Adsorption Behavior of Methyl Orange onto Wheat Bran : Role of Surface and pH

Application of N‐Doped MoS2 Nanocrystals for Removal of Azo Dyes in Wastewater

“…The results could be well explained by previous studies which revealed that pH has an impact not only on the surface charge of the adsorbent but also on the structure of an MO molecule , . Under acidic conditions, MO formed several mono‐protonated zwitterionic structures.…”

“…Under acidic conditions, MO formed several mono‐protonated zwitterionic structures. With the pH increasing to more basic conditions, the MO molecule rearranged and formed negatively charged species , . On the other hand, the surface of the adsorbent would be positively or negatively charged due to excess cations or anions in acidic or basic solution, respectively .…”

Adsorption of Nickel Ions from Petroleum Wastewater onto Calcined Kaolin Clay: Isotherm, Kinetic and Thermodynamic Studies

“…The high removal rate was due to the large surface area initially available for adsorption of Ni(II) ions but the capacity of the adsorbent was gradually exhausted over time since the occupation of the few vacant surface sites that remained was inhibited due to repulsive forces between the solute molecules in the solid and bulk phases [9]. As the adsorption sites on the surface become exhausted, the uptake rate is controlled by the rate at which the nickel ions are transported from the exterior to the interior sites of the adsorbent particles [10]. It was reported that during the adsorption of metal ions, initially the Ni(II) ions reach the boundary layer; then have to diffuse onto the surface of the adsorbent and finally, must diffuse into its porous structure.…”

Sol-Gel Synthesis of NiO Nanoparticles and Investigation on Adsorption Capacity in the Removal of Cr(VI) from Aqueous Solution

“…In the other words, the second linear portion is due to intra-particle diffusion or pore diffusion. Therefore, the slope of the second linear portion of the plot has been considered the k ip 26,27 .…”