Adsorption characteristics of metronidazole on CoZr-LDH and its GO nanocomposite: Experimental and theoretical study

Highlights•First-time synthesis of CoZr-LDH and its composite with graphene oxide (GO) using a green, solventless mechanochemical method alongside hydrothermal synthesis.•Novel adsorption study of metronidazole, a critical environmental antibiotic pollutant, revealing detailed interactions within the CoZr-LDH/GO structure.•Comprehensive evaluation of adsorption capacity, demonstrating the structural benefits and pollutant interaction mechanisms for the first time.•Innovative comparison using quantum calculations and Monte Carlo adsorption locator simulations, applied for the first time to predict and analyze adsorption mechanisms on LDH and LDH/GO surfaces, providing significant insights into adsorption efficiency.AbstractCoZr-LDH and its Graphene Oxide (GO) nanocomposite were synthesized by mechanochemical and hydrothermal methods, respectively, and were applied to absorb metronidazole as a pollutant antibiotic from an aqueous solution. In this study, Tetravalent and divalent metal cations were employed. The LDH and LDH/GO were characterized by SEM, EDS, IR, BET, and XRD analyses. In the adsorption process of metronidazole using both the CoZr-LDH and CoZr-LDH/GO nanocomposite as adsorbents, parameters such as initial solution pH, adsorbent dose, initial drug concentration, and contact time were optimized to obtain the maximum adsorption capacity. The adsorption performance of CoZr-LDH and its nanocomposite with graphene oxide (GO) was thoroughly investigated for the removal of metronidazole (MNZ), a significant environmental contaminant. CoZr-LDH demonstrated optimal adsorption, yielding an experimental qe value of 189.1376 mg g-1. Conversely, the CoZr-LDH/GO nanocomposite exhibited superior adsorption performance under optimum conditions, achieving a remarkable experimental qe value of 906.5688 mg g-1.The adsorption isotherms, including Langmuir, Freundlich, and Redlich-Peterson models, were fitted to the experimental data to describe the interaction mechanisms and surface characteristics. Additionally, kinetic studies involving pseudo-first-order and pseudo-second-order models were performed, revealing critical insights into the adsorption process. Post-adsorption characterization confirmed the successful interaction between MNZ and the adsorbents. This study emphasizes the potential of GO-enhanced CoZr-LDH for effective removal of metronidazole, addressing its status as a critical pollutant in wastewater.To comprehensively study the adsorption process in CoZr-LDH and CoZr-LDH/GO, theoretical analyses were conducted using Monte Carlo computational method. This approach, known for simulating numerous particle trajectories and statistical averaging, allowed for an in-depth examination of adsorption mechanisms under various conditions. The findings, validated against experimental data, enhanced model accuracy and provided deeper insights into adsorption behaviors in complex environments.Graphical abstract