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In this study the selective adsorption method was chosen to enable the recovery of erythromycin. The following sorbents were tested: neutral resins (XAD-4, XAD-7 and XAD-16) and an anionic resin (IRA-410). A mathematical kinetic m...
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In this study the selective adsorption method was chosen to enable the recovery of erythromycin. The following sorbents were tested: neutral resins (XAD-4, XAD-7 and XAD-16) and an anionic resin (IRA-410). A mathematical kinetic model for the adsorption of erythromycin against time, on XAD-4, XAD-7 and XAD-16 resins, is proposed. Both Freundlich and Langmuir models showed a good fit for the sorbents XAD-7 and IRA-410 resins. The highest adsorption efficiency was observed when synthetic neutral resin, XAD-7 and XAD-16, were used. The estimated affinity and concentration factors show that the neutral resins tested are adequate for the selective adsorption of erythromycin. The estimated values of enthalpy and free energy of adsorption, lower than 12 kJ mol~(-1) and –2 kJ mol~(-1), respectively, indicate that a physiosorption process occurred.
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Six resins (Amberlite XAD-16, Amberlite XAD-2, Sepabeads SP207, DIAION HP-20, DM11 and H103) were tested for vanillin adsorption in aqueous solution. All of the resins gave more than 95% adsorption rate except for Amberlite XAD-2 ...
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Six resins (Amberlite XAD-16, Amberlite XAD-2, Sepabeads SP207, DIAION HP-20, DM11 and H103) were tested for vanillin adsorption in aqueous solution. All of the resins gave more than 95% adsorption rate except for Amberlite XAD-2 and DM11. Resin H103 was selected for the subsequent work due to its high adsorption capacity and low cost. A kinetic analysis revealed that the adsorption process followed pseudo-second-order kinetic model and occurred rapidly. The equilibrium point was reached after 90 minutes of reaction. Adsorption isotherm was also determined at 25 C and it was fitted to Langmuir and Freundlich equations using linear regression and non-linear regression (sum of squares) methods. The regression shows that the adsorption of vanillin onto resin H103 followed Langmuir model (R2 = 0.9984) with a maximum capacity of 73.015 mg/g.
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The experiments on the adsorption of phenols from aqueous solution by Amberlite XAD-4, a polystyrene-divinylbenzene resin without functional group, were carried out under different con- ditions. The phenols studied in this researc...
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The experiments on the adsorption of phenols from aqueous solution by Amberlite XAD-4, a polystyrene-divinylbenzene resin without functional group, were carried out under different con- ditions. The phenols studied in this research include 2-chlorophenol, 2, 4-dichlorophenol, 2, 4, 6- trichlorophenol, 2-nitrophenol, 2-4-dinitrophenol, 2-methylphenol, and 2, 4-dimethylphenol.
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This work pertains to the synthesis, characterization, DFT, and sorption studies of a novel polystyrene-supported 4-(5-mercapto-1,3,4-thiadiazol-2-ylimino) pentan-2-one Schiff bases from 5-amino-1,3,4-thiadiazole-2-thiol (PSAc5A) ...
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This work pertains to the synthesis, characterization, DFT, and sorption studies of a novel polystyrene-supported 4-(5-mercapto-1,3,4-thiadiazol-2-ylimino) pentan-2-one Schiff bases from 5-amino-1,3,4-thiadiazole-2-thiol (PSAc5A) and acetylacetone chloromethylated polystyrene (PSAc). This material was characterized by FTIR, elemental analysis, transmission electron microscopy, and thermogravimetric analysis (TGA). The chelating properties of the newly synthesized polymer toward the divalent metal Cu(II), Mn(II), Zn(II), and Ni(II) ions in aqueous solutions was studied by means of batch equilibration technique as a function of contact time, pH, mass of resin, and concentration of metal ions using atomic absorption spectrometry (AAS). Results obtained from this investigation revealed that this polymer can be used to remove heavy metal ions from the aquatic environment. In addition, the molecular structural geometry, the theoretical description of charge distribution, chemical reactivity descriptors, frontier molecular orbitals, molecular electrostatic potential (MEP), and electronic and bonding nature of the monomer structure have been investigated by using the density functional theory (DFT) in order to gain insights into the nature of this compound. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48289.
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Heavy metal removal from wastewater is crucial for the proper management of discharged water from mining operations. This residual water is typically unusable for other purposes such as for human/animal, crop, or industrial consum...
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Heavy metal removal from wastewater is crucial for the proper management of discharged water from mining operations. This residual water is typically unusable for other purposes such as for human/animal, crop, or industrial consumption. Eco-friendly adsorption materials are necessary to ensure the sustainable treatment of this wastewater. Therefore, the sorption of Cu(II), Cd(II), Pb(II), and Zn(II) ions onto chitosan-tripolyphosphate (CTPP) beads was investigated using real mining wastewater and prepared ion metal solutions. The effects of pH, contact time, temperature, selectivity, and maximum sorption capacity in successive batches at different concentrations were studied. The optimum sorption of cations, except for copper (pH 3) was found at pH 5. Equilibrium in the adsorption of all metals was reached at 24 h of contact. Studies of the maximum sorption capacity at different concentrations showed that the CTPP beads could adsorb 158, 55, 47, and 47 mg/g of Pb(II), Cu(II), Cd(II), and Zn(II), respectively. Experimental data for the sorption of Pb(II) were optimally correlated with the Langmuir model. The thermodynamic parameters such as the changes in enthalpy (H-0), entropy (S-0), and free energy (G(0)) were determined. (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45511.
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Poly(acrylic acid-amidoxime) [P(AA-AO)] and poly(maleic acid-amidoxime) [P(MA-AO)] resins were prepared by the γ-radiation-induced copolymerization of acrylonitrile with acrylic acid and maleic acid, respectively. The obtained re...
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Poly(acrylic acid-amidoxime) [P(AA-AO)] and poly(maleic acid-amidoxime) [P(MA-AO)] resins were prepared by the γ-radiation-induced copolymerization of acrylonitrile with acrylic acid and maleic acid, respectively. The obtained resins were amidoximated by reaction with hydroxylamine. The prepared resins were used for the removal of methyl violet (MV) dye from aqueous solutions. Batch adsorption studies were made by the measurement of the effects of pH, the amount of adsorbent, the contact time, and the adsorbate concentration. The adsorption isotherm of MV onto P(AA-AO) and P(MA-AO) was determined at 25°C with initial MV dye concentrations of 10-70 mg/L. The equilibrium data were analyzed with the Langmuir and Freundlich isotherm models. The equilibrium process was described well by the Langmuir isotherm model with maximum adsorption capacities of 398.4 and 396.8 mg/L for P(AA-AO) and P(MA-AO), respectively. The kinetics of adsorption of MV onto P(AA-AO) and P(MA-AO) are discussed. The pseudo-second-order kinetic model described the adsorption of MV onto P(AA-AO) and P(MA-AO) very well.
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We present a methodology to study the adsorption behavior of resins on asphaltenes, which we call silica-asphaltene complex methodology (SACOM), and compare it to a methodology regularly used by many researchers (Acevedo et al, 19...
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We present a methodology to study the adsorption behavior of resins on asphaltenes, which we call silica-asphaltene complex methodology (SACOM), and compare it to a methodology regularly used by many researchers (Acevedo et al, 1995; Gonzalez et al., 2003; Le6n et al., 2002; Marczewski et al., 2002; Pereira et al., 2007) that we call traditional methodology. Three isotherms of resins adsorbed on the complex substrates (asphaltene and its colloidal fractions A_1 and A_2 adsorbed on silica) were built, analyzed, and then compared with two isotherms built by applying a traditional methodology where resins were adsorbed on two organic substrates: asphaltene and its fraction A_1.
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We synthesized chitosan-based sorbents for the uptake of metal cations in acidic solutions. Chitosan was reacted with 2-formylbenzene sodium sulfonate and 4-formyl-1,3-benzene sodium disulfonate in the presence of NaCNBH3 to yield...
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We synthesized chitosan-based sorbents for the uptake of metal cations in acidic solutions. Chitosan was reacted with 2-formylbenzene sodium sulfonate and 4-formyl-1,3-benzene sodium disulfonate in the presence of NaCNBH3 to yield N-benzyl mono- and disulfonate derivatives of chitosan. IR and NMR spectra confirmed the presence of benzyl sulfonate groups. The degrees of substitution of the monosulfonate chitosan derivatives were in the range of 80%, while those of disulfonate derivatives were about 50%. These sulfonate derivatives of chitosan were tested on the sorption of heavy metals Cd2+, Zn2+, Ni2+, Pb2+, Cu2+, Fe3+, and Cr3+. The sorption capacities for disulfonate compounds were better than for monosulfonate compounds. This phenomenon was attributed to the amphoteric character of the monosulfonate derivatives. To improve the capacity of adsorption of monosulfonate compounds, the amino groups of these compounds were protected by the benzyloxycarbonyl groups. The protection of amino groups of disulfonate derivatives by benzyloxycarbonyl also improved their sorption capacity. The resulting protected polymers were tested for sorption of heavy metals. Both protected polymers were more efficient than are the parent nonprotected polymers. The synthesized sulfonate derivatives of chitosan are especially adapted to the sorption of heavy metals from the acidic industrial effluents. (C) 1996 John Wiley & Sons, Inc. [References: 19]
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Four kinds of hypercrosslinked resins (acidic resins labeled SAMR and TAMR and heterocyclic resins IDLMR and PRLMR) were synthesized as adsorbents to remove m-phenylenediamine (MPD) from aqueous solution comparably. The Brunauer-E...
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Four kinds of hypercrosslinked resins (acidic resins labeled SAMR and TAMR and heterocyclic resins IDLMR and PRLMR) were synthesized as adsorbents to remove m-phenylenediamine (MPD) from aqueous solution comparably. The Brunauer-Emmett-Teller specific surface area and pore size distribution of the two types of resins have been compared, and the infrared spectra of the resins confirm the presence of the modified groups. The adsorption isotherms illustrate that the Freundlich equation fits more appropriately than the Langmuir equation or the Temkin equation. In addition, the kinetic curves indicate that the pseudo-second-order model is a better fit than the pseudo-first-order model. The thermodynamic studies show that the isosteric adsorption enthalpy changes (Delta H) and the Gibbs free energy change (Delta G) are both negative, revealing that all of the adsorption processes are spontaneous and exothermic. All of the modified resins exhibit the best adsorption capacity at pH = 6.24. The results show that the acidic resins have better adsorption of MPD. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47378.
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ln this paper a detailed experimental and theoretical analysis of the adsorption process of mercury by ion exchange resins is presented. Experiments have been performed to study adsorption efficiency, the effect of pH on the uptak...
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ln this paper a detailed experimental and theoretical analysis of the adsorption process of mercury by ion exchange resins is presented. Experiments have been performed to study adsorption efficiency, the effect of pH on the uptake of mercury and the adsorption kinetics. The experimental apparatus was a batch mechanically stirred reactor (volume l.5 dm~3), under almost isothermal conditions (±0.ldeg.C). The resin used in this study is Duolite GT-73, a chelating resin, macroreticular with thiol (S-H) functional groups. The studied resin has a very high adsorption efficiency, reaching 30-40/100 in weight and the efficiency decreases, decreasing pH, due to competition between ions H~+ and Hg~2+. Such a high efficiency confirms previous results and justifies the great interest for the application of ion exchange resins in water treatment plants. As in previous works, measurements of process kinetics show that the adsorption rate decreases as the initial mercury concentration is increased. This fact suggests that intraparticle diffusion rate can be the controlling step for the adsorption process. To verify this, a simplified mathematical model has been identified, accounting for a diffosional resistance inside solid particles and where the equilibrium relationship between Hg concentration in the liquid and in the solid is described by the Freundlich isotherm, neglecting H~+ competition: this model is very effective in the prediction of the change in the adsorption kinetics with the initial Hg concentration. Hence this preliminary approach can be held as the reference starting point for the adsorption model: further developments will concern the equilibrium thermodynamics (H~+ competition).
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