Comparison of Modifiers for Coal Gangue Biochar Modification to Improve the Absorption of Heavy Metals from Aqueous Solution

Abstract

In this paper, gangue Coal biochar GCC was developed to absorb heavy metals from an aqueous solution. There is currently insufficient information on the identification of the best biochar modifiers for the purpose of removing heavy metals as well as changes in physicochemical and morphological compositions after modification. For this purpose, after physical treatment GCC ware modified with 5 different offending chemical methods (GCCacidic), (GCCalkaline), (GCCoxidic), (GCCMnOx), and (GCCFeOx). Physical and chemical changes in Both modified and unmodified GCC properties were investigated by using (XRF), (FT-IR), (XRD), (SEM-EDX), and (BET) assortment. Adsorption tests of 3 heavy metals (Cu, Pb, and Cd) ions under different conditions, ion concentration, pH, Adsorbent dosage, and contact time were investigated in batch experiments. Improved post-modification GCC properties, especially (GCCalkaline) and (GCCMnOx) Significant changes in its surface area as well as functional groups (hydroxyl group, and Manganese oxide group). To will know adsorption capacity of every modified GCC, experimental data were placed in Langmuir and Freundlich’s isotherms models. The GCC process follows pseudo-second-order and pseudo-first-order kinetic curves with linear regression. GCC modified with Manganese oxide shows it has the best adsorbent for adsorption of Pb and GCC modified with alkaline is the best adsorbent for adsorption of Cd and Cu metals. For adsorption of mixed metals solution (Pb, Cd, and Cu) GCCMnOx was more suitable than other GCC and modified GCCs biochars. The results show that GCC modified with an acidic component is the worst attraction for removing heavy metals from an aqueous solution. HIGHLIGHTS Coal gangue modified with 5 deferent chemical methods Acidic, alkaline, oxidic, MnOx, and FeOx Physicochemical Properties and heavy metals removals Competition of adsorbent Coal gangue modified with MnOx and alkaline improves their functions group, surface area and better for heavy metals removal, and the worst was modified Coal gangue with Acidic GRAPHICAL ABSTRACT