Adsorption isotherm studies of Cd (II), Pb (II) and Zn (II) ions bioremediation from aqueous solution using unmodified and EDTA-modified maize cob

Igwe, J. C.; Abia, A. A.

doi:10.1590/s0100-46702007000100005

Cited by 127 publications

(73 citation statements)

References 32 publications

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“…K f and n values determine the steepness and distortedness of the isotherm (Igwe and Abia 2007). K f represents the parameter of the relative adsorption capacity of adsorbent, and n is the characteristic constant for the adsorption system.…”

Section: Resultsmentioning

confidence: 99%

“…The adsorption enthalpy determines the spontaneity and nature of the adsorption: whether it is exothermic or endothermic (Singh and Srivastava 2001). The lower value 1/n indicates the stronger connection between adsorbate and adsorbent, whereas the higher value K f indicates that the level of removing adsorbate is higher, higher adsorption intensity (Igwe and Abia 2007). The processes in the water-sediment system are influenced by numerous factors.…”

Section: Resultsmentioning

confidence: 99%

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Arsenic distribution in water/sediment system of Sevojno

Aksentijević

Kiurski

Vasić

2011

Environ Monit Assess

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Arsenic is a toxic and carcinogenic element. Its toxicity depends on its oxidation state and its concentration. The aim of this paper is to determine, for the first time, the concentration levels of arsenic in water and sediment during the spring/summer period of 2009 in Sevojno, a region in West Serbia with a long industrial tradition, as well as to determine the model of arsenic distribution in water/sediment system and the level of its compatibility with the existing theoretical model. Adsorption is a continual process in the environment. It plays a very important role in the transport and fate of pollutants, especially in sediment. The adsorption of arsenic was examined using the Freundlich adsorption isotherm.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Arsenic distribution in water/sediment system of Sevojno

Aksentijević

Kiurski

Vasić

2011

Environ Monit Assess

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“…From the isotherm constants, the best isotherm that described better the adsorption Pb(II) is Freundlich isotherm model (Figures 16-18) which showed high Kf values, indicative of the high adsorption capacity and intensity of the nanomaterials. Therefore, kf values for further modified samples (Azeh10 and Azeh-TDI) were found higher than H3PO4 acid modified sample (Azeh2) (Igwe & Abia, 2007). The Temkin equation showed goodness of fit for the adsorption of Cd(II) and Pb(II) ions, but lack the parameter describing the adsorption capacity of any given adsorbent.…”

Section: Adsorption Isothermsmentioning

confidence: 88%

Modified/Unmodified Nanoparticle Adsorbents of Cellulose Origin With High Adsorptive Potential for Removal of Pb(II) From Aqueous Solution

Azeh

Olatunji

Adekola

2017

ESJ

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This investigation was conducted to evaluate the adsorption capacity of nanoparticles of cellulose origin. Nanoparticles were synthesized by acid hydrolysis of microcrystalline cellulose/cellulose acetate using 64% H3PO4 and characterized using FTIR, XRD, TGA-DTGA, BET and SEM analysis. Adsorption kinetics of Pb (II) ions in aqueous solution was investigated and the effect of initial concentration, pH, time, adsorbent dosage and solution temperature. The results showed that adsorption increased with increasing concentration with removal efficiencies of 60% and 92.99% for Azeh2 and Azeh10 respectively for initial lead concentration of 3 mg/g. The effects of contact time showed that adsorption maximum was attained within 24h of contact time. The maximum adsorption capacity and removal efficiency were achieved at pH6. Small dose of adsorbent had better performance. The kinetics of adsorption was best described by the pseudo-second-Order model while the adsorption mechanism was chemisorption and pore diffusion based on intra-particle diffusion model. The isotherm model was Freundlich. Though, all tested isotherm models relatively showed good correlation coefficients ranging from 0.969-1.000. The adsorption process was exothermic for Azeh-TDI, with a negative value of -12.812 X 10 3 KJ/mol. This indicates that the adsorption process for Pb by Azeh-TDI was spontaneous. Adsorption by Azeh2 was endothermic in nature.

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“…This isotherm is based on the assumptions that metal ions are chemically adsorbed on a fixed number of well-defined sites. Each site can hold only one ion (monolayer adsorption), all sites are energetically equivalent (homogeneous surface), and there is no interaction between the ions [34,35]. The linearized Langmuir isotherm allows the calculation of adsorption capacities and the Langmuir constant.…”

Section: Adsorption Isothermmentioning

confidence: 99%