Matrix-type certified reference materials for quality control of metal determination from solid environmental and vegetation samples

In the context of monitoring environmental factors, metals are one of the major analytical components. Applying appropriate determination methods and obtaining accurate results is a requirement imposed on environmental laboratories that perform quality control of water, soil, waste or vegetation. This study presents some examples of certified reference materials for quality control of the results of toxic metal determination from solid environmental and vegetation samples. The analyzed and verified metals were As, Cd, Cr, Cu, Ni, Pb and Zn. The pre-treatment of the samples, the determination methods of metals and the obtained results are also presented. Inductively Coupled Plasma Optical Emission Spectrometry (ICP-EOS) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) techniques are suitable for low metal concentrations, while ICP-EOS and Flame Atomic Absorption Spectrometry (FAAS) methods can be used at high concentrations

Different routes of MgAl–LDH synthesis for tailoring the adsorption of Pb(II) pollutant from water

In this study, new adsorbents based on MgAl–LDHs were synthesized using combined precipitation (co-precipitation) route by modifying temperature and ageing time synthesis parameters, thus tailoring the adsorption capacity of Pb(II) ions from water. The synthesized materials were characterized by SEM, FTIR, XRD and $\text{N}_2$ adsorption–desorption techniques, highlighting the specific lamellar structure of layered double hydroxides (LDHs), as well as the functional groups present on the adsorbent’s surface. The maximum adsorption capacity for Pb(II) ions was 1151.97 mg/g for the MgAl–LDH synthesized at 55 °C and aged for 24 h. Sorption of Pb(II) ions occurs not only through co-precipitation in the form of characteristic compounds, $\text{Pb(OH)}_2$, $\text{PbCO}_3$ or $\text{Pb}_3(\text{CO}_3)_2(\text{OH})_2$, but also by complexation with surface hydroxyl groups

Different routes of MgAl–LDH synthesis for tailoring the adsorption of Pb(II) pollutant from water

In this study, new adsorbents based on MgAl–LDHs were synthesized using combined precipitation (co-precipitation) route by modifying temperature and ageing time synthesis parameters, thus tailoring the adsorption capacity of Pb(II) ions from water. The synthesized materials were characterized by SEM, FTIR, XRD and $\text{N}_2$ adsorption–desorption techniques, highlighting the specific lamellar structure of layered double hydroxides (LDHs), as well as the functional groups present on the adsorbent’s surface. The maximum adsorption capacity for Pb(II) ions was 1151.97 mg/g for the MgAl–LDH synthesized at 55 °C and aged for 24 h. Sorption of Pb(II) ions occurs not only through co-precipitation in the form of characteristic compounds, $\text{Pb(OH)}_2$, $\text{PbCO}_3$ or $\text{Pb}_3(\text{CO}_3)_2(\text{OH})_2$, but also by complexation with surface hydroxyl groups

Spectrophotometric determination of Ru(III) using rhodanine

1019-1020A simple and direct spectrophotometric method using 2-thion-thiazolid-4-one has been developed for determination of Ru (III).Molar absorptivity and Sandell' s sensitivity are calculated to be 6.5555×103 L mol-1 cm-1 and 0.0154 μg cm-2 respectively. The effect of various parameters including time, pH and volume of reagent has been studied. The Beer's law is obeyed over the range 0.202-6.873 μg of Ru(III). The method has been applied for the determination of Ru(III) in various synthetic and real samples

Adsorptive removal of cadmium and copper from water by mesoporous silica functionalized with N-(aminothioxomethyl)-2-thiophen carboxamide

International audienceCopper and cadmium ions were removed from aqueous solutions by adsorption onto a new organic-inorganic hybrid material. N-(aminothioxomethyl)-2-thiophen carboxamide (TAC) was covalently anchored on SBA-15 mesoporous silica. Various characterization techniques [X-ray diffraction, nitrogen adsorption-desorption, thermogravimetric analysis, 29Si, 13C nuclear magnetic resonance (NMR), and Fourier-transform infrared (FTIR) spectroscopy] have proved that the organic ligand was successfully anchored and the ordering of the inorganic support was preserved during the chemical modifications. Metal cations in aqueous solution were adsorbed onto this material with multichelating atoms by a complexation mechanism. Adsorption capacity for the divalent copper and cadmium cations were 0.74 and 0.21 mmol g−1, respectively. Cu(II) was selectively eliminated from contaminated water with Cu(II) and Cd(II). TAC-functionalized silica sorbent presented a good regeneration capacity without significantly losing its adsorption capacity and could be used for the development of an in-flow wastewater purification technology

Spectrophotometric study of binary system Bi(III)-solochrom violet RS and determination of Bi(III)

1101-1102A simple and direct spectrophotometric method using solochrom violet RS has been developed for determination ofBi(III). The molar absorbtivity and the sandell's sensitivity are calculated to be 1.5 x 104 1-mol-1 cm-1 and 0.0114 mg-cm-2 respectively. The effect of various parameters including time. pH and added reactant volume have been studied. The Beer's law is obeyed over the range 0.42-7.52 mg /ml of Bi(lII). The method has been applied for the determination of Bi(III) in various alloys and salt-water samples

Mesoporous silica functionalized with 1-furoyl thiourea urea for Hg(II) adsorption from aqueous media

International audienceNew organic–inorganic hybrid materials were prepared by covalently anchoring 1-furoyl thiourea on mesoporous silica (SBA-15). By means of various characterization techniques (X-ray diffraction, nitrogen adsorption–desorption, thermogravimetric analysis, and FTIR spectroscopy) it has been established that the organic groups were successfully anchored on the SBA-15 surfaces and the ordering of the inorganic support was preserved during the chemical modifications. The hybrid sorbents exhibited good ability to remove Hg(II) from aqueous solution. Thus, at pH 6, the adsorption capacity of mercury ions reached 0.61mmolg−1

Cu(II) and Mn(II) Anchored on Functionalized Mesoporous Silica with Schiff Bases: Effects of Supports and Metal–Ligand Interactions on Catalytic Activity

New series of Cu(II) and Mn(II) complexes with Schiff base ligands derived from 2-furylmethylketone (Met), 2-furaldehyde (Fur), and 2-hydroxyacetopheneone (Hyd) have been synthesized in situ on SBA-15-NH2, MCM-48-NH2, and MCM-41-NH2 functionalized supports. The hybrid materials were characterized by X-ray diffraction, nitrogen adsorption–desorption, SEM and TEM microscopy, TG analysis, and AAS, FTIR, EPR, and XPS spectroscopies. Catalytic performances were tested in oxidation with the hydrogen peroxide of cyclohexene and of different aromatic and aliphatic alcohols (benzyl alcohol, 2-methylpropan-1-ol, and 1-buten-3-ol). The catalytic activity was correlated with the type of mesoporous silica support, ligand, and metal–ligand interactions. The best catalytic activity of all tested hybrid materials was obtained in the oxidation of cyclohexene on SBA-15-NH2-MetMn as a heterogeneous catalyst. No leaching was evidenced for Cu and Mn complexes, and the Cu catalysts were more stable due to a more covalent interaction of the metallic ions with the immobilized ligands

Selective Cu2+ adsorption and recovery from contaminated water using mesoporous hybrid silica bio-adsorbents

International audienc

Bioavailability, Accumulation and Distribution of Toxic Metals (As, Cd, Ni and Pb) and Their Impact on Sinapis alba Plant Nutrient Metabolism

This study presents the behavior of white mustard seedlings Sinapis alba grown for three months in laboratory polluted soil containing As, Cd, Ni and Pb. Four different experiments were performed in which As was combined with the other three toxic metals in different combinations (As, AsCd, AsCdNi, AsCdNiPb), keeping the same concentrations of As and Cd in all tests and following the national soil quality regulations. The effects of these metals were monitored by the analytical control of metal concentrations in soil and plants, bioavailability tests of mobile metal fractions using three different extracting solutions (DTPA + TEA + CaCl2-DTPA, DTPA + CaCl2-CAT, and CH3COONH4 + EDTA-EDTA) and calculation of bioaccumulation and translocation factors. Additionally, micro, and macro-nutrients both in soil and plant (root, stem, leaves, flowers and seeds) were analyzed in order to evaluate the impact of toxic metals on plant nutrient metabolism. Metals were significantly and differently accumulated in the plant tissues, especially under AsCdNi and AsCdNiPb treatments. Significant differences (p < 0.05) in the concentration of both As and Cd were highlighted. Translocation could be influenced by the presence of other toxic metals, such as Cd, but also of essential metals, through the competition and antagonism processes existing in plant tissues. Significantly, more Cd and Ni levels were detected in leaves and flowers. Cd was also detected in seeds above the WHO limit, but the results are not statistically significant (p > 0.05). The extraction of metallic nutrients (Zn, Cu, Mn, Ni, Mg, K, Fe, Ca, Cr) in the plant was not influenced by the presence of toxic metal combinations, on the contrary, their translocation was more efficient in the aerial parts of the plants. No phytotoxic effects were recorded during the exposure period. The most efficient methods of metal extraction from soil were for As-CAT; Cd-all methods; Pb and Ni-DTPA. The Pearson correlations (r) between applied extraction methods and metal detection in plants showed positive correlations for all toxic metals as follows: As-CAT > DTPA > EDTA, Cd-DTPA > CAT > EDTA, Ni-EDTA = DTPA > CAT, Pb-EDTA = DTPA = CAT). The results revealed that Sinapis alba has a good ability to accumulate the most bioavailable metals Cd and Ni, to stabilize As at the root level and to block Pb in soil