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Pb(II) ions were separated/preconcentrated and detected by a two-step preconcentration method (Amberlite CG-120 resin and slotted quartz tube (SQT) flame atomic absorption). The first preconcentration step was the adsorption of Pb(II) on Amberlite CG-120 resin in the drinking, spring and lake water samples before detection and then its elution using 5 mL of 3 M nitric acid. The second preconcentration step was conducted using SQT device with flame atomic absorption detection. Using a two-step preconcentration method, enrichment factor of 560 was found and detection and quantitation limits were 0.23 and 0.8 [micro]g/L, respectively. The accuracy of the method was tested by analysis of standard reference material (Environmental Matrix Reference Material, Lake Water, TMDA-70.2) at a 95% confidence level., Author(s): Erdal Kendüzler [sup.1], Merve Duman Dinç [sup.1], Digdem Trak [sup.1], Burcu Kabak [sup.1], Yasin Arslan [sup.2] Author Affiliations: (1) grid.411761.4, 0000 0004 0386 420X, Chemistry Department, Faculty of Arts [...]

This paper describes the simple and environmentally friendly production of AgNPs using Dimrit raisin, grown in Burdur, extract. To optimize the synthesis of AgNPs, a number of variables, including extract concentration, silver solution concentration, synthesis time, and synthesis temperature, were investigated. AgNPs were obtained after 173 h at 1% extract concentration and 10-1 M silver concentration. The structure of the synthesised AgNPs was investigated by Transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-visible spectroscopy, and Fourier transform infrared spectroscopy (FT-IR). TEM analysis showed that the majority of the AgNPs had a spherical shape, and the average particle size was 30 nm. Antimicrobial activity was seen against Staphylococcus aureus ATTC43300, Enterococcus faecalis ATTC29212, Bacillus subtilis, Listeria monocytogenes, Klebsiella pneumoniae and Gram-negative Salmonella enterocolitis, E. coli 0157:H7 ATTC 43895, and Escherichia coli ATTC 35150. [ABSTRACT FROM AUTHOR]

BACKGROUND Low‐cost biosorbent (derived from peanut shells) with abundant oxygen‐containing functional groups can effectively adsorb the naproxen drug in solution. This study aimed to explore the main interactions responsible for adsorbing naproxen and develop several conventional methods for identifying primary adsorption mechanism. Some important operation parameters strongly effecting the adsorption process and mechanism were investigated and discussed. RESULTS: A fast adsorption equilibrium can be reached at approximately 120 min. The Langmuir maximum adsorption capacity of biosorbent towards naproxen (Qomax; mg g−1) was 55.1 mg g−1. The study of adsorption thermodynamics indicated that the adsorption process was spontaneous (∆G° ≈ −21 kJ mol−1) and exothermic (∆H° = −14.9 kJ mol−1), and van der Waals force played an important role in the adsorption mechanism. Another important contribution of n–π interaction between the carbonyl groups on the biosorbent's surface and the aromatic rings in naproxen molecules was confirmed by Fourier‐transform infrared spectroscopy and a traditional method. Such n–π interaction cannot be well performed when carbonyl groups were oxidized into carboxylic groups under H2O2 treatment. Peanut shells exhibited an excellent adsorption capacity to various pollutants such as lead (Qomax = 167 mg g−1), cadmium (103 mg g−1), cobalt (88.8 mg g−1), diclofenac (56.1 mg g−1), and bisphenol A (24.5 mg g−1). CONCLUSIONS: Simple methods were developed to identify the important role of van der Waals force and n–π interaction in the adsorption process of naproxen. Such methods might be applied to identify the similar adsorption mechanisms of other aromatic adsorbates onto other materials with similar properties. Peanut shells can serve as a promising biosorbent for eliminating naproxen and other pollutants from water environment. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Chocolate is consumed by people of all ages in every part of society. Chocolate is a very rich source of many essential metals for the body but it also may involve toxic metals. Therefore, the accurate and precise method should be selected and applied to determine the essential and toxic metals in the chocolate samples. In present study, Na, K, Mg (II), Ca(II), Cu(II), Fe(III), Zn(II), Cd(II), Cr(III), Pb(II) and Ni(II) metals were determined by using flame atomic absorption spectrometry (FAAS) in 24 different chocolate samples of 3 different types including 8 different brands of bitter, milk and white. The microwave-assisted digestion system was also used for the chocolate samples digestions. All results were given at 95% of confidence level. In addition, the accuracy of the method was also investigated by the analysis of a standard reference material (spinach leaves, NIST-1570a). [ABSTRACT FROM AUTHOR]

The ubiquitous appearance of nonsteroidal anti-inflammatory drugs (i.e., naproxen) in water bodies has raised enormous concerns among general public. Development of promising materials for eliminating such contaminants from water environment has attracted much attention in the scientific community. In this study, three (direct, post-treated and pre-treated) methods were developed to prepare biochars (800-PSB, 800-800-PSB, and 190-800-PSB, respectively) derived from the wastes of peanut shells (PS). They were thoroughly characterized by various important properties (i.e., porosity and superficial functional group) and applied to remove naproxen drug from water. Results indicated that although the pre- and post-treatments had a slight effect on the surface area of biochars (i.e., 571 m2/g for 800-PSB, 596 m2/g for 800-800-PSB, and 496 m2/g for 190-800-PSB), such treatments remarkably improved the adsorption capacity of biochar. The maximum adsorption capacity of biochar (obtained from the Langmuir model) towards naproxen in solution at 25 decreased in the following order: 800-800-PSB (324 mg/g) > 190-800-PSB (215 mg/g) > 800-PSB (105 mg/g). The thermodynamic study demonstrated that the adsorption was spontaneous and exothermic. Depending the preparation process, the contribution of each mechanism in the adsorption process was dissimilar. The overall adsorption mechanism was regarded as pore filling, π - π interaction, hydrogen bonding formations, n- π interaction, van der Waals force, and electrostatic attraction. Two methods used to identify the important role of π - π interaction were proposed herein. The possible desorption and reuse of laden-biochars were investigated by the chemical and thermal methods. The prepared biochar samples can serve as potential carbonaceous porous adsorbents for effectively removing naproxen from water media. Unlabelled Image • Different carbonization processes were applied to convert biomass into biochars. • Biochars were applied to remove naproxen from water and wastewater. • Biochar produced from interrupted pyrolysis exhibited excellent adsorption capacity. • Adsorption mechanism was explored and proposed from various experimental data. • Pore filling and π-π interaction played a proper role in adsorption mechanism. [ABSTRACT FROM AUTHOR]

Commercial micro-mesoporous carbonaceous material (MCM; 56.8% mesopores) was applied for investigating the removal phenomenon of naproxen drug in aqueous solutions through batch adsorption experiments. Results demonstrated that the adsorption capacity of MCM to naproxen was slightly affected by different pH eq (2.0-11) and ionic strength (0-1 M NaCl). Adsorption kinetics, isotherms, thermodynamics, and mechanisms were evaluated at pH 7.0. Adsorption kinetics indicated the rate constants for adsorption (0.2 × 10 -3  L/(mg × min) and desorption (0.076/min) and the adsorption equilibrium constant (2.6 × 10 -3  L/mg). Adsorption isotherm showed that MCM exhibited a high-affinity adsorption capacity to naproxen (even at low concentrations) and its Langmuir maximum adsorption capacity (Q max ) was 252.7 mg/g at 25°C. Adsorption thermodynamics proved that the adsorption process was endothermic and physisorption (ΔH° = 9.66 kJ/mol). The analysis result of pore size distribution demonstrated that the internal pore structure of MCM was appropriate for adsorbing naproxen molecules. Pore-filing mechanism (pore diffusion phenomenon) was confirmed by a considerable decrease in BET-surface area (585 m 2 /g) and total pore volume (0.417 cm 3 /g) of MCM after adsorbing naproxen (~1000 mg/L and pH 7.0) at 5 min (341 and 0.256), 60 min (191 and 0.205), 120 min (183 and 0.193), 360 min (144 and 0.175), and 24 h (71.6 m 2 /g and 0.123 cm 3 /g, respectively). The pore diffusion occurred rapidly (even at the initial adsorption period of 5 min). The FTIR technique was applied to identify the existence of C-H···π and n-π interaction. π-π interaction (evaluated through I D /I G ratio and C=C band) played a minor contribution in adsorption mechanisms. The I D /I G ratio (determined by the Raman technique) of MCM before adsorption (1.195) was similar to that after adsorption (1.190), and the wavenumber (C=C band; its FTIR spectrum) slightly shifted from 1638 to 1634 cm -1 after adsorption. A decrease in the Q max value of MCM from 249 to 217 (H 2 O 2 -oxidized MCM) or to 224 mg/g (HNO 3 -oxidized MCM) confirmed the presence of π-π interaction. Electrostatic attraction was a minor contribution. MCM can serve as a promising material for removing naproxen from water environment through a pore-filling mechanism. PRACTITIONER POINTS: Pore-filling mechanism was proposed by comparing textural properties of MCM before and after adsorbing naproxen. C-H···π and n-π interactions were identified via FTIR technique. π-π interaction was observed by FTIR and Raman techniques. Oxidation of MCM with HNO 3 or H 2 O 2 was a helpful method to explore π-π interaction. Electrostatic attraction was explained through studies: effects of pH and NaCl along with desorption., (© 2024 Water Environment Federation.)