Rapid adsorption of Cd2+ and Cu2+ onto nZVMn depends on operational parameters.
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Kinetics and isotherm models were validated by sum of square error (SSE) and non-linear chi-square (χ2) statistical models.
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Kinetics data fitted well to pseudo second-order and the mechanism was pore diffusion controlled.
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Desorption index and efficiency are valid parameters for confirmation of regeneration of loaded nZVMn.
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Renaissance of nZVMn via the desorption studies was best achieved using HCl.
Abstract
Nanostructured zerovalent manganese (nZVMn) was successfully synthesized and characterized by a combination of analytical and spectroscopic techniques. nZVMn was utilized in scavenging of Cd (II) and Cu (II) ions from aqueous solution. The BET surface area of nZVMn was 131.3490 m2/g, adsorption average pore width (170.4736 Å), BJH Adsorption average pore diameter (185.147 Å), and pH(pzc) (5.01). The scavenging process was found to depend on effect of various adsorption physicochemical parameters investigated in batch process. The results revealed a fast kinetics for the adsorption systems; the data fitted well to pseudo second-order and the mechanism was governed by pore diffusion confirmed by Bangham model. The equilibrium data were tested with Langmuir, Freundlich, Temkin, Dubinin-Raduskevuch (D-R), and Halsey Isotherm models. However, equilibrium data were best interpreted by Langmuir and Freundlich isotherm models. Both Kinetic and isotherm models were validated by sum of square error (SSE) and non-linear chi-square (χ2). The Langmuir monolayer maximum adsorption capacities of nZVMn for adsorption of Cd2+ and Cu2+ were 116.28 mg/g and 181.82 mg/g respectively and these superseded several other adsorbents reported. The feasibility, spontaneous and endothermic nature of the adsorption process was unraveled from thermodynamics parameters. Judging from the desorption index and efficiency, effective desorption of loaded nZVMn was achieved using HCl which is further supported chemisorption mechanism. The micrographs of Scanning Electron Microscopy (SEM) before and after adsorption further confirmed the liquid scavenging of the adsorption process. This study unraveled the effective adsorption of Cd2+ and Cu2+ onto novel nZVMn from synthetic industrial waste
