Ind. Eng. Chem. Res. 2004, 43, 623-628
623
Copper(II) Removal from Wastewaters by a New Synthesized Selective Extractant and SLM viability Raffaele Molinari,*,†,‡ Teresa Poerio,†,‡ Roberta Cassano,§ Nevio Picci,| and Pietro Argurio† Departments of Chemical and Materials Engineering, Chemistry, and Pharmaceutical Science and Institute on Membrane Technology, ITM-CNR (formerly IRMERC-CNR), University of Calabria, Via P. Bucci, 17/C, I-87030 Rende (CS), Italy
Copper(II) removal and/or recovery from wastewaters, e.g., washing water of contaminated soils, was investigated by using a new chelant, the molecule 2-hydroxy-5-dodecylbenzaldehyde (2-H5-DBA), never used before as a ligand for metal ions. This material was designed and synthesized by improving a method reported in the literature, obtaining a very high yield (80 vs 19%). Process selectivity and supported liquid membrane (SLM) viability were studied. The operating conditions and selectivity of the process were found by means of L-L extraction tests performed at different carrier concentrations (10, 30, and 50% v/v) using kerosene as the solvent. At 50% v/v carrier concentration and pH 5, the selectivities of Cu2+ separation vs Ni2+, Zn2+, and Mn2+ were 4.25, 315.0, and 280.0, respectively. The carrier concentration had a strong influence on the viability of the SLM process: indeed, by increasing the concentration of the carrier, the operating pH could be decreased, thereby avoiding copper precipitation in the feed phase. The enrichment factor of Cu2+ in the strip ([Cu2+]strip/[Cu2+]feed)final was 23.5. Introduction Contamination of soil by heavy metals is common at many hazardous waste sites in many industrial nations.1 Soil washing, a water-based process that employs chemical and physical extraction processes to remove contaminants from soil, has recently become a common ex situ technique for remediating sites contaminated with organic and inorganic pollutants. This process has been proven successful in the remediation of various heavy-metal-contaminated sites, including certain Superfund sites in the U.S.2 Several studies have attempted to optimize the extraction of heavy metals from contaminated soil using various washing solutions, including reducing agents, surfactants, chelating agents, and strong mineral acids. An interesting approach to this problem was proposed by Bassi et al.,3 who considered the extraction of metals from a contaminated sandy soil using citric acid. Their results showed that a 24-h washing of their soil with 0.5 M citric acid reduced the levels of Cd, Cu, Zn, and Pd from 0.01, 0.04, 0.42, and 41.52 mg/g to 0, 0.02, 0.18, and 5.21 mg/g, respectively. As a consequence of the extractant solution employed, the solution containing extracted metal ions was at an acidic pH of 5.5. Cadmium, copper, lead, mercury, nickel, and zinc are considered the most hazardous heavy metals and are included on the U.S. Environmental Protection Agency’s (EPA’s) list of priority pollutants.4 In fact, metal ions play an essential role in many biological processes, and their deficiency, unusual accumulation, or imbalance * To whom correspondence should be addressed. Tel.: +39 0984496699.Fax: +390984496655.E-mail:
[email protected]. † Department of Chemical and Materials Engineering. ‡ Institute on Membrane Technology, ITM-CNR (formerly IRMERC-CNR). § Department of Chemistry. | Department of Pharmaceutical Science.
can lead to biological problems. Some metals, especially heavy metals, do not seem to be essential to living mammals. Nevertheless, because or their competition with essential metals in binding with proteins, heavy metal ions are potent enzyme inhibitors, exerting toxic effects on living systems. Redistribution of these metals by human industrial activities constitutes a major health hazard; indeed, Cu2+ ions, for example, are essential nutrients, but when a person is exposed to Cu levels above 1.3 mg/L for a short period of time, stomach and intestinal problems occur. Long-term exposure to Cu2+ leads to kidney and liver damage.5-7 In addition, the continuous increase in the world’s needs for most of the known metals and the decrease in the quality of the available ores makes important the identification of effective and efficient methods for processing waste solutions containing metal ions, even at very low concentrations, so that the water can be recycled and the metals reused. Hydrometallurgical processing,8-11 process-water and wastewater detoxification, and potable-water production are other applications in which the selective separation of metal ions is required. A variety of separation processes for metal ions have been developed for industrial needs, including precipitation, inorganic and polymeric adsorption, evaporation, and reverse osmosis. Such techniques produce water within international health standards but entail some drawbacks, such as the following: (i) Sedimentation produces large amounts of sludges12-14 containing residual of reagents, which results in pollution problems. (ii) Treated water can contain residual of coagulants if the process is not correctly controlled or operated.15 (iii) The ion-exchange process is not continuous, because of the necessity for regeneration. (iv) Reverse osmosis produces good water quality but requires a high operating pressure, which results in a high cost.16-18
10.1021/ie030392t CCC: $27.50 © 2004 American Chemical Society Published on Web 12/20/2003
624
Ind. Eng. Chem. Res., Vol. 43, No. 2, 2004
Figure 1. 2-Hydroxy-5-dodecylbenzaldeyde (2-H-5-DBA).
Liquid-liquid (L-L) extraction procedures have proven to be very useful in the separation and/or recovery of metal ions. In developing extraction methods for metal removal, a major problem arises from the low selectivity of complexing agents.19,20 Consequently, the development of chelating materials with specific binding abilities toward heavy metal ions has received considerable attention. In particular, the selective removal of Cu(II) in the treatment of wastewater is one of the most important problems that must be solved. In the present work, the problem of obtaining a specific complexing agent for Cu(II) was explored. A compound never previously used as a chelant that is able to selectively complex copper ion was synthesized and tested. The selectivity of the new carrier was determined by L-L extraction tests by using aqueous phases containing copper, nickel, manganese, and zinc ions. Some supported liquid membrane (SLM) experiments were also carried out to test the performance of the carrier in operating conditions. Stability tests were not performed with this new synthesized carrier because addressing the problem of membrane stability was not the objective of this work. Experimental Section Reagents. The reagents used for the synthesis of the carrier 2-hydroxy-5-dodecylbenzaldeyde (2-H-5-DBA, Figure 1) (obtained in distilled purity, MW ) 290 g/mol, d ) 1.047 g/L, teb ) 200 °C at 1 mmHg) were 4-dodecyl phenol (d ) 0.940 g/mL, teb ) 310 °C), p-formaldehyde powder (purity 95%), dry toluene (purity 99.8%, d ) 0.865 g/mL), and Mg metal from Sigma-Aldrich. Kerosene (purum, d ) 0.78 g/mL) from Fluka as the organic solvent; copper sulfate pentahydrate (CuSO4‚5H2O, MW ) 249.68 g/mol, purity > 99%) from Fluka; zinc sulfate heptahydrate (ZnSO4‚7H2O, MW ) 287.54 g/mol, purity 99.9%), manganese sulfate monohydrate (MnSO4‚H2O, MW ) 169.02, purity 99%), nickel sulfate hexahydrate (NiSO4‚6H2O, MW ) 262.86, purity 99.9%), and sulfuric acid (H2SO4, 96% purity, d ) 1.84 g/mL) from Carlo Erba Reagenti; and sodium hydroxide NaOH from Merck were used for carrying out L-L extractions and SLM tests. Synthesis of 2-Hydroxy-5-dodecylbenzaldeyde. The o-formylation of 4-dodecylphenol is likely to occur through the following steps, as reported in Figure 2: (a) exchange reaction between the substrate and Mg(OMe)2 to give a magnesium (p-dodecyl)phenoxide intermediate I; (b) electrophilic attack by HCHO ortho to the phenoxide oxygen, leading to chelate complex II; (c) β-H elimination from the -CH2OMg moiety of II to generate the formyl group and Mg-H species; (d) reaction between the latter and HCHO to give MeOH; and (e) acid washing to give the final product (2-H-5-DBA). First, Mg metal (0.32 mol) was added to a solution of magnesium metoxide (2.6 mL), toluene (75 mL), and methanol (141 mL). This mixture was stirred and heated to reflux under a nitrogen atmosphere until the metal was completely dissolved.
Figure 2. Scheme of the synthesis procedure.
After the solution had been cooled to room temperature, 0.5 mol (131.22 g) of 4-dodecylphenol was added to the solution, which was then refluxed for 3 h. Next, 120 mL of toluene was added to the mixture, generating the methanol azeotrope, which was removed by means of distillation. During the distillation, the formation of a white solid was noticed. Subsequently, a suspension composed of p-formaldehyde powder (1.5 mol) in toluene (65 mL) was added to the mixture in a time of 50 min. During this step, the volatile azeotrope had to be removed by means of distillation. Then, the solution was left under agitation at a temperature of 100 °C for 2 h. Later, it was cooled to room temperature, and 500 mL of sulfuric acid (20% w/w) was added; the resulting solution was stirred at 50 °C for 2 h. Next, the organic phase was washed first with 50 mL of sulfuric acid (10% w/w) and then with 50 mL of distilled water. Subsequently, organic phase was left on sodium sulfate anhydrous and evaporated in vacuo and dried under vacuum. Finally, a yellow oil was obtained by means of distillation at a pressure of 10 mm/Hg and a temperature of 200 °C and was confirmed to be the desired product by the agreement of its IR, NMR, and mass spectra with those reported in the literature.21 Equipment and Methods. 1H nuclear magnetic resonance (NMR) spectra were obtained with a Bruker VM-300 nuclear magnetic resonance spectrometer. The chemical shifts are expressed as δ and are referred to TMS or D2O. Mass spectra were obtained on a HewlettPackard GC-MSD 5972 instrument. Infrared (IR) spectra were measured with a Perkin-Elmer FT-IR Paragon 1000 PC spectrometer using laminas of KBr.
Ind. Eng. Chem. Res., Vol. 43, No. 2, 2004 625
Figure 3. Apparatus of flat-sheet SLM operating in continuous recirculation flow: (1, 2) feed and strip containers, respectively; (3, 4) peristaltic pumps; (5, 6) membrane cell elements; (7) SLM; (8) feed-phase circuit; (9) strip-phase circuit; (10) thermostatic water bath at 25°C; (11, 12) manometers; (13, 14) valves; (TC) temperature controller.
Copper, nickel, manganese, and zinc concentrations were determined using an analytical kit (Carlo Erba Reagenti), based on a colorimetric reaction and absorbance readings at wavelengths of 600, 445, 445, and 630 nm, respectively. Absorbance readings were obtained using a UV-visible 160 A recording spectrophotometer (Shimadzu Corporation). A pH meter (Orion Research Incorporated, Expandable Ion Analyzer EA 920) with a combined glass electrode was used for pH measurements. L-L Extraction Tests. All L-L extraction tests were carried out in a test tube, mixing 5 mL of aqueous copper solution ([Cu2+]in ) 50 mg/L) with 5 mL of organic phase at 25 °C. The organic phase was prepared by mixing the organic solvent (kerosene) with the carrier in appropriate ratios, to obtain solutions at 10, 30, and 50% v/v. In each extraction step, the phases were stirred three times by means of a tube stirrer at 10-min intervals. After a resting period of no less than 1 h to leave time for phase separation and to ensure that equilibrium was reached, the copper concentration in the aqueous phase was measured. The chosen time of 1 h was the result of previous kinetics tests that showed that equilibrium of complexation was practically complete in a few minutes. The data from the L-L extraction tests were used to calculate the extraction percentage (E%) according to the following equation
E% )
(nCu2+)org (nCu2+)org + (nCu2+)aq (nCu2+)org
(nCu2+)aq ×
[
(nCu2+)org (nCu2+)aq
]
× 100 ) × 100 )
+1
Kd × 100 (1) Kd + 1
where Kd is the partition coefficient, defined as
Kd )
(nCu2+)org (nCu2+)aq
and equal to
Kd )
[Cu2+]org [Cu2+]aq
when Vaq ) Vorg. Permeation Tests. Supported liquid membranes were prepared by immersion of a flat polymeric support (polypropylene, Accurel, Enka E2 (PP), thickness ) 142 µm, pore size ) 0.2 µm, porosity ) 70%) in the organic solution (20 mL) for approximately 1 h. The impregnated membranes were then dried with a soft paper sheet before being placed in the cell holder. Measurements of the transport rate of copper through the SLM were carried out in the experimental setup of Figure 3. The global system operated in a batch mode, but the SLM module operated under continuous flux. The latter was constituted by two circuits in which feed and strip phases were separately recirculated with equal flow rates of 65 mL/min. The feed and strip reservoirs had volumes of 75 mL and were immersed in a thermostated water bath at 25 °C, so that the process took place under isothermal conditions, at the same temperature used in L-L extractions tests. The permeation module containing the SLM had an exposed surface area of 4 cm × 6 cm ) 24 cm2. Two peristaltic pumps (Masterflex Easy Load, model 7518-12), splined to the same shaft operated by an electric engine (Masterflex Console Drive, model 752147, Cole-Parmer Instruments Company), were used to recirculate the stripping solution and feed through the SLM module. Pipes of Tygon (Masterflex, 6429-15 Tygon LFL, MFG by Norton) were used for plant realization. At established time intervals, samples were withdrawn from the feed and strip reservoirs, and the copper concentrations were measured. The feed and strip pH’s were corrected to the operating value by adding some drops of 0.5 M NaOH to the feed and 1 M H2SO4 to the stripping solution. Calculation of the fluxes in the SLM tests was carried out by using the following mass balance equation for
626
Ind. Eng. Chem. Res., Vol. 43, No. 2, 2004
copper in the feed
JCu2+ )
(
)
VF d[Cu2+] Sexp dt
Feed
(2)
where VF is the feed-phase volume and Sexp is the membrane surface exposed to the feed and stripping phases (that is, the real membrane surface that is needed for the construction of a plant). This is different from the effective membrane surface (Seff), where transport really occurs because of membrane porosity (m): Seff ) Sexpm, but in the approach used in this work, it is more useful to correlate the experimental data in terms of Sexp. Results and Discussion The molecule 2-H-5-DBA can complex copper via the reaction
Cu2+(aq) + 2 HA(org) / CuA2(org) + 2H+(aq)
(3)
where the subscripts aq and org signify the aqueous and organic phases, respectively. This reversible reaction shows the influence of the aqueous-phase pH on the copper extraction process. Its equilibrium constant is given by
Keq )
[CuA2]org[H+]aq2 [Cu2+]aq[HA]org2
(4)
In particular, the idea of using salicylaldehyde as chelant was suggested by the literature,22 where it is reported that nitrogenous derivatives of salicylaldehyde can form complexes with copper cations. However, these complexes have stability constants that are too high to permit the release mechanism in the SLM process. Thus, it was thought that modified salicylaldehyde compounds should be able to form complexes with metal cations with stabilities compatible with the process requirements. Indeed, to realize reversible L-L extraction, the chelating agent should be able to form a weak complex, to have a capture and release mechanism for Cu(II). Salicyladehyde does not respond perfectly to the process requirements because of its lack of lipophilic properties. With the purpose of overcoming this difficulty, it was thought that a 5-alkyl-substituted derivative of salicylaldehyde could be useful, so that the molecule 2-hydroxy-5-dodecylbenzaldehyde (2-H-5-DBA) (see Figure 1) was chosen. This molecule contains hydroxyl and carbonyl groups as ion binding groups, as well as a long aliphatic chain for enhancing its solubility in the hydrophobic phase of the SLM. The molecule 2-H-5-DBA was previously reported in the literature, but it had been synthesized with a yield that was too low to ensure a good possibility for industrial application.21 Starting from this consideration, in analogy with other methods used in the preparation of similar derivatives,23 a new method for synthesizing the selected molecule was developed. The main advantage of this new synthesis method is the obtained yield, which is approximately 80%, compared to the 19% yield obtained by means of the method reported in the literature.21 This molecule should be able to complex metal ions by means of the following mechanism: At high pH, the hydroxyl group (-OH) bound to the aromatic ring can
Figure 4. E% in the L-L extraction tests with four different metals at a carrier concentration of 10% v/v in kerosene (T ) 25 °C).
release H+ ions. As a result, the -O- group becomes able to complex the positive charges of metal ions. In addition to this main interaction, electrostatic in nature, the oxygen of the carbonyl group can coordinate metal ions. In particular, doubly positive ions, M2+ (e.g., Fe2+, Mg2+, Ca2+, Cu2+, Ni2+, etc.) should give an ionexchange complexation reaction in addition to the previous coordination. Similar to this chelant is the molecule Acorga M5640, used in the literature as an extractant for selective copper separation over iron.24,25 For this chelant and for carriers, such as D2EHPA, largely used in the literature26 for copper separations,27-29 only an ion-exchange reaction takes place
M2+(aq) + 2HA(org) / MA2(org) + 2H+(aq)
(5)
which results in less specificity. The hypothesized selectivity of the molecule 2-H-5DBA toward the copper ion can be explained by the formation of a neutral complex in the organic phase, MA2(org), where the metal should be present in a tetracoordinate geometry. It is known, in fact, that copper30,31 can form these complexes, whereas other metals, such as Mn and Zn,32,33 preferably form hexa-coordinate complexes. To verify the selectivity of the new carrier, some L-L extraction tests were carried out using aqueous phases containing copper, nickel, manganese, and zinc ions. In Figure 4, the extraction percentages (E%) of these ions are reported for a fixed carrier concentration (10% v/v). The results obtained demonstrate the selectivity of 2-H5-DBA toward copper ions. Indeed, at pH 6.5, the E% of copper is 75%, whereas the values for nickel, zinc, and manganese are 9.4, 7, and 3%, respectively. Thus, the selectivity, calculated as the ratio E%(Cu)/E%(M), where M ) Ni, Zn, and Mn, for copper with respect to each of the ions, is 8.0, 10.7, and 25.0, respectively. The low E% value of nickel was probably due to the feed pH and not to geometric factors; indeed, complexes of nickel in a tetra-coordinate structure have been observed using chelants similar to 2-H-5-DBA.32 E% represents a measure of the complexation tendency of the chelating agent toward the target metal: a higher E% means a greater facility to form complexes. This means that the removal of copper ions from a solution also containing zinc, nickel, and manganese can be achieved with good selectivity at an equilibrium pH of 6.5.
Ind. Eng. Chem. Res., Vol. 43, No. 2, 2004 627
Figure 5. Results of L-L extraction test at different carrier concentrations ([Cu2+]aq,in ) 50 mg/L, T ) 25 °C).
Figure 6. E% in the L-L extraction tests with four different metals at 50% v/v carrier concentration in kerosene (T ) 25 °C).
From the plot of Figure 4, one can derive optimal conditions for complexation at pH g 6.5 (a value also recommended by the selectivity information) and for release at pH e 4. It was observed that the pH value of 6.5 can be acceptable only for some applications at low Cu2+ concentration. In fact, one might be required to work at lower feed pH’s to avoid metal hydroxide formation in the SLM process because of the high Cu2+ concentration in the feed or because the solution is acidic. To avoid copper hydroxide formation and precipitation in the feed phase, the E%-pH sigmoid, reported in Figure 4, was translated to the left in a suitable pH range by increasing the carrier concentration in the organic phase. In fact, taking into account the previously reported extraction reaction 3 and its equilibrium constant eq 4, it is clear that, to respect the equilibrium constant value (maintaining the operating temperature constant at 25 °C), an increase in the carrier concentration, [HA], corresponds to an increase in the H+ ion concentration, meaning a decrease in pH. When the L-L extraction tests were performed at higher 2-H-5-DBA concentrations (30 50% and v/v), the extraction curve (Figure 5) moved to lower pHs. To find the carrier selectivity at the higher concentrations, L-L extraction tests were carried out for Ni(II), Zn(II), and Mn(II) at 50% v/v carrier. The results obtained, reported in Figure 6, show that, at pH 5, the E% of copper is 85%, whereas the values are 20, 0.27, and 0.30% for nickel, zinc, and manganese, respectively. Thus, the selectivities, calculated as the ratio E%(Cu)/E%(M), where M ) Ni, Zn, and Mn, for copper with respect to these ions are 4.25, 315.0, and 280.0, respectively.
Figure 7. Results of an SLM test with 50% v/v carrier concentration in kerosene (feed pH ) 5, strip pH ) 2.2, T ) 25°C).
Comparing these values with the previous results (obtained at pH 6.5 and 10% v/v carrier concentration), it can be seen that the selectivity with respect to nickel is reduced, but the selectivities with respect to zinc and manganese are significantly greater, thanks to the different types of coordination structures. The possibility of usinfg the synthesized carrier in an SLM process was also tested. From Figure 6, a feed of pH 5 and a strip of pH 2.2 are obtained and can be used to run the SLM process. Thus, operating the SLM system with a 50% v/v carrier concentration, the obtained results (Figure 7) showed a very good countercoupled transport of copper. The average flux during periods of 30-270 min was about constant with a value of 266 mg/h‚m2 (4.18 mmol/h‚m2). A copper concentration in the strip equal to 46.5 mg/L compared ot 50 mg/L in the initial feed was obtained, and no copper hydroxide in the feed was observed during the test. Incomplete transport of copper ion from the feed to the stripping solution was obtained because of equilibrium being reached in SLM operation. Moreover, the SLM system did not show evidence of instability throughout the run, as indicated by the linear trends of the feed and strip concentrations. Conclusion The new method for synthesizing the molecule 2-H5-DBA, proposed and realized in this work, provided a yield of 80%, much higher than that reported in the literature (19.4%). A very selective extraction of Cu(II) over Ni(II), Zn(II), and Mn (II) from aqueous solutions to an organic phase was observed for the 2-H-5-DBA chelant. The E%-pH sigmoid was translated to lower pH by increasing the chelant concentration in the organic phase, thus allowing the possibility of treating water at different pH’s, depending on the particular requirements. Operating at a carrier concentration of 50% v/v, the obtained results showed an enhanced carrier selectivity, a copper countercoupled transport, and no hydroxide formation, with a concentration factor, ([Cu2+]strip/ [Cu2+]feed)final, of 23.5. Moreover, the SLM system did not exhibit any evidence of instability during the run. Acknowledgment One of the authors (T.P.) acknowledges the CNR (Italy) for a fellowship (July 2001 to July 2002) at ITMCNR of Rende (CS), Italy. Financial support within the
628
Ind. Eng. Chem. Res., Vol. 43, No. 2, 2004
National Plane “Soil Remediation” of the Interuniversity National Consortium “Chemistry for the Environment” (INCA) is acknowledged. Literature Cited (1) Chen, T. C.; Hong, A. Chelating extraction of lead and copper from an authentic contaminated soil using N-(2-acetamido)iminodiacetic acid and S-carboxymethyl-L-cysteine. J. Hazard. Mater. 1995, 41, 147. (2) Anderson, W. C. Innovative Site Remediation Technology: Soil Washing and Flushing; American Academy of Environmental Engineers: Annapolis, MD, 1993. (3) Bassi, R.; Prasher, S. O.; Simpson, B. K. Extraction of Metals from a Contaminated Sandy Soil Using Citric Acid. Environ. Prog. 2000, 19, 275. (4) Cameron, R. E. Guide to Site and Soil Description for Hazardous Waste Site Characterization; Report EPA/600/4-91/029; U.S. Environmental Protection Agency, U.S. Government Printing Office: Washington, DC, 1992; Vol. I: Metals. (5) Steenkamp, G. C.; Keizer, K.; Neomagus, H. W. J. P.; Krieg, K. M. Copper(II) removal from polluted water with alumina/ chitosan composite membranes. J. Membr. Sci. 2002, 197, 147. (6) Barron-Zambrano, J.; Laborie, S.; Viers, Ph.; Rakib, M.; Durand, G. Mercury removal from aqueous solution by complexation-ultrafiltration. Desalination 2002, 144, 201. (7) Hatfield, T. L.; Pierce, D. T. Electrochemical remediation of metal-bearing wastewaters Part II: Corrosion-based inhibition of copper removal by iron(III). J. Appl. Electrochem. 1998, 28, 397. (8) Zumriye, A.; Gonul, D. The use of molasses in copper(II) containing wastewaters: Effects on growth and copper(II) bioaccumulation properties of Kluyveromyces marxianus. Process Biochem. 2000, 36, 451. (9) Price, M. S.; Classen, J. J.; Payne, G. A. Aspergillus niger absorbs copper and zinc from swine wastewater. Bioresour. Technol. 2001, 77, 41. (10) Purnendu, B.; Bose, A.; Sunil, K. Critical evaluation of treatment strategies involving adsorption and chelation for wastewater containing copper, zinc and cyanide. Adv. Environ. Res. 2002, 7, 179. (11) Lofti, M.; Nafaa, A. Modified activated carbon for the removal of copper, zinc, chromium and cyanide from wastewater. Sep. Purif Technol. 2002, 26, 137. (12) Kruithof, J. C.; Kopper, H. M. M. Experiences with groundwater treatment and disposal of the eliminated substances in The Netherlands. Aqua 1989, 38, 207. (13) Drioli, E.; Molinari, R. Membrane operations in the management of industrials waters. In Towards Hybrid Membrane and Biotechnology Solutions for Polish Environmental Problems; Howell, J. A., Noworita, A. J., Eds.; Wroclaw Technical University Press: Wroclaw, Poland, 1995. (14) Howell, J. A.; Noworita, A. J. Towards Hybrid Membrane and Biotechnology Solutions for Polish Environmental Problems; Wroclaw Technical University Press: Wroclaw, Poland, 1995. (15) Scott, K. Handbook of Industrial Membranes; Elsevier Advanced Technology: Oxford, U.K., 1995. (16) Duyvesteijn, C. P. T. M. Water reuse in an oil refinery. Desalination 1998, 119, 357. (17) Ciardelli, G.; Corsi, L.; Marcucci, M. Membrane separation for wastewater reuse in the textile industry. Res. Conserv. Recycl. 2001, 31, 189. (18) Atkinson, S. Treatment system tackles water purification and reuse in the pulp and paper industry. Membr. Technol. 2001, 136, 10.
(19) Gherrou, A.; Kerdjoudj, H.; Molinari, R.; Drioli, E. Facilitated cotransport of Ag(I), Cu(II), and Zn(II) ions by DB18C6 crown ethers as carriers: Interface behaviour on ion transport. Sep. Sci. Technol. 2001, 36, 2293. (20) Buonomenna, M. G.; Molinari, R.; Drioli, E. Selective mass transfer of iron(III) in supported liquid membrane using highly acidic extractants, 3-phenyl-4-acyl-5-isoxazolones. Desalination 2002, 148, 257. (21) Spepniak-Biniakiewicz, D. 2-Hydroxy-5-alkylbenzaldehydes and Their Oximes. Pol. J. Chem. 1980, 54, 1567. (22) Das, G.; Shukla, R.; Mandal, S.; Singh, R.; Bharadwaj, P. K.; van Hall, J.; Whitmire, K. H. Syntheses and X-ray Structures of Mixed-Ligand Salicylaldehyde Complexes of Mn(III), Fe(III), and Cu(II) Ions: Reactivity of the Mn(III) Complex toward Primary Monoamines and Catalytic Epoxidation of Olefins by the Cu(II) complex. Inorg. Chem. 1997, 36, 323. (23) Alfred, R.; Johnston, R.; Levin, D.; Neilan, J. Magnesiummediated ortho-specific formylation and formaldoximation of phenols. J. Chem. Soc., Perkin Trans. 1 1994, 1823. (24) Alguacil, F. J.; Cobo, A.; Alonso, M. Copper separation from nitrate/nitric acid media using Acorga M5640 extractant. Part I: Solvent extraction study. Chem. Eng. J. 2002, 85, 259. (25) Alguacil, F. J.; Alonso, M.; Sastre, A. M. Copper separation from nitrate/nitric acid media using Acorga M5640 extractant. Part II. Supported liquid membrane study. Chem. Eng. J. 2002, 85, 265. (26) Molinari, R.; Pirillo, F.; Argurio, P. Sandwich Liquid Membrane in the separation and concentration of Cu2+. Ann. Chim. (Rome) 2002, 92, 973. (27) Yang, C.; Cussler, E. L. Reaction dependent extraction of copper and nickel using hollow fibers. J. Membr. Sci. 2000, 166, 229. (28) Bhandare, A. A.; Argekar, A. P. Separation and recovery of platinum and rhodium by supported liquid membrane using bis(2-ethylhexyl)phosphoric acid (HDEHP) as a mobile carrier. J. Membr. Sci. 2000, 201, 233. (29) Chakraborty, R.; Datta, S. Transport of Te4+ through liquid surfactant membrane using D2EHPA as the carrier. J. Membr. Sci. 1994, 96, 233. (30) Halcrow, M. A.; Chia, L. M. L.; Liu, X.; McInnes, E. J. L.; Yellowlees, L. J.; Mabb, F. E. Syntheses, structures and electrochemistry of copper(II) salicylaldehyde/tris(3-phenylpyrazolyl)borate complexes as models for the radical copper oxidases. J. Chem. Soc., Dalton Trans. 1999, 1753. (31) Sakamoto, R.; Ohba, M.; Fukita, N.; Takahashi, K.; Okawa, H.; Tompson, L. K. Copper(II) Compounds Extended by 5-Carboxysalicylaldehyde and Its Schiff Bases: Interplay of Two MetalBinding Sites and Intermolecular Stacking Contributing to Their Network and Bulk Structures. Bull. Chem. Soc. Jpn. 1998, 71, 2365. (32) De Munno, G.; Poerio, T.; Julve, M.; Lloret, F.; Viau, G.; Caneschi, A. Synthesis, crystal structure and magnetic properties of the manganese(II) chains [Mn(bipym)(NO3)2] and [Mn(bipym)(NCO)2]. J. Chem. Soc., Dalton Trans. 1997, 601. (33) De Munno, G.; Armentano, D.; Poerio, T.; Julve, M.; Real, J. A. Novel sheetlike manganese(II) network. Synthesis and structure of [Mn(bpe)(NCS)2(CH3OH)2] and [Mn(bpe)(NCS)2(CH3OH)2]‚bpe [bpe ) 1,2-trans (4-pyridil)ethene]. J. Chem. Soc., Dalton Trans. 1999, 1813.
Received for review May 5, 2003 Revised manuscript received October 27, 2003 Accepted November 5, 2003 IE030392T
