scholarly journals Efficacy of Alkaline-Treated Soy Waste Biomass for the Removal of Heavy-Metal Ions and Opportunities for Their Recovery

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7413
Author(s):  
Laura Bulgariu ◽  
Daniela Ionela Ferţu ◽  
Irina Gabriela Cara ◽  
Maria Gavrilescu

In this study, soy waste biomass (SW) resulting from oil extraction was treated with alkaline solution, and the obtained material (Na-SW) was used as biosorbent for the removal of Pb(II), Cd(II), and Zn(II) ions from aqueous media. The performance of this biosorbent was examined in batch systems, at different initial metal ion concentrations and contact times (pH 3.4; 5 g of biosorbent/L). Isotherm and kinetic modeling was used to calculate the equilibrium and kinetics of the biosorption processes. The maximum biosorption capacity, calculated from the Langmuir isotherm model, followed the order Zn(II) (0.49 mmol/g) > Cd(II) (0.41 mmol/g) ≈ Pb(II) (0.40 mmol/g), while the kinetics of biosorption processes fit the pseudo-second-order model. Three cycles of biosorption/desorption were performed to estimate the reusability of Na-SW biosorbent, and the regeneration efficiency was higher than 97% in all cases. The practical applicability of Na-SW biosorbent in treating of wastewater contaminated with Pb(II), Cd(II), and Zn(II) ions was examined using simulated wastewater samples, and the main quality characteristics of the effluents obtained after treatment were evaluated. All these aspects highlight the potential applicability of Na-SW for large-scale wastewater treatment.

2019 ◽  
Vol 31 (12) ◽  
pp. 3035-3040
Author(s):  
Sazmal Effendi Arshad ◽  
Zarina Amin ◽  
Perng Yang Puah ◽  
Mohd Sani Sarjadi ◽  
Baba Musta ◽  
...  

Organic-inorganic hybrid polymers have been demonstrated to be an efficient technique for the adsorption of pollutants present in water. Silica gel adsorbent has been applied in this field due to promising characters, such as thermally stable, reusability and high metal ion adsorption capacities. Here, silica gel supported acrylonitrile functional group (silica-APTS-DPN) was reacted with hydroxylamine to yield silica gel supported amidoxime ligand (SBA). All the functionalized silica gel adsorbents were characterized by FTIR. In terms of metal ions adsorption, SBA revealed good absorption capacities towards both copper (Cu2+) (172 mg g-1) and iron (Fe3+) (168 mg g-1) ions at pH 6 and followed the order of Cu2+ > Fe3+. Increased pH condition was beneficial for both metal ions adsorption. The adsorption kinetics of both ions followed the pseudo-first-order model within 0-60 min of adsorption time. Langmuir and Freundlich isotherm models were both applied to study the adsorption behaviour, Freundlich isotherm model (R2 > 0.99) proved to be a better fit, which propose that multilayer adsorption occurred on the silica gel grafted with amidoxime ligand. Finally, this study proved that the silica gel supported amidoxime ligand was successfully applied as an absorbent for the removal of both copper and iron from aqueous media.


Author(s):  
Neetu Tewari ◽  
P Vasudevan

The adsorption of Hexavalent chromium [Cr (VI)] from aqueous solution by raw baggase was studied as a function of initial pH, contact time, dose, concentration and temperature. The optimum initial pH for Cr (VI) uptake was 2.0. At the optimal conditions, Cr (VI) uptake was increased as the dose of adsorbent; the initial metal ion concentration and temperature were increased. Adsorption was fast initially and within the first 30 minutes of contact, the adsorption of Cr (VI) on baggase showed a total uptake of 84.4%. The adsorption data fitted well to Langmuir isotherm model. The maximum adsorption of baggase was found to be 9.4 mg/g. The kinetics of the adsorption was found to be pseudo-second-order. Thermodynamic parameters like activation energy, Gibbs free energy change, enthalpy and entropy were also evaluated. The values for activation energy and enthalpy were found to be 13.4 and 10.7 kJ/mol. Adsorption was found to be endothermic.


2011 ◽  
Vol 8 (2) ◽  
pp. 887-895 ◽  
Author(s):  
Mohammad S. Tawfiq Makki ◽  
R. Mohammady Abdel-Rahman ◽  
K. Ommar Alfooty ◽  
Mohammad S. El-Shahawi

Two new thiazolidinone steroids namely sulfadiazino-imino- steroid (I) and 3-sulfonamoyl-phenyl-spiro[4-oxo-thiazolidin-2, 2`steroid](II)were prepared and characterized from their molecular weight determination and spectroscopic measurements. CompoundIIwere physically immobilized onto polyurethane foams (PUFs) for the preconcentration of cadmium(II) from acidic aqueous media containing iodide ions. The kinetics of the retention step of cadmium(II) from aqueous solutions by compoundIItreated PUFs was studied. Particle diffusion was the most probable operating mechanism and did not control the kinetics of cadmium(II) retention by compoundIIimmobilized PUFs. A preconcentration / separation procedure is presented for the solid phase extraction of trace cadmium(II) from aqueous media as its ternary complex ion associate with compoundIIin industrial wastewater samples onto compoundIItreated PUFs prior to determination by flame atomic absorption spectrometry (FAAS). Compound II treated PUFs sorbent was successfully packed in glass column for complete extraction and / or determination of trace concentrations of cadmium(II) in wastewater samples with satisfactory recovery (95±2.6). The cyclic voltammetry of compoundIIshowed two well defined irreversible redox couples and suggested its possible use as complexing agent in stripping voltammetric determination of trace concentrations of toxic metal ions in wastewater.


2012 ◽  
Vol 27 (2) ◽  
pp. 139-145 ◽  
Author(s):  
Dong XU ◽  
Jun ZHANG ◽  
Gang LI ◽  
Penny XIAO ◽  
Paul WEBLEY ◽  
...  

1990 ◽  
Vol 55 (8) ◽  
pp. 1984-1990 ◽  
Author(s):  
José M. Hernando ◽  
Olimpio Montero ◽  
Carlos Blanco

The kinetics of the reactions of iron(III) with 6-methyl-2,4-heptanedione and 3,5-heptanedione to form the corresponding monocomplexes have been studied spectrophotometrically in the range 5 °C to 16 °C at I 25 mol l-1 in aqueous solution. In the proposed mechanism for the two complexes, the enol form reacts with the metal ion by parallel acid-independent and inverse-acid paths. The kinetic constants for both pathways have been calculated at five temperatures. Activation parameters have also been calculated. The results are consistent with an associative activation for Fe(H2O)63+ and dissociative activation for Fe(H2O)5(OH)2+. The differences in the results for the complexes of heptanediones studied are interpreted in terms of steric factors.


Nephron ◽  
2021 ◽  
pp. 1-7
Author(s):  
Ilaria Godi ◽  
Anna Lorenzin ◽  
Silvia De Rosa ◽  
Gianlorenzo Golino ◽  
Maira Knust ◽  
...  

<b><i>Introduction:</i></b> A critical point for using blood purification during sepsis may be the potential interaction with antimicrobial therapy, the mainstay of sepsis treatment. The aim of our study was to investigate the vancomycin removal during hemoperfusion (HP) using HA380 cartridge. <b><i>Methods:</i></b> This is an experimental study, in which 500 mL of solution was circulated in a closed-circuit (blood flow of 250 mL/min) simulating HP ran using HA380. Vancomycin was added to reach a through concentration or a very high concentration to evaluate the removal ratio (RR) during 120 min of HP. Comparison between blood-crystalloid solution and balanced solution was performed by using Kruskal-Wallis test. The kinetics of vancomycin removal and the adsorption isotherm were evaluated. <b><i>Results:</i></b> We found a complete removal of vancomycin at baseline through concentration of 23.0 ± 7.4 mg/L. Using extremely high concentration (baseline 777.0 ± 62.2 mg/L), RR was 90.1 ± 0.6% at 5 min and 99.2 ± 0.6% at 120 min. No difference in terms of RR was found between blood-crystalloid mixture and balanced solution. The kinetics of the vancomycin reduction followed an exponential decay. Repeated boluses (total amount of 2,000 mg) resulted in cumulative adsorption of 1,919.4 mg with RR of 96.6 ± 1.4%, regardless of the amount injected (100 vs. 500 mg). Vancomycin adsorption onto HA380 followed the Langmuir isotherm model. <b><i>Conclusions:</i></b> A considerable amount of vancomycin was rapidly removed during in vitro HP with HA380. Clinical studies are needed to determine whether this may lead to underdosing. Drug therapeutic monitoring is highly recommended when using HA380 for blood purification in patients receiving vancomycin.


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