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Remediation studies of trace metals in natural and treated water using surface modified biopolymer nanofibers

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... Adsorption techniques have significant advantages, such as profitability, availability, low cost (for example, the price of adsorption by vermiculite is only 20% of osmotic membrane technology), high efficiency (for example, the adsorption efficiency of kyanite for Cu(II) can reach 100%), and ease of operation in comparison with other techniques (Ajmal et al. 2001;Keng et al. 2014). Moreover, it offers simple operation and high efficiency (the maximum efficiency can reach 100%) in the removal of toxic heavy metals, even at trace levels (Musyoka et al. 2013). The key to adsorption technology is to prepare environmentally friendly, cheap and efficient adsorbents. ...
... Clay is a type of small particle existing naturally on the earth's surface. It mainly consists of water, alumina, silica and weathered rocks (Murray 1991). Clay and clay composite materials have been developed as highly efficient adsorbents for heavy metal removal from aqueous solutions (Kasgoz et al. 2008;Mockovciakova et al. 2010). ...
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Heavy metal pollution such as water contamination by Pb, Hg, Cu, Cd and Cr ions is induced by rapid urbanization and industrialization and is a major threat to human health. One of the most efficient processes to clean contaminated water is adsorption. Adsorbents such as clay minerals and modified clays are efficient for the removal of metal ions from wastewater. This manuscript reviews current research in heavy metal adsorption by clay minerals such as halloysite, bentonite, montmorillonite, vermiculite and attapulgite, from 2013 to 2017, and highlights the main adsorption mechanisms. The structure, composition and synthesis of various clay minerals and modified clays are presented.
... proposed modified chitosan as promising, environmentally friendly adsorbents for use in pharmaceutical wastewater treatment. Nanofiber mats made of chitosan or cellulose were tested for adsorption of five trace toxic metals from water (Musyoka et al., 2013). Both materials were able to remove metals from river and treated water, though chitosan out-performed the cellulose. ...
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... Researchers proposed modified chitosan as promising, environmentally friendly adsorbents for use in pharmaceutical wastewater treatment. Nanofiber mats made of chitosan or cellulose were tested for adsorption of five trace toxic metals from water (Musyoka et al., 2013). Both materials were able to remove metals from river and treated water, though chitosan out-performed the cellulose. ...
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This literature review summarizes publications appearing in 2012 on water and wastewater research pertaining to chemical or biological emerging pollutants. Part I: Occurrence, Fate, and Transport (the companion to this review) includes discussion of occurrence of emerging pollutants, sources of emerging pollutants, fate and transport of emerging pollutants in the environment, monitoring approaches, modeling, and regulatory discussions. Part II: Treatment (this review) includes discussion of various water and wastewater treatment technologies on emerging pollutants.
... As regards the functionalization of fibers (point i), rhodanine is a heterocyclic molecule that belongs to the sulfur-containing N and O organic compounds which possesses uptake performance toward Ag (I), Pb (II), and Hg (II) ions (Lee et al. 2013). On the other hand cellulose and chitosan-/polyacrylamide-modified nanofibers have been proven to be suitable for the adsorption of trace of metals (Cd, Pb, Cu, Cr, and Ni) from the river water and treated water (Musyoka et al. 2013). Their adsorption capacity has been enhanced (point ii) by surface modification using furan-2,5-dione. ...
... However, after percolation through the functionalised biosorbents in cartridges, detectability of the metal ions was enhanced. These materials are useful tools in improving the quality of drinking water for household consumers (Musyoka et al., 2013). ...
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Biopolymers are substances naturally produced by living organisms and are hence considered to be eco-friendly and sustainable. Chitosan and cellulose are of specific significance owing to their abundant availability, ease of modification, and application potential. On the environmental front, their coagulating and flocculating effects have helped in wastewater clarification, while minimizing the dependability on synthetic polyelectrolytes. Biopolymer based hydrogels and nanocomposite films have functioned as effective biosorbents in removing an array of organic and inorganic pollutants, including xenobiotics, from wastewater. Specifically, they have been vastly harnessed for heavy metal and dye adsorption. They have also played a pivotal part in other environmental applications including anti-desertification, natural bio-sealants for preventing concrete leaks and proton conducting membranes in electrochemical devices. Such recent research on the environmental applications of biopolymers has been comprehensively analysed, thus providing a fresh insight into the future prospects of research in this domain.
... Human activities such as agriculture, irrigation, industrialization, urbanization and technological activities often release high levels (toxic) of heavy metal ions in the aquatic environment posing serious health hazard to the environment (Musyoka, Ngila, & Mamba, 2013).Usually, these toxic ions are stable under ambient conditions. They are not biodegradable and hence accumulate over time(Anuja Ashok Bhatt, 2015). ...
... Researchers proposed modified chitosan as promising, environmentally friendly adsorbents for use in pharmaceutical wastewater treatment. Nanofiber mats made of chitosan or cellulose were tested for adsorption of five trace toxic metals from water (Musyoka et al., 2013). Both materials were able to remove metals from river and treated water, though chitosan out-performed the cellulose.Molecularly imprinted silica sorbents were fabricated via an acid-catalyzed sol-gel process in the presence of a templating pollutant (Morais et al., 2013). ...
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The goal of this review is to summarize new research published in the field of emerging pollutants in the past year. For the purpose of the review, unregulated and relatively new compounds found in wastewater, drinking water, recycled water and the environment were considered. The review consists of two parts, with Part I focusing on the occurrence of the contaminants in the media mentioned above, and Part II focusing on the treatment technologies.
... The metal affinity to the mixed oxide nanocomposite fibers was found to be in the sequence of Cu < Pb < Ni < Hg [18]. Functionalized cellulose and chitosan nanofibers showed to be effective adsorbents for remediation of Pb(II) and Cu(II) ions from natural water samples and wastewater [19]. Aminated polyacrylonitrile (APAN) nanofiber mat was used for the removal of Ag(I), Cu(II), Pb(II), and Fe(II) from an aqueous solution. ...
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Bioinspired hybrid nanofibers on the basis of polystyrene and Spirulina biomass—pristine and modified—were produced. These nanofibers were characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The hybrid nanofibers have been utilized as adsorbents for the removal of copper and manganese ions from synthetic solution in batch mode at pH = 7, during a 2-h experiment. The maximum adsorption capacity was achieved for nanofibers with maximum Spirulina biomass loading: q = 8.7 mg/g for copper and 7.3 mg/g for manganese (with pristine biomass); q = 8.2 mg/g for copper and 7.0 mg/g for manganese (with modified biomass). The obtained results showed that the hybrid nanofiber could be successfully applied for metal removal from industrial effluents.
... Adsorption and catalysis are the best ways to reduce pollutants [14,15]. Adsorption processes are characterized by their low cost, efficient removal of heavy metals and are environmentally friendly [16,17]. ...
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Cellulose material C1 was prepared by grafting of glycidyl methacrylate (GMA) in the presence of Fenton-type reagent. This one-pot procedure provided C1 with glycidyl isobutyrate branches. Glycidyl epoxide ring opening with water turned C1-C2 material branched with glycerol isobutyrate. So, C1 surface bears hydrophobic branches ending with the glycidyl group, while C2 surface presents hydrophilic branches ending with the glycerol group. The adsorption of aromatic polluting substances like phenol (Ph), 4-nitrophenol (pNPh), 2,4-dinitrophenol (dNPh), 2,4,6-trinitrophenol (picric acid, tNPh) and 2-naphtol (BN) from their water solutions was tested with C1, C2 and with the untreated cellulose material C0. Phenol adsorption did not occur. All the other aromatic molecules were removed in different amount both by C1 and C2. C1 and C2 showed different affinities towards nitrophenols and 2-naphtol. While C1 was much more effective for removing the hydrophobic 2-naphtol, C2 had higher adsorption capacity towards the hydrophilic nitrophenols, in agreement with their branches polarity, respectively.
Article
In the present paper, a simultaneous pre-concentration procedure for the sequential determination of cadmium and lead in table salt samples using flame atomic absorption spectrometry is proposed. This method is based on the liquid-liquid extraction of cadmium(II) and lead(II) ions as dithizone complexes and direct aspiration of the organic phase for the spectrometer. The sequential determination of cadmium and lead is possible using a computer program. The optimization step was performed by a two-level fractional factorial design involving the variables: pH, dithizone mass, shaking time after addition of dithizone and shaking time after addition of solvent. In the studied levels these variables are not significant. The experimental conditions established propose a sample volume of 250mL and the extraction process using 4.0mL of methyl isobutyl ketone. This way, the procedure allows determination of cadmium and lead in table salt samples with a pre-concentration factor higher than 80, and detection limits of 0.3ngg(-1) for cadmium and 4.2ngg(-1) for lead. The precision expressed as relative standard deviation (n = 10) were 5.6 and 2.6% for cadmium concentration of 2 and 20ngg(-1), respectively, and of 3.2 and 1.1% for lead concentration of 20 and 200ngg(-1), respectively. Recoveries of cadmium and lead in several samples, measured by standard addition technique, proved also that this procedure is not affected by the matrix and can be applied satisfactorily for the determination of cadmium and lead in saline samples. The method was applied for the evaluation of the concentration of cadmium and lead in table salt samples consumed in Salvador City, Bahia, Brazil.
Article
In the present study ion exchange of Pb(2+), Cu(2+), Fe(3+), and Cr(3+) on natural Greek clinoptilolite was examined in terms of selectivity toward the above heavy metals in single- and multicomponent solutions in batch systems. Also examined are the influence of clinoptilolite on solution acidity and the effect of acidity on the ion exchange process. Clinoptilolite increases solution acidity due to the exchange of H(+) cations with the cations initially present in its structure. H(+) cations should be considered as competitive ones in ion exchange processes, and consequently ion exchange of metals is favored at high acidity values. Cu(2+) and Cr(3+) are the most sensitive cations with respect to acidity. Selectivity determination demonstrates that the selectivity at total concentration 0.01 N and acidity 2 in both single- and multicomponent solutions is following the order Pb(2+)>Fe(3+)>Cr(3+) > or =Cu(2+). This order is set since the first days of equilibration. However, Cu(2+) shows remarkable changes in selectivity and generally its uptake and selectivity are increasing with time. On the other hand selectivity in single metal solutions where acidity is not adjusted is following the order Pb(2+)>Cr(3+)>Fe(3+) congruent with Cu(2+).
Article
In this study, akaganeite (beta-FeO(OH)) an ironoxyhydroxide material, was used as a low-cost potential adsorbent for the removal of hexavalent chromium from aqueous solutions. The influence of agitation speed, solution pH, initial chromium concentration, sorbent concentration and temperature were evaluated at batch kinetic runs. It was shown that the solid diffusion model, in comparison to simple reaction kinetic models, described better the sorption kinetics. Freundlich and Frumkin isotherm best fitted the equilibrium results. Akaganeite presented a sorption capacity approximately 80 mg Cr(VI) g(-1), under the conditions studied. Flotation was used as a downstream process for the effective removal of the loaded material.
Article
This paper describes the adsorption of heavy metal ions from aqueous solutions by oak (Quercus coccifera) sawdust modified by means of HCl treatment. Our study tested the removal of three heavy metals: Cu, Ni, and Cr. The optimum shaking speed, adsorbent mass, contact time, and pH were determined, and adsorption isotherms were obtained using concentrations of the metal ions ranging from 0.1 to 100mgL(-1). The adsorption process follows pseudo-second-order reaction kinetics, as well as Langmuir and D-R adsorption isotherms. The paper discusses the thermodynamic parameters of the adsorption (the Gibbs free energy, entropy, and enthalpy). Our results demonstrate that the adsorption process was spontaneous and endothermic under natural conditions. The maximum removal efficiencies were 93% for Cu(II) at pH 4, 82% for Ni(II) at pH 8, and 84% for Cr(VI) at pH 3.
Article
Cellulose was first modified with thionyl chloride, giving 99% substitution at C6, and then reacted with ethylene-1,2-diamine to produce 6-(2'-aminoethylamino)-6-deoxy-cellulose. From the 8.5% of nitrogen incorporated in the polysaccharide backbone, the amount of ethylene-1,2-diamine anchored per gram of modified cellulose was determined to be 3.03+/-0.01mmol. This chemically immobilized surface was characterized by FTIR, TG, (13)C NMR, and SEM techniques. The available basic nitrogen centers covalently bonded to the biopolymer skeleton were studied for copper, cobalt, nickel, and zinc adsorption from aqueous solutions and the respective thermal adsorption effects were determined by calorimetric titration. The ability to adsorb cations gave a capacity order of Co(2+)>Cu(2+)>Zn(2+)>Ni(2+) with affinities of 1.91+/-0.07, 1.32+/-0.07, 1.31+/-0.02, and 1.08+/-0.04mmol/g, respectively. The net thermal effects obtained from calorimetric titration measurements were adjusted to a modified Langmuir equation and the enthalpy of the interaction was calculated to give the following exothermic values: -20.8+/-0.05, -11.72+/-0.03, -7.32+/-0.01, and -6.27+/-0.02kJ/mol for Co(2+), Cu(2+), Zn(2+), and Ni(2+), respectively. With the exception of the entropic value for copper, the other thermodynamic data for these systems are favorable for cation adsorption from aqueous solutions at the solid/liquid interface, suggesting the use of this anchored biopolymer for cation removal from the environment.
Article
A novel activated nylon-based membrane was prepared and applied as an adsorbent for the removal of Cu2+ from aqueous solutions. It involved three stages: (i) deposition of a chitosan layer that functionalized the nylon membrane, (ii) cross-linking with epichlorohydrin to stabilize the polymer layer and enabling grafting, and (iii) iminodiacetic acid grafting. SEM and EDX techniques were used to characterize the composition of the membranes. Dynamic adsorption experiments on membranes were carried out at various pH values, contact times, adsorption dosages and initial metal concentrations to determine optimum membrane adsorption properties. The adsorption isotherm relating to Cu2+ fitted the Langmuir equation and an adsorption equilibrium constant and adsorption capacity of 2.345x10(-3)mg/ml and 10.794mg/g were determined, respectively. The experimental data was analyzed using two adsorption kinetic models, pseudo-first-order and pseudo-second-order with the latter system providing the best fit. Finally complete regeneration of the activated nylon membrane was possible using 100mmol/l Na2EDTA.
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