Desorption of zinc, copper and lead ions from loaded flax fibers

2021 ◽  
pp. 1-34
Author(s):  
Meriem Kajeiou ◽  
Abdellah Alem ◽  
Soumaya Mezghich ◽  
Nasre-Dine Ahfir ◽  
Mélanie Mignot ◽  
...  
Keyword(s):  
Lead Ions ◽  
Flax Fibers

Heavy metals removal by flax fibers to a further use in urban runoff management systems

2020 ◽  
Author(s):  
Meriem Kajeiou ◽  
Abdellah Alem ◽  
Anne Pantet ◽  
Soumaya Mezghich ◽  
Nasre-Dine Ahfir
Keyword(s):  
Heavy Metals ◽  
Low Cost ◽  
Industrial Effluents ◽  
Local Economy ◽  
Lead Ions ◽  
Management Systems ◽  
Flax Fibers ◽  
Metals Removal ◽  
Retention Basin ◽  
Adsorption Rates

<p>Abstract</p><p>Water pollution has long been considered a major problem causing environmental and public health issues. A range of contaminants are encountered in wastewater, industrial effluents and also road runoff, they include total suspended solids, nutrients, hydrocarbons and heavy metals. These latter have been found very toxic and hazardous, either for human health, or fauna and flora. In recent decades, studies have demonstrated a good removal efficiency of heavy metals by adsorption technique, and especially biosorption. Numerous biosorbents have been investigated, mainly lignocellulosic materials which have shown high adsorption capacity. Within this context, this study aims to investigate flax fibers capacity of zinc, copper and lead ions removal from aqueous solutions, in order to examine the best conditions to test a full-scale device designed to treat stormwater runoff. The choice of flax is related to its high availability, low cost and local economy reasons. The device consists of sand and layers of flax fibers geotextiles. It will be placed on a parking at the entrance of a retention basin in Le Havre. For this purpose, batch experiments were carried out with ternary and mono-metal solutions of zinc, copper and lead ions at room temperature with molar concentrations of 0.04 mmol.l<sup>-1</sup>, at pH around 6.4. Biosorption kinetics and biosorption equilibrium were performed and analyzed. The results showed a favorable adsorption for the three metals in the order Pb > Cu > Zn for both types of solutions, with adsorption rates of 94%, 75% and 62% respectively in the ternary metal solution and 94%, 81% and 82% in the mono-metal solutions. The effect of competition was important for zinc, barely visible for copper, and non-existent for lead.</p><p>Keywords: Biosorption, heavy metals, pollutants, stormwater management systems.</p><p> </p>

Binding of calcium and lead ions to carboxystarch prepared by action of nitrogen dioxide on native starch and its 2,3-dialdehyde derivatives

1986 ◽  
Vol 51 (6) ◽  
pp. 1340-1351 ◽  
Author(s):  
Rudolf Kohn ◽  
Karol Tihlárik
Keyword(s):  
Nitrogen Dioxide ◽  
Alkaline Medium ◽  
Binding Capacity ◽  
Lead Ions ◽  
Carbonyl Groups ◽  
Weakly Alkaline ◽  
Exchange Cations ◽  
Counter Ions ◽  
The Stability ◽  
Derivatives Of

The binding of calcium and lead ions to carboxy derivatives of starch prepared by allowing nitrogen dioxide to act on native maize starch (procedure A) and on starch 2,3-dialdehyde derivatives of degrees of oxidation DO(d.a.) ≥ 0.94 (procedure B) was studied. The carboxy group content of the samples in the H+ form was 4.6 - 12.1 mmol g-1. The effect of alkaline medium on the stability of the carboxy derivatives and on their ability to bind and exchange cations was examined. The Ca2+ → 2K+ exchange was evaluated in terms of the decrease in the electrostatic free enthalpy Δ(Gel/N)KCa, determined by alkalimetric potentiometric titrations, and the binding of Pb2+ ions was evaluated in terms of the activity of the Pb2+ counter-ions determined in suspensions of Pb salts of the carboxy derivatives by means of an ion specific electrode. The IR and CD spectra revealed that the carboxystarch preparations obtained by procedure A contained, in addition to free carboxy groups, a considerable amount of carbonyl groups. During the conversion of the latter groups to the former, even in a weakly alkaline medium, the carboxy derivatives undergo an appreciable degradation and lose, to a great extent, their ability to bind and exchange cations. Procedure B, on the other hand, leads to highly selective starch and amylose carboxy derivatives, exhibiting a small amount of carbonyl groups and featuring a relative stability towards alkaline medium; their binding capacity is as high as 12 milliequivalents of cations per g of sample.

Investigation of the Static Behavior and Failure Mechanisms of a 3D Printed Bio-Based Sandwich with Auxetic Core

2020 ◽  
Vol 12 (05) ◽  
pp. 2050051
Author(s):  
Khawla Essassi ◽  
Jean-Luc Rebiere ◽  
Abderrahim El Mahi ◽  
Mohamed Amine Ben Souf ◽  
Anas Bouguecha ◽  
...  
Keyword(s):  
Failure Mechanisms ◽  
Three Dimensional ◽  
Acoustic Emissions ◽  
Shear Stiffness ◽  
Tensile Tests ◽  
Sandwich Composite ◽  
Static Behavior ◽  
Flax Fibers ◽  
Data Points ◽  
3D Printed

In this research contribution, the static behavior and failure mechanisms are developed for a three-dimensional (3D) printed dogbone, auxetic structure and sandwich composite using acoustic emissions (AEs). The skins, core and whole sandwich are manufactured using the same bio-based material which is polylactic acid reinforced with micro-flax fibers. Tensile tests are conducted on the skins and the core while bending tests are conducted on the sandwich composite. Those tests are carried out on four different auxetic densities in order to investigate their effect on the mechanical and damage properties of the materials. To monitor the invisible damage and damage propagation, a highly sensitive AE testing method is used. It is found that the sandwich with high core density displays advanced mechanical properties in terms of bending stiffness, shear stiffness, facing bending stress and core shear stress. In addition, the AE data points during testing present an amplitude range of 40–85[Formula: see text]dB that characterizes visible and invisible damage up to failure.

scholarly journals Preparation of Porous Hydroxyapatite Using Cetyl Trimethyl Ammonium Bromide as Surfactant for the Removal of Lead Ions from Aquatic Solutions

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1617
Author(s):  
Silviu-Adrian Predoi ◽  
Carmen Steluta Ciobanu ◽  
Mikael Motelica-Heino ◽  
Mariana Carmen Chifiriuc ◽  
Monica Luminita Badea ◽  
...  
Keyword(s):  
Cetyl Trimethyl Ammonium Bromide ◽  
Morphological Changes ◽  
Low Cost ◽  
Lead Ions ◽  
Ammonium Bromide ◽  
Porous Hydroxyapatite ◽  
X Ray ◽  
Composition And Structure ◽  
Cetyl Trimethyl Ammonium ◽  
Co Precipitation

In the present study, a new low-cost bioceramic nanocomposite based on porous hydroxyapatite (HAp) and cetyl trimethyl ammonium bromide (CTAB) as surfactant was successfully obtained by a simple chemical co-precipitation. The composition and structure of the HAp-CTAB were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscope (SEM) equipped with an energy dispersive X-ray (EDX) spectrometer, and N2 adsorption/desorption analysis. The capacity of HAp-CTAB nanocomposites to remove the lead ions from aqueous solutions was studied by adsorption batch experiments and proved by Langmuir and Freundlich models. The Pb2+ removal efficiency of HAp-CTAB biocomposite was also confirmed by non-destructive ultrasound studies. The cytotoxicity assays showed that the HAp-CTAB nanocomposites did not induce any significant morphological changes of HeLa cells after 24 h of incubation or other toxic effects. Taken together, our results suggests that the obtained porous HAp-CTAB powder could be used for the decontamination of water polluted with heavy metals, such as Pb2+.

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