Sorption Profile and Thermodynamic Characteristics of Nitrosonaphthol Functionalized Sorbent for Metal Ion Enrichment

2005 ◽  
Vol 70 (9) ◽  
pp. 1341-1356 ◽  
Author(s):  
Saima Q. Memon ◽  
Muhammad I. Bhanger ◽  
Muhammad Y. Khuhawar
Keyword(s):  
Metal Ion ◽  
Tap Water ◽  
Thermodynamic Characteristics ◽  
Chelating Agent ◽  
Standard Addition ◽  
Absorption Spectrometry ◽  
Sorption Data ◽  
Maximum Sorption ◽  
Styrene Divinylbenzene ◽  
Two Phases

A simple and reliable method has been developed using styrene-divinylbenzene-based polymeric material containing 1-nitroso-2-naphthol as chelating agent, to concentrate ultratrace amounts of Ni(II) and Cu(II) ions in aqueous samples. Sorption of both the ions on the new synthetic resin under static and dynamic conditions has been investigated. The sorption has been optimized with respect to pH, shaking and contact time of two phases. Maximum sorption has been achieved from solution of pH 5-8 after 8 min of agitation. Total saturation capacities were 516 ± 2 and 316 ± 2.5 μmol g-1 for Ni(II) and Cu(II) ions, respectively. The lowest concentration for quantitative recovery (98 ± 1%) is 1.33 and 5 ppb with the preconcentration factor of 750 and 200 for Ni(II) and Cu(II), respectively. Monitoring of the influence of diverse ions on the sorption of metal ions has revealed that phosphate, hydrogencarbonate and citrate reduce the sorption to some extent. Under optimum conditions the sorption data followed Langmuir, Freundlich, and Dubinin-Radushkevich isotherms. The kinetics and thermodynamics of sorption are studied in detail. The sorption procedure is utilized to preconcentrate these ions prior to their determination in tea, human hair, and tap water samples by atomic absorption spectrometry using direct and standard addition methods.

scholarly journals Simultaneous Adsorptive Stripping Voltammetric Analysis of Heavy Metals at Graphenated Cupferron Pencil Rods

2022 ◽  
Author(s):  
Nelia Abraham Sanga ◽  
Nazeem Jahed ◽  
Zandile Leve ◽  
Emmanuel Iwuoha ◽  
Keagan Pokpas
Keyword(s):  
Metal Ion ◽  
Tap Water ◽  
Low Cost ◽  
Simultaneous Detection ◽  
Chelating Agent ◽  
Acetate Buffer Solution ◽  
Buffer Solution ◽  
Solution Ph ◽  
Voltammetric Analysis ◽  
Electrochemically Reduced Graphene Oxide

Abstract Electroanalysis of heavy metal ions in the presence of cupferron ligands has been extensively studied due to its ability to form stable metallic coordination complexes. Herein, electrochemically reduced graphene oxide (ERGO) sheets were for the first time employed in conjunction with low-cost, disposable pencil graphite rods and in-situ plated thin mercury films (HgF) for the simultaneous detection of Cd2+, Cu2+, Pb2+, and Zn2+ in the presence of cupferron as a chelating agent by square-wave adsorptive cathodic stripping voltammetry (SW-AdCSV). The technique is based on the catalytic reduction of adsorbed cupferron-metal ion complexes at the surface of the ERGO-HgF-PGE at 0.1 V for 60 s in 0.1 M acetate buffer solution (pH 4.6). Owing to the improved electronic and surface effects associated with ERGO inclusion, improved sensitivity was further achieved. Under optimized conditions, the ERGO-HgF-PGE showed a linear relationship from 20 to 200 µg.L-1 with detection limits below the US-EPA of 0.17 μg.L-1 , 0.02 μg.L-1 , 0.17 μg.L-1 and 0.14 μg.L-1 for Cd2+, Cu2+, Pb2+ and Zn2+, respectively at a deposition time of 60 s. The ERGO-HgF-PGE exhibited highly reproducible results with negligible intermetallic interferences and applied successfully to the determination of trace metals in tap water with satisfactory results.

Separation and Preconcentration of Trace Amounts of Rhodium Using a Dispersive Liquid–Liquid Microextraction Method and Its Determination by Flame Atomic Absorption Spectrometry

2014 ◽  
Vol 97 (3) ◽  
pp. 933-937 ◽  
Author(s):  
Fateme Mirrahimi ◽  
Mohammad Ali Taher
Keyword(s):  
Tap Water ◽  
Chelating Agent ◽  
Absorption Spectrometry ◽  
Flame Atomic Absorption ◽  
Separation And Preconcentration ◽  
Dispersive Liquid Liquid Microextraction ◽  
Ph Range ◽  
Extracting Solvent ◽  
Liquid Microextraction

Abstract A sensitive and selective method for the determination of low levels of rhodium (Rh) in environmental samples is needed. In the proposed method, an extracting solvent with a lower toxicity and density than the other solvents typically used in dispersive liquid–liquid microextraction was used to extract trace amounts of Rh from aqueous samples. Rh ions were complexed with 1-(2-pyridylazo)-2-naphthol in the pH range of 3.2–4.7 and extracted with dispersive liquid–liquid microextraction. The type and volume of the extracting solvent and dispersive solvent, centrifugation time, pH, amount of the chelating agent, and sample ionic strength were carefully studied. Under the optimal conditions, the LOD and RSD were 0.36 ng/mL (3Sb/m, n = 7) and ±2.0% (n = 7), respectively. The calibration curve was linear in the range of 4.0–800 ng/mL. The method was applied to the determination of Rh in well and tap water, and spiked recoveries were in the range of 96–103.7%.

ECOLOGICAL AND PHYSIOLOGICAL ASSESSMENT OF CHEMICAL COMPOSITION OF DRINKING TAP WATER IN KHANTY-MANSIYSK AND SALEKHARD

2020 ◽  
pp. 159-167
Author(s):  
V.V. Lapenko ◽  
L.N. Bikbulatova ◽  
E.M. Ternikova
Keyword(s):  
Drinking Water ◽  
Chemical Composition ◽  
Water Samples ◽  
Tap Water ◽  
Iron Concentration ◽  
Absorption Spectrometry ◽  
Northern Region ◽  
Transport Processes ◽  
Magnesium Concentration ◽  
Geochemical Environment

Water is very important for humans, as it is a solvent for metabolic products. Moreover, it is necessary for metabolism, biochemical and transport processes. The elemental status in persons depends on the geochemical environment and consumption of bioelements with food and water. The aim of the paper is to conduct a comprehensive assessment of chemical composition of drinking tap water in Khanty-Mansiysk and Salekhard. Materials and Methods. The chemical composition of 100 samples of drinking tap water was analyzed by atomic absorption spectrometry, spectrophotometry and capillary electrophoresis. All in all, there were 50 samples from Khanty-Mansiysk and 50 samples from Salekhard. The results were compared with Sanitary Rules and Norms 2.1.4.1074-01. Results. Drinking tap water in Salekhard contains a significantly higher concentration of iron, which is much above the maximum allowable concentration, if compared to water samples in Khanty-Mansiysk (p=0.03). In the cities under consideration, the water undergoes high-quality reagent-free treatment. However, the deterioration of the water supply networks in Salekhard is 3 times as high as in Khanty-Mansiysk. Calcium and magnesium concentration in water samples from Khanty-Mansiysk is 5.6 and 3.9 times lower than the MAC; in water samples from Salekhard calcium concentration is 6.3 (p=0.008) and magnesium concentration 4.6 (p<0.001) times lower than the MAC. Conclusion. The consumption of ultra-fresh drinking water leads to low intake of bioelements, which are a part of enzymes contributing to the human antioxidant defense and can result in manifestation of cardiovascular diseases. This is especially true for Salekhard with very soft drinking water and high iron concentration, which excess can exhibit prooxidant properties. Keywords: tap water, bioelements, northern region, antioxidants. Вода является важнейшим соединением для человека: необходима в качестве растворителя продуктов метаболизма и протекания обменных, биохимических и транспортных процессов. Элементный статус организма человека зависит от геохимического окружения и поступления биоэлементов с пищей и водой. Цель. Провести комплексную оценку химического состава водопроводной воды городов Ханты-Мансийск и Салехард. Материалы и методы. Методами атомно-абсорбционной спектрометрии, спектрофотометрии и капиллярного электрофореза проанализирован химический состав 100 проб водопроводной воды: по 50 из Ханты-Мансийска и Салехарда. Результаты сравнивали с СанПиН 2.1.4.1074-01. Результаты. В водопроводной воде Салехарда установлена превышающая ПДК и достоверно более высокая концентрация железа сравнительно с водой Ханты-Мансийска (р=0,03). При условии качественной безреагентной водоподготовки в изучаемых городах это обусловлено изношенностью водопроводных сетей в Салехарде, более чем в 3 раза превышающей этот показатель в Ханты-Мансийске. Концентрация кальция и магния в воде Ханты-Мансийска в 5,6 и 3,9 раза ниже ПДК; в воде Салехарда – в 6,3 (р=0,008) и 4,6 (р<0,001) раза ниже ПДК соответственно. Заключение. Употребление ультрапресной питьевой воды на фоне очень малого поступления с водой биоэлементов, входящих в состав ферментов антиоксидантной защиты организма человека, может привести к манифестации кардиоваскулярных заболеваний. Это особенно актуально для г. Салехарда с очень мягкой питьевой водой с повышенным содержанием железа, избыток которого может проявлять прооксидантные свойства. Ключевые слова: водопроводная вода, биоэлементы, северный регион, антиоксиданты.

scholarly journals Determination of ultra-trace levels of palladium in water samples by cloud point extraction and graphite furnace atomic absorption spectrometry

2021 ◽  
pp. 174751982110273
Author(s):  
Quan Han ◽  
Yanyan Huo ◽  
Xiaohui Yang ◽  
Xing Yao
Keyword(s):  
Water Samples ◽  
Cloud Point Extraction ◽  
Graphite Furnace ◽  
Chelating Agent ◽  
Absorption Spectrometry ◽  
Graphite Furnace Atomic Absorption ◽  
Ultra Trace ◽  
Triton X ◽  
Optimized Conditions

A highly sensitive method for the determination of ultra-trace levels of palladium in water samples by cloud point extraction and graphite furnace atomic absorption spectrometry is developed. The procedure is based on complexation of palladium with a laboratory-prepared novel chelating agent, 2-(5-bromo-4-methyl-2-pyridylazo)-5-dimethylaminoaniline (5-Br-4-CH3-PADMA) and subsequent micelle-mediated extraction of the product using the non-ionic surfactant octylphenoxypolyethoxyethanol (Triton X-114) as an extracting agent. Analytical parameters affecting the separation and detection process, such as pH, concentration of the chelating agent and surfactant, equilibration temperature, and time are investigated. The optimized conditions are as follows: pH 6.0 HAc–NaAc buffer solution, 1 × 10−5 mol L−1 5-Br-4-CH3-PADMA, and 0.1% (w/v) Triton X-114. Under the optimized conditions, the calibration graph is linear in the range of 0.1–12 ng/mL, the detection limit is 0.05 ng/mL for palladium, and the relative standard deviation is 2.9% ( c = 1.0 ng/mL, n = 10). The enrichment factor, defined as the ratio of the aqueous solution volume to that of the surfactant-rich phase volume after dilution with HNO3–methanol solution, is 200. The proposed method is applied to the determination of palladium in water samples with satisfactory results.

Potentiation by L-cysteine of the bactericidal effect of hydrogen peroxide in Escherichia coli

1982 ◽  
Vol 152 (1) ◽  
pp. 81-88
Author(s):  
E H Berglin ◽  
M B Edlund ◽  
G K Nyberg ◽  
J Carlsson
Keyword(s):  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Metal Ion ◽  
Chelating Agent ◽  
Fold Increase ◽  
Bactericidal Effect ◽  
Anaerobic Conditions ◽  
Dna Breakage ◽  
E Coli ◽  
K 12

Under anaerobic conditions an exponentially growing culture of Escherichia coli K-12 was exposed to hydrogen peroxide in the presence of various compounds. Hydrogen peroxide (0.1 mM) together with 0.1 mM L-cysteine or L-cystine killed the organisms more rapidly than 10 mM hydrogen peroxide alone. The exposure of E. coli to hydrogen peroxide in the presence of L-cysteine inhibited some of the catalase. This inhibition, however, could not fully explain the 100-fold increase in hydrogen peroxide sensitivity of the organism in the presence of L-cysteine. Of other compounds tested only some thiols potentiated the bactericidal effect of hydrogen peroxide. These thiols were effective, however, only at concentrations significantly higher than 0.1 mM. The effect of L-cysteine and L-cystine could be annihilated by the metal ion chelating agent 2,2'-bipyridyl. DNA breakage in E. coli K-12 was demonstrated under conditions where the organisms were killed by hydrogen peroxide.

scholarly journals Equilibrium modeling of mono and binary sorption of Cu(II) and Zn(II) onto chitosan gel beads

2016 ◽  
Vol 37 (4) ◽  
pp. 485-501 ◽  
Author(s):  
Józef Nastaj ◽  
Małgorzata Tuligłowicz ◽  
Konrad Witkiewicz
Keyword(s):  
Metal Ion ◽  
Ph Value ◽  
Experimental Studies ◽  
Process Conditions ◽  
Optimal Process ◽  
Sorption Data ◽  
Gel Beads ◽  
Two Component ◽  
Equilibrium Data ◽  
Chitosan Gel

Abstract The objective of the work are in-depth experimental studies of Cu(II) and Zn(II) ion removal on chitosan gel beads from both one- and two-component water solutions at the temperature of 303 K. The optimal process conditions such as: pH value, dose of sorbent and contact time were determined. Based on the optimal process conditions, equilibrium and kinetic studies were carried out. The maximum sorption capacities equaled: 191.25 mg/g and 142.88 mg/g for Cu(II) and Zn(II) ions respectively, when the sorbent dose was 10 g/L and the pH of a solution was 5.0 for both heavy metal ions. One-component sorption equilibrium data were successfully presented for six of the most useful three-parameter equilibrium models: Langmuir-Freundlich, Redlich-Peterson, Sips, Koble-Corrigan, Hill and Toth. Extended forms of Langmuir-Freundlich, Koble-Corrigan and Sips models were also well fitted to the two-component equilibrium data obtained for different ratios of concentrations of Cu(II) and Zn(II) ions (1:1, 1:2, 2:1). Experimental sorption data were described by two kinetic models of the pseudo-first and pseudo-second order. Furthermore, an attempt to explain the mechanisms of the divalent metal ion sorption process on chitosan gel beads was undertaken.

scholarly journals MODIFYING WASTE POLYSTYRENE TO ION EXCHANGE MATERIAL: OPTIMIZING THE SULFONATION PROCESS AND COLUMN STUDY FOR THE REMOVAL OF Cr3+

2020 ◽  
Vol 58 (5A) ◽  
pp. 150
Author(s):  
Thuy Thi Pham ◽  
Hung Quoc Nguyen ◽  
Khai Manh Nguyen
Keyword(s):  
Ion Exchange ◽  
Metal Ion ◽  
Tap Water ◽  
Plastic Waste ◽  
Wildlife Habitat ◽  
Experimental Result ◽  
Model Parameters ◽  
Operational Parameter ◽  
Waste Polystyrene ◽  
Exchange Material

The incredible growth of plastic waste is a major concern for the whole society in recent years. The accumulation of plastic waste has badly effects on wildlife, habitat, and humans. Plastics that act as pollutants are categorized into different sizes, from micro to macro. Disposable plastic waste was collected at the bakery shop and removed the residue food by tap water and NaOH 1M to remove residual food. This study focuses on modify waste plastic by sulfuric acid to bind the sulfonated function group on the structure of the polystyrene chain at room temperature. The sulfonated product was used for removing heavy metal ion in water with the mechanism of the ion exchange process. The prepared ion exchange material was characterized by FTIR and SEM to ensure that the sulfonation process has happened. The chromium (III) ion removal by modified ion exchange product in continuous mode was affected by an operational parameter such as the bed height of sulfonated material. The Yoon-Nelson and Thomas model were used to analyze the experimental result and the model parameters were evaluated. From this result, it can be concluded that with the increasing amount of sulfonated waste polystyrene, exchange capacity, and the time required for a 50% adsorbate breakthrough was higher.

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