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•Efficient grafting of hydrazinyl amine on chitosan-coated magnetite.•High sorption capacity for divalent metals at near neutral pH.•Sorption isotherms are fitted by Sips ...equation.•Sorbent can be reused for at least 5 cycles using 0.5 M HCl as eluent.•Selectivity for Pb(II) for decontaminating multi-metal stormwater.
The sorption properties of a functionalized magnetic chitosan sorbent have been investigated for the recovery of Ni(II) and Pb(II) from aqueous solutions. This material was prepared by one-pot co-precipitation of chitosan with formation of magnetic core, followed by a series of grafting steps to immobilize hydrazinyl amine derivative at the surface of chitosan layer. The physico-chemical characteristics of this composite material were investigated using FTIR, XRD, XPS, thermogravimetric, titration, elemental analyses. In a second step, the sorbent was tested for heavy metal sorption on synthetic solutions through the study of pH effect, sorption isotherms and uptake kinetics, selective sorption (in function of pH), metal desorption and sorbent recycling. Sorption isotherms were modeled using the Sips equation while the uptake kinetics was fitted by the pseudo-second order rate equation. The sorption capacity reached 4.3 mmol Ni g−1 and 2.5 mmol Pb g−1 but the sorbent was more selective to Pb(II) over Ni(II), especially in acidic conditions. The decrease in sorption capacity at the fifth cycle does not exceed 8%. In the final step of the study, the sorbents were successfully applied for metal recovery from multi-metal synthetic solution and from a contaminated stormwater collected in a local mining area.
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•Functionalization of magnetic-chitosan microparticles for chromate removal.•High efficiency and selectivity for imidazole carboxamide derivative.•Sorption capacities as high as ...6 mmol Cr g−1, at pH 2 (including Cr(VI) reduction).•Sips and pseudo-first order rate equations for isotherm and kinetic fitting, resp.•Highly efficient Cr desorption with 0.5 M HCl and sorbent recycling (5 cycles).
Textile and tannery industries are highly contaminating with discharge of high Cr concentrations. Developing bio-based sorbents with strong affinity for chromate, fast kinetics, and high recyclability is strategic for better reuse of industrial wastewater. Magnetic chitosan micro-particles (MC, for enhancing mass transfer) may constitute a solution for chromate removal from acidic solutions. The functionalization of this support with aminothiazole groups (ATA@MC) or imidazole carboxamide (AIC@MC) significantly improves chromate removal, with sorption capacities close to 6 mmol Cr g−1, at pH 2. The Langmuir and the Sips equations finely fit sorption isotherms, while the pseudo-first order rate equation fits well uptake kinetics (equilibrium within 60 min). Sorption and desorption properties are remarkably stable: sorption efficiency decreases by less than 6% at the fifth cycle (while the desorption efficiency maintains above 99%). The sorbents are highly selective for chromate removal from acidic tannery wastewater (against base metals). FTIR and XPS analyses are used for characterizing the materials and for identifying the binding mechanisms (including chromate reduction into Cr(III)). The sorbents are both showing promising performances for Cr(VI) removal in acidic solutions, including in very complex solutions such as tannery wastewater. AIC@MC is more selective for Cr(VI) removal, while ATA@MC has a broader reactivity for a wider family of metal ions. The antimicrobial properties of the functionalized sorbents are characterized by the determination of the zone of inhibition (ZOI) against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli and Candida albicans: the inhibition is slightly improved compared with magnetite chitosan microparticles. More generally, the Gram- bacteria are slightly more sensitive to the functionalized sorbents than Gram+ bacteria and Candida fungus.
Efficient removal of Cd(II) and Pb(II) from contaminated water is considered a fundamental point of view. Synthetic hydrogel biopolymers based on chitosan and alginate (cost-effective and ...eco-friendly) were successfully designed and characterized by highly efficient removal contaminants. The sorbents are characterized by FTIR, SEM-EDX, TGA, XPS analyses and textural properties which are qualified by N
adsorption. The sorption properties are firstly investigated by the effect of pH, sorption isotherms, uptake kinetics, and selectivity from multi-metal solution with equi-molar concentration. The sorbent with 1:3 ratios (of chitosan and alginate respectively) is the most effective for metal removal (i.e., 0.81 mmol Cd g
and 0.41 mmol Pb g
). Langmuir and Sip's models fitted better the adsorption isotherms compared to the Freundlich model. Uptake kinetics was well fitted by pseudo-first-order rate equation, while the saturation was achieved within 40 min. The sorbent shows good reproducibility through duplicate the experiments with negligible decreasing efficiency (>2.5%). The sorbent was applied for water treatment on samples collected from the industrial area (i.e., 653 and 203 times over the MCL for Cd(II) and Pb(II) respectively according to WHO). The concentration of Cd and Pb was drastically decreased in the effluents as pH increased with removal efficiency up to 99% for both elements at pH 5.8 and SD equivalent 1 g L
for 5 h.
A new series of thieno2,3-
1,2,4triazolo1,5-
pyrimidines was designed and synthesized using readily available starting materials, specifically,
-enaminoester. Their cytotoxicity was screened against ...three cancer cell lines, namely, MCF-7, HCT-116, and PC-3. 2-(4-bromophenyl)triazole
and 2-(anthracen-9-yl)triazole
afforded excellent potency against MCF-7 cell lines (IC
= 19.4 ± 0.22 and 14.5 ± 0.30 μM, respectively) compared with doxorubicin (IC
= 40.0 ± 3.9 μM). The latter derivatives
and
were further subjected to in silico ADME and docking simulation studies against EGFR and PI3K and could serve as ideal leads for additional modification in the field of anticancer research.
The recovery of strategic metals such as rare earth elements (REEs) requires the development of new sorbents with high sorption capacities and selectivity. The bi-functionality of sorbents showed a ...remarkable capacity for the enhancement of binding properties. This work compares the sorption properties of magnetic chitosan (MC, prepared by dispersion of hydrothermally precipitated magnetite microparticles (synthesized through Fe(II)/Fe(III) precursors) into chitosan solution and crosslinking with glutaraldehyde) with those of the urea derivative (MC-UR) and its sulfonated derivative (MC-UR/S) for cerium (as an example of REEs). The sorbents were characterized by FTIR, TGA, elemental analysis, SEM-EDX, TEM, VSM, and titration. In a second step, the effect of pH (optimum at pH 5), the uptake kinetics (fitted by the pseudo-first-order rate equation), the sorption isotherms (modeled by the Langmuir equation) are investigated. The successive modifications of magnetic chitosan increases the maximum sorption capacity from 0.28 to 0.845 and 1.25 mmol Ce g−1 (MC, MC-UR, and MC-UR/S, respectively). The bi-functionalization strongly increases the selectivity of the sorbent for Ce(III) through multi-component equimolar solutions (especially at pH 4). The functionalization notably increases the stability at recycling (for at least 5 cycles), using 0.2 M HCl for the complete desorption of cerium from the loaded sorbent. The bi-functionalized sorbent was successfully tested for the recovery of cerium from pre-treated acidic leachates, recovered from low-grade cerium-bearing Egyptian ore.
A new magnetic functionalized derivative of chitosan is synthesized and characterized for the sorption of metal ions (environmental applications and metal valorization). The chemical modification of ...the glycine derivative of chitosan consists of: activation of the magnetic support with epichlorohydrin, followed by reaction with either glycine to produce the reference material (i.e., Gly sorbent) or glycine ester hydrochloride, followed by hydrazinolysis to synthesize the hydrazide functionalized sorbent (i.e., HGly sorbent). The materials are characterized by titration, elemental analysis, FTIR analysis (Fourrier-transform infrared spectrometry), TGA analysis (thermogravimetric analysis) and with SEM-EDX (scanning electron microscopy coupled to energy dispersive X-ray analysis). The sorption performances for U(VI), Cu(II), and Zn(II) are tested in batch systems. The sorption performances are compared for Gly and HGly taking into account the effect of pH, the uptake kinetics (fitted by the pseudo-second order rate equation), and the sorption isotherms (described by the Langmuir and the Sips equations). The sorption capacities of the modified sorbent reach up to 1.14 mmol U g
, 1.69 mmol Cu g
, and 0.85 mmol Zn g
. In multi-metal solutions of equimolar concentration, the chemical modification changes the preferences for given metal ions. Metal ions are desorbed using 0.2 M HCl solutions and the sorbents are re-used for five cycles of sorption/desorption without significant loss in performances.
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•The sulfonation of algal/PEI composite beads produce very efficient sorbent for Sc.•The sorption process is fast (30–40 min equilibrium time).•At pHeq ~ 4, the maximum sorption ...capacity reaches 2.68 mmol Sc g−1.•Rare earth elements totally desorbed using HCl/CaCl2, with good sorbent recycling.•REEs strongly enriched onto S-ALPEI after the treatment of a red mud solution.
The one-pot synthesis of algal biomass/polyethyleneimine beads, ALPEI (electrostatic interaction followed by calcium ionotropic gelation), produces a stable sorbent whose sorption properties for rare earth elements (REEs) are significantly improved by functionalization. The grafting of sulfonic groups (S-ALPEI), which have high affinity for REEs, increases sorption capacities as high as 2.68 mmol Sc g−1, 0.61 mmol Ce g−1 and 0.53 mmol Ho g−1, at pH close to 4 (equilibrium pH). Sorption isotherms are fitted by the Langmuir equation for scandium and cerium; for holmium, the Freundlich and the Sips equations show better fits. Sorption occurs within 30–40 min; kinetic profiles are fitted by the pseudo-first order rate equation and the Crank equation (resistance to intraparticle diffusion). The sorbent has a marked preference for Sc(III) against Ce(III) and Ho(III) (confirmed by selectivity tests). The sorbent is also selective for REEs against alkali-earth elements. The three metals are readily desorbed (within 20–30 min) using HCl/CaCl2 solution. Desorption remains higher than 99% for 5 cycles while sorption performance is decreased by less than 6% at the fifth cycle. The sorbent is tested for the recovery of valuable metals from red mud solution at different pH values. Despite the large excess of heavy metals in the industrial solution, S-ALPEI shows a good affinity for REEs at pH close to 3.46 with important enrichment factors (in the range 19–118 depending on the metal). The material is fully characterized by BET, TGA, FTIR, XPS, elemental analysis, titration and SEM-EDX analysis. The sorption involves different mechanisms (on amine and sulfonic groups) including electrostatic attraction and chelation depending on pH and metal speciation.
Modification of steroid molecules by introducing heterocyclic ring into the core structure of steroids has been utilized as an attractive approach for either cancer prognosis or diagnosis. Several ...new cholestanoheterocyclic steroids were synthesized, and analytical and spectral data proved the validity of the novel synthesized steroid derivatives. The cytotoxicity of synthesized compounds
3
,
4
,
5
,
7
,
9
,
10
,
13
,
15b
, and
16b
was evaluated using human colorectal cancer HCT 116 and Caco-2, cervical cancer HeLa, hepatoma HepG2, and breast cancer MCF7 cell lines. Intriguingly, compound
13
has the highest cytotoxic effect when applied on the majority of cancer cells. In conclusion, compound
13
may be considered as a promising anticancer candidate against all cancer cell lines, because it recorded the lowest IC
50
of the majority of the cancer cell lines used. Furthermore, a molecular docking study was employed to determine the binding modes against aromatase cytochrome P450 (CYP19), cyclin-dependent kinase 2 (CDK2), and B-cell lymphoma (BCL-2) proteins, which are major proteins involved in the pathogenesis of cancer. Molecular docking analyses revealed that compounds
13
,
3
, and
5
(free energy of binding = − 9.2, − 9.1, and − 9.0 kcal/mol, respectively) were the best docked ligand against aromatase CYP19; compounds
16b
,
3
,
9
, and
10
(free energy of binding = − 9.6, − 9.3, and − 9.2 kcal/mol, respectively) were the best docked ligand against CDK2, while compounds
15b
,
16b
, and
13
(free energy of binding = − 9.1, − 9.0, and− 8.7 kcal/mol, respectively) were the best docked ligand against BCL2. In conclusion, compounds
3
,
13
, and
16b
were the most promising compounds with the lowest IC
50
s against most of the tested cancer cell lines, and they displayed the lowest binding energies, critical hydrogen bonds, and hydrophobic interactions with the three molecular targets compared to other tested compounds.
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