Silver nanoparticles were produced using Poria cocos extract (PC-AgNPs). • The PC-AgNPs solution ... more Silver nanoparticles were produced using Poria cocos extract (PC-AgNPs). • The PC-AgNPs solution showed a high stability with a zeta potential of − 47.3 mV. • PC-AgNPs exhibited excellent catalytic activity and stability in 4-NP reduction. • PC-AgNPs can be used as highly sensitive probes for the detection of Fe 3+ ions.
The study describes the qualitative and quantitative analysis of benzene, toluene, ethylbenzene, ... more The study describes the qualitative and quantitative analysis of benzene, toluene, ethylbenzene, xylene (BTEX) in the ambient air based on chemical desorption with a less toxic solvent followed by gas-chromatography combined mass-spectroscopy (GC-MS). The analytical procedure was modified OSHA's method in the sampling procedure, the toxic extraction solvent-carbon disulfide (CS2) was changed by the less toxic solvent (acetone), subsequent analysis by GC-MS. The parameters and conditions of the method have been optimized. BTEX quantitative concentration ranging from 2.5 ppb to 450 ppb with detection limits were 1.4 ppb (benzene), 1.1 ppb (toluene), 1.0 ppb (ethylbenzene), 0.7 ppb (xylene (m,p)) and 1.2 ppb (xylene(o)). At a concentration of 100 ppb, the relative standard deviations (RSDs) for BTEX ranged from 3.2% (benzene) to 7.5% (xylene (o)). The new method has also been applied to analyze the real ambient air samples in Ho Chi Minh City. All results indicated that this method can offer a robust, sensitive, and environmentally friendly method for determination of BTEX and other gaseous volatile organic compounds in ambient air.
Developing low-cost and highly effective adsorbent materials to decolorate wastewater is still ch... more Developing low-cost and highly effective adsorbent materials to decolorate wastewater is still challenging in the industry.
This study attempted to develop carrageenan/chitosan based microparticles loading α-mangostin whi... more This study attempted to develop carrageenan/chitosan based microparticles loading α-mangostin which was extracted from Vietnamese mangosteen skin. The carrageenan/chitosan/α-mangostin microparticles were prepared by ionic gelation method by mixing chitosan, carrageenan with α-mangostin and subsequently cross-linking the mixtures with sodium tripolyphosphate crosslinking agent. The content of α-mangostin in microparticles was changed to evaluate the effect of α-mangostin content on physical, morphological properties, particles size and bioactivities of the carrageenan/chitosan/α-mangostin microparticles. The obtained results showed that carrageenan, chitosan was interacted together and with α-mangostin. The presence of polymers matrix improved the release ability of α-mangostin into ethanol/pH buffer solutions. The carrageenan/chitosan/ α-mangostin microparticles have antibacterial (gram (+) strains) and anti-oxidant activities. The results suggested that combination of chitosan and ...
A rapid, sensitive, and selective method for determination of thorium based on the complex withor... more A rapid, sensitive, and selective method for determination of thorium based on the complex withortho-ester tetra-azophenylcalix[4]arene (TEAC) was described. In the presence of pH of 4–6, TEAC-Th(IV) complex is extracted from an acidic aqueous solution into chloroform layer. The absorbance intensity of complex was measured by UV-Vis spectrometer at 525 nm and the molar absorptivity was found to be 2.4 × 104. Beer’s law was obeyed in the range of 1.0 to 25 × 10−5 M thorium(IV). The effects of pH, TEAC concentration, and shaking time were also studied. The tolerance limits for several metal ions were calculated. The proposed method was applied to the determination of thorium in synthetic solution and in the monazite sand samples with good results.
The simultaneous spectrophotometric method is described for the determination of Cu(II) and Co(II... more The simultaneous spectrophotometric method is described for the determination of Cu(II) and Co(II) by 5bromosalicylaldehyde thiosemicarbazone (5-BSAT) using partial least squares regression method. The ligand reacts with two ions to form greenish yellow and brown colored [Cu(II)-5-BSAT] and [Co(II)-(5-BSAT)2] complexes, respectively. The absorption peaks of these complexes were found overlapping at λmax of 378 nm and 381 nm, respectively. Formation of all of these complexes was complete within 20 min at pH 5.0. The linear ranges were 4.0×10-6 M-9.6×10-6 M for Cu(II) and 8.0×10-6 M-8.0×10-5 M for Co(II) with molar absorptivity, ε of 1.09×10 4 L.mol −1 .cm −1 and 1.42×10 4 L.mol −1 .cm −1 , respectively. Partial least squares (PLS) regression method is proposed for the simultaneous determination of these ions with the spectrophotometric absorbance data between wavelengths 370 and 446 nm at an interval of 4 nm. A training set was generated and its accuracy was tested in a test set. The test set garnered a root mean square error (RMSE) of 0.192 for copper and 0.489 for cobalt. The relatively small RMSE suggests only a small difference between predicted versus measured concentrations, demonstrating the accuracy of our model. The proposed method is successfully employed in the analysis of water sample for determining concentrations of copper and cobalt.
A new complex of Zn(II) and 5-Bromosalicylaldehyde thiosemicarbazone (5-BSAT) has been studied. I... more A new complex of Zn(II) and 5-Bromosalicylaldehyde thiosemicarbazone (5-BSAT) has been studied. In solution, the 5-BSAT reacts with Zn(II) to form a complex with the maximum absorbance at 381 nm. Zn(II) ion forms a 1:1 stoichiometric complex. The stability constant is 4.21x10 5. The formation of the complex was completed within 20 min at pH 6.8 and VDMF = 2 mL. Beer's law is obeyed over the range from 0.13 mg. L-1 to 0.39 mg. L-1 Zn (II) and the apparent molar absorptivity (ε) is 1.08×10 4 L.mol −1 .cm −1. The complex has been formulated and characterized by mass spectrometry, FT-IR, 1 H-NMR and 13 C-NMR spectroscopies and IQmol program. The molecular formula of the complex is C8H8O2N3SBrZn. The ligand coordinated as an ONS tridentate dianion through the oxygen atom of the deprotonated phenolic OH-group, the azomethine nitrogen atom and the sulfur atom after deprotonation of the thiosemicarbazide residue in its thiol form. Based on these results, the 5-BSAT reagent was applied to determine zinc in waste water samples and the complex showed an effective antimicrobial activity.
Optimized and validated spectrophotometric method has been proposed for the determination of nick... more Optimized and validated spectrophotometric method has been proposed for the determination of nickel and zinc simultaneously. 5-bromosalicylaldehyde thiosemicarbazone (5-BSAT) reacts with nickel(II) and zinc(II) to form [Ni(II)-(5-BSAT) 2 ] and [Zn(II)-5-BSAT] complexes, respectively. The maximum absorbance of these complexes was found at 378 nm and 381 nm, respectively. For [Ni(II)-(5-BSAT) 2 ], Beer’s law is obeyed over the concentration range of 2.0×10 -6 M – 6.0×10 -5 M with molar absorptivity, e of 0.92×10 4 L.mol −1 .cm −1 . [Zn(II)-5-BSAT] complex obeys Beer’s law in 2.0×10 -6 M – 6.0×10 -5 M range with molar absorptivity, e of 1.08×10 4 L.mol −1 .cm −1 . A simultaneous spectrophotometric H-point standard addition method (HPSAM) is proposed for the determination of these metals. The proposed method is successfully employed in the analysis of waste water sample for the determination of nickel and zinc content.
In this study, the sorption of Cr(VI) from aqueous solution onto the cross-linked chitosan grafti... more In this study, the sorption of Cr(VI) from aqueous solution onto the cross-linked chitosan grafting with citric acid (C-Gch) was investigated in a bath system. The optimum conditions for the adsorption were found to be pH 1 and 720 min of contact time. The maximum adsorption capacity of Cr(VI) at pH 1 was found to be 32 mg Cr(VI) /g C-Gch after 720 min of contact time. Adsorption kinetic data were tested using pseudo-first order and pseudo-second order. The obtained results confirmed that the adsorption process of Cr(VI) followed the pseudo-second kinetic model. It was shown that the adsorption process is presumably a chemisorption. Thermodynamic parameters including changes in the standard free energy (∆G), enthalpy (∆H) and entropy (∆S) were also calculated. Keywords. Cr(VI), modified chitosan, citric acid, adsorption thermodynamic.
... VAN TOAN, LE VAN HOANG, LE VAN TAN, LE THI LIEN THANH, CHU ... ANH HUONG CUA RETAIN - AVG (AM... more ... VAN TOAN, LE VAN HOANG, LE VAN TAN, LE THI LIEN THANH, CHU ... ANH HUONG CUA RETAIN - AVG (AMINOETHOXYVINYLGLYCINE) DEN TH6I HAN BAO QUAN SAU THU HOACH ... ciia chat khang etylen Retain - AVG (aminoethoxyvinylglycine) d cac ndng do khac nhau ...
The accumulation and elimination of arsenic (As), cadmium (Cd), lead (Pb) and its effect on Oreoc... more The accumulation and elimination of arsenic (As), cadmium (Cd), lead (Pb) and its effect on Oreochromis sp. growth were studied after exposing fish to 1.0, 1.5 and 3.0 mgAs/L or 0.66, 1.0 and 2.0 mgCd/L or 0.12, 0.18 and 0.33 mgPb/L for 20 days in exposure phase and 10 days in the recovery phase. As Cd and Pb significantly affect on increases in weight of fish. In the exposure phase, the ratio of Metal fish organs / Metal H2O in tissues of fish was in the order muscle >> liver > gill in the case As exposure; muscle << gill << liver for Cd exposure, and muscle << liver << gill in the case of Pb exposure. On day 10 of the recovery phase, the elimination of accumulated As, Cd, Pb in the fish organs was approximately from 12% to 29% for As, from 33% to 54% for Cd and from 14% to 39% for Pb
Among soil pollutants, lead (Pb) is one of the toxic metal pollutants widely used in many industr... more Among soil pollutants, lead (Pb) is one of the toxic metal pollutants widely used in many industrial processes and occurs as a contaminant in environment. In this study, a field experiment was carried out to investigate the accumulation of lead from soil contaminated by this metal ion on the biomass of some vegetables, including spinach, lettuce, carrots, and potatoes. The results showed that lead was cumulative metal. Besides, the level of lead accumulation in soil of the studied vegetables decreased in the order of tubers of carrots, tubers of potato, spinach root, lettuce root, stems and leaves of spinach, stem and leaves of carrot, stems and leaves of potato, and stem and leaves of lettuce, respectively. Our investigations demonstrate the effect of copper and zinc micronutrient elements which play an important role in the growth and development of plants, on the accumulation of lead from contaminated soil of the studied vegetables. The obtained results showed that high concentra...
New chromogenic diazophenylcalix[4]arenes 1 and 2 were synthesized in cone conformation. Compound... more New chromogenic diazophenylcalix[4]arenes 1 and 2 were synthesized in cone conformation. Compound 1 with the ortho-carboxyl groups in CH 3 CN solution preferentially binds with alkaline earth and transition metal ions, whereas no significant changes in absorption spectra are observed in the presence of alkali metal ions. While 2 with the ortho-ester groups shows selective complexation properties towards transition metal ions over alkali and alkaline earth metal ions. The detection of metal ions gives rise to bathochromic shifts in the absorption spectra (from orange/yellow to red), which is clearly visible even to the naked eye. According to the selective color changes using both receptors upon cation complexation, one can set up a qualitative analytical routine to screen alkali, alkaline earth, and transition metal ions.
In this study, the complex of difluoroboron, curcumin (BF2-Cur), has been synthesized and charact... more In this study, the complex of difluoroboron, curcumin (BF2-Cur), has been synthesized and characterized via the combination of Boron trifluoride-diethyl etherate ((C2H5)2OBF3) and curcumin. However, the new dissociation constants, pKa1 and pKa2 of the BF2-Cur complex, have been indicted by the values of 8.44 ± 0.16 and 9.76 ± 0.13, respectively. On the other hand, the reagent was also used to determine As(III) in aqueous solutions by UV–Vis spectrophotometry. As a result, the method was validated for accuracy, precision, linearity, and sensitivity, and the linear range was from 1.0 to 25.0 µmol/L, with the linear regression, A = 0.0027 C + 0.0106, correlation coefficient R2 = 0.9969. Besides, the limit of detection (LOD) and limit of quantification (LOQ) were determined as 0.83 and 2.10 µmol/L, respectively. Thus, the developed method is successfully used for quantitative analysis of total arsenic in wastewater by reducing As(V) to As(III), then determining As(III) with high accurac...
In this work, a well-developed surface area amorphous magnesium silicate was synthesized and seri... more In this work, a well-developed surface area amorphous magnesium silicate was synthesized and seriously optimized the preparation process by Box-Wilson Design Model. Therein, the amorphous nature of magnesium silicate after being synthesized was confirmed by the X-ray diffraction method, the presence of functional groups was determined by Fourier-transform infrared spectroscopy and the surface area was analyzed by Brunauer–Emmett–Teller method. The synthesized material was then applied to simultaneously adsorb Pb, Cd and As from three water types: the simulated polluted water, the real wastewater and real polluted well water. According to the obtained results, magnesium silicate was synthesized at optimum conditions that have a special surface area of 454 m2/g, a pore volume of 0.325 mL/g and an average particle size of 116 μm. The synthesized magnesium silicate is excellently capable of simultaneous Pb, Cd, As adsorption in three types of water samples. The total content of these he...
Silver nanoparticles were produced using Poria cocos extract (PC-AgNPs). • The PC-AgNPs solution ... more Silver nanoparticles were produced using Poria cocos extract (PC-AgNPs). • The PC-AgNPs solution showed a high stability with a zeta potential of − 47.3 mV. • PC-AgNPs exhibited excellent catalytic activity and stability in 4-NP reduction. • PC-AgNPs can be used as highly sensitive probes for the detection of Fe 3+ ions.
The study describes the qualitative and quantitative analysis of benzene, toluene, ethylbenzene, ... more The study describes the qualitative and quantitative analysis of benzene, toluene, ethylbenzene, xylene (BTEX) in the ambient air based on chemical desorption with a less toxic solvent followed by gas-chromatography combined mass-spectroscopy (GC-MS). The analytical procedure was modified OSHA's method in the sampling procedure, the toxic extraction solvent-carbon disulfide (CS2) was changed by the less toxic solvent (acetone), subsequent analysis by GC-MS. The parameters and conditions of the method have been optimized. BTEX quantitative concentration ranging from 2.5 ppb to 450 ppb with detection limits were 1.4 ppb (benzene), 1.1 ppb (toluene), 1.0 ppb (ethylbenzene), 0.7 ppb (xylene (m,p)) and 1.2 ppb (xylene(o)). At a concentration of 100 ppb, the relative standard deviations (RSDs) for BTEX ranged from 3.2% (benzene) to 7.5% (xylene (o)). The new method has also been applied to analyze the real ambient air samples in Ho Chi Minh City. All results indicated that this method can offer a robust, sensitive, and environmentally friendly method for determination of BTEX and other gaseous volatile organic compounds in ambient air.
Developing low-cost and highly effective adsorbent materials to decolorate wastewater is still ch... more Developing low-cost and highly effective adsorbent materials to decolorate wastewater is still challenging in the industry.
This study attempted to develop carrageenan/chitosan based microparticles loading α-mangostin whi... more This study attempted to develop carrageenan/chitosan based microparticles loading α-mangostin which was extracted from Vietnamese mangosteen skin. The carrageenan/chitosan/α-mangostin microparticles were prepared by ionic gelation method by mixing chitosan, carrageenan with α-mangostin and subsequently cross-linking the mixtures with sodium tripolyphosphate crosslinking agent. The content of α-mangostin in microparticles was changed to evaluate the effect of α-mangostin content on physical, morphological properties, particles size and bioactivities of the carrageenan/chitosan/α-mangostin microparticles. The obtained results showed that carrageenan, chitosan was interacted together and with α-mangostin. The presence of polymers matrix improved the release ability of α-mangostin into ethanol/pH buffer solutions. The carrageenan/chitosan/ α-mangostin microparticles have antibacterial (gram (+) strains) and anti-oxidant activities. The results suggested that combination of chitosan and ...
A rapid, sensitive, and selective method for determination of thorium based on the complex withor... more A rapid, sensitive, and selective method for determination of thorium based on the complex withortho-ester tetra-azophenylcalix[4]arene (TEAC) was described. In the presence of pH of 4–6, TEAC-Th(IV) complex is extracted from an acidic aqueous solution into chloroform layer. The absorbance intensity of complex was measured by UV-Vis spectrometer at 525 nm and the molar absorptivity was found to be 2.4 × 104. Beer’s law was obeyed in the range of 1.0 to 25 × 10−5 M thorium(IV). The effects of pH, TEAC concentration, and shaking time were also studied. The tolerance limits for several metal ions were calculated. The proposed method was applied to the determination of thorium in synthetic solution and in the monazite sand samples with good results.
The simultaneous spectrophotometric method is described for the determination of Cu(II) and Co(II... more The simultaneous spectrophotometric method is described for the determination of Cu(II) and Co(II) by 5bromosalicylaldehyde thiosemicarbazone (5-BSAT) using partial least squares regression method. The ligand reacts with two ions to form greenish yellow and brown colored [Cu(II)-5-BSAT] and [Co(II)-(5-BSAT)2] complexes, respectively. The absorption peaks of these complexes were found overlapping at λmax of 378 nm and 381 nm, respectively. Formation of all of these complexes was complete within 20 min at pH 5.0. The linear ranges were 4.0×10-6 M-9.6×10-6 M for Cu(II) and 8.0×10-6 M-8.0×10-5 M for Co(II) with molar absorptivity, ε of 1.09×10 4 L.mol −1 .cm −1 and 1.42×10 4 L.mol −1 .cm −1 , respectively. Partial least squares (PLS) regression method is proposed for the simultaneous determination of these ions with the spectrophotometric absorbance data between wavelengths 370 and 446 nm at an interval of 4 nm. A training set was generated and its accuracy was tested in a test set. The test set garnered a root mean square error (RMSE) of 0.192 for copper and 0.489 for cobalt. The relatively small RMSE suggests only a small difference between predicted versus measured concentrations, demonstrating the accuracy of our model. The proposed method is successfully employed in the analysis of water sample for determining concentrations of copper and cobalt.
A new complex of Zn(II) and 5-Bromosalicylaldehyde thiosemicarbazone (5-BSAT) has been studied. I... more A new complex of Zn(II) and 5-Bromosalicylaldehyde thiosemicarbazone (5-BSAT) has been studied. In solution, the 5-BSAT reacts with Zn(II) to form a complex with the maximum absorbance at 381 nm. Zn(II) ion forms a 1:1 stoichiometric complex. The stability constant is 4.21x10 5. The formation of the complex was completed within 20 min at pH 6.8 and VDMF = 2 mL. Beer's law is obeyed over the range from 0.13 mg. L-1 to 0.39 mg. L-1 Zn (II) and the apparent molar absorptivity (ε) is 1.08×10 4 L.mol −1 .cm −1. The complex has been formulated and characterized by mass spectrometry, FT-IR, 1 H-NMR and 13 C-NMR spectroscopies and IQmol program. The molecular formula of the complex is C8H8O2N3SBrZn. The ligand coordinated as an ONS tridentate dianion through the oxygen atom of the deprotonated phenolic OH-group, the azomethine nitrogen atom and the sulfur atom after deprotonation of the thiosemicarbazide residue in its thiol form. Based on these results, the 5-BSAT reagent was applied to determine zinc in waste water samples and the complex showed an effective antimicrobial activity.
Optimized and validated spectrophotometric method has been proposed for the determination of nick... more Optimized and validated spectrophotometric method has been proposed for the determination of nickel and zinc simultaneously. 5-bromosalicylaldehyde thiosemicarbazone (5-BSAT) reacts with nickel(II) and zinc(II) to form [Ni(II)-(5-BSAT) 2 ] and [Zn(II)-5-BSAT] complexes, respectively. The maximum absorbance of these complexes was found at 378 nm and 381 nm, respectively. For [Ni(II)-(5-BSAT) 2 ], Beer’s law is obeyed over the concentration range of 2.0×10 -6 M – 6.0×10 -5 M with molar absorptivity, e of 0.92×10 4 L.mol −1 .cm −1 . [Zn(II)-5-BSAT] complex obeys Beer’s law in 2.0×10 -6 M – 6.0×10 -5 M range with molar absorptivity, e of 1.08×10 4 L.mol −1 .cm −1 . A simultaneous spectrophotometric H-point standard addition method (HPSAM) is proposed for the determination of these metals. The proposed method is successfully employed in the analysis of waste water sample for the determination of nickel and zinc content.
In this study, the sorption of Cr(VI) from aqueous solution onto the cross-linked chitosan grafti... more In this study, the sorption of Cr(VI) from aqueous solution onto the cross-linked chitosan grafting with citric acid (C-Gch) was investigated in a bath system. The optimum conditions for the adsorption were found to be pH 1 and 720 min of contact time. The maximum adsorption capacity of Cr(VI) at pH 1 was found to be 32 mg Cr(VI) /g C-Gch after 720 min of contact time. Adsorption kinetic data were tested using pseudo-first order and pseudo-second order. The obtained results confirmed that the adsorption process of Cr(VI) followed the pseudo-second kinetic model. It was shown that the adsorption process is presumably a chemisorption. Thermodynamic parameters including changes in the standard free energy (∆G), enthalpy (∆H) and entropy (∆S) were also calculated. Keywords. Cr(VI), modified chitosan, citric acid, adsorption thermodynamic.
... VAN TOAN, LE VAN HOANG, LE VAN TAN, LE THI LIEN THANH, CHU ... ANH HUONG CUA RETAIN - AVG (AM... more ... VAN TOAN, LE VAN HOANG, LE VAN TAN, LE THI LIEN THANH, CHU ... ANH HUONG CUA RETAIN - AVG (AMINOETHOXYVINYLGLYCINE) DEN TH6I HAN BAO QUAN SAU THU HOACH ... ciia chat khang etylen Retain - AVG (aminoethoxyvinylglycine) d cac ndng do khac nhau ...
The accumulation and elimination of arsenic (As), cadmium (Cd), lead (Pb) and its effect on Oreoc... more The accumulation and elimination of arsenic (As), cadmium (Cd), lead (Pb) and its effect on Oreochromis sp. growth were studied after exposing fish to 1.0, 1.5 and 3.0 mgAs/L or 0.66, 1.0 and 2.0 mgCd/L or 0.12, 0.18 and 0.33 mgPb/L for 20 days in exposure phase and 10 days in the recovery phase. As Cd and Pb significantly affect on increases in weight of fish. In the exposure phase, the ratio of Metal fish organs / Metal H2O in tissues of fish was in the order muscle >> liver > gill in the case As exposure; muscle << gill << liver for Cd exposure, and muscle << liver << gill in the case of Pb exposure. On day 10 of the recovery phase, the elimination of accumulated As, Cd, Pb in the fish organs was approximately from 12% to 29% for As, from 33% to 54% for Cd and from 14% to 39% for Pb
Among soil pollutants, lead (Pb) is one of the toxic metal pollutants widely used in many industr... more Among soil pollutants, lead (Pb) is one of the toxic metal pollutants widely used in many industrial processes and occurs as a contaminant in environment. In this study, a field experiment was carried out to investigate the accumulation of lead from soil contaminated by this metal ion on the biomass of some vegetables, including spinach, lettuce, carrots, and potatoes. The results showed that lead was cumulative metal. Besides, the level of lead accumulation in soil of the studied vegetables decreased in the order of tubers of carrots, tubers of potato, spinach root, lettuce root, stems and leaves of spinach, stem and leaves of carrot, stems and leaves of potato, and stem and leaves of lettuce, respectively. Our investigations demonstrate the effect of copper and zinc micronutrient elements which play an important role in the growth and development of plants, on the accumulation of lead from contaminated soil of the studied vegetables. The obtained results showed that high concentra...
New chromogenic diazophenylcalix[4]arenes 1 and 2 were synthesized in cone conformation. Compound... more New chromogenic diazophenylcalix[4]arenes 1 and 2 were synthesized in cone conformation. Compound 1 with the ortho-carboxyl groups in CH 3 CN solution preferentially binds with alkaline earth and transition metal ions, whereas no significant changes in absorption spectra are observed in the presence of alkali metal ions. While 2 with the ortho-ester groups shows selective complexation properties towards transition metal ions over alkali and alkaline earth metal ions. The detection of metal ions gives rise to bathochromic shifts in the absorption spectra (from orange/yellow to red), which is clearly visible even to the naked eye. According to the selective color changes using both receptors upon cation complexation, one can set up a qualitative analytical routine to screen alkali, alkaline earth, and transition metal ions.
In this study, the complex of difluoroboron, curcumin (BF2-Cur), has been synthesized and charact... more In this study, the complex of difluoroboron, curcumin (BF2-Cur), has been synthesized and characterized via the combination of Boron trifluoride-diethyl etherate ((C2H5)2OBF3) and curcumin. However, the new dissociation constants, pKa1 and pKa2 of the BF2-Cur complex, have been indicted by the values of 8.44 ± 0.16 and 9.76 ± 0.13, respectively. On the other hand, the reagent was also used to determine As(III) in aqueous solutions by UV–Vis spectrophotometry. As a result, the method was validated for accuracy, precision, linearity, and sensitivity, and the linear range was from 1.0 to 25.0 µmol/L, with the linear regression, A = 0.0027 C + 0.0106, correlation coefficient R2 = 0.9969. Besides, the limit of detection (LOD) and limit of quantification (LOQ) were determined as 0.83 and 2.10 µmol/L, respectively. Thus, the developed method is successfully used for quantitative analysis of total arsenic in wastewater by reducing As(V) to As(III), then determining As(III) with high accurac...
In this work, a well-developed surface area amorphous magnesium silicate was synthesized and seri... more In this work, a well-developed surface area amorphous magnesium silicate was synthesized and seriously optimized the preparation process by Box-Wilson Design Model. Therein, the amorphous nature of magnesium silicate after being synthesized was confirmed by the X-ray diffraction method, the presence of functional groups was determined by Fourier-transform infrared spectroscopy and the surface area was analyzed by Brunauer–Emmett–Teller method. The synthesized material was then applied to simultaneously adsorb Pb, Cd and As from three water types: the simulated polluted water, the real wastewater and real polluted well water. According to the obtained results, magnesium silicate was synthesized at optimum conditions that have a special surface area of 454 m2/g, a pore volume of 0.325 mL/g and an average particle size of 116 μm. The synthesized magnesium silicate is excellently capable of simultaneous Pb, Cd, As adsorption in three types of water samples. The total content of these he...
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