Probing the interaction effects of metal ions in Mn_xFe_(3−x)O₄ on arsenite oxidation and adsorption

Abstract

Modelling the interaction effects of manganese, and iron species in magnetite nanoparticles on trivalent arsenic adsorption and oxidation to less toxic pentavalent species.

Hydroprocessing of oleic acid for production of jet fuel range hydrocarbons over Sn(1)‐Fe(3)‐Cu(13)/SiO2‐Al2O3 catalyst: Process parameters optimization, kinetics, and thermodynamic study

“…Adequate precision of a model is the ratio of its signal and noise. A ratio greater than 4 is desirable, indicating that the regression model is sufficient to navigate the design space 49–51 . Adequate precisions of 24.83 and 15.69 were obtained for the reduced cubic oleic acid conversion model and reduced quadratic selectivity model as shown in Tables 6 and 7, respectively.…”

“…A ratio greater than 4 is desirable, indicating that the regression model is sufficient to navigate the design space. [49][50][51] Adequate precisions of 24.83 and 15.69 were obtained for the reduced cubic oleic acid conversion model and reduced quadratic selectivity model as shown in Tables 6 and 7, respectively. This indicates that the two models can be used to navigate the design.…”

Oxidative sorption of arsenite from water by iron: a mechanistic perspective

“…Though nano-sized metal oxides exhibit higher oxidativesorption behavior due to larger surface areas, separation of these particles after treatment is a time consuming, tedious process. 140,141 To maintain the large surface areas but aide post-treatment, magnetic nanoparticles possessing superparamagnetic properties have been developed. Magnetite contains both Fe 2+ and Fe 3+ species at octahedral sites and doping of Mn could yield enhanced magnetic properties within a bimetallic oxide.…”

“…142 Thus, magnetic Fe–Mn binary metal oxides could be easily recovered from the treated water using an external magnetic field. Ouma and Ofomaja 141 studied the influence of varying the ratio of Fe 2+ : Fe 3+ and level of Mn doping in the Mn x Fe (3− x ) O 4 adsorbent to remove As( iii ) through central composite design of the response surface methodology. Removal of As( iii ) was positively influenced by the interaction between Fe 3+ and Mn, negatively impacted by the Fe 2+ and Fe 3+ species, and insignificant for the interaction between Fe 3+ and Mn.…”

“…Removal of As( iii ) was positively influenced by the interaction between Fe 3+ and Mn, negatively impacted by the Fe 2+ and Fe 3+ species, and insignificant for the interaction between Fe 3+ and Mn. 141 Further, increasing the doping level of Mn in magnetite could improve the oxidation of As( iii ) species and also increase the adsorption sites for the removal of resulting As( v ) species. Finally, shell and core structured magnetic metal oxides containing maghemite and Fe–Mn binary metal oxide, respectively, with a particle size of 20–50 nm resulted in effortless separation from the solution through the saturation magnetization of 23.2 emu g −1 .…”