Personal Research Database

Full Text: 2005\Sep Pur Tec46, 208.pdf

Abstract: A magnetic chelating resin was obtained from polymerization of glycidyl methacrylate in the presence of divinylbenzene as a crosslinker and finely divided magnetic particles of Co₃O₄. The resin obtained was investigated by means of XRD, IR, magnetic susceptibility and DTA/TGA thermal analysis. The measurements showed that the particles of Co₃O₄ became completely coated with a film of the resin. The embedded metal oxide particles impart magnetic properties to the resin in addition to increasing the chelating active sites on the surface. The resin obtained was modified with amine functionality and evaluated towards the uptake of Hg²⁺, Cu²⁺ and Ni²⁺ from their aqueous solutions. Various factors affecting the uptake behaviour such as contact time, pH and initial concentration of the metal ions were investigated. Uptake values of 2.10, 2.00 and 1.10 mmol/g were recorded for Hg²⁺, Cu²⁺ and Ni²⁺, respectively. The adsorption results were found to fit Langmuir model. The modified resin displays higher uptake capacity compared to the metal oxide-free resin. The loaded resin with metal ions was regenerated to efficiency of 97.5% using 1 M H₂SO₄.

Keywords: Heavy Metals, Chelating Resins, Metal Oxides, Adsorption, Recovery

? Wu, F.C., Tseng, R.L. and Juang, R.S. (2005), Preparation of highly microporous carbons from fir wood by KOH activation for adsorption of dyes and phenols from water. Separation and Purification Technology, 47 (1-2), 10-19.

Full Text: 2005\Sep Pur Tec47, 10.pdf

Abstract: The carbonaceous adsorbents with controllable pore sizes were prepared from carbonized fir wood (i.e., char) by KOH and steam activation. Pore properties of the carbons including the BET surface area, pore volume, pore size distribution, and pore diameter were characterized from N₂ isotherms. Through varying KOH/char ratio from 0.5 to 6, the KOH-activated carbons exhibited the surface area ranging from 891 to 2794 m² g^-1 with a fraction of micropore volume of 0.76-0.82. On the other hand, carbons activated by steam at 900°C for 5 and 7 h had a surface area of 1016 and 1131 m² g^-1 with a fraction of micropore volume of 0.51 and 0.48, respectively. The kinetics of adsorption of methylene blue, basic brown 1, acid blue 74, 2,4-dichlorophenol, 4-chlorophenol, p-cresol, and phenol from water on all the carbons studied were examined to check their chemical characteristics. The effective particle diffusivities within carbon particles were also evaluated. (C) 2005 Elsevier B.V. All rights reserved.

Keywords: Fir Wood, Activated Carbons, KOH Activation, Steam Activation, Physical Properties, Adsorption Kinetics, Liquid-Phase Adsorption, Surface-Area, Physical Activation, Pore Structure, Plum Kernels, Sorption, Adsorbents, Diffusion, Porosity, Shell

? Saffaj, N., Persin, M., Alami Younssi, S., Albizane, A., Bouhria, M., Loukili, H., Dach, H. and Larbot, A. (2005), Removal of salts and dyes by low ZnAl₂O₄–TiO₂ ultrafiltration membrane deposited on support made from raw clay. Separation and Purification Technology, 47 (1-2), 36-42.

Full Text: 2005\Sep Pur Tec47, 36.pdf

Abstract: This paper reports the dynamic characterizations of a ZnAl₂O₄–TiO₂ membrane deposited on a macroporous support prepared from Moroccan clay coated with a zirconia microfiltration interlayer. The water permeability of the membrane is 0.26×10⁻¹⁰ m s⁻¹ Pa⁻¹, its thickness is less than 700 nm with an average pore diameter of 5 nm, and a cut off about 4500 Da. The investigations of filtrations performed with different salts (NaCl, CaCl₂, Na₂SO₄, CaSO₄) prove the rejection mechanism is governed by a Donnan exclusion of the coion. Results obtained with solutions charged in heavy metal ions such as CrIII and synthetic dyes are very promising to consider the use of this membrane in depolluting filtration processes.

Keywords: Multilayer, Ultrafiltration, Electrical Interactions, Colour Removal, Heavy Metals

? Tunali, S., Akar, T., Özcan, A.S., Kiran, I. and Özcan, A. (2006), Equilibrium and kinetics of biosorption of lead(II) from aqueous solutions by Cephalosporium aphidicola. Separation and Purification Technology, 47 (3), 105-112.

Full Text: 2006\Sep Pur Tec47, 105.pdf

Abstract: Biosorption of lead(II) onto Cephalosporium aphidicola was examined and the effects of pH, contact time, biosorbent and lead(II) concentrations and temperature on biosorption were investigated. The nature of the possible cell and metal ion interactions was examined by the FTIR technique. The lead(II) biosorption was fast and equilibrium was attained within 30 min. It was found that the overall biosorption process was best described by pseudo-second-order kinetic model. Data obtained from batch studies fitted well with the Langmuir, Freundlich and Dubinin–Radushkevich (D–R) isotherm models. Maximum adsorption capacity (q_max) of lead(II) onto C. aphidicola was 4.46×10⁻⁴ mol g⁻¹. The change of free energy, enthalpy and entropy of the biosorption of lead(II) onto C. aphidicola are −1.387 kJ mol⁻¹ at 20 °C, +30.54 kJ mol⁻¹ and +109.43 J K⁻¹ mol, respectively.

Keywords: Biosorption, Lead, Fungus, Isotherms, Kinetics

? Üçer, A., Uyanik, A. and Aygün, Ş.F. (2006), Adsorption of Cu(II), Cd(II), Zn(II), Mn(II) and Fe(III) ions by tannic acid immobilised activated carbon. Separation and Purification Technology, 47 (3), 113-118.

Full Text: 2006\Sep Pur Tec47, 113.pdf

Abstract: In this study, adsorption of the toxic metal ions onto tannic acid immobilised activated carbon was investigated depending on pH, contact time, carbon dosage, adsorption capacity and adsorption isotherms by employing batch adsorption technique. In the optimum conditions, the percent adsorption of metal ions were determined for Cu(II) (23.5%), Cd(II) (17.8%), Zn(II) (14.0%), Mn(II) (11.3%) and Fe(III) (17.9%) and results were compared with that of the untreated activated carbon. The order of affinity based on uptake by tannic acid immobilised activated carbon and untreated activated carbon was the same as Cu(II) > Fe(III) > Cd(II) > Zn(II) > Mn(II), but differing in the adsorption capacities. In the studied conditions, the adsorption capacity of tannic acid immobilised activated carbon followed the order of Cu(2.23) > Fe(1.77) > Cd(1.51) > Zn(1.23) > Mn(1.13) in single systems and Fe(1.56) > Cd(1.48) > Zn(1.19) > Mn(1.11) in Cu(II) coupled competitive systems. The adsorption data was correlated to Langmuir and Freundlich isotherm for each metal ion and the data fitted better to the Langmuir isotherm model. A combined ion exchange, complex formation and surface adsorption processes were believed the major adsorption mechanisms playing role in the binding of metal ions. Adsorbed metal ions were effectively desorbed (90.2–98.4%) by using 0.1 M HCl without destroying the modified adsorbent.

Keywords: Adsorption, Immobilisation, Modification, Heavy Metal Ions, Activated Carbon, Tannic Acid

? Shukla, S.R., Pai, R.S. and Shendarkar, A.D. (2006), Adsorption of Ni(II), Zn(II) and Fe(II) on modified coir fibres. Separation and Purification Technology, 47 (3), 141-147.

Full Text: 2006\Sep Pur Tec47, 141.pdf

Abstract: The potential of a cheap lignocellulosic fibre, coir was assessed for removal of heavy metal ions like Ni(II), Zn(II) and Fe(II) from their aqueous solutions. The fibre was also chemically modified by oxidising it with hydrogen peroxide for use as adsorbent. Langmuir type adsorption was followed by the coir fibres. The modified coir fibres gave higher metal ion uptake as 4.33, 7.88 and 7.49 mg/g for Ni(II), Zn(II) and Fe(II), respectively, against 2.51, 1.83 and 2.84 mg/g for the unmodified coir fibres. The metal ion uptake values decreased with lowering of pH. The desorption efficiency, regenerative and reuse capacity of these adsorbents were also assessed for three successive adsorption–desorption cycles. The adsorptive capacity was retained only when regeneration with dilute NaOH solution is carried out as an intermediate step after desorption. An ion-exchange mechanism has been proposed for the enhanced metal ion uptake on modified coir.

Keywords: Adsorbent, Adsorbents, Adsorption, Adsorption-Desorption, Aqueous-Solution, Cadmium, Capacity, Cations, Cellulose, Coir, Cu(II), Desorption, Efficiency, Fe(II), Heavy Metal, Heavy Metal Ions, Heavy-Metal Removal, Hydrogen, Hydrogen Peroxide, Ion, Ion Exchange, Ion Removal, Langmuir, Mechanism, Metal Ions, Modified, Oxidation, Peroxide, pH, Regeneration, Removal, Reuse, Sawdust, Sorption, Uptake, Water

? Aksu, Z. and Çağatay, Ş.Ş. (2006), Investigation of biosorption of Gemazol Turquise Blue-G reactive dye by dried Rhizopus arrhizus in batch and continuous systems. Separation and Purification Technology, 48 (1), 24-35.

Full Text: 2006\Sep Pur Tec48, 24.pdf

Abstract: Gemazol Turquise Blue-G, a vinyl sulfone mono-azo type reactive dye, containing copper-phtlalocyanine as cromofor group, was removed from its aqueous solution in batch and continuous packed bed sorption systems by using dried Rhizopus arrhizus as a biosorbent. Operating variables studied were temperature, initial pH, initial dye concentration and sorbent dosage in the batch stirred system and flow rate and inlet dye concentration in the continuous packed bed. In the batch system, the fungal biomass exhibited the highest dye uptake as 773.0 mg g⁻¹ at 45 °C, at an initial pH value of 2.0, at an initial dye concentration of 812.6 mg l⁻¹ for a biomass dosage of 0.5 g l⁻¹. The Freundlich, Langmuir and Redlich–Peterson adsorption models were used for the mathematical description of the biosorption equilibrium and isotherm constants were evaluated at different temperatures. Equilibrium data fitted well the Langmuir model in the studied concentration (100–800 mg l⁻¹) and temperature (25–45 °C) ranges. Sorption data were fitted to pseudo first-order, pseudo second-order and saturation type kinetic models assuming that the external mas transfer limitations in the system can be neglected. The dye uptake process was found to follow pseudo second-order and saturation type kinetics. The thermodynamic parameters calculated showed that the adsorption process is feasible and has an endothermic character. The effect of operating parameters on the sorption characteristics of R. arrhizus in the continuous packed bed was investigated at pH 2.0 and at 25 °C. Data confirmed that the total amount of sorbed dye and column sorption capacity decreased with increasing flow rate and increased with increasing inlet dye concentration. The maximum column biosorption capacity of dried R. arrhizus cells was 823.8 mg g⁻¹ at the highest inlet dye concentration of 776.3 mg l⁻¹ at the minimum flow rate of 0.8 ml min⁻¹. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design and to predict the breakthrough curves. The model was found suitable for describing the whole part of dynamic behavior of the column with respect to flow rate and inlet dye concentration.

Keywords: Biosorption, Gemazol Turquise Blue-G, Reactive Dye, R. Arrhizus, Continuous Packed Bed

? del Mar de la Fuente García-Soto, M. and Camacho, E.M. (2006), Boron removal by means of adsorption with magnesium oxide. Separation and Purification Technology, 48 (1), 36-44.

Full Text: 2006\Sep Pur Tec48, 36.pdf

Abstract: The presence of boron compounds in waters increases in a continuous and parallel way to industrial development. Therefore, their harmful effects on living organisms also increases, especially on plants, since this element manifests an important micronutrient–toxic boron duality. The aim of this study is to investigate the influence of different operation variables within the adsorption process of the boron compounds with magnesium oxide when liquid waste of urban, agricultural or industrial origin is being treated. The results obtained indicate that the process is strongly influenced by the quality of added reagent and by the contact time between the reagent and solution. Moreover, the temperature variable also stands out, as it has a very positive influence, reducing the necessary contact time to obtain specific boron removal yields. On the one hand, it has been observed that this process appears to be inextricably linked to pH. The removal process improves as the pH increases, presenting a maximum at pH value between 9.5 and 10.5, which is where borate ion predominates. The reagent used in the study has an important alkalinising capacity. Due to the fact that the pH of the solutions is situated around this range, it is not necessary to adjust this variable during the process. Therefore, using this reagent is an attractive option. As for the metallic cations that usually accompany boron in industrial waste, it seems that the reagent’s presence also facilitates the removal of these cations and a simultaneous treatment of industrial waste can thus be carried out. Furthermore, interrelationships between the different variables have been established. When the optimum conditions are selected, the process reaches over 95% of boron removal.

Keywords: Adsorption, Boron, Pollution, Removal, Variable Influence

? Coleman, N.J. (2006), Interactions of Cd(II) with waste-derived 11 angstrom tobermorites. Separation and Purification Technology, 48 (1), 62-70.

Full Text: 2006\Sep Pur Tec48, 62.pdf

Abstract: Paper recycling gives rise to significant volumes of secondary waste materials which undermine its economic and environmental sustainability. In response to this problem, a waste combustion ash arising from newsprint recycling has been evaluated as a feedstock material for the hydrothermal synthesis of Al-substituted 11 angstrom tobermorites. Highly crystalline tobermorite (NRR-H₂O) was obtained from a stoichiometrically optimised mixture of newsprint recycling residue, sodium silicate and calcium oxide, whereas a less well-ordered product (NRR-NaOH) was acquired when sodium hydroxide was also incorporated into the reagent mixture.

Structural disorder within the tobermorite lattice was found to accelerate the kinetics of Cd²⁺ for Ca²⁺ ion exchange although had little impact on the total number of available exchange sites per unit formula. The Langmuir isotherm model provided a suitable description for the steady state uptake of Cd²⁺ by both tobermorite specimens under single metal ion batch sorption conditions, from which, maximum adsorption capacities of 167 and 179 mg g^-1 were obtained for NRR-NaOH and NRR-H₂O, respectively. (C) 2005 Elsevier B.V. All rights reserved.

Keywords: Calcium Silicate Hydrate, Langmuir Isotherm, Ion Exchange, Hydrothermal Synthesis, Recycling, Calcium Silicates, Crystal-Structure, Real Structure, OD Character, Heavy-Metals, Si-29, Adsorption, Exchange, Substitution, Spectroscopy

? O’Connor, A.J., Hokura, A., Kisler, J.M. Shimazu, S., Stevens, G.W. and Komatsu, Y. (2006), Amino acid adsorption onto mesoporous silica molecular sieves. Separation and Purification Technology, 48 (2), 197-201.

Full Text: 2006\Sep Pur Tec48, 197.pdf

Abstract: Mesoporous molecular sieves are promising as adsorbents for purification of biological molecules, such as amino acids, due to their tuneable mesopore sizes and high surface area. In this study, the adsorption of the basic amino acid, lysine, onto MCM-41, a siliceous mesoporous molecular sieve, has been investigated under a range of solution conditions. It was found to adsorb according to a Langmuir-type isotherm with a maximum capacity at pH 6 of 0.21 mmol/g. The extent of adsorption depends strongly on the pH and ionic strength of the adsorbate solution, due to a combination of ion exchange and electrostatic interactions governing the adsorption process.

Keywords: Amino Acid, Adsorption,, Mesoporous Molecular Sieve, MCM-41, Lysine

? Donia, A.M., Atia, A.A., El-Boraey, H.A. and Mabrouk, D.H. (2006), Adsorption of Ag(I) on glycidyl methacrylate/N,N’-methylene bis-acrylamide chelating resins with embedded iron oxide. Separation and Purification Technology, 48 (3), 281-287.

Full Text: 2006\Sep Pur Tec48, 281.pdf

Abstract: Glycidyl methacrylate/N,N’-methylene bis-acrylamide (GMA/MBA) resins modified by embedded iron oxide (Fe₂O₃) were prepared. Amino and thiol functionalities were immobilized on the obtained resins. The uptake of Ag(I) by the resins using batch and column techniques was investigated. The oxide-containing resins showed higher uptake values relative to the corresponding oxide-free ones. The uptake of Ag(I) on the resins was found to follow pseudo second-order kinetics. The uptake process was investigated at different temperatures and ΔH°, ΔS° and ΔG° were calculated. Regeneration of the resins was achieved using thiourea, HNO₃ and acidified thiourea with HNO₃. Regeneration efficiency was found to be 98% over five cycles with no appreciable change in durability.

Keywords: Chelating Resins, Adsorption, Silver, Kinetics, Thermodynamics

? Singh, T.S. and Pant, K.K. (2006), Experimental and modelling studies on fixed bed adsorption of As(III) ions from aqueous solution. Separation and Purification Technology, 48 (3), 288-296.

Full Text: 2006\Sep Pur Tec48, 288.pdf

Abstract: This paper deals with the experimental investigation on removal of arsenic [As(III)] ions from drinking water by activated alumina and iron oxide impregnated activated alumina (IOIAA). Effect of inlet flow rate, sorbent bed height and initial As(III) concentration on the adsorption of As(III) from aqueous solution were studied. Increase in throughput volume was observed with increase in bed height whereas inverse relationship of flow rate and initial As(III) concentration with removal of arsenite ions was observed by these sorbents. Compared to activated alumina, iron oxide impregnated activated alumina was found more effective in removing As(III) ions. The dynamics of adsorption process was modelled by bed depth service time (BDST) and pore diffusion model. Adsorption rate constant (ka) was found to increase with increase in flow rate indicating the overall system kinetics was dominated by external mass transfer in the initial part of the adsorption in the column. Critical bed depth (Z0) increased with increase in flow rate for both the adsorbent. Relatively lower critical bed height was observed for As(III) removal onto IOIAA (0.56 cm) compared to AA (1.12 cm) at identical flow rate (0.083 cm³/s). Time required for traveling a unit length of adsorber bed varied from 17,280 to 43,920 s (4.8–12.2 h) and 21,240–54,360 s for AA and IOIAA depending upon the conditions. Pore diffusion model explained the breakthrough behaviour for As(III) removal with a high degree of correlation.

Keywords: Arsenic, Breakthrough Studies, BDST Model, Pore Diffusion Model, Adsorption Zone

? Juang, R.S., Kao, H.C. and Chen, W. (2006), Column removal of Ni(II) from synthetic electroplating waste water using a strong-acid resin. Separation and Purification Technology, 49 (1), 36-42.

Full Text: 2006\Sep Pur Tec49, 36.pdf

Abstract: Ion exchange is widely used for the recovery and removal of metals from waste streams in chemical process industries. The removal of Ni(II) from synthetic electroplating waste water using a strong-acid resin in fixed beds was investigated. Besides NiSO₄, the water contained NH₄Cl and anionic ligands NaH₂PO₄ and citrate. Batch studies showed that the exchange isotherms were well fitted by the Langmuir equation. Column experiments were performed under different pH values (0.5–5.0), metal concentrations (5.1–11.9 mol/m³), volumetric flow rates (5–12 cm³/min), and bed volumes (3.7–9.8 cm³). The Thomas model that consists of two parameters was applied to describe the breakthrough curves. It was shown that the calculated breakthrough curves agreed well with the measured ones (standard deviation 6%), except the curves before break point obtained at pH > 3.0. The non-zero Ni(II) concentration in the effluent at the early stage of the whole process was ascribable to the presence of anionic ligands. A chemical model that considers possible aqueous complexation reactions was proposed to explain such breakthrough characteristics.

Keywords: Ni(II) Removal, Cation Exchange Resins, Electroplating Waste Water, Fixed Bed

? Donia, A.M., Atia, A.A., El-Boraey, H. and Mabrouk, D.H. (2006), Uptake studies of copper(II) on glycidyl methacrylate chelating resin containing Fe₂O₃ particles. Separation and Purification Technology, 49 (1), 64-70.

Full Text: 2006\Sep Pur Tec49, 64.pdf

Abstract: Two glycidyl methacrylate (GMA) chelating resins were prepared and characterized by IR and thermal analysis (DTA/TGA). The preparation process was carried out through copolymerization of GMA with N,N’-methylenebisacrylamide cross-linker in presence and absence of iron oxide (Fe₂O₃). The resins obtained were subsequently treated with ethylenediamine to give the corresponding amine-chelating resins. The resins were characterized by IR and thermal analysis (DTA/TGA). The uptake behaviour of both resins towards Cu(II) ions in aqueous solutions using batch and column techniques was studied. The oxide containing resin (ROA) displayed higher uptake and fast equilibrium time relative to that of oxide free resin (RA). This was attributed to the higher amine group content in ROA due to the stretching of the resin’s film over iron oxide particles. Thermodynamic parameters ΔH°, ΔS° and ΔG° of the uptake process were also calculated. Regeneration of the resins was carried out using 1 M HCl where 98% desorption of the metal ions was obtained. The resins showed good durability for adsorption/desorption over 10 cycles.

Keywords: Adsorption, Copper(II), Glycidyl Methacrylate, Chelating Resins, Thermodynamics

? Coşkun, R., Soykan, C. and Saçak, M. (2006), Adsorption of copper(II), nickel(II) and cobalt(II) ions from aqueous solution by methacrylic acid/acrylamide monomer mixture grafted poly(ethylene terephthalate) fiber. Separation and Purification Technology, 49 (2), 107-114.

Full Text: 2006\Sep Pur Tec49, 107.pdf

Abstract: A reactively fibrous adsorbent was prepared by graft copolymerization of methacrylic acid (MAA)/acrylamide (AAm) monomer mixture onto poly(ethylene terephthalate) (PET) fiber and characterized by Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA). The adsorption of Cu(II), Ni(II) and Co(II) ions from aqueous solution by the reactive fiber was examined by batch equilibration technique. The effects of graft yield, pH, adsorption time, initial ion concentrations and adsorption temperature on the adsorption amount of ions were investigated. The reusability and selectivity of the reactive fiber were also investigated. The results showed that the adsorption of the metal ions followed the following order Cu(II) > Ni(II) > Co(II). The adsorption amounts of ions increased with the increase of grafting yield, shaking time, and pH of the medium. The adsorption amounts of Ni(II) and Co(II) ions increased but Cu(II) ions were not affected with increasing adsorption temperature. It was found that the adsorption isotherm of the ions fitted Langmuir-type isotherms. From the Langmuir equation the adsorption capacity was found as 31.25 mg/g fiber for Cu(II), 43.48 mg/g fiber for Ni(II), and 27.17 mg/g fiber for Co(II), respectively. The competitive adsorption tests verified that this reactive fiber possessed good adsorption selectivity for Cu(II) with the coexistence of Co(II) and Ni(II). It can be regenerated by 1 M HNO₃ without losing their activity.

Keywords: Grafted Poly(Ethylene Terephthalate) Fiber, Adsorption Properties, Copper(II), Nickel(II), Cobalt(II)

? Wang, Y., Mu, Y., Zhao, Q.B. and Yu, H.Q. (2006), Isotherms, kinetics and thermodynamics of dye biosorption by anaerobic sludge. Separation and Purification Technology,