Presence Of Other Competitive Ions Research Articles

Removal of cobalt and strontium by adsorption using Brewer's spent grain formed by pyrolysis.

One byproduct of brewing beer is Brewer's spent grain (BSG), which is reused in animal feed. However, BSG has valuable potential for other products such as biochar because of its high protein and fiber content. Radioactive waste is one of the biggest concerns in Korea because of the permanent shutdown of the Gori nuclear power plant. In this study, we aimed to use BSG-850, a biochar originating from BSG after pyrolysis at 850°C, for the adsorption of cobalt (Co) and strontium (Sr), which are two radionuclides that contribute to radioactive waste. The adsorption capacity of Co and Sr was reinforced with increased temperature which are 3.304, 4.659, 5.516mg/g (Co) and 1.462, 2.54, 3.036mg/g (Sr) at 298, 308, and 318K, respectively. The reusability of BSG-850 capacity was 75.3, 47.8, 43.6, 36.2% and 93.6, 84.2, 57.2, and 32.7% after 1, 2, 3, and 4 cycles, for Co and Sr, respectively. In the presence of other competitive ions, the adsorption capacity decreased. The adsorption capacity and properties of BSG-origin biochar for Co and Sr were confirmed and BSG can be a desirable option for solving radioactive waste issue.

A coumarin-salicylidene based fluorescent chemodosimeter for sub-ppb level detection of aluminium ion via metal ion induced hydrolytic cleavage of aldimine bond

In this report, we have synthesized a coumarin-functionalized salicylidene receptor, DTC and evaluated its metal ion recognition characteristics by using UV–visible, fluorescence spectroscopy and ESI-MS techniques. It is observed that the receptor acts as a chemodosimeter to detect Al3+ ion selectively amongst various interfering cations. It shows a detection limit of 0.94 ppb (parts per billion) which is superior over the salicylidene-based receptors reported earlier and is far below the detection limit of aluminium ions in drinking water as recommended by WHO. The receptor (DTC) undergoes the hydrolytic cleavage only upon interaction with Al3+ ions even in the presence of other competitive ions and elicits a distinct visual colour change from yellow to colourless accompanied by the quenching of green fluorescent signal at 520 nm in the receptor solution. The mechanism of interaction of Al3+ with DTC has been evaluated from UV–visible and fluorescence studies along with ESI-MS analysis and further corroborated by quantum mechanical calculations.

Removal of arsenic by metal organic framework/chitosan/carbon nanocomposites: Modeling, optimization, and adsorption studies

In this work removal of the arsenic (As) spiked in water through adsorption using synthesized nanocomposites as a adsorbent. The Zn-BDC@chitosan/carbon nanotube (Zn-BDC@CT/CNT) and Zn-BDC@chitosan/graphene oxide (Zn-BDC@CT/GO) were synthesized from metal organic framework, carbon nanotube/graphene oxide and natural polysaccharide. Results of adsorption experiments showed that the Zn-BDC@CT/GO possessed a higher adsorption capacity than that of the Zn-BDC@CT/CNT. A study on the adsorption of As onto Zn-BDC@CT/GO was conducted and the process parameters were optimized by response surface methodology (RSM). A five-level, four-factor central composite design (CCD) has been used to determine the effect of various process parameters on As uptake from aqueous solution. By using this design a total of 20 adsorption experimental data were fitted. The regression analysis showed good fit of the experimental data to the second-order polynomial model with coefficient of determination (R2) value of 0.9997 and model F-value of 1099.97. The adsorption matched with the pseudo-second-order model and the Freundlich model. The thermodynamic parameters revealed that the nature of adsorption was feasible, spontaneous and endothermic process. Adsorption of As in the presence of other competitive ions was not significantly affected The effective adsorption performance also sustained even after ten adsorption-desorption cycles, indicating favorable reusability.

A new subtle and integrated detector to sense Hg2+ ions: A vision towards its applicability on water samples and live cells

A facile and efficient optical fluorescent probe [(2,2′-((propane-2,2-diylbis(6-vinyloxy)-3,1-(phenylene))bis(methaneylylidene))dimalanonitrile] (BMC) was designed and synthesized to sense Hg2+ ions via intramolecular cyclization process. The synthesized probe BMC exhibits a selective and sensitive absorption and emission wavelength for Hg2+ ions in presence of other competitive ions with the LOD of 18.4 nM. The control compound BM was also synthesized and the spectral properties were compared with BMC + Hg2+ ions solution. Moreover, the excellent specificity nature of the probe BMC contributes its usage towards the detection of Hg2+ ions in real samples and live HeLa cancer cells visualization.

A Novel Colorimetric Chemosensor Based on Ferene-S-Conjugated Silver Nanoparticles for Selective Recognition of Fe2+

Ferene is the most commonly used chromogenic agent for the determination of serum iron in blood. In this work we have successfully synthesized Ferene-S-conjugated silver nanoparticles (Ferene-S-AgNPs) for the first time characterized by UV-visible, Fourier-Transform Infrared Spectroscopy (FTIR), and Matrix-Assisted Laser Desorption/Ionization-Time Of Flight (MALDI-TOF) mass spectrometry techniques. Particle size of the synthesized nanoparticles was determined by atomic-force microscopy and scanning electron microscopy techniques with size ranges from 10–90 nm in diameter. Ferene-S-AgNPs were explored for their chemosensing potential with various metal ions such as Sb3+, Pb2+, Ca2+, Fe2+, K+, Co2+, Ba2+, V5+, Cu+, Cd2+, Hg2+, Ni2+, Cu2+, Fe3+, Mg2+, Mn2+, Al3+, and Cr3+. Ferene-S-AgNPs were found to show selective quenching effects and slight bathochromic shifts to the surface plasmon resonance absorption band after treatment with Fe2+. Furthermore, the developed chemosensor also exhibited substantial selectivity towards Fe2+ in the presence of other competitive ions. We observed that Ferene-S-AgNPs mimic the selectivity of the parent compound of Ferene towards Fe2+. The system obeyed Beer’s law over concentration ranges of 110–190 nM. The detection limit was found to be 110 nM.

Fabrication of nickel-tagged magnetic imprinted polymeric network for the selective extraction of Ni(II) from the real aqueous samples.

A new nickel ion, magnetic imprinted polymer was fabricated through the precipitation polymerization process, using amine-functionalized silica-capped iron oxide particles as a core material, and 4-vinyl pyridine as complexing agent methacrylic acid as functional monomer. The resulted magnetic adsorbent was employed to eliminate toxic Ni2+ ions from industrial wastewater. The different parameters were optimized, such as pH, shaking speed, and adsorbent dose, to obtain the maximum adsorption capacity. The synthesized material showed high selectivity coefficient for Ni+2 ions in the presence of other competitive ions and followed pseudo-second-order kinetics and Langmuir isotherm. A good adsorption capacity of 158.73 mg g-1 was obtained at optimized pH 6 in the concentration of 5 mg L-1 nickel ions aqueous solution. The limit of detection, quantification, and the percent relative standard deviation was found to be 0.58, 1.93, and 3.4%. This proves the excellent performance of prepared magnetic Ni(II) ion-imprinted polymer for selective detoxification of Ni2+ ions from real aqueous samples. Due to tunable magnetic properties, the prepared MMIPs are highly selective and sensitive and highly porous in nature; due to excellent magnetic properties, there is no need for centrifugation. Just use external magnetic field, it has good reusability. Showing preparation of Ni (II) imprinted magnetic polymer.

A quick accelerating microwave-assisted sustainable technique: permutated spiro-casing for imaging experiment.

A quick access tool for the one-pot, chromatography-free synthesis of the diversified dihydrospiro[indeno[1,2-b]pyridine-4,3'-indoline or acenaphthylene-1,4'-indeno[1,2-b]pyridine spiro-analogous via sustainable microwave condition in minimal 1:1 (v/v) aqueous ethanol without any metal catalyst is demonstrated here. This permutated spiro-casing was designed as fluorescence probe at physiological pH for selective detection of Zn2+, even in the presence of other competitive ions and showed a fluorescent enhancement with 1:1 metal/ligand complex. Moreover, this spiro sensor was successfully applied as an effective intracellular Zn2+ imaging agent in the biomedical study of human hepatocellular liver carcinoma cells (HepG2) due to its cell permeability property. A quick access technique for the permutated dihydrospiro-pyridine via chromatography-free sustainable microwave condition and its applications as organic fluorescence probe at physiological pH for selective detection of Zn2+ and effective intracellular Zn2+ imaging in HepG2 cells.

Unprecedented chemosensing behavior of novel tetra-substituted benzimidazole zinc(II) phthalocynine for selective detection of Bi3 + ion: Synthesis, characterization and ROS generation

In this work, synthesis of novel symmetrical 4-(2-bromo-4-(5-bromo-1H-benzo[d] imidazol-2-yl) phenoxy) tetra substituted zinc phthalocyanine has been reported. The novel benzimidazole zinc phthlocynine compound (3) has been characterized by MALDI-TOF MS, FT-IR, UV–vis, and 1H NMR spectroscopy. This new compound 3 displayed excellent selectivity towards Bi3+ ion in the presence of other competitive ions including Ca2+, Cd2+, Co2+ Cu2+, Fe3+, Hg2+, Sn2+, Mg2+, Na+, Ni2+ and Pb2+ respectively. Upon addition of Bi3+ into the solution of compound 3 in DMSO, dramatic change was observed in the Q- and the B-bands in UV–visible spectra as a result of donor acceptor interactions. Reactive oxygen species (ROS) were also studied using 2,7-dichlorofluorescin diacetate (DCFH-DA) a fluorescent probe which is converted to highly fluorescent dichlorofluorescein (DCF) in the presence of ROS. This property of non-aggregating zinc phthalocyanine is promising as a photosensitizer in photodynamic therapy of cancer.

An azine based sensor for selective detection of Cu2 + ions and its copper complex for sensing of phosphate ions in physiological conditions and in living cells

A simple and cost effective unsymmetrical azine based Schiff base, 5-diethylamino-2-[(2-hydroxy-benzylidene)hydrazonomethyl]-phenol (1) was synthesized which selectively detect Cu2+ ions in the presence of other competitive ions through “naked eye” in physiological conditions (EtOH–buffer (1:1, v/v, HEPES 10mM, pH=7.4)). The presence of Cu2+ induce color change from light yellow green to yellow with the appearance of a new band at 450nm in UV–Vis spectra of Schiff base 1. The fluorescence of Schiff base 1 (10μM) was quenched completely in the presence of 2.7 equiv. of Cu2+ ions. Sub-micromolar limit of detection (LOD=3.4×10−7M), efficient Stern–Volmer quenching constant (KSV=1.8×105Lmol−1) and strong binding constant (log Kb=5.92) has been determined with the help of fluorescence titration profile. Further, 1−Cu2+ complex was employed for the detection of phosphate ions (PO43−, HPO42− and H2PO4−) at micromolar concentrations in EtOH–buffer of pH7.4 based on fluorescence recovery due to the binding of Cu2+ with phosphate ions. Solubility at low concentration in aqueous medium, longer excitation (406nm) and emission wavelength (537nm), and biocompatibility of Schiff base 1 formulates its use in live cell imaging.

Iron oxide and its modified forms as an adsorbent for arsenic removal: A comprehensive recent advancement

Abstract Arsenic, one of the elements having most terrible impact on the human being, is threatening the world continuously. It exists in the combined form in rocks under earth which on dissolution contaminates ground water. The contamination has led to a massive epidemic in East and South-East Asia, and the problem is more dangerous for Bangladesh and adjoining province, Bengal of India, where more than 100 million people are currently affected by arsenic contaminated ground water. Arsenic exists in water as oxyacids in two oxidation states, As(III) and As(V), the former is more toxic. Various techniques are under use for the removal of both forms of arsenic but most of these are not suitable for As(III) form. Adsorption has been proved most preferable technique for the removal of both forms of arsenic. Various types of solid materials had been used as adsorbent but nanomaterials have been reported more effective. However, some of these materials are toxic, difficult to separate after adsorption, and ineffective in the presence of water constraints. Iron oxides and its modified forms overcome all these shortcomings. Arsenic adsorption using various types of iron oxides has been surveyed and their sorption efficiencies have been compared herein. The effect of presence of other competitive ions in water has also been discussed. The valuable literature available on arsenic remediation, latest advancement, implementation of iron oxides in filters, and future perspective along with safe disposal of sludge produced have been incorporated.

Ammonium removal from high-strength aqueous solutions by Australian zeolite

ABSTRACTRemoval of ammonium nitrogen (NH4+-N) particularly from sources which are highly rich in nitrogen is important for addressing environmental pollution. Zeolites, aluminosilicate minerals, are commonly used as commercial adsorbents and ion-exchange medium in number of commercial applications due to its high adsorption capacity of ammonium (NH4+). However, detailed investigations on NH4+ adsorption and ion exchange capacities of Australian natural zeolites are rare, particularly under higher NH4+ concentrations in the medium. Therefore, this study was conducted to determine NH4+ adsorption characteristics of Australian natural zeolites at high NH4+ concentrations with and without other chemical compounds in an aqueous solution. Results showed that initial NH4+ concentration, temperature, reaction time, and pH of the solution had significant effects on NH4+ adsorption capacity of zeolite. Increased retention time and temperature generally had a positive impact on adsorption. Freundlich model fitted well with adsorption process of Australian natural zeolites; however, Langmuir model had best fitted for the adsorption process of sodium (Na+) treated zeolites. NaCl treatment increased the NH4+ adsorption capacity of Australian zeolites by 25% at 1000 mg-N, NH4+ solution. The maximum adsorption capacity of both natural Australian zeolites and Na+ treated zeolites were estimated as 9.48 and 11.83 mg-N/g, respectively, which is lower than many zeolites from other sources. Compared to the NH4+ only medium, presence of other competitive ions and acetic acid in the medium (resembling composition in digested swine manure slurries) reduced NH4+ removal of natural and Na+ treated zeolites by 44% and 57%, respectively. This suggests detailed investigations are required to determine practically achievable NH4+ -N removal potential of zeolites for applications in complex mediums such as animal manure slurries.

Solvent impregnated carbon nanotube embedded polymeric composite beads: An environment benign approach for the separation of rare earths

An environment benign process for the separation of rare earths has been delineated for the first time by developing polyethersulfone based composite beads through phase inversion method, where the use of hazardous organic diluents could be circumvented. The porosity and pore structure of these beads were controlled through different additives, of which, polyvinyl alcohol and multiwall carbon nanotubes proved to be the most efficacious. The extraction efficiency of rare earths was ameliorated by four fold with the application of the developed nanotube incorporated beads. The influence of various process parameters, namely, aqueous phase acidity, metal ion concentration, presence of other competitive ions and temperature on the separation of representative yttrium ion has been elaborated in the present investigation. The experimental results attribute to the excellent stability and reusability of the developed beads. The feasibility of employing this novel technology in large scale has been established by successful operation in continuous column mode. The developed assay exhibits profound application towards a greener approach due to the elimination of hazardous organic diluents and prevention of significant organic extractant loss during the process of recovery of rare earths from aqueous media.

Fluorescent sensor for selective detection of Al3+ based on quinoline–coumarin conjugate

A fluorescence probe, 8-formyl-7-hydroxyl-4-methyl coumarin – (2′-methylquinoline-4-formyl) hydrazone (L) has been synthesized. The chemosensor is found preferential binding to Al3+ in presence of other competitive ions with associated changes in its optical and fluorescence spectra behavior. Upon addition of Al3+ to a solution of L, it shows 200-fold enhancement of fluorescence intensity which might be attributed to form a 2:1 stoichiometry of the binding mode of LAl(III) and the chelation enhanced fluorescence (CHEF) process at 479nm in ethanol. The lowest detection limit for Al3+ is determined as 8.2×10−7M.

Chemical treated laterite as promising fluoride adsorbent for aqueous system and kinetic modeling

Efficiency of acid–base treated raw laterite (RL) is investigated for removal of fluoride. FTIR, SEM-EDX, and surface area analyzer are used to characterize the treated laterite (TL). The batch adsorption of fluoride is explored using TL under varying process conditions like adsorbent dose, pH of solution, temperature, particle size and contact time. The adsorption isotherm data of fluoride ions on TL are fitted well to both Langmuir and Freundlich models. The temperature dependent maximum Langmuir adsorption capacities of fluoride ion on TL are found to be 36.3, 37.9, and 39.1 mg/g at 288, 305, and 315 K, respectively. A simple shrinking core model is applied to predict the batch adsorption kinetics of fluoride ions onto treated laterite (TL). In the proposed two-resistance model, external mass transfer (K f) and pore diffusion coefficient (D e) are estimated by comparing the simulated concentration profile with the experimental data using a non-linear optimization technique. Estimated values of D e and K f are found to be 4.8 × 10 −10 m 2/s and 8.5 × 10 −4 m/s at 305 K, respectively. The fluoride adsorption in presence of other competitive ions as well as desorption of fluoride ions from spent adsorbent are studied in detail.

Adsorption Characteristics of Oxycellulose in a Competitive Environment with other Substances

A comparison was undertaken of the sorption response of oxycellulose and initial linters, i.e. the short fibres that adhere to cotton seed after ginning, towards Fe2+, Ca2+ and Cd2+ ions in fibrous slurries. The exceptional adsorption capability of oxycellulose towards metal ions (particularly Cd2+ ions) was confirmed. However, such adsorption processes are quite complicated and are influenced by the solubility of oxycellulose, its composition and the character of the components released into the supernatant, as well as by the presence of other competitive substances and ions in the aqueous solution. The adsorption capacity of oxycellulose increases with increasing -COOH group content and is distinctly increased by the presence of other competitive ions in the aqueous solution. Most probably, this enhanced adsorption capacity of the support bears some analogy to the superficial aggregation (flocculation) induced by the presence of foreign substances.