Sorption of toxic metal ions by solid sorbents: A predictive speciation approach based on complex formation constants in aqueous solution

2012 ◽  
Vol 256 (1-2) ◽  
pp. 212-221 ◽  
Author(s):  
Valeria Marina Nurchi ◽  
Isabel Villaescusa
2009 ◽  
Vol 97 (4-5) ◽  
Author(s):  
Takayuki Sasaki ◽  
Taishi Kobayashi ◽  
I. Takagi ◽  
Hirotake Moriyama ◽  
A. Fujiwara ◽  
...  

AbstractThe complex formation constants of tetravalent plutonium ion with malonic and succinic acids in aqueous solution were determined by the solvent-extraction method. Also, by taking the known values of the solubility products, the hydrolysis constants and the formation constants, the experimental solubility data of plutonium in the presence of carboxylates were analyzed.


2018 ◽  
Vol 42 (10) ◽  
pp. 7640-7648 ◽  
Author(s):  
Salvatore Cataldo ◽  
Gabriele Lando ◽  
Demetrio Milea ◽  
Santino Orecchio ◽  
Alberto Pettignano ◽  
...  

The leachate humic fraction is a good sequestering agent towards toxic metal ions, influencing their aqueous solution behaviour and their environmental impact.


2016 ◽  
Vol 52 (13) ◽  
pp. 2831-2834 ◽  
Author(s):  
Anindita Chakraborty ◽  
Sohini Bhattacharyya ◽  
Arpan Hazra ◽  
Ashta Chandra Ghosh ◽  
Tapas Kumar Maji

An anionic MOF shows the potential to capture toxic metal ions from water and the CuII@AMOF hybrid obtained through post-synthetic metalation is used as a Lewis acid catalyst.


2020 ◽  
Vol 12 (19) ◽  
pp. 7909
Author(s):  
Minh Trung Dao ◽  
T. T. Tram Nguyen ◽  
X. Du Nguyen ◽  
D. Duong La ◽  
D. Duc Nguyen ◽  
...  

Abundantly available biomass wastes from agriculture can serve as effective environmental remediation materials. In this study, activated biochar was fabricated from macadamia nutshell (MCN) through carbonization and chemical modification. The resultant biochars were used as adsorbents to remove toxic metal ions such as Cu2+ and Zn2+ from aqueous solutions. The results showed that the activated MCN biochar has a high adsorption capacity for toxic metal ions. When MCN biochar was activated with K2CO3, the adsorption efficiencies for Cu2+ and Zn2+ were 84.02% and 53.42%, respectively. With H3PO4 activation, the Cu2+- and Zn2+-adsorption performances were 95.92% and 67.41%, respectively. H2O2-modified MCN biochar had reasonable Cu2+- and Zn2+-adsorption efficiencies of 79.33% and 64.52%, respectively. The effects of pH, adsorbent concentration and adsorption time on the removal performances of Cu2+ and Zn2+ in aqueous solution were evaluated. The results exhibited that the activated MCN biochar showed quick adsorption ability with an optimal pH of 4 and 4.5 for both Cu2+ and Zn2+, respectively.


2021 ◽  
Vol 33 (7) ◽  
pp. 1611-1619
Author(s):  
Ntandokazi Mabungela ◽  
Ntaote David Shooto ◽  
Fanyana Mtunzi ◽  
Eliazer Bobby Naidoo

Discharge of copper(II) and lead(II) ions into rivers and streams by industries and other human activities has gained serious consideration from regulatory bodies. These toxic metals are harmful to human beings and aquatic life when in high concentrations. Therefore, their removal from wastewater is very important. Hence, this work reports the binary adsorption of toxic metal ions of Cu(II) and Pb(II) from aqueous solution by pristine and modified fennel seeds. Pristine fennel seeds (PFS) were treated with acidic and alkaline solutions to develop modified adsorbents designated ATFS and BTFS, respectively. SEM images revealed that PFS had an amorphous surface with irregular cavities. However, upon acid and base treatment, the surface was more refined. The ATFS had interconnected pores while BTFS had somewhat honeycomb pores. The UV-Vis results confirmed that some of the components were removed from PFS during acid and base pre-treatment. FTIR spectra revealed that the adsorbents had functional groups such as (-OH) and (-C=O), which were involved in the uptake of the metal ions. It was observed that the uptake of Cu(II) and Pb(II) ions onto all adsorbents progressively increased when the initial concentration of the solution was increased. The maximum adsorption capacity was obtained when the initial concentration of the solution was 100 mg/L. The uptake of Cu(II) and Pb(II) on PFS was 3.345 and 11.524 mg/g. While for ATFS 3.78 and 13.07 mg/g and BTFS 8.143 and 14.85 mg/g, respectively. It was observed that the isotherm data fitted Freundlich better for the uptake of both metal ions onto all adsorbents. It was observed that there was a rapid uptake when contact time increased from 5 to 60 min. However, when time increased above 60 min the uptake stabilized and reached equilibrium this was due to the saturation of active sites on the surface for all adsorbents. The kinetics study revealed that PSO fitted the data better than PFO. IPD data revealed that the uptake of metal ions was controlled by the synergistic of ESA and EPA. The ΔHº values for Cu(II) and Pb(II) uptake onto all adsorbents were all negative. This suggested that the reactions were exothermic.


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