Mechanisms and chemistry of dye adsorption on manganese oxides-modified diatomite

Microcolumn studies of dye adsorption onto manganese oxides modified diatomite

“…From the experimental curves, it is also evident that, in order to saturate the MOMD, higher volumes of RB solution, contrast with, smaller volumes of MB and RY are necessary. It was evident that the predominant adsorption mechanism of RB is adsorption in the octahedral layers [22]. This could be explained in that the exhaustion point was not attained (maximum of 75% C 0 effluent concentration after 50 mL).…”

“…Breakthrough curve of adsorption of RB onto MOMD using microcolumn. Experimental conditions: mass of MOMD, 0.1 g; initial reactive dye concentration, 64.81 mg/L; flow rate, 3.77 mL/min; pH 2; particle size, 106-250 m; temperature, 20 • C. results in Al-Ghouti et al [22] in which the main RB mechanism onto MOMD is by intercalation in the octahedral layers and the rate limiting-step might be intraparticle diffusion. The same behaviour was also obtained by Chu [17].…”

Utilization of diatomite/chitosan–Fe (III) composite for the removal of anionic azo dyes from wastewater: Equilibrium, kinetics and thermodynamics

“…In the acidic solution, the protonation of -SO3 -groups could shift the -SO 3 Na of 2GL dye molecule to form -SO 3 H, resulting in formation of -NH 2 + SO 3 -or =NH + SO 3 - [11,31]. Moreover, Huang et al [32] reported that the adsorption process was an electrostatic interaction between anionic azo dye and the protonated amine groups of chitosan on the adsorbent [1].…”

Adsorption mechanism of copper and lead ions onto graphene nanosheet/δ-MnO2

“…The changes in peak at 1120 cm À1 can represent alcohols, OeH stretching in phenolic groups, hydroxyl groups on metal oxides (M À OH) or CeO stretching of eCOOH due to the hydroxyl group complexes of Pb(II) or Cu(II) with the sites [21]. The band variety at 525 cm À1 can be ascribed to the MneO vibrations of MnO 2 [31]. Therefore, the peak shifts sorption confirm the hydroxyl groups on the adsorbent surface are involved in the Cu(II) or Pb(II) adsorption.…”