Biosorption of aquatic cadmium(II) by unmodified rice straw

Incorporation of selectivity factor in modeling binary component adsorption isotherms for heavy metals-biomass system

“…With respect to R L values, all systems exhibit favorable biosorption nature. Moreover, the magnitude of all isotherm parameters obtained in this work agreed well with those reported previously in the literature for metal ion-biomass sorption systems [19][20][21]32,40].…”

“…Graphically, Langmuir isotherm is characterized by a plateau curve, which means that no further adsorption can be occurred when equilibrium established. Originally, this empirical model was developed for describing adsorption phenomena in the gas phase but it had been extensively used for the correlation of adsorption equilibrium data of various solute-sorbent interactions in the liquid phase [19][20][21]. The mathematical form of Langmuir isotherm model is given as follows:…”

“…Although biosorption studies of heavy metal ions in single system using pristine or chemically-modified rice straw have been well reported in the last few years [18][19][20][21], however, the adsorption equilibria aspect of multicomponent system and its modeling still needs to be explored. Several adsorption models such as extended-Langmuir, extended-Freundlich, and ideal adsorption solution theory (IAST) models (e.g.…”

Assessment of the Use of Moringa oleifera Seeds for Removal of Manganese Ions from Aqueous Systems

“…It can be observed that the kinetics of the manganese ion adsorption onto Moringa seeds did not fit the pseudo-first-order kinetic model due to the low R 2 value (0.8297) and the lack of agreement between the calculated q e (1.34 mg g -1 ) and the experimental q e (3.03 mg g -1 ) values. A pseudo-second-order kinetic model also can be derived based on an assumption that the sorption rate is controlled by a chemical sorption mechanism involving electron sharing or electron transfer between the adsorbent and the adsorbate (Ding et al 2012). This can be expressed as,…”

“…where q t and q e (mg g −1 ) are the amounts of metal ions adsorbed per unit mass of the adsorbent at time t (min) and equilibrium, respectively, and k 2 (g mg -1 min −1 ) is the pseudo-second-order rate constant of the sorption process (Ding et al 2012). The graph plotted according to Eq.…”