Synthesis, characterization, and adsorption properties of phenolic hydroxyl group modified hyper-cross-linked polymeric adsorbent

Equilibrium and kinetic adsorption study of the adsorptive removal of Cr(VI) using modified wheat residue

“…Values of intercept C i give an idea of the thickness of the boundary layer; i.e., the larger the intercept, the greater the boundary layer effect [46]. If intraparticle diffusion is involved in the adsorption process, then the plot of q t versus t 1/2 will be linear; and if these lines pass through the origin, then the rate-limiting process is due only to the intraparticle diffusion [47]. In this model, it is assumed that the mechanism for a solid-liquid adsorption process involves the following four steps: (i) the migration of solute from the bulk solution to the adsorbent's surface via bulk diffusion, (ii) the transport of solute molecules or ions from the boundary layer toward the external surface of the adsorbent through film diffusion, (iii) solute transfer from the exterior surface of the adsorbent to the interior pores of the particle through a pore diffusion or intraparticle diffusion mechanism, and (iv) adsorption of the adsorbate molecules or ions onto the interior surface of the adsorbent by chemical reaction via ion exchange, complexation, and/or chelation.…”

Methylene blue adsorption by the waste of Abu-Tartour phosphate rock

“…where q is the amount adsorbed (mg/g) at time t. This model has been successfully applied to various adsorption systems [49][50][51]. It can be seen from Eq.…”

Surface chemical modification on hyper-cross-linked resin by hydrophilic carbonyl and hydroxyl groups to be employed as a polymeric adsorbent for adsorption of p-aminobenzoic acid from aqueous solution

“…That is, p-aminobenzoic acid is a weak acid and has its own ionization equilibrium (Scheme s2), it will be ionized to be a negative ion as the solution pH is higher than 3.79, whereas the amino group will accept a proton and it will be presented as a positive ion as the solution pH is lower than 3.79. The fact that the maximum adsorption capacity of p-aminobenzoic acid presents at solution pH of 3.79 indicates that molecular form of p-amniobenzoic acid is suitable for the adsorption [33]. In addition, it is observed that the adsorption is greatly reduced as the pH is higher or lower than 3.79, and the basic solution (pH > 6.0) is especially unfavorable for the adsorption, which reveals that the carboxyl group of p-amniobenzoic acid is important for the adsorption, and this in turn implies that the formaldehyde carbonyl and quinone carbonyl groups on HJ-Y10 resin are helpful for the adsorption.…”