Mohammad Saleh Shafeeyan

Exploring Potential Methods for Anchoring Amine Groups on the Surface of Activated Carbon for CO2 Adsorption

Activated carbon can be effectively modified for CO2 adsorption with amine groups due to their high affinity for CO2. Using approaches such as impregnation, some modifiers containing amine groups are physically adsorbed on the surface of carbon, whereas other amine groups can be directly or indirectly chemically bound to the activated carbon matrix. In the context of exploring potential techniques for grafting amine groups onto activated carbon surfaces, we herein review the literature on modifications applied to different materials and supports for a variety of applications, limited to neither activated carbon nor CO2-adsorption applications. We focus on the processes of grafting amine groups and the parameters influencing these processes. Moreover, the mechanism of CO2 adsorption involving amine groups is discussed.

Effects of niobium and molybdenum impregnation on adsorption capacity and Fenton catalytic activity of magnetite

In the present study, a number of modified magnetite samples were prepared by impregnating magnetite with Nb and Mo (Fe3−x−yNbxMoyO4, x + y = 0.2). The characteristics of the samples in terms of durability, crystalline phase, morphology, size, surface area and composition, and magnetic property were determined. Subsequently, the effect of Nb and Mo incorporation on adsorption capacity of magnetite and its activity in heterogeneous Fenton oxidation of methylene blue was investigated. The amount of MB adsorbed on the synthesized samples increased considerably, mainly due to the increase in their specific surface area. In addition, the presence of Nb and Mo significantly improved degradation of MB, especially at higher contents of Nb + Mo. About 90% of MB (100 mg L−1) and 46% of TOC were removed under the studied conditions. MB adsorption and Fenton degradation using synthesized samples were well described by pseudo-second-order and pseudo-first-order equations in kinetics, respectively. The samples demonstrated good durability and insignificant loss of performance in three consecutive experiments. The obtained results verified that Nb and Mo co-incorporation could effectively improve magnetite properties towards higher adsorption and remarkable activity in heterogeneous Fenton process at neutral condition.

Transition Metal-Substituted Magnetite as an Innovative Adsorbent and Heterogeneous Catalyst for Wastewater Treatment

Iron oxides are conventionally used as adsorbent and/or heterogeneous catalyst because of their abundance, easy magnetically separation, affordability, and applicability in broad pH range. This is especially reported for magnetite due to the presence of Fe2+ cations in its structure. However, the pure magnetite has lower adsorption capacity and degradation rate in Fenton reaction, which led to the introduction of transition metal-substituted magnetite (TMSM). This section gives an overview on the adsorption potential and Fenton catalysis performance of various transition metal-substituted magnetite samples. This recently introduced group is produced with incorporation of appropriately identified transition metal/metals into the naturally available magnetite with simple synthesis method. TMSM has showed a great capacity for treating polluted water bodies using physical and chemical processes. A combination of factors affects the activity: the increased adsorption capacity of the samples evidenced by larger surface area, the participation of thermodynamically favorable redox pairs in regeneration of Fe2+ and •OH radical generation, and the presence of oxygen vacancies serving as active sites on the surface of TMSM. Nevertheless, there is a need for further understanding and expansion of this class of adsorbents and heterogeneous catalysts.