Equilibrium and kinetic studies of Cr (VI) removal from synthetic wastewater by Acroptilon repense flower powder

Abstract

In this study the removal of Cr (VI) from synthetic wastewater was investigated using Acroptilon repens (Russian Knapweed) fl ower powder under various conditions (pH, contact time and initial concentration of Cr). The capacity of chromium adsorption at equilibrium conditions by this biosorbent was increased by adsorbate concentration. The results also showed that the removal effi ciency of Cr (VI) was increased by increasing the contact time. By increasing the initial concentration of Cr (VI) solution, chromium removal was reduced. The suitability of adsorbents and their constants was tested or evaluated with the Langmuir, Freundlich and Temkin isotherms models. The results indicated that the Freundlich and Langmuir models (R 2 > 0.99) gave a better concordance to the adsorption data in comparison with the Temkin equation (R 2 = 0.97). The adsorption of Cr (VI) followed the pseudo-second-order kinetics (R 2 = 0.991). The study showed that Acroptilon repens fl ower powder can be used as an effective lignocellulosic biomaterial and biosorbent for the removal of Cr (VI) from wastewater.

Adsorption of humic acid from aqueous solutions onto shellfish ash: Kinetic and isotherm studies and artificial neural network modeling

“…(5) (5). where q e is the amount of HA adsorbed per unit mass of adsorbent (mg/g), K f is the adsorption capacity (mg/g), C e is the solute concentration (mg/L), and n is the adsorption intensity (g/L) (31).…”

“…Where K t is the binding constant which represents the maximum binding energy (L/mg) and B T is related to the heat of adsorption (kJ/mol) (31). K t and B T parameters are calculated based on the slope and intercept of the plot of q e against lnC e , respectively (28,32,33).…”

“…Where k 1 is the rate constant in the pseudo-first-order (1/ min). q e and q t are the adsorption equilibrium capacity (mg/g) and the amount of HA adsorbed at time t (mg/g), respectively (31). The constant and adsorption capacity were determined by plotting of ln (q e −q t ) versus time (5,35).…”

“…The pseudo-second-order model is based on the assumption that the adsorption follows chemisorptions (31,34). Its linear form is described by Eq.…”

Chromate ion removal by water‐soluble functionalized chitosan

“…Several methods and materials have been developed for environmental clean‐up and remediation of chromium from wastewater and synthetic wastewater, such as adsorption, 11‐14 biomaterials, 15,16 nanocomposites, 17 ion exchange, 18 membrane separation 19‐21 . All methods have advantages and disadvantages; however, ion exchange and adsorption are well studied since they are efficient for heavy metal recovery and water deep purification.…”