▎ 摘　　要

Tetracycline (TC) as an antibiotic with high consumption causes the spread of contamination in an aqueous solution. In recent decades, antibiotics are the main cause of hindering the growth of microorganisms. Also, they are one of the important groups of pharmaceuticals with extensive usage in human and veterinary medicine. In the first work of its kind, we used a suitable adsorbent of biodegradable hydroxyethylcellulose (HEC) with graphene oxide (GO) by crosslinking ethylene glycol dimethacrylate (EGDMA) and the Fe/Zn with mole ratio 1:1 bimetallic nanoparticles with HEC-GO support. The materials were identified using FTIR, FE-SEM, EDX, TEM, and TG-DSC analyses. The factors affecting the adsorption process (contact time, initial concentration of TC, solution pH, adsorbent dosage, and reaction temperature) were evaluated in a series of batch systems. The adsorption data showed that the high adsorption capacity was obtained on the HEC-GO and HEC-GO/Fe-Zn (mole ratio 1:1) nanocomposites at pH 3. Also, the contact time as the main factor affecting the adsorption process by adsorbents was investigated and the best contact time was 100 and 20 min. The TC removal per-centages of both adsorbents were 85% and 95% for HEC-GO and HEC-GO/Fe-Zn, respectively. The maximum adsorption capacity for TC was evaluated by the isotherm models. The experimental data fitted well with the Langmuir model. In addition, pseudo-first-order, pseudo-second-order, intraparticle diffusion, and the Elovich models were applied to kinetic data. The data indicated that TC adsorption on HEC-GO and HEC-GO/Fe-Zn (mole ratio 1:1) followed the pseudo-second-order kinetic model. The thermodynamic parameters implied that the adsorption process was spontaneous and exothermic. Nano-biocomposite (HEC-GO/Fe-Zn) can be used as an adsorbent to remove water pollutants.