Biosorption Kinetic Models on the Removal of Congo red onto Unripe Calamansi (Citrus microcarpa) peels

Abstract

Unripe calamansi peels were prepared and used as a bioadsorbent in the removal of congo red from an aqueous solution using batch adsorption studies. The efficiency of adsorption was evaluated by varying adsorbent dose and contact time. The removal of congo red increased at higher adsorbent dose and longer contact time. The overall rate of adsorption processes appeared to be in accordance with the pseudo-second order reaction mechanism. Higher initial adsorption rate, extent of surface coverage, and activation energy were favored at a lower adsorbent dose, while the intraparticle diffusion was relatively faster at a higher adsorbent dose. The intraparticle diffusion, Elovich, and MacArthur-Wilson models were adequate in describing the chaotic behavior of the kinetic processes involved in the removal of congo red dye onto unripe calamansi peels.

Batch Adsorption Study and Kinetic Profile of Cr(VI) Using Lumbang (Aleurites moluccana)-Derived Activated Carbon-Chitosan Composite Crosslinked With Epichlorohydrin

“…Due to the rapid adsorption of all available sites and a relatively small amount of adsorbent used, removal efficiency of Cr(VI) decreased, an increase in the amount of adsorbent may therefore reverse adsorption trend 28 . The percentage removal of Cr(VI) remarkably increases at an increasing dose until 3 g possibly explained by the increase in the surface area for the metal to bind with the available additional sorption sites 26,28,29 .…”

“…interval using chitosan 25 . Moreover, the uptake of Cr(VI) increases up to a certain threshold and then remains almost unchanged possibly due to the presence of repulsive forces between adsorbate molecules on the solid and bulk phases contributing to the observed moderate rates of adsorption as it approaches the equilibrium 26 . Adsorption curves are single, smooth, and continuous leading to saturation and indicate the possible monolayer coverage 26,27 on the surface of adsorbents by Cr(VI).…”

“…Moreover, the uptake of Cr(VI) increases up to a certain threshold and then remains almost unchanged possibly due to the presence of repulsive forces between adsorbate molecules on the solid and bulk phases contributing to the observed moderate rates of adsorption as it approaches the equilibrium 26 . Adsorption curves are single, smooth, and continuous leading to saturation and indicate the possible monolayer coverage 26,27 on the surface of adsorbents by Cr(VI). Due to the rapid adsorption of all available sites and a relatively small amount of adsorbent used, removal efficiency of Cr(VI) decreased, an increase in the amount of adsorbent may therefore reverse adsorption trend 28 .…”

Adsorption Mechanism of Direct Red on Cellulose Acetate from Ananas Comous Leaves

“…In this system, the adsorption process was controlled by chemisorptions which involved valence forces through sharing or exchange of electrons between the sorbent and the sorbate. 20,26 The adsorption process was conducted as a slow process (Figure. 4).…”

“…Exhaustive exploration on the adsorption kinetics involving wastewater treatment is important to providing better understanding of the reaction pathways and possible mechanisms involved 20 . We are reporting the use of cellulose acetate membrane obtained from leaves of pineapple (Ananas comosus) as an adsorbent to remove direct red in water.…”