Crossflow filtration of iron(III), copper(II), and cadmium(II) aqueous solutions with alginic acid/cellulose composite membranes

The removal of Fe(III), Cu(II), and Cd(II) ions from aqueous solutions was investigated with a crossflow filtration technique. Alginic acid (AA)/cellulose composite membranes were used for retention. In the filtration of Fe(III) solutions, the effects of the crossflow velocity, applied pressure, AA content of the membranes, and pH on the retention percentage and the permeate flux were examined. The maximum retention percentage was found to be 89% for a 1 × 10^?4M Fe(III) solution at the flow velocity of 100 mL/min and the pressure of 60 kPa with 0.50% (w/v) AA/cellulose composite membranes at pH 3. Aqueous solutions of Cu(II) and Cd(II) were filtered at the flow velocity of 100 mL/min and pressure of 10 kPa. The effects of the AA content of the membranes and pH of the waste medium on the retention percentage and the permeate flux were determined. For 1 × 10^?4M Cu(II) and Cd(II) solutions, the maximum retention percentages were found to be 94 and 75%, respectively, at pH 7 with 0.50% (w/v) AA/cellulose composite membranes. When metal‐ion mixtures were used, the retention percentages of Fe(III), Cu(II), and Cd(II) were found to be 89, 48, and 10%, respectively, at pH 3 with 0.50% (w/v) AA/cellulose composite membranes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Use of Poly(methyl methacrylate-co-methacrylic acid) Membranes in the Ultrafiltration of Aqueous Fe3+ Solutions by Complexing with Poly(vinyl pyrrolidone) and Dextran

Abstract

In this study water soluble complexible polymers, poly(vinyl pyrrolidone) (PVP) and dextran, were used for the ultrafiltration (UF) of aqueous Fe⁺³ solutions by using poly(methyl methacrylate-co-methacrylic acid) (PMMA-co-MA) membranes. Effects of polymer concentration and pH on the volume collected in the filtration of Fe⁺³ solutions and percent retentions (R%) were examined. It was determined that increase in polymer concentration decreased the permeability of PMMA-co-MA membrane and pH increased the retention of Fe³⁺ solutions. R% for Fe³⁺ solutions were obtained as 62% and 48% with PVP and dextran respectively at pH 3.0, for a filtration period of 80 minutes and retention for Fe³⁺ solution without using any complex forming polymer was found as 14%. Membranes were characterized by AFM analysis and contact angle measurements.     

Hydrogels with Acid Groups for Removal of Copper(II) and Lead(II) Ions

Acrylamide-maleic acid (AAM-MA) hydrogels having high acid group content prepared with different maleic acid ratios were used for the removal of Cu(II) and Pb(II) ions from aqueous solutions in competitive and noncompetitive conditions. The effects of pH, time, and initial metal ion concentration on the metal ion adsorption capacity were investigated. The adsorption isotherm models were applied on experimental data and it is shown that the Freundlich equation was the best model for Cu(II) ion while the Langmuir isotherm model was the best one for Pb(II) ion. The stability constants of acrylamide-maleic acid hydrogel-Cu(II) and Pb(II) complexes were also determined by van den Berg/Ruzic transformation, and K values obtained were 1.60 × 10³ and 1.81 × 10³ for Cu(II) and Pb(II) ions, respectively. The experiments under competitive conditions showed that the hydrogels prefered Pb(II) ion and this preference increased with increasing of carboxylic acid group content (AGC) of polymers. It is stated that these hydrogels can be regenerated efficiently (>95%) and used repeatedly.     

Selective transport of cobalt (II) from ammoniacal solutions containing cobalt (II) and nickel (II) by emulsion liquid membranes using 8-hydroxyquinoline

The selective transport of cobalt (II) from ammoniacal solutions containing nickel (II) and cobalt (II) by emulsion liquid membranes (ELMs) using 8-hydroxyquinoline (8-HQ) as extractant has been presented. Membrane solution consists of a diluent (kerosene), a surfactant (ECA 4360J), and an extractant (8-HQ). Very dilute sulphuric solution buffered at pH 5.0 has been used as a stripping solution. The ammoniacal feed solution pH was adjusted to 9.0 with hydrochloric acid. The important variables governing the permeation of cobalt (II) have been studied. These variables are membrane composition, pH of the feed solution, cobalt (II) and nickel (II) concentrations of the feed solution, stirring speed, surfactant concentration, extractant concentration, complexing agent concentration and pH of the stripping solution, and phase ratio. After the optimum conditions had been determined, it was possible to selectively transport 95.0% of cobalt (II) from ammoniacal feed solution containing Co²⁺ and Ni²⁺ ions. The separation factors of cobalt (II) with respect to nickel (II), based on initial feed concentration, have experimentally found to be of as high as 31 for equimolar Co(II)–Ni(II) feed solution.     

Selective Transport of Cu(II) across a Polymer Inclusion Membrane with 1-Alkylimidazole from Nitrate Solutions

The selective transport of copper(II), zinc(II), cobalt(II), and nickel(II) ions from nitrate solutions across polymer inclusion membranes (PIMs), which consist of cellulose triacetate as polymeric support, o-nitrophenyl pentyl ether as plasticizer, and 1-alkylimidazole (alkyl from hexyl- to decyl) as ion carrier was reported. PIM was characterized by using atomic force microscopy (AFM) technique. The results show that Cu(II) can be separated very effectively from other transition metal cations as Zn(II), Co(II), and Ni(II) (at a concentration of 10^?3 mol/dm³ each). Alkyl substituents at position 1 of the imidazole ring have been found to affect the hydrophobic properties and initial flux of the transported metal ions. The efficiency of separation of metal ions by 1-alkylimidazole followed the sequence: Cu(II) > Zn(II) > Co(II) > Ni(II). The highest selectivity coefficient for Cu(II) was found with 1-hexylimidazole and its 1 mol/dm³ solution in PIM. Separation of the ions was more effective for the nitrates(V) than for chlorides.     

Removal Characteristics of Cd(II), Cu(II), Pb(II), and Zn(II) by Natural Mongolian Zeolite through Batch and Column Experiments

The removal characteristics of Cd(II), Cu(II), Pb(II), and Zn(II) from model aqueous solutions by 5 natural Mongolian zeolites were investigated. The adsorption of metals on zeolites reached a plateau value within 6 h. The adsorption kinetic data were fitted with adsorption kinetic models. The equilibrium adsorption capacity of the zeolites was measured and fitted using Langmuir and Freundlich isotherm models. The order of adsorption capacity of zeolite was Pb(II) > Zn(II) > Cu(II) > Cd(II). The maximum adsorption capacity of natural zeolite depends on its cation exchange capacity and pH. The leaching properties of metals were simulated using four leaching solutions. The results show that natural zeolite can be used as an adsorbent for metal ions from aqueous solutions or as a stabilizer for metal-contaminated soils.     

Removal of Fe(III) ions from dilute aqueous solutions by alginic acid‐enhanced ultrafiltration

The removal of Fe(III) ions from aqueous solutions was studied using membrane filtration. A water‐soluble polymer alginic acid (AA) was used to bind the metal ions, which was followed by batch ultrafiltration using poly(methyl methacrylate‐methacrylic acid) membranes modified with poly(ethylene glycol) (PMMA‐MA‐PEG). The complexation behavior of AA and the effect pH on the rejection of iron were investigated. Maximum recovery of 87.13% was obtained when the filtration was carried out in the presence of AA at pH 3.1. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1096–1101, 2000     

Synthesis and properties of hydrophilic polymers. IX. Synthesis,biodegradability, and metal complexation of copolymers of ethylenediaminetetraacetic acid dianhydride and lactose

The synthesis and characterization of poly(ethylenediaminetetraacetic acid‐co‐lactose) with pendant carboxylic groups of high molar mass (132 kg mol^?1) is described. The polycondensate was hydrolytically and microbiologically degradable with conventional microbiological methods. The metal‐complexing properties of the polyester were studied for Cr(III), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Sr(II), Cd(II), Pb(II), and Al(III) ions in aqueous solution with the liquid‐phase polymer‐based retention (LPR) method. In addition, the complexing capacity of the Cu(II)‐saturated copolymer was determined by thermogravimetric analysis to be 182 mg g^?1 of polymer. According to the retention profiles determined as a function of the filtration factor with LPR in conjunction with inductively coupled plasma spectrometry, Cr(III) and Fe(III) showed a strong interaction with this polymer under these conditions, as indicated by retention values of about 100% at pH 5. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 650–657, 2003     

Synthesis and properties of hydrophilic polymers,part 11: Synthesis,biodegradability, and metal complexation of copolymers of ethylenediaminetetraacetic acid dianhydride and lactose

The synthesis and characterization of poly(ethylenediaminetetraacetic acid‐co‐lactose) of high molar mass (132 kg mol^?1) is described. The polycondensate with pendant carboxylic groups was shown to be hydrolytically and microbiologically degradable by using conventional microbiological methods. The metal complexing properties of the polyester were studied for Cr(III), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Sr(II), Cd(II), Pb(II), and Al(III) ions in aqueous solution using the liquid‐phase polymer‐based retention (LPR) method. In addition, the complexing capacity of the Cu(II)‐saturated copolymer was determined by TGA to be 182 mg g^?1 polymer. According to the retention profiles determined as a function of filtration factor by using LPR in conjunction with inductively coupled plasma spectrometry, Cr(III) and Fe(III) showed a strong interaction with this polymer under these conditions, indicated by retention values of 100% at pH 5. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2932–2939, 2007     

Adsorption of copper(II) and chromium(III) ions onto amidoximated cellulose

Chemical modification of cellulose powder is performed by successive reactions with acrylonitrile in an alkaline medium followed by aqueous hydroxylamine to prepare amidoximated cellulose. Due to complexation, the amidoxime groups immobilize heavy cations from buffered solutions at various pH values. The capacity of adsorption for Cu(II) and Cr(III) ions is related to the amount of amidoxime groups in the support and to the metal concentration of the polluted solution. The formation of a 1/1 complex is proved by the adsorption limit values. Desorption of the cations is possible by treatment with a stronger complexing agent such as ethylenediaminetetracetic acid. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1624–1631, 2000     

Recovery of Zn(II), Mn(II) and Cu(II) in Aqueous Solutions by Foam Fractionation with Sodium Dodecyl Sulphate in Combination with Chelating Agents

Abstract

Adsorptive bubble separation was used to remove polyvalent ion colligends Zn(II), Mn(II) and Cu(II) from aqueous solutions, for which optimum parametrical values that influenced the recovery of these ions were scrutinized. Additionally, the effect of some auxiliary ligands (malic acid, maleic acid, and EDTA) on the recovery was investigated. Sodiumdodecylsulphate (SDS) was used as a collector. The pH was measured as 5.5 and 4.0 for the solutions, which include metal∶SDS and metal∶SDS∶auxiliary ligand, respectively. In the metal : SDS mixtures, SDS has retained metal ions at pH 5.5, which was exactly the value of the membrane filtered water. Therefore, no further pH adjustment was necessary throughout the experiments. The metal ions were determined by inductively coupled plasma optical emission spectroscopy (ICP‐OES). The optimum experimental conditions (run time, SDS concentration, and the concentration of feed solution) on the recovery and enrichment of metal ions were also discussed. The maximum recovery rate was reached within 60 min. The optimum molar ratio between metal and SDS was found to be 1∶5, and it was shown that the recovery of metal ions increased with increasing concentration of SDS. The most suitable initial concentration of metal ions was 2×10^?5 M. The recovery rates for Zn(II), Mn(II) and Cu(II) in the presence of SDS was found to be 90.5, 99.8 and 73.4%, respectively. By adding malic acid, and maleic acid as auxiliary ligands, higher recovery rates were achieved, even in a shorter foaming time. For optimal recovery, the best molar ratio between metal:SDS:auxiliary ligand was 1∶5∶5.     

Removal of Copper(II) and Zinc(II) from Aqueous Solutions Using a Lignocellulosic-Based Polymeric Adsorbent Containing Amidoxime Chelating Functional Groups

In this study, the adsorption of Cu(II) and Zn(II) ions from aqueous solutions onto amidoximated polymerized banana stem (APBS) has been investigated. Infrared spectroscopy was used to confirm graft copolymer formation and amidoxime functionalization. The different variables affecting the sorption capacity such as pH of the solution, adsorption time, initial metal ion concentration, and temperature have been investigated. The optimum pH for maximum adsorption was 10.5 (99.99%) for Zn²⁺ and 6.0 (99.0%) for Cu²⁺ at an initial concentration of 10 mg L^?1. Equilibrium was achieved approximately within 3 h. The experimental kinetic data were analyzed using pseudo-first-order and pseudo-second-order kinetic models and are well fitted with pseudo- second-order kinetics. The thermodynamic activation parameters such as ΔG^o, ΔH^o, and ΔS^o were determined to predict the nature of adsorption. The temperature dependence indicates an exothermic process. The experimental isotherm data were well fitted to the Langmuir model with maximum adsorption capacities of 42.32 and 85.89 mg g^?1 for Cu(II) and Zn(II), respectively, at 20°C. The adsorption efficiency was tested using industrial effluents. Repeated adsorption/regeneration cycles show the feasibility of the APBS for the removal of Cu(II) and Zn(II) ions from water and industrial effluents.     

Sorption of Pb(II), Cd(II), and Ni(II) From Single- and Multimetal Solutions by Recycled Waste Porous Glass

Selective sorption of lead, cadmium, and nickel ions on recycled waste porous glass beads was investigated. Single-metal equilibrations were carried out in demineralized water and ternary metal equilibrations were carried out in demi- and tap water. Freundlich isotherm gave a good correlation of the experimental data. Maximum metal retention (q_max) in single-ion solutions were 18.66 mg/g_RPWG (0.090 mmol/g_RPWG), 4.83 mg/g_RPWG (0.043 mmol/g_RPWG), 4.00 mg/g_RPWG (0.068 mmol/g_RPWG), respectively, for Pb⁺², Cd⁺², and Ni⁺², and lower figures were in the case of ternary systems: 13.50 mg/g_RPWG(0.065 mmol/g_RPWG), 2.23 (0.020 mmol/g_RPWG), 2.05 mg/g_RPWG(0.034 mmol/g_RPWG), respectively, for Pb⁺², Cd⁺², and Ni⁺², with further drastic reduction in tap water. Metal exhausted beads were used as thermal insulators in cement mortars, minimizing their potential impact in the environment.     

Reverse osmosis of lactic acid fermentation broths

Lactic acid model solutions and fermentation broths were concentrated using a tubular thin-film composite reverse osmosis membrane. Flux increased linearly with applied transmembrane pressure and was relatively unaffected by flow rate. Osmotic pressures of 1% lactate solutions were 280–560 kPa, depending on the pH or degree of dissociation. Rejections increased with applied pressure. Higher pH caused a slight decrease in flux (due in part to the higher osmotic pressure) and a significant increase in rejection. Above pH 5·6, rejections of lactate and residual sugars were > 97%. In contrast, with cellulose acetate membranes, flux was generally lower and lactate rejection was proportional to the degree of dissociation at lower pressures.     

Removal of Cu(II), Fe(III), and Cr(III) from Aqueous Solution by Aniline Grafted Silica Gel

Abstract

The aniline moiety was covalently grafted onto silica gel surface. The modified silica gel with aniline groups (SiAn) was used for removal of Cu(II), Fe(III), and Cr(III) ions from aqueous solution and industrial effluents using a batch adsorption procedure. The maximum adsorption of the transition metal ions took place at pH 4.5. The adsorption kinetics for all the adsorbates fitted better the pseudo second‐order kinetic model, obtaining the following adsorption rate constants (k₂): 1.233 · 10^?2, 1.902 · 10^?2, and 8.320 · 10^?3 g · mg^?1 min^?1 for Cr(III), Cu(II), and Fe(III), respectively. The adsorption of these transition metal ions were fitted to Langmuir, Freundlich, Sips, and Redlich‐Peterson isotherm models; however, the best isotherm model fitting which presented a lower difference of the q (amount adsorbed per gram of adsorbent) calculated by the model from the experimentally measured, was achieved by using the Sips model for all adsorbates chosen. The SiAn adsorbent was also employed for the removal of the transition metal ions Cr(III) (95%), Cu(II) (95%), and Fe(III) (94%) from industrial effluents, using the batch adsorption procedure.     

Removal of Cu(II) and Zn(II) Using Lignocellulosic Fiber Derived from Citrus reticulata (Kinnow) Waste Biomass

Abstract

The biosorption of Cu(II) and Zn(II) using dried untreated and pretreated Citrus reticulata waste biomass were evaluated. The Cu(II) and Zn(II) sorption were found to be dependent on the solution pH, the biosorbent dose, the biosorbent particle size, the shaking speed, the temperature, the initial metal ions (800 mg/L), and the contact time. Twenty-eight physical and chemical pretreatments of Citrus reticulata waste biomass were evaluated for the sorption of Cu(II) and Zn(II) from aqueous solutions. The results indicated that biomass pretreated with sulphuric acid and EDTA had maximum Cu(II) and Zn(II) uptake capacity of 87.14 mg/g and 86.4 mg/g respectively. Moreover, the Langmuir isotherm model fitted well than the Freundlich model with R ² > 0.95 for both metal ions. The sorption of Cu(II) and Zn(II) occurred rapidly in the first 120 min and the equilibrium was reached in 240 min. FTIR and SEM studies were also carried out to investigate functional groups present in the biomass and the surface morphological changes of biomass.     

Synthesis,characterization, and metal complexation of poly(N‐phenylmaleimide‐co‐acrylic acid) and poly(N‐phenylmaleimide‐co‐acrylamide) as polychelatogens in aqueous solution

We carried out the free‐radical copolymerization of N‐phenylmaleimide with acrylic acid and acrylamide with an equimolar feed monomer ratio. We carried out the synthesis of the copolymers in dioxane at 70°C with benzoyl peroxide as the initiator and a total monomer concentration of 2.5M. The copolymer compositions were obtained by elemental analysis and ¹H‐NMR spectroscopy. The hydrophilic polymers were characterized by elemental analysis, Fourier transform infrared spectroscopy, ¹H‐NMR spectroscopy, and thermal analysis. Additionally, viscosimetric measurements of the copolymers were performed. Hydrophilic poly(N‐phenylmaleimide‐co‐acrylic acid) and poly(N‐phenylmaleimide‐co‐acrylamide) were used for the separation of a series of metal ions in the aqueous phase with the liquid‐phase polymer‐based retention method in the heterogeneous phase. The method is based on the retention of inorganic ions by the polymer in conjunction with membrane filtration and subsequent separation of low‐molecular‐mass species from the formed polymer/metal‐ion complex. The polymer could bind several metal ions, such as Cr(III), Co (II), Zn(II), Ni(II), Cu(II), Cd(II), and Fe(III) inorganic ions, in aqueous solution at pH values of 3, 5, and 7. The interaction of the inorganic ions with the hydrophilic polymer was determined as a function of pH and a filtration factor. Hydrophilic polymeric reagents with strong metal‐complexing properties were synthesized and used to separate those complexed from noncomplexed ions in the heterogeneous phase. The polymers exhibited a high retention capability at pH values of 5 and 7. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Co-Adsorption/Filtration of Heavy Metal Ions from Water using Regenerated Cellulose UF Membranes Modified with DETA Ligand

The current study investigates the coupled filtration/adsorption performance of regenerated cellulose (RC) ultrafiltration membranes functionalized with diethylenetriamine (DETA) as a metal-chelating ligand. Lead and copper ions with various concentrations (10–50 ppm) were selected as model adsorbing metals. To investigate the dynamic adsorption performance of the ions, different parameters including initial metal concentration, time of oxidization reaction, ligand concentration, and solution pH were studied. The maximum removal of Pb(II) and Cu(II) proposed by the modified membranes from their single salt solutions were 87% and 83%. Besides, the removal percentages of 56 and 50 were obtained for the competitive adsorption of Pb(II) and Cu(II) ions from their mixed solution, respectively. The selectivity factor was calculated as 1.25 indicating the potential of the process for selective adsorption of the ions. Langmuir and Freundlich isotherms were employed to describe the adsorption equilibria with the first model providing the best fit. Reusability tests showed that the modified membranes can be effectively regenerated by 0.1 M HCl eluting solution and successively reused in dynamic adsorption process.     

Methods for correction of selectivity of N-(2-sulfoethyl)chitosan-based materials towards platinum(IV) and palladium(II) ions

In this paper, we report methods for correction of selectivity of sorbents based on N-(2-sulfoethyl)chitosan towards platinum(IV) and palladium(II) in HCl solutions. The common method for correction of selectivity of the sorbents is variation of their modification degree with complexing groups. An increase in the degree of sulfoethylation of the chitosan leads to the significant increase in selectivity of sorption of palladium(II) over platinum(IV). Application of the N-(2-sulfoethyl)chitosan with the highest degree of sulfoethylation allows for selective separation palladium(II) from platinum(IV) (рН = 5.0). Palladium is quantitatively desorbed from the surface of the N-(2-sulfoethyl)chitosans by 3.5 mol/dm³ solution of HCl.     

Comparison of Biosorption of Nickel (II) and Copper (II) Ions from Aqueous Solution by Sphaeroplea Algae and Acid Treated Sphaeroplea Algae

Abstract

Biosorption of nickel (II) and copper (II) ions from aqueous solution by dead sphaeroplea algae in natural and acid treated forms were studied as a function of concentration, pH, and adsorbent dose. The optimum pH for nickel (II) and copper (II) biosorption was found to be 6.0 and 4.0 respectively. The metal ion uptake increased with initial metal ion concentration studied up to 500 mg/L. Both the Freundlich and Langmuir adsorption models could fit the equilibrium data. The adsorption reasonably fitted the Lagergren kinetic model. Further the biomass was characterized by FTIR spectra. Surface area values are measured to be 0.9 and 2.1 m²/g for natural and acid treated forms respectively. The maximum adsorption capacity was found to be 3.40, 4.15 mmol/g for nickel (II) and 2.21, 3.41 mmol/g for copper (II) in natural and acid treated forms respectively.