Colloids and Surfaces A: Physicochemical and Engineering Aspects 611 (2021) 125791 Available online 24 October 2020 0927-7757/© 2020 Elsevier B.V. All rights reserved. Biomass-derived porous aminated graphitic nanosheets for removal of the pharmaceutical metronidazole: Optimization of physicochemical features and exploration of process mechanisms Ziaeddin Bonyadi a, 1 , FarzanehAkhound Noghani a, 1 , Aliakbar Dehghan a , Jan Peter van der Hoek b , Dimitrios A. Giannakoudakis c, *, Seid Kamal Ghadiri d, *, Ioannis Anastopoulos e , Maryam Sarkhosh a , Juan Carlos Colmenares c , Mahmoud Shams a, * a Social Determinants of Health Research Center, Mashhad University of Medical Sciences, Mashhad, Iran b Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Delft, the Netherlands c Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland d Department of Environmental Health Engineering, School of Public Health, Shahroud University of Medical Sciences, Shahroud, Iran e Department of Chemistry, University of Cyprus, P.O. Box 20537, CY-1678 Nicosia, Cyprus G R A P H I C A L ABSTRACT A R T I C L E INFO Keywords: Metronidazole Adsorption Amine-modifed green-graphene RSM Hospital wastewater Regeneration ABSTRACT The presence of trace levels of pharmaceutically active compounds (PhACs) in the aquatic environment threatens human health and the environment. Metronidazole (MNZ) is a soluble PhAC with low biodegradability, a possible human mutant and carcinogen. This study aimed the synthesis, physicochemical characterizations, and employment of porous amine-modifed green-graphene (AMGG) for MNZ removal from aqueous solutions. Response-surface methodology (RSM) based on Box-Benken design (BBD) was used to assess the MNZ adsorption effciency of AMGG as a function of pH (4–12), contact time (5–60 min), AMGG dose (0.1–1 g/L) and MNZ concentration (10–100 mg/L). From the model optimization, the highest MNZ removal was predicted at a pH of 5.9, a contact time of 27 min, an AMGG dose of 0.86 g /L, and an MNZ concentration of 100 mg /L. The experimental data were in agreement with the pseudo-second order kinetic model and the Langmuir isotherm model. The maximum adsorption capacity of AMGG for MNZ was 416.7 mg/g. The MNZ concentration at equilibrium increased about 4.8 mg/L when the solution temperature increased by 20 oC (from 30 to 50 ◦ C), indicative of an exothermic process. AMGG showed an effciency decrement from 84 % to 57 %, after fve * Corresponding authors. E-mail addresses: dagchem@gmail.com (D.A. Giannakoudakis), kamalgh2005@gmail.com (S.K. Ghadiri), ShamsMH@mums.ac.ir (M. Shams). 1 These authors are co-frst author with equal contribution. Contents lists available at ScienceDirect Colloids and Surfaces A: Physicochemical and Engineering Aspects journal homepage: www.elsevier.com/locate/colsurfa https://doi.org/10.1016/j.colsurfa.2020.125791 Received 1 September 2020; Received in revised form 10 October 2020; Accepted 17 October 2020