Adsorption of fluoride, arsenate and phosphate in aqueous solution by cerium impregnated fibrous protein

Batch adsorptive removal of benzoic acid from aqueous solution onto modified natural vermiculite: Kinetic, isotherm and thermodynamic studies

“…In region I, the protonation of amine groups on the adsorbent surface leads to the consumption of hydronium cations and consequently, the equilibrium solution pH increases [52]. In region II, the release of part of hydronium cations into the adsorption medium as well as the competition between benzoate anions and hydroxide anions (at pH values higher than 7.0) for the vacant adsorption sites and consequently, the consumption of hydroxide anions are responsible for the decrease in solution pH after equilibrium [53].…”

Physico-chemical characterization of metal-doped bone chars and their adsorption behavior for water defluoridation

“…4, where the intraparticle diffusion is present in adsorption process but it is not the rate controlling step. 2 ] in all adsorbents but at different grades of crystallinity. Note that after surface modification of bone char, the crystal structure changed depending on the doping metal.…”

“…It has been estimated that over 260 million people worldwide consume groundwater with fluoride concentrations higher than the international threshold value (i.e., 1.0-1.5 mg/L) for preventing dental and skeletal fluorosis [1][2][3]. This context has encouraged the development of effective and low-cost processes for water defluoridation [3][4][5].…”

Adsorption performance and mechanism of As(V) uptake over mesoporous Y–Al binary oxide

“…Therefore, the adsorption of arsenate on the Y-Al surface was regarded as pseudo-second-order kinetic model rather than pseudo-first-order. And it was reasonably assumed that "surface reaction" is the rate-determining step, which may be a chemical sorption involving valence force and ion exchange [30][31][32] .…”