Two–three parameters isotherm modeling, kinetics with statistical validity, desorption and thermodynamic studies of adsorption of Cu(II) ions onto zerovalent iron nanoparticles

Abstract

Adsorption of problematic copper ions as one of the endocrine disruptive substances from aqueous solution onto nanoscale zerovalent iron (nZVI) was studied. The high pore size 186.9268 Å, pore diameter 240.753 Å, and BET surface area 20.8643 m2 g−1 and pH(pzc) enlisted nZVI as an efficient nano-adsorbent for treatment of heavy metals from synthetic wastewater. SEM and EDX revealed the morphology and elemental distribution before and after adsorption. 98.31% removal efficiency was achieved at optimum adsorption operational parameters. Of all the thirteen isotherm models, equilibrium data were well fitted to Langmuir. Kinetics and mechanism data across the concentrations from 10 to 200 mg L−1 were analyzed by ten models. PSO best described kinetics data as confirmed by various statistical error validity models. The intraparticle diffusion model described that the intraparticle diffusion was not the only rate-limiting step. The adsorption mechanism was diffusion governed established by Bangham and Boyd models. Feasible, spontaneous, endothermic, and degree of randomness were reveal by the thermodynamic studies. Better desorption index and efficiency were obtained using HCl suggesting multiple mechanism processes. The performance of ZVI suggested it has a great potential for effective removal of endocrine disruptive cationic contaminant from wastewater.

Preparation and characterization of rice husk activated carbon-supported zinc oxide nanocomposite (RHAC-ZnO-NC)

“…The synthesis of ZnO nanocomposites was carried out by slight modification to the method as described in our previous studies [ 7 , 11 , 12 , 13 , 14 ]. 1.5 M (NH 4 ) 2 CO 3 solution was stirred vigorously with 5 g as-prepared RHAC.…”

Effect of Modified Surface of Cotton Straw Nanocellulose and Their Application for Removal of Lead from Aqueous Solution

“…As with the Sips equation, the parameter n is therefore stated to describe the heterogeneity of the system (Chilev et al, 2022). According to the Elovich model, the chemical processes that cause adsorption form the basis of the adsorption mechanism (Dada et al, 2021). The fundamental reason for the development of the Baudu isotherm model was the discovery of a difference in the calculation of the Langmuir coefficient and constant from the slope, a tangent over a wide range of concentrations.…”

The Flory–Huggins Isotherm and Water Contaminant Adsorption: Debunking Some Modeling Fallacies

“…In this contribution, we set out to prove that the mathematical form of the FH isotherm as used in water contaminant adsorption research is fallacious because it has been inappropriately linearized. This erroneous form of the FH isotherm can be found in all the articles listed in Table as well as the reviews cited above. − Furthermore, we draw attention to another fallacy concerning the use of faulty equilibrium constants derived from the linearized FH isotherm to calculate the Gibbs free energy change.…”

“…Since the mid-2000s, many studies have reported the modeling of water contaminant adsorption by means of the FH isotherm. Table presents a selection of such studies published across a broad spectrum of scholarly journals. − As can be seen in Table , the experimental isotherms of numerous water contaminants, ranging from toxic metals to organic compounds, have been described by the FH isotherm. The inclusion of the FH isotherm in several reviews has no doubt promoted its use in this field of research. − …”