Synergy of adsorption and visible light-induced photocatalytic degradation of doxycycline by cellulose modified CuAl...

The problem of antibiotic-induced water pollution has attracted public attention in the modern world. Antibiotics have the capacity to cause massive hazardous damage at very low dosages due to their long-lasting biological stability. To address this issue, a new highly stable, reusable, greener, nontoxic, easily accessible composite material (CuAl-LDH/CL) consisting of Cellulose (CL) modified CuAl-layered double hydroxide was successfully synthesized. The fabricated photocatalyst was extensively studied for its optical, structural, and morphological properties using XRD, Raman, HR-TEM, FE-SEM, FTIR, BET, and UV-visible DRS methods. The CuAl-LDH/CL composite possesses a synergistic effect of adsorption and photocatalysis in the elimination of doxycycline (DOX) antibiotics from wastewater systems. The detailed thermodynamic information (ΔG = -24.27 KJ mol^-1) including adsorption maximum capacity q_max (150.16 mg/g), adsorption equilibrium constant (k = 0.18 × 10⁵ M^-1), and adsorption efficiency (40.36 %) along with degradation rate constant (k = 0.0116 min^-1) and degradation efficiency (96.2 %) was evaluated. The pathways of DOX degradation were also examined using HR-MS analysis. An adsorption-photocatalytic synergistic reaction mechanism was postulated, in addition to TOC testing and active species detection. The combination of cellulose and LDH is proposed in this work as a potential strategy for the efficient removal of harmful pollutants from wastewater.