Promoted removal of metformin hydrochloride anti-diabetic drug from water by fabricated and modified nanobiochar from artichoke leaves

Biochars are economic and ecofriendly biosorbents normally prepared from different agricultural or animal wastes with some functional groups that afford strong capability for binding with cationic, anionic or neutral species. In this study, artichoke leaves were subjected to pyrolysis under low oxygen atmosphere to prepare nanobiochar material (Artich-Bch) and additionally modified to load the surface with sodium hydroxide to produce (Artich-Bch-NaOH). The FT-IR of Artich-Bch and Artich-Bch-NaOH confirmed the existence of COOH, OH and C=C functional groups. Five and three thermal decomposition steps were observed by Artich-Bch and Artich-Bch-NaOH at the range of (25-800 degrees C) with weight loss (Total = 81.8%) and (Total = 69.73%), respectively. The performance of biochars for removal of metformin hydrochloride anti-diabetic drug (MFH) from aqueous solution was compared and revealed higher removal results by the modified biochar, Artich-BchNaOH. Various operating factors impacted on the elimination of MFH including shaking time, dose of adsorbents, initial concentration of MFH, pH of MFH solution, temperature of medium and interfering ions. Langmuir, Freundlich, Dubinin-Radushkevitch (D-R) and Temkin were the four applied models of adsorption isotherm for clarifying the elimination process of MFH by Artich-Bch-NaOH. The maximum correlation coefficient (R-2) was achieved by Langmuir model (R-2 = 0.996). The kinetic studies revealed that the pseudo-second-order was the best fit model for explaining the adsorption of (20 mg L-1 MFH) onto Artich-Bch-NaOH based on the attained R-2 value as 0.9999. The values and signs of parameters which acquired from the thermodynamics experiments referred the reaction as spontaneous and exothermic.