Sulfadiazine removal with low-cost structured nano and micro-composite hydrogel beads on moroccan clays with alginate-CMC-biochar.

Abstract

The primary goal of the current work was to construct pH-sensitive nano and microcomposite hydrogel beads based on alginate (AL), carboxymethyl cellulose (CMC), biochar (BC), and two Moroccan clays: Ghassoul (swelling SW) and red (not swelling NSW) nano and microhybrid. The adsorbents, SW + AL, SW + AL + BC, SW + AL + CMC, NSW + AL, NSW + AL + BC, NSW + AL + CMC, AL, and AL + CMC were prepared for the adsorption of the antibiotic sulfadiazine (SDZ). The test samples were characterized using a variety of techniques, including X-Ray Diffraction (XRD), IR spectroscopy (FT-IR), and scanning electron microscopy (SEM), with the molecular structures of the studied additives geometrically optimized using the DFT/B3LYP method and the function 6-311G(d). Molecular electrostatic potential (MEP) and Mulliken charge analysis were utilized to estimate the adsorption sites of the additives under study, with conformational analysis using Monte Carlo (MC) simulations and Hirshfeld surface (HS) analysis to gain a better understanding of the SDZ's adsorption process on the clay and polymer surfaces through its sulfonyl, amino, and carboxylate groups. The study found that SW + AL + CMC beads had a maximum adsorption capability of 800 μmol/kg for SDZ. Furthermore, this composite demonstrated more than 100% adsorption and 0% subsequent desorption. The findings of this study point to the possibility of using SW + AL + CMC nanocomposite for SDZ removal, which would be useful for the environment and public health.