دانلود رایگان مقاله لاتین جذب پالادیم از سایت الزویر
عنوان فارسی مقاله:
جذب پالادیم (II) یون های کلسیم آلژینات مهره ژل در غلظت کلرید مختلف و pH. مطالعه جنبشی و تعادل
عنوان انگلیسی مقاله:
Sorption of Pd(II) ion by calcium alginate gel beads at different chloride concentrations and pH. A kinetic and equilibrium study
سال انتشار : 2016
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مقدمه انگلیسی مقاله:
1. Introduction
The particular physical and chemical properties, especially the catalytic ones, make palladium one of the most important platinum group elements (PGE). This metal is very useful for several purposes in different fields such as industry, agriculture and medicine (Renner and Schmuckler, 1991; Zereini and Alt, 2006). The subsequent recovery of palladium from wastewaters and from no longer used materials is of great importance because of: (i) its toxicity towardsplants, animals and humans that imposes very low concentration limits in the environment; (ii) its relatively low availability that makes the recovery of the metal ion very important from the economical point of view (Renner and Schmuckler, 1991; Zereini and Alt, 2006). Among the different techniques (Hubicki et al., 2008; Liu et al., 2009; Spitzer and Bertazzoli, 2004) commonly used for the removal/recovery of metal ions from wastewaters and other aqueous solutions the biosorption is the most promising (Das, 2010; Mack et al., 2007; Wang and Chen, 2009; Wase and Forster, 1997). The biomaterials used in this technique for the removal of metal ions should be available in large quantities, inexpensive and biodegradables and usually should have high yields in terms of metal ion uptake. Several articles and reviews have been published on the use of different types of biomasses as sorbent material, e.g., algae, bacteria, fungi, pulp and peel of different fruits, etc (Volesky, 2001, 2003). All these biomaterials contain large amounts of polyelectrolytes with high binding capacity towards metal ions that are mainly responsible for the metal uptake ability of these substances (Bailey et al., 1999; Reddad et al., 2002; Volesky, 2003; Wang and Chen, 2009; Wase and Forster, 1997). Among these natural polyelectrolytes the most studied are alginic acid (AA), chitosan and pectin, which are present in large amounts in algae, shell of crustaceans and pulp and peel of several fruits, respectively (Bailey et al., 1999; Kelco, 1987; Mata et al., 2009; Reddad et al., 2002; Thakur et al., 1997). The use of raw materials as biosorbent for the removal of palladium(II) from water solutions was proposed from several authors (Das, 2010; de Vargas et al., 2004; Mack et al., 2007) but few studies were carried out on the direct use of the natural polyelectrolytes contained therein. In particular, among the cited polyelectrolytes only chitosan and modified chitosan gels were considered for palladium(II) ion removal (Ramesh et al., 2008; Ruiz et al., 2000, 2002; Zhou et al., 2009). The direct use of these polyelectrolytes can be very useful since their extraction is usually simple and inexpensive (Kelco, 1987; Mata et al., 2009; Thakur et al., 1997) and their sorption capacity towards metal ions may be greater than that of the raw materials from which they are extracted. Moreover, the reuse of the sorbent and the recovery of the metal ion are usually possible and easy to do (Mata et al., 2009, 2010). In this work the use of gel beads of calcium alginate (CaAA) as sorbent material for Pd(II) removal from aqueous solutions is proposed and different techniques were used for its characterization (Section 4.1). Alginic acid is a copolymer of 1,4 linked b-D-mannuronic and a-L-guluronic acid residues contained in high percentages in brown algae (Kelco, 1987) whose acid–base properties are due to the carboxylic groups of the monomer units (Crea et al., 2009; Lagoa and Rodrigues, 2007). Alginic acid can easily gel in the presence of divalent cations, especially calcium(II) ion, and calcium alginate salt gel has been widely tested as sorbent material for different metal ions’ removal (Cataldo et al., 2013a,b; Gotoh et al., 2004a; Papageorgiou et al., 2006). According to the chemical behaviour of the metal ion to be removed from aqueous solution and the acid–base properties of the sequestering agent, the right experimental conditions of the solution have to be assessed before the sorption studies. In particular, the formation of uncharged or negatively charged hydrolytic or complex species and low soluble species of Pd(II) were avoided or reduced. Therefore, a solution speciation study is preliminary needed: (i) to define the pH value useful to avoid metal hydrolysis and to assure an adequate amount of deprotonated binding sites of the sorbent material; (ii) to check for the formation of complex species formed by the metal ion with other ligands potentially present in the solution; (iii) to know the strength of interaction between the metal ion and the sequestering agent. This study is particularly important for Pd(II) ion which undergoes strong hydrolysis at very low pH and is able to form quite stable species with chloride ion which is usually present in natural aqueous systems. Details on the results from the speciation study carried out on the Pd-AA in aqueous solution are reported in Section 4.2. Adsorption of palladium(II) ion from solution onto calcium alginate gel beads was evaluated by kinetic and thermodynamic investigations carried out in batch mode as function of contact time, chloride concentration and pH, by considering the solution conditions more favourable to the metal sorption, as results from speciation studies. Data from kinetic and thermodynamic measurements were processed by a pseudo second order equation and Langmuir and Freundlich models, respectively (see Sections 4.3 and 4.4). Several mechanisms of biosorption have been proposed by different authors to justify the sorption ability of CaAA and other biomaterials, towards metal ions such as ion exchange, complexation, chelation, physical adsorption and microprecipitation (Park et al., 2010; Volesky, 2001). In order to verify the hypothesis according to which the sorption process occurs by an ion exchange mechanism, as we found for other metal ions sorption by calcium alginate gel beads (Cataldo et al., 2013a,b), a parallel study on the kinetics of calcium release from gel beads was also carried out. Some similarities were found between the parameters of alginate sequestering ability towards Pd(II) ion in aqueous solution (% PdAA species, pL0.5), obtained by the results of speciation analysis, and the parameters of sorption process by CaAA gel beads (qe, qmax). A detailed discussion on this point is reported in Section 4.5. Finally, to put into perspective these results, our data were compared with those of the literature (see Section 4.6)
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[PDF]Sorption of Pd(II) ion by calcium alginate gel beads at different ... iranarze.ir/wp-content/uploads/2016/10/E2200.pdf Oct 23, 2014 - towards Pd(II) ion was made in aqueous solution at different pH and chloride ... 6 10 the gel beads showed good sorption ability towards Pd(II). Sorption of Pd(II) ion by calcium alginate gel beads at different ... https://unipa.pure.elsevier.com/.../sorption-of-pdii-ion-by-calcium-alginate-gel-beads-... A kinetic and thermodynamic study on the sorption ability of calcium alginate gel beads towards Pd(II) ion was made in aqueous solution at different pH and ... [PDF]sorption of palladium(ii) on lewatit mp 62 – equilibrium and ... - IAEA www.iaea.org/inis/collection/NCLCollectionStore/_Public/39/093/39093601.pdf by A WOŁOWICZ - Related articles 2.0 M HCl – 1.0 M NaCl – 100 ppm Pd(II); 0.1 – 2.0 M HCl – 2.0 M NaCl – 100 ppm Pd(II) was discussed. The sorption research of Pd(II) complexes on this resin. Sorption of palladium(II) from nitric acid solutions by silica modified ... link.springer.com/article/10.3103/S1067821216050175 by EV Volchkova - 2016 - Related articles Abstract. The sorption of Pd(II), Ag(I), and Cu(II) from nitric acid solutions with silicas chemically modified with γ-(aminopropyl)trietoxysiloxane is investigated. Radionuclide and Metal Sorption on Cement and Concrete https://books.google.com/books?isbn=3319236512 Michael Ochs, Dirk Mallants, Lian Wang - 2015 - Technology & Engineering Solubility equilibria controlled by Pd(OH)2(s) at different states of cement degradation are ... No sorption data for Pd on cementitious materials have been found. Sorption of palladium(II) - Taylor & Francis Online www.tandfonline.com/doi/pdf/10.1080/01496395.2017.1281953?needAccess=true The sorption kinetics of Pd(II) from hydrochloric acid solutions by 1 and 2 ... efficiently adsorb Pd(II) from single metal solution and automotive catalyst residue ... Chemical activity of palladium clusters: Sorption of hydrogen. - NCBI https://www.ncbi.nlm.nih.gov/pubmed/17064140 by SY Huang - 2006 - Cited by 36 - Related articles Chemical activity of palladium clusters: Sorption of hydrogen. ... Samples of Pd/SiO2 with average cluster size of palladium (d(Pd)) ranging from 1 to 10 nm were ...
