Amberlite IR-120 Resin Research Articles

Removal of hexavalent chromium from electroplating wastewater by ion-exchange in presence of Ni(II) and Zn(II) ions

This study presents the ion-exchange elimination of hexavalent chromium [Cr(VI)] from electroplated industrial wastewater. The effects of experimental factors such as pH, contact time, adsorbent dose, temperature, and co-ions on Cr(VI) removal were investigated. The metal ions were maximally removed (up to 96.7 %) and obtained with a resin dosage of 3 g L−1 at pH 2 for 70 min. Thermodynamic parameters, such as the standard Gibbs free energy change (ΔG0), standard enthalpy change (ΔH0),and standard entropy change (ΔS0), were calculated. The negative value of ΔG0(−8.031 kJ/mol K)indicates the spontaneity of the ion exchange process. The Freundlich and Langmuir isotherms fit the adsorption data well. The adsorption kinetics of Cr(VI) on the Amberlite IRA400 resin were analyzed using reversible first-order kinetics. The presence of Zn(II) and Ni(II) increased the efficiency of the adsorption process in the order Zn(II) > Ni(II). Column experiments were conducted to determine the breakthrough point of the packed-bed resin column, and a break-even concentration of 0.1 mgL−1 was deducted after the treatment of 4.5 L of the effluent. The adsorption data from the column studies were fitted using the Adam–Bohart adsorption model and the results fit the model well. A mathematical approach to the regeneration process is described in this study. The reusability of the resin was tested for 30 cycles and its efficiency of the regenerated resin was found to be above 97 % after the 30th cycle.

Evaluation of clavulanic acid recovery techniques from Streptomyces clavuligerus cultivation broths

Clavulanic acid (CA) is a soft β-lactam antibiotic with a strong inhibitory effect on β-lactamase enzymes and it is produced by the filamentous Gram-positive bacterium Streptomyces clavuligerus (S. clavuligerus) as a secondary metabolite; the complete pathway (known as the clavam pathway) derives from the condensation of arginine and glyceraldehyde-3-phosphate, as anabolic precursors. In this work, the potential of two distinct operations for CA recovery was re-evaluated: first, the adsorption of CA through the utilization of the anion exchange resin Amberlite IRA 400, and second, the application of liquid–liquid extraction systems. For the liquid–liquid extraction, two experimental designs were developed aimed at finding the best conditions of the process. For the case of adsorption, the same experimental design, used in the previous strategy, was carried out, for comparison purposes. CA loss was minimized at 10°C and pH 2.0. The adsorption was favored by increasing the adsorbent-to-liquid ratio. Thus, the highest separation was attained in the range of 40%–45% solid/liquid ratio, adsorbing a mean value of 47.7% of the CA present in the broth. Results showed that there is still room for further improvements in CA recovery using both, adsorption and extraction, as the most advantageous techniques.

Optimizing ciprofloxacin removal using ion exchange resin: Exploring operational parameters and assessing toxicity

The present study investigates the adsorption behavior of ciprofloxacin hydrochloride (CIP) onto the cationic resin Amberlite IR120. Equilibrium and kinetic experiments were conducted to assess the influence of resin mass (0.02 to 0.19 g), agitation rate (200 to 500 rpm), pH (2 to 11), and temperature (15 to 45 °C) on the efficiency of CIP removal. Non-linear models, coupled with error functions such as coefficient of determination (r2) and the sum of squared residuals (SQR), were employed to assess the compatibility between kinetic models (pseudo-first order, pseudo-second order, Elovich) and isotherm adsorption equations (Langmuir and Freundlich). The IR120 resin underwent characterization through scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), laser granulometry, nitrogen adsorption–desorption isotherms (BET), and attenuated total reflection infrared spectroscopy (ATR-FTIR). Utilizing the Langmuir model, the maximum adsorption capacity of CIP was determined to be 37 mg g−1. Based on the r2 values obtained from the kinetic models, the pseudo-first order and pseudo-second order models exhibited the best fit for all experimental data. Optimal conditions for the adsorption occurred at pH 7, temperature of 15 °C, resin mass of 0.08 g, and agitation rate at 300 rpm. Remarkably, complete elimination of toxicity towards Escherichia coli organisms was achieved, evidenced by the absence of antibacterial effects after 60 min of operation. Consequently, the results suggest that IR120 holds promising potential as an adsorbent for CIP removal.

Sorption of Lead, Zinc and Copper from Simulated Wastewater by Amberlite Ir-120 Resin

The presence of heavy metals in the environment is major concern due to their toxicity. In the present study a strong acid cation exchange resin, Amberlite IR 120 was used for the removal of lead, zinc and copper from simulated wastewater. The optimum conditions were determined in a batch system of concentration 100 mg/L, pH range between 1 and 8, contact time between 5 and 120 minutes, and amount of adsorbent was from 0.05 to 0.45 g/100 ml. A constant stirring speed, 180 rpm, was chosen during all of the experiments. The optimum conditions were found to be pH of 4 for copper and lead and pH 6 for zinc, contact time of 60 min and 0.35 g of adsorbent. Three different temperatures (25, 40 and 60°C) were selected to investigate the effect of adsorption temperature on heavy metals adsorption onto Amberlite IR. The equilibrium data were analyzed by the Langmuir and Freundlich isotherms. The thermodynamic parameters such as Gibbs free energy, enthalpy and entropy changes were calculated. Moreover, in order to understand the heavy metal extraction kinetics in the presence of Amberlite IR 120, the ion exchange kinetics was also studied. The ion exchange kinetics data were regressed by the pseudo first-order, second-order models. The results obtained show that the Amberlite IR 120 strong acid cation exchange resin performed well for the removal of lead, zinc and copper.

Selective removal of ammonia from wastewater using Cu(II)-loaded Amberlite IR-120 resin and its catalytic application for removal of dyes

Cationic ligand exchange is one of the most predominant mechanisms for the removal of ammonia from wastewater through complex formation. The complexation technique occurs between the metal ions loaded on the surface of Amberlite IR-120 and ammonia which is present in the medium. Cu(II)-loaded Amberlite IR-120 (R-Cu2+) was prepared and described using FT-IR, TGA, SEM, and EDX techniques. The prepared R-Cu2+ was applied for the elimination of ammonia from an aqueous solution. Different cations such as Co2+ and Ni2+ were loaded onto Amberlite IR-120 to study the impact of counter cation on the removal efficiency of ammonia. The ammonia removal percentage followed the order; R-Cu2+ > R-Ni2+ > R-Co2+. The effects of contact time, pH, initial concentration, temperature, and coexisting ions on the removal of ammonia from wastewater by R-Cu2+ were investigated. The equilibrium adsorbed amount of ammonia was found to be 200 mg/g at pH = 8.6 and 303 K within 60 min using 0.1 g R-Cu2+ and an initial concentration of ammonia of 1060 mg/L. The removal of ammonia using R-Cu2+ obeyed the non-linear plot of both Freundlich and Langmuir isotherms. According to the thermodynamic parameters, the adsorption of ammonia onto R-Cu2+ was an endothermic and spontaneous process. The time-adsorption data followed the pseudo-second-order and intraparticle diffusion models. Moreover, the resulting product (R-Cu(II)-amine composite) from the adsorption process exhibited high catalytic activity and could be low-cost material for the elimination of dyes such as aniline blue (AB), methyl green (MG), and methyl violet 2B (MV2B) from wastewater.Graphical

Boron extraction using selective ion exchange resins enables effective magnesium recovery from lithium rich brines with minimal lithium loss

• Li + loss decreases from 13.7 to 1.4% during Mg(OH) 2 precipitation in the absence of boron. • Chemical-grade Mg(OH) 2 precipitation was possible from brines free of B. • Amberlite IRA743 resin selectivity extract boron from raw Li reach brines. • Resin saturated with boron can be regenerated and reused with the same efficiency. • The high water intake in the presence of B is associated with hydroboracite formation. Magnesium hydroxide is a commodity chemical, produced in almost pure form from seawater through precipitation. Even though Li brines contain high concentrations of Mg 2+ cations, the precipitation of Mg(OH) 2 from them is not common. Rather it is typically coprecipitated with other salts and becomes a waste. The crystallization of chemical-grade Mg(OH) 2 from a Li + rich brine that contained 3.1 g/L Mg 2+ and 1.3 g/L Li + , was investigated by means of NaOH and CaO addition. Direct precipitation of Mg(OH) 2 leads to considerable Li loss and impure crystals due to the brine uptake into the crystal cake. In order to increase the sedimentation rate and decrease the brine loss, a boron extraction step was introduced, which consisted of initial polishing using Amberlite IRA743. It was possible to extract B to below the ICP detection limit from native salt lake brines selectively and regenerate the ion exchangers for repetitive cycles. Upon the extraction of boron, the Mg(OH) 2 sedimentation rate, increased while the loss of Li + from the brine decreased from 13.7 ± 1.2 to 1.5 ± 0.4%. Precipitation with CaO as an alkalizing agent generated a mixture of crystals and a Li + loss between 6.7 ± 0.8 and 3.8 ± 0.7%. When the boron-free brine was alkalized by NaOH, an increase in the degree of crystallinity of Mg(OH) 2 crystal structure was verified by XRD and a purity of 95 ± 2% for the solid was obtained. The high water intake in the presence of B was associated with the presence of hydroboracite in intercalation within the brucite. It was expected that, if the hydroboracite was present as an intercalation, this structure would be disrupted more easily by the ultrasound, potentially resulting in a loss of the hydroboracite d-spacings. Concluding, subsequent B and Mg removal steps from Li + rich brines result in the production of 95% pure Mg(OH) 2 leaving a brine for high purity lithium salt precipitation, thereby bringing a second attractive product from brine processing.

Impact of Different Epoxidation Approaches of Tall Oil Fatty Acids on Rigid Polyurethane Foam Thermal Insulation.

A second-generation bio-based feedstock—tall oil fatty acids—was epoxidised via two pathways. Oxirane rings were introduced into the fatty acid carbon backbone using a heterogeneous epoxidation catalyst-ion exchange resin Amberlite IR-120 H or enzyme catalyst Candida antarctica lipase B under the trade name Novozym® 435. High functionality bio-polyols were synthesised from the obtained epoxidated tall oil fatty acids by oxirane ring-opening and subsequent esterification reactions with different polyfunctional alcohols: trimethylolpropane and triethanolamine. The synthesised epoxidised tall oil fatty acids (ETOFA) were studied by proton nuclear magnetic resonance. The chemical structure of obtained polyols was studied by Fourier-transform infrared spectroscopy and size exclusion chromatography. Average molecular weight and polydispersity of polyols were determined from size exclusion chromatography data. The obtained polyols were used to develop rigid polyurethane (PU) foam thermal insulation material with an approximate density of 40 kg/m3. Thermal conductivity, apparent density and compression strength of the rigid PU foams were determined. The rigid PU foams obtained from polyols synthesised using Novozym® 435 catalyst had superior properties in comparison to rigid PU foams obtained from polyols synthesised using Amberlite IR-120 H. The developed rigid PU foams had an excellent thermal conductivity of 21.2–25.9 mW/(m·K).

Potential separation of zirconium and some lanthanides of the nuclear and industrial interest from zircon mineral using cation exchanger resin

The present study is conducted for developing separation of some elements of nuclear interest from zirconium-concentrate explored from Egyptian zircon mineral, using certain cationic exchangers. The main results revealed that Amberlite IR-120 is more efficient than Chelex-100 for separating La and Zr in 0.01 mol. L−1 (various acid, carbonate) from single or binary solution with separation factor (SF) of ∼2.1 × 103 (HCl) > 239 (HNO3) >56 (K2CO3) > 17.5 (HClO4). Separation of La and Zr was largely influenced by acid concentration, equilibration period, and temperature. Thermodynamically, values of and indicated that retention of the metal ions is disordered and endothermic nature. In a column application, Zr is separately eluted without La; with recoveries reached to 98% for Zr and 50% to 67% for La. The larger negativity of free energy of hydration of Zr (−6950 KJ/mol) that of La (−3418 KJ/mol) confirm that Zr exists as a non-sorptive species; meanwhile La forms adsorptive species onto the column bed resin. As a result, this study can be extended in the future to help exploration of the strategic elements (e.g., Zr, Hf, lanthanides) from their minerals in Egypt. Moreover, developed procedure by Amberlite IR-120 resin can be considered as highly efficient and promising for separation and purification of tri-valence lanthanides (e.g., La3+) and/or actinides (e.g., Am3+) from tetra-valence metal ions such as Zr4+ and Hf4+ or their homologous as Ce4+, Th4+ and Np4+.

Imparting UiO-66 with fast cation exchange property via sulfonating organic linkers for selective adsorption

Adsorption is the simplest in operation and most cost-effective approach to remove pollutants in an aqueous environment. Advanced adsorbents providing selective ion adsorption of target dyes in an aqueous environment are desirable to ensure good water quality before discharged as wastewater. Metal organic frameworks (MOFs), despite high surface area and high porosity, generally exhibit poor ion-selectivity, thus, hindering their applications in dye removal from industrial wastewater. We report, for the first time, the high cation exchange performance of UiO-66 functionalized via sulfonation of its organic linkers (UiO-66-SO3H). More than 90% of cationic methylene blue dye solution was adsorbed by the UiO-66-SO3H while rejecting 100% anionic acid blue dye. The cation adsorption selectivity of UiO-66-SO3H is superior to the performance of the commercially available cation exchange Amberlite IR-120 resin. The synthesis of the sulfonated UiO-66 is simple and scalable. This material is promising for the industrial-based applications in aqueous-based separations of ions, and dye removal from wastewater.

Sorption behavior and mechanism of oxytetracycline from simulated wastewater by Amberlite IR-120 resin

The adsorption of oxytetracycline from aqueous solution by the resin Amberlite IR 120 was studied. The effect of different experimental parameters such as contact time, initial concentration of OTC 40-200 mg/l, initial pH 2-12 of aqueous solution, adsorbent dose 0.5-3 g/l, and stirring speed 100-700 rpm on the adsorption of OTC were investigated. The kinetic adsorption experimental results were analyzed using pseudo-first order, pseudo-second order and Elovich kinetic models. The adsorption process was found to follow a pseudo-second order kinetic model and the corresponding rate constants were obtained. A film-pore diffusion (FPD) mass transfer model has been developed to predict the concentration distribution in the fluid phase, based on the external mass transfer coefficient and the effective diffusion coefficient. The values of the external mass transfer coefficient (βL) and effective diffusion coefficient (Deff) were found to decrease with increasing OTC concentration. The comparison between the experimental and the theoretical curves allowed us to note that the film-pore diffusion mass transfer model gave a good agreement with the experimental data for all the values of initial OTC concentration.

Honeycomb-structured solid acid catalysts fabricated via the swelling-induced self-assembly of acidic poly(ionic liquid)s for highly efficient hydrolysis reactions

The development of heterogeneous acid catalysts with higher activity than homogeneous acid catalysts is critical and still challenging. In this study, acidic poly(ionic liquid)s with swelling ability (SAPILs) were designed and synthesized via the free radical copolymerization of ionic liquid monomers, sodium p-styrenesulfonate, and crosslinkers, followed by acidification. The 31P nuclear magnetic resonance chemical shifts of adsorbed trimethylphosphine oxide indicated that the synthesized SAPILs presented moderate and single acid strength. The thermogravimetric analysis results in the temperature range of 300–345 °C revealed that the synthesized SAPILs were more stable than the commercial resin Amberlite IR-120(H) (245 °C). Cryogenic scanning electron microscopy testing demonstrated that SAPILs presented unique three-dimensional (3D) honeycomb structure in water, which was ascribed to the swelling-induced self-assembly of the molecules. Moreover, we used SAPILs with micron-sized honeycomb structure in water as catalysts for the hydrolysis of cyclohexyl acetate to cyclohexanol, and determined that their catalytic activity was much higher than that of homogeneous acid catalysts. The equilibrium concentrations of all reaction components inside and outside the synthesized SAPILs were quantitatively analyzed using a series of simulated reaction mixtures. Depending on the reaction mixture, the concentration of cyclohexyl acetate inside SAPIL-1 was 7.5–23.3 times higher than that outside of it, which suggested the high enrichment ability of SAPILs for cyclohexyl acetate. The excellent catalytic performance of SAPILs was attributed to their 3D honeycomb structure in water and high enrichment ability for cyclohexyl acetate, which opened up new avenues for designing highly efficient heterogeneous acid catalysts that could eventually replace conventional homogeneous acid catalysts.

Automation of boron chromatographic purification for δ11 B analysis of coral aragonite.

To detect the small changes in past pH, the boron isotope ratio of coral carbonates, expressed as the δ11 B value, needs to be both precise and accurate (2sd <<1‰). Boron measurements by Multi-Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICPMS) require the boron to be carefully purified before analysis, which is time consuming, and requires specialist training. Here, we use the prepFAST-MC method that enables the automatic extraction of B (up to 25 ng load) from a CaCO3 matrix. Samples were purified using the prepFAST-MC automated system with a ~25-μL column of Amberlite IRA743 resin. Boron isotope measurements were performed by MC-ICPMS. The effects of matrix load, speed of sample loading onto the column, and blank contamination were tested to evaluate the effects on the purification process. The optimised protocol was tested on various standards and samples of aragonite corals. The blank contribution for the approach is ~60 pg and is negligible given our sample size (<0.2% sample size). Efficiency of matrix removal is demonstrated with the addition of up to 1.6 mg of dissolved low-B calcium carbonate to NIST SRM 951 with no impact on the accuracy of δ11 B values. The Japanese Geological Survey Porites reference material JCp-1, boric acid standard NIST SRM 951, and seawater, all processed on the prepFAST-MC system, give δ11 B values within error of literature values (δ11 BJCp-1 = 24.31 ± 0.20‰ (2sd, n = 20); δ11 BNIST 951 = -0.02 ± 0.15‰ (2sd, n = 13) and δ11 BSeawater = 39.50 ± 0.06‰ (2sd, n = 2)). Results obtained from the coral Siderastrea siderea purified with the prepFAST-MC system show an average offset from the manual ion-exchange protocols of Δδ11 B = 0.01 ± 0.28‰ (2sd, n = 12). Our study demonstrates the capacity of the prepFAST-MC method to generate accurate and reproducible δ11 B values for a range of materials, without fractionation, with efficient matrix removal and with negligible blank contribution.

Tall Oil Fatty Acid Epoxidation Using Homogenous and Heterogeneous Phase Catalysts

Tall oil fatty acids were epoxidized by in-situ generation of peracetic acid in the presence of two different acidic catalysts, commonly used catalyst—sulfuric acid and ion exchange resin. The described epoxidation was carried out without the use of organic solvents to comply with the principles of Green chemistry. The epoxidation process was monitored by the change of the relative oxirane conversion and alkenic unsaturation. Furthermore, the changes in the chemical structure of the epoxidized tall oil fatty acids were investigated using FTIR spectroscopy. It was shown that ion exchange resin Amberlite IR-120 H catalyst was superior to sulfuric acid catalyst as it delivered fewer by-products from oxirane group opening reactions. The oxirane value reached up to 2.31 mmol/g of epoxy groups, which is 41.9% of theoretically possible oxirane oxygen yield, when tall oil was epoxidized using Amberlite IR-120 H. The reusability of ion exchange resin was also studied, the 6.2% decrease in relative oxirane conversion value was registered after Amberlite IR-120 H was reused up to 10 times.

The purification of natural coagulant extracted from common bean on IRA 958 Cl anion exchange resin

Natural coagulants are of organic nature and can increase the organic load of treated water and thus, they require purification in order to remove compounds that do not have coagulation activity. In this work, natural coagulant was extracted from 50 g L-1 of ground common bean with 0.5 mol L-1 NaCl. Proteins from this crude extract were precipitated by addition of ammonium sulphate. After the precipitation, separation and resolution of proteins, further purification was performed using the anion-exchange resin Amberlite IRA 958 Cl in a batch process. Partially purified coagulant eluted with 2 mol L-1 NaCl solution achieved the highest coagulation activity of 53.3 % at a dose of 1 mL L-1 although it contained the lowest amount of proteins, but a slightly lower coagulation activity of 49.8 % was achieved at more than 5 times lower dosage of the same fraction. The organic load in treated water when the purified fraction was applied as coagulant was almost 4 times lower than in case of the crude extract as coagulant.

Low resolution benchtop nuclear magnetic resonance for the follow-up of the removal of Cu2+ and Cr3+ from water by amberlite IR120 ion exchange resin

Water pollution by heavy metals is a major environmental concern. For example, copper and chromium are produced by metal and electronic industries and must be removed from wastewater. But Cu2+ and Cr3+ are also paramagnetic ions which previously allowed the use of Magnetic Resonance Imaging (MRI) and Nuclear Magnetic Resonance (NMR) relaxometry to follow their migration in several matrixes and their adsorption on different compounds. In this work, the removal of Cu2+ and Cr3+ from water by amberlite IR120 resin is studied with T2 relaxometry. The ion exchange process obeys a pseudo-second-order kinetics model, while the equilibrium isotherms can be fitted by the Langmuir theory providing values of 79 and 10.1 mg/g for the maximum metal content per gram of resin for Cu2+ and Cr3+ respectively. The equilibrium constants are 2.07 and 0.61 mM−1 for Cu2+ and Cr3+ respectively. pH does not influence the removal capacity of the resin in the studied range (pH 2–4.5). The longitudinal and transverse relaxation of the wet resin are shown to be biexponential. The relaxation rate of the fast relaxing water fraction of the wet resin is correlated with its Cu2+ or Cr3+ content. This paves the way of column experiments in which the gradual loading of the resin with Cu2+ or Cr3+ could be followed on-line by NMR relaxometry.

Remediation of Simulated Landfill’s Leachate Using Waterworks Sludge and Other Conventional Materials

The possibility of utilizing waterworks sludge as byproduct from water supply treatment plant for the remediation of simulated leachate contaminated with cadmium, dissolved organic matter (COD), and ammonia nitrogen (NH3-N) was investigated through batch study in comparison with conventional sorbents specifically activated carbon and ion-exchange resin Amberlite IR120 Na. Batch sorption experiments of single and multi-components systems were conducted to represent the acetogenic phase (pH= 5.5). Results proved that the sludge, activated carbon and ion-exchange resin are efficient sorbents for removal of cadmium, COD, and NH3-N respectively with removal efficiencies ranged from 35 to 95% for all experiments. Equilibrium isotherms were analyzed using the Langmuir and Freundlich models. Kinetic data were obtained and analyzed using pseudo-first-order and pseudo second-order equations. The sorption isotherm data were fitted well to the Langmuir isotherm and the monolayer adsorption capacity was found as 5.634, 14.908 and 3.938 mg/g for sorption of Cd (II) onto sludge, NH3-N onto resin and COD onto activated carbon respectively.

Kinetics of uranium carbonate leaching process from carbonaceous shale, southwestern Sinai, Egypt

The present work dealt with selective leaching of uranium from Alloga carbonaceous shale which assays 0.136% of U associated to 0.177% Cu and 0.068% of rare earth elements, based on an environmentally friendly method, using Na2CO3/NaHCO3 solution. The carbonate leaching kinetics was studied to determine the nature of the dissolution process. Applying the un-reacted shrinking-core model in the solid–liquid phase reactions, it can be inferred that the predominant dissolution mechanism of uranium is diffusion controlled only. The apparent activation energy (Ea) was estimated to be 9.320 kJ/mol. The study focus was then shifted to the recovery of 99.7 U using anion exchange Amberlite IRA400 resin at pH 8.5 and about 93% of the adsorbed U were regenerated using 10% sodium bicarbonate solution. Finally, the regenerated U-rich solution was treated with H2O2 solution to precipitate UO4∙2H2O which achieved a precipitation efficiency of 99%. The latter was carefully washed and ignited at 850 °C to prepare pure U3O8.

URANIUM REMOVAL FROM NITRATE SOLUTION BY CATION EXCHANGE RESIN (AMBERLITE IR 120), ADSORPTION AND KINETIC CHARACTERISTICS

The present work aims to study the adsorption behavior of uranium ions from nitrate solutions usingthe strong acid cation exchange Amberlite IR120 resin. Batch shaking sorption experiments are carriedout to evaluate the performance of the studied resin in the uranium adsorption. The adsorption parametersincluding contact time, pH, initial uranium concentration and temperature have been optimized. Thephysical parameters including the adsorption kinetics, the isotherm models and the thermodynamic datahave also been determined to describe the nature of the uranium adsorption by the investigated resin.The modellated data has been found to agree with both the exothermic pseudo first order reaction and theLangmuir isotherm. The applied procedure was used for uranium ions removal from scrub and raffinateliquors.

La eliminación de metales tóxicos presentes en efluentes líquidos mediante resinas de cambio iónico. Parte IX: Plomo(II))/H+/Amberlite IR-120

El plomo está considerado como un metal altamente peligroso para los seres humano, por lo que su eliminación, de cualquier medio que lo contenga, suele ser de la máxima importancia. Comúnmente y a valores de pH inferiores a 5-6, este elemento esta presente en los medios acuosos como catión Pb2+. En el presente trabajo se investiga la eliminación de este catión de disoluciones acuosas empleando la tecnología de cambio iónico con la resina Amberlite IR-120. Se consideran una serie de variables que pueden afectar al proceso de carga del metal en la resina: velocidad de agitación del sistema, temperatura, dosificación de la resina y tamaño de partícula de la misma y pH del medio acuoso. La carga del metal responde a la isoterma de Freundlich, siendo el proceso endotérmico y no espontáneo, el mecanismo de carga no depende del tamaño de partícula de la resina y responde a un mecanismo por difusión en el medio acuoso. La eliminación del plomo(II) de disoluciones acuosas mediante la resina compite de forma favorable con respecto a los resultados obtenidos cuando se emplean nanotubos de carbono de pared múltiple como adsorbentes del Pb2+. En ensayos llevado a cabo con disoluciones binarias, la carga del Pb2+ en la resina también compite favorablemente con respecto a la de otros metales base en forma catiónica. La elución del plomo(II) se puede llevar a cabo de forma casi cuantitativa con disoluciones de HCl y distintas condiciones experimentales.

Removal of the Acid Orange 10 by ion exchange and microbiological methods

The persistent pollutant azo dye, Acid Orange 10, was removed from the environment by an Amberlite IRA 400 anion-exchange resin and then biodegraded by two bacterial strains. Moreover, the pollutant ecotoxicity was studied by a bacterial model. The objective of this study was to offer a new synergetic/compatible physico-chemical and biological method to remove and biodegrade the azo dye, Acid Orange 10, from the environment. Bach method was applied. The Acid Orange 10 sorption on the resin (Acid Orange 10 concentration, its contact time and stability) was characterized based on the various parameters such as pH and temperature. The biodegradation and the ecotoxicity effect of Acid Orange 10 have been monitorized on two bacterial strains such as Salmonella enterica (gram-negative bacteria) and Enterococcus faecalis (gram-positive bacteria). Experimental data detected from ion-exchange studies showed that the strongly basic anion-exchange resin Amberlite IRA 400, can removed efficiently up to 96.8% at 10−2 M of Acid Orange 10 concentration. Moreover, 10−2 M Acid Orange 10 induced in 1 h a significant 50% growth inhibition on S. enterica, but not on the E. faecalis. This result was linked to E. faecalis ability to degrade more than 60% of Acid Orange 10 compared to S. enterica (30% Acid Orange 10 degradation). The methods tested in this study can be used for removed/biodegradation of Acid Orange 10 from different polluted waters.