Equilibrium and kinetic studies in adsorption of heavy metals using biosorbent: A summary of recent studies

2009 ◽  
Vol 162 (2-3) ◽  
pp. 616-645 ◽  
Author(s):  
Jonathan Febrianto ◽  
Aline Natasia Kosasih ◽  
Jaka Sunarso ◽  
Yi-Hsu Ju ◽  
Nani Indraswati ◽  
...  
Keyword(s):  
2013 ◽  
Vol 67 (11) ◽  
pp. 2622-2629 ◽  
Author(s):  
Chandima Gunawardana ◽  
Ashantha Goonetilleke ◽  
Prasanna Egodawatta

The research study discussed in the paper investigated the adsorption/desorption behaviour of heavy metals commonly deposited on urban road surfaces, namely, Zn, Cu, Cr and Pb, for different particle size ranges of solids. The study outcomes, based on field studies and batch experiments, confirmed that road deposited solids particles contain a significantly high amount of vacant charge sites with the potential to adsorb additional heavy metals. Kinetic studies and adsorption experiments indicated that Cr is the most preferred metal element to associate with solids due to the relatively high electronegativity and high charge density of trivalent cation (Cr3+). However, the relatively low availability of Cr in the urban road environment could influence this behaviour. Comparing total adsorbed metals present in solids particles, it was found that Zn has the highest capacity for adsorption to solids. Desorption experiments confirmed that a low concentration of Cu, Cr and Pb in solids was present in water-soluble and exchangeable form, whilst a significant fraction of adsorbed Zn has a high likelihood of being released back into solution. Among heavy metals, Zn is considered to be the most commonly available metal among road surface pollutants.


2014 ◽  
Vol 7 (1) ◽  
Author(s):  
O. Olaofe ◽  
S. A. Olagboye ◽  
P. S. Akanji ◽  
E. Y. Adamolugbe ◽  
O. T. Fowowe ◽  
...  
Keyword(s):  

1978 ◽  
Vol 51 (2) ◽  
pp. 613-617 ◽  
Author(s):  
Kiyochika Yahikozawa ◽  
Toshiro Aratani ◽  
Ryuzo Ito ◽  
Takataro Sudo ◽  
Takeo Yano

2019 ◽  
Vol 1 ◽  
pp. 167-175
Author(s):  
L Leke ◽  
T H Dekaa ◽  
S O Olawuyi ◽  
F O Nwosu

The presence of heavy metals was analysed from oil samples employing the dry ashing method. The specific densities and viscosities of the spent and virgin AZ oil samples were determined and found to be 0.9230, 0.9501 and 70.27, 73.27cP respectively. Kinetic and thermodynamic studies of the adsorption of lead (Pb) and chromium (Cr) from the spent oil was also investigated. The spent oil samples were digested and mixed with methyl isobutyl ketone (MIBK), agitated with activated carbon produced from Thevetia peruviana (bush milk) shells at various contact times of 2, 4, 5, 10, 15, 20, 30, 40, 50, 60, 90 and 120 minutes. Kinetic studies revealed that for lead (Pb), the rate constants were found to be 0.044, 0.060 and 0.067 ppm/min at 27oC, 35 oC and 45 oC, respectively, while higher values or rate constants of 0.126, 0.127 and 0,168 ppm/min were observed at 27 oC, 35 oC and 45 oC, respectively, for chromium (Cr). For the thermodynamic studies the Gibb's free energy (ΔG) values were; –1.29, -1.61 and –1.82 KJmol-1at 27 oC, 35 oC and 45 oC, respectively, indicating spontaneity. However, the Gibb's free energy (ΔG) for chromium showed +0.050, -2.13 and -2.14 KJmol-1at 27 oC, 35 oC and 45 oC, indicating non-spontaneity at 27 oC. The positive values of ΔS for both metals with Pb (21 - 30 Jmol-1) and Cr (695 – 1867 Jmol-1 ) indicated that the metals were dissociatively adsorbed onto the adsorbent while for the E values, Cr (8 – 61 KJmol-1) had a higher than with Pb (6 – 35 KJmol-1) further explaining the non-spontaneity of the process for Cr at some reaction condition.


2010 ◽  
Vol 113-116 ◽  
pp. 632-638
Author(s):  
Feng Yu Li ◽  
Xiao Mei Sun ◽  
Bu Hai Li

Batch adsorption experiments were carried out to remove heavy metals Cu(II)and Ni(II) by pyromellitic dianhydride (PMDA) grafted β-Cyclodextrin (β-CD). The effects concerning the pH of the solution, contact time and initial heavy metal concentration were studied and discussed. The adsorption values increased significantly after a large number of carboxyl groups were gragfted on the microspheres surface. In order to investigate the mechanism of sorption, adsorption data were modeled using the pseudo-first-order and pseudo-second-order kinetic equation. It was found that kinetic studies showed good correlation coefficients for a pseudo-second-order kinetic model, confirming that the sorption rate was controlled by chemical adsorption. The equilibrium process was better described by the Langmuir isotherm than the Freundlich isotherm. XPS analysis further confirmed that the carboxyl group which grafted on the surface of the β-CD microspheres play a very important role in the removal of heavy metals.


Author(s):  
HUDA N AL-ANI

Objective: Chelating therapy is a medical procedure that involves the administration of chelating agents to remove heavy metals from the body; chelating agents detoxify heavy metals and toxins, converting them to inactive forms which were excreted out from the body. This work demonstrates the complication of the drug with toxic heavy metal lead (Π) ion. Methods: All the experiments were performed at different temperature (303, 308, 313, 318, and 323) °K, by spectrophotometric method. The electronic spectra of the mixture of drug and lead ion show a bathochromic (red) shift in ʎmax, the absorbance change caused by a complex arrangement between the lead ion and drug. Results: The stoichiometry of the complex formed was calculated using continuous variation method, it was found (1:2) that the durability constant was estimated that the standard thermodynamic parameters ΔH°, ΔG°, and ΔS° were determined, the negative values of free energy changes ΔG° indicate a spontaneous complexation process. The positive values of enthalpy change indicate an endothermic process with an increase in entropy change ΔS° (positive), that means the process in an entropy driven. Conclusion: The kinetic studies of the complexation of drug and ion were found to follow the second-order reaction, which was confined by the straight line and a high rate constant.


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