Comments on “Removal of methylene blue dye using nano zerovalent iron, nanoclay and iron impregnated nanoclay – a comparative study” by M. M. Tarekegn, R. M. Balakrishnan, A. M. Hiruy and A. H. Dekebo, RSC Adv., 2021, 11, 30109

Abstract

The study mentioned in the title of this comment paper contains some calculations/results that disagree with some basic chemistry concepts.

Removal of pharmaceuticals from wastewater: a review of different adsorptive approaches

“…Numerous methods, such as computer simulation, rapid-small scale column tests, and response surface methodology, can be used to carry out scale-up research. According to researcher (Lima et al 2021), full-scale field testing conducted under various continuous-flow circumstances are the most effective method for predicting the long-term performance of adsorption systems. In order to optimise crucial operating parameters including breakthrough curves, conduct and mass transfer zones, pilot scale column studies should be carried out.…”

Improper Estimation of Thermodynamic Parameters in Adsorption Studies with Distribution Coefficient KD (qe/Ce) or Freundlich Constant (KF): Considerations from the Derivation of Dimensionless Thermodynamic Equilibrium Constant and Suggestions

“…Similar to the Gibbs energy change of reaction (Equation ( 17)), the Gibbs energy change of adsorption process (ΔG ads ) is commonly expressed as Equation ( 18) [2]. By replacing Gibbs energy changes (ΔG Adsorbent-Adsorbate , ΔG Adsorbent , and ΔG Adsorbate ) by chemical potentials (μ Adsorbent-Adsorbate , μ Adsorbent , and μ Adsorbate , respectively), Equation (18) becomes Equation (19).…”

“…Therefore, it cannot be directly applied as the constant K Eq o for calculating the thermodynamic parameters. This problem has been intensively discussed in the literature [2, 7, 18–21, 84–86].…”

“…Meanwhile, the Freundlich model is more suitable for describing adsorption processes that do not reach a strict plateau region in adsorption isotherms. In essence, adsorption isotherms describe the relationship: q e = f(C e ) [18]. Simultaneously, many scholars give some critical comments on this problem [7,[19][20][21].…”

From molecular salt to layered network: cation-driven tuning of band gap, structure, and charge transport in A3Bi2I9 (A = Cs, Rb) perovskites

“…The burgeoning demand for environmentally sustainable and stable optoelectronic materials has prompted intensive exploration into lead-free alternatives, particularly in the realm of halide perovskites. [1][2][3][4][5][6][7][8][9][10] Among these, all-inorganic lead-free halide perovskites have emerged as promising candidates owing to their potential for high performance and reduced environmental impact. [11][12][13] These materials have shown versatility beyond traditional applications, including their potential utility in advanced X-ray detection technologies.…”