorption capacity, and environmental safety concerns associated with the regeneration capability of the used adsorbents. Here, surface modification of the synthesized Fe-metal organic gel (Fe-MOG) was performed via dielectric barrier discharge (DBD) plasma treatment to enhance the adsorption efficiency. Fe-MOG modified with plasma (Fe-MOG/plasma) exhibited increased active sites and enhanced affinity toward Cefixime (FIX) and Ceftriaxone (CTX) antibiotics compared to the bare Fe-MOG. Adsorption capacity using Fe-MOG/plasma indicated 203.72 mg g-1 and 141.91 mg g-1 for FIX and CTX, respectively. We also evaluated the effect of pH, drug concentration, adsorbent dosage, and temperature on the adsorption of FIX and CTX using both Fe-MOG and Fe-MOG/plasma. Furthermore, the adsorption isotherm and kinetic models, as well as the thermodynamic analyses, were studied. Subsequently, the adsorbent was regenerated using methanol and DBD-plasma, demonstrating the potential for repeated use. The results showed that the cold plasma is a practical and eco-friendly method for the surface modification and regeneration of the adsorbents based on metal-organic gels.