Adsorption of metal ions on lignin

Abstract

This study investigated the adsorption of the heavy metal ions Pb(II), Cu(II), Cd(II), Zn(II), and Ni(II) on a lignin isolated from black liquor, a waste product of the paper industry. Lignin has affinity with metal ions in the following order: Pb(II) > Cu(II) > Cd(II) > Zn(II) > Ni(II). The adsorption kinetic data can be described well with a pseudosecond-order model and the equilibrium data can be fitted well to the Langmuir isotherm. Metal ion adsorption was strongly dependent on pH and ionic strength. Surface complexation modelling was performed to elucidate the adsorption mechanism involved. This shows that lignin surfaces contain two main types of acid sites attributed to carboxylic-and phenolic-type surface groups and the phenolic sites have a higher affinity for metal ions than the carboxylic sites.

Adsorption Studies on Rhodamine-B Removal from Aqueous Solution Using Acid Activated Strychnos Nux-Vomica Leaf Powder

“…Pseudo-first-order and pseudo-second-order equations can be used assuming that the measured concentrations are equal to surface concentrations 13 . The pseudo-first-order rate lagergren model is 14 : dq = k 1 , ads(q e -q) dt Where, q (mg/g) is the amount of adsorbed heavy metals on the adsorbent at time t and k 1 , ads (min -1 ) is the rate constant of first-order adsorption 15 [17][18][19][20][21][22][23][24][25][26] q e the equilibrium sorption uptake, is extrapolated from the experimental data at time t = infinity. A straight line of log(q e -q) versus t suggests the applicability of this kinetic model.…”

“…Chem Sci Trans., 2018, 7(1), [17][18][19][20][21][22][23][24][25][26] Where, R is the universal gas constant (8.314 JK -1 mol -1 ), T is the absolute temperature (Kelvin) and K represents the equilibrium adsorption constants of the isotherm fits (K L , Langmuir equilibrium constant and K f , Freundlich equilibrium constant, which must be converted to SI units, by using the molecular mass of the RB dye) obtained from the isotherm plots. ∆H o and ∆S o values can be calculated from the slope and intercept of the linear plot of ln(K) versus 1/T.…”

“…Besides, it is consistent with the dehydration of dye molecule before its adsorption to carbon surface, and the releases water molecules to the bulk solution. The increase in the adsorption capacities of adsorbent at higher temperatures may be attributed to the enhanced mobility and penetration of dye molecules within the adsorbent porous structures by overcoming the activation energy barrier and enhancing the rate of intra-particle diffusion 24 . …”

Removal of lead(II) ions by an adsorption process with the use of an advanced SiO2/lignin biosorbent

“…Lead nitrate, Pb(NO 3 Prepared solutions of lead(II) ions (100 mL) in various concentrations were placed in conical fl asks, and the silica/lignin hybrid sorbent was added to the model solution. The solution was mixed with the adsorbent using a magnetic stirrer (Ika Werke GmbH, Germany).…”

Copper (II) Removed from Aqueous Solutions by Aminated Bagasse Pith

“…These metals, such as Cu, Pb, Cr and Zn, are toxic. Their presence could cause some diseases [1][2][3][4]. For restoration, a lot of effective methods are used to remove polluted ions [5,6].…”