Initial Cation Concentration Research Articles

The role of chitosan grafted copolymer/zeolite Schiff base nanofiber in adsorption of copper and zinc cations from aqueous media

The objective of this research was to develop and assess chitosan-grafted copolymer/HZSM5 zeolite Schiff base nanofibers for Cu2+ and Zn2+ adsorption from aqueous media. Nanofibers were prepared via electrospinning and characterized using XRD, FTIR, 1H NMR, FESEM, TGA, BET, and XPS. The study evaluated the effect of unmodified HZSM5 and Schiff base functionalization on adsorption capacities. Incorporating 10.0 wt% zeolite Schiff base as the optimum content into the chitosan-grafted copolymer significantly enhanced adsorption, achieving increases of 98.2 % for Zn2+ and 42.2 % for Cu2+. Specifically, Zn2+ adsorption increased from 27.6 to 54.7 mg/g, and Cu2+ from 67.1 to 95.4 mg/g. Factors such as temperature, pH, adsorption time, and initial cation concentration were analyzed. Kinetic studies revealed a double-exponential model, and isotherm analysis indicated a good fit with the Redlich-Peterson model, showing maximum monolayer capacities of 310.1 mg/g for Cu2+ and 97.8 mg/g for Zn2+ (pH 6.0, 240 min, 45 °C). The adsorption thermodynamics indicated a spontaneous and endothermic adsorption. Reusability tests showed minimal capacity loss (4.91 % for Cu2+ and 5.59 % for Zn2+) after five cycles. The nanofiber displayed greater selectivity for Cu2+ over Zn2+ in multi-ion systems and real electroplating wastewater, highlighting its potential for targeted heavy metal removal.

Determination of Ce3+, Co2+, Mn2+ and Fe2+ diffusion coefficients in Nafion® membrane

Concentration gradient diffusion coefficients for Ce3+, Co2+, Mn2+ and Fe2+ cations are determined in Nafion®211 membranes over a wide range of environmental conditions. Measurements are made using finite-width cation-rich bands introduced to NR211 via a hot-pressing procedure. A robust method of accurate diffusion coefficient determination of the finite-width deposits is developed using a Fick's second law of diffusion solution for one-dimensional systems. The transition metal dications are found to have nearly identical NR211 diffusion coefficients under water saturated conditions over the 22–80 °C range. The powerful chemical mitigant, Ce3+, is about one-half as diffusive as the dications under identical conditions. Derived diffusion coefficients for Ce3+ and Co2+ are found to be independent of initial cation concentration over the range of 12.5–70 mol% exchange level. The diffusion behavior of Ce3+ in 80 °C liquid water and saturated water vapor is identical. The diffusion coefficients of Ce3+ are shown to have a strong dependence on membrane hydration level varying by a factor of more than 30 over the range of 95 to 40% RH. The implications of these new diffusion findings are applied to a discussion of potential guidelines for the development of highly durable fuel cell systems, which employ mobile metal cations as lifetime-extending redox stabilizers.

Fe3O4@SiO2‐APTES@Isophthaloyl Dichloride/Montmorillonite Magnetic Nanoparticles for Efficient Removal of Pb2+ and Cd2+

AbstractA novel magnetic nanocomposite for removing Cd2+ and Pb2+ was prepared by surface coating of Fe3O4 nanoparticles with (3‐aminopropyl)triethoxysilane (APTES), followed by functionalization with isophthaloyl dichloride and hybridization with nano montmorillonite (MMT). The structure of the resulting nanocomposite was determined. The Fe3O4@SiO2‐APTES@isophthaloyl dichloride/MMT nanocomposite was successfully used to remove Cd2+ and Pb2+ from aqueous solutions. Several tests were designed using response surface methodology and the variables were predicted by the reduced quartic model. Absorption parameters such as time, pH, and initial cation concentration were considered as independent variables. The effects of each on the removal of Cd2+ and Pb2+ ions were examined. The efficiency of the model was evaluated by analysis of variance.

Exsolution Modeling and Control to Improve the Catalytic Activity of Nanostructured Electrodes.

In situ exsolution for nanoscale electrode design has attracted considerable attention because of its promising activity and high stability. However, fundamental research on the mechanisms underlying particle growth remains insufficient. Herein, cation-diffusion-determined exsolution is presented using an analytical model based on classical nucleation and diffusion. In the designed perovskite system, the exsolution trend for particle growth is consistent with this diffusion model, which strongly depends on the initial cation concentration and reduction conditions. Based on the experimental and theoretical results, a highly Ni-doped anode and an electrochemical switching technique are employed to promote exsolution and overcome growth limitations. The optimal cell exhibits an outstanding maximum power density of 1.7Wcm-2 at 900°C and shows no evident degradation when operating at 800°C for 240h under wet H2 . This study provides crucial insights into the developing and tuning of heterogeneous catalysts for energy-conversion applications.

Sorption of some rare earth elements from aqueous solutions using copolymer/activated carbon composite: Multivariate optimization approach

The present study investigated the sorption of Ce3+, Nd3+ and Gd3+ cations from aqueous solutions via the use of a synthesized poly (acrylamide-acrylic acid)/activated carbon ((P-AM-AA)/AC) prepared by ϒ Radiation-Induced Templatepolymerization technique. The effect of absorbed ϒ radiation dose rate (kGy/hr) and cross linker concentration on the sorption efficacy of the synthesized composite toward the concerned lanthanides was studied. The structure of the synthesized composite was confirmed by different characterization techniques. Batch sorption studies for Ce3+, Nd3+ and Gd3+ onto (P-AM-AA)/AC were investigated as a function of contact time, pH and cations concentration. The response surface methodology (RSM) was employed to optimize and simulate the sorption of the concerned cations from the solution onto the synthesized material. The studied factors include initial cation concentration, solution pH, contact time and temperature. From the desirability analysis it is found that, the optimal sorption efficacy of the cations onto the synthesized sorbent was determined as 50 mg/l, 3.9 pH, 7 min and 333 K for acquiring percentage sorption more than 98% with optimal desirability of 0.99.

The first data regarding the effect of the exotic Eisenia ventripapillata (Oligochaeta, Lumbricidae) on the cation composition of soils in Western Siberia

We have performed laboratory experiments to determine the impact of earthworms (exotic Eisenia ventripapillata and peregrine Aporrectodea caliginosa) on the water-soluble forms of ammonium, potassium, sodium, magnesium, calcium in Calcic Chernozem, Greyic Phaeozem, and Haplic Chernozem, which are widespread in the south of Western Siberia. The differences between the impacts made by the two above-mentioned species have been estimated according to the changes they make in the initial cation concentrations in soil. For E. ventripapillata, the obtained evidence regarding the influence of this species on soil characteristics is first-ever data. We found that E. ventripapillata and A. caliginosa changed the content of all cations in the soils under this study, but the nature of these changes varied from one soil type to another. In contrast to A. caliginosa, E. ventripapillata reliably increased the content of potassium and calcium ions in Calcic Chernozem. In comparison with the A. caliginosa influence, the E. ventripapillata variants reliably differed in the content of ammonium, potassium, and sodium ions in Greyic Phaeozem. In Haplic Chernozem, the ammonium, magnesium, and sodium ions content in the E. ventripapillata variants was reliably lower than in the A. caliginosa variants. Thus, the observed difference between native and exotic species in the effects on the content of available cations can trigger changes in the mineral nutrition of plants growing in the examined soils. The article contains 2 Figures, 1 Table and 49 References

Aminopropyl bentonites obtained by microwave-assisted silylation for copper removal

In this work, sodium bentonite was silylated with 3-aminopropyltrimethoxysilane (APTMS) under microwave irradiation at 50 °C at different times (5, 10 and 15 min). Silylation was performed in presence and absence of ethylene glycol. Infrared and 29Si NMR spectroscopies were used to monitor the grafting process, while the degree of functionalization was calculated by using CHN elemental analysis and thermogravimetry. X-ray diffraction and transmission electron microscopy (TEM) were carried out to evaluate alterations in the basal spacing. The silylation degree of bentonite was higher at short reaction time. The modified solids were used to remove Cu(II) from aqueous solutions. Parameters such as contact time and initial cation concentration for the Cu(II) were investigated. Fast copper retention occurred in the pristine and silylated solids with saturation time of 40 min and maximum adsorption capacity of 1.54 mmol g−1 for organofunctionalized sample. The adsorption equilibrium data were fitted using the Langmuir and Freundlich isotherms. Zeta potential measurements, UV–vis spectra and X-ray spectroscopy were used to understand the adsorption mechanism. The silylated solids obtained by microwave irradiation behaved as good sorbents for rapid Cu(II) removal from aqueous solution.

New strategy to enhance heavy metal ions removal from synthetic wastewater by mercapto-functionalized hydrous manganese oxide via adsorption and membrane separation.

The development of efficient materials and methods for the elimination of heavy metals contamination from water bodies is increasingly demanded as these toxic cations can acute diseases to humans or make serious threat to the environment. The aim of this research is to evaluate the effectiveness of the organosilane coupling agent for the modification of hydrous manganese oxide and the application of the functionalized nanoadsorbent for the removal of nickel and copper ions from synthetic wastewater samples. The synthesized thiol-functionalized hydrous manganese oxide was characterized in terms of their morphology, surface area, functional groups, surface elemental compositions, and the structural properties. In the adsorption process of Ni(II) and Cu(II), the effective parameters including the initial metal cation concentration (20-150 mg/L), operation temperature (298-318 K), and the contact time at the optimum pH were investigated. The uptake of Ni(II) and Cu(II) ions on the prepared adsorbents followed by the Freundlich isotherm model reveals the heterogeneous adsorption, with the adsorption capacities of 24.96 mg/g and 31.2 mg/g for the modified adsorbent and 23.92 mg/g and 29.6 mg/g for the virgin adsorbent, respectively. Based on the results, both the virgin and the functionalized adsorbents exhibited high affinity to copper ions than nickel in the single-component system. Kinetic experiments of both metal ions clarified that the experimental data was well predicted by pseudo-second-order model and the equilibrium was achieved after 10 min of contact time. Additionally, the incorporation of the as-prepared adsorbents in the electrospun nanofibers membrane matrix showed the promising potential for the removal of metal cations. The nickel and copper removal efficiency by the membranes containing 1.5 wt% of the modified adsorbent was 80% and 89%, respectively which implying that the modified adsorbent could be employed more efficiently in other treatment techniques for the removal of metallic pollutants. The modification of hydrous manganese oxide by the functional mercaptosilane increases the adsorption sites for trapping the metal ions and improves the adsorption capacity, making high capability for the removal of metal ions from the effluent.

Adsorptive removal of lead and cadmium ions from aqueous solutions by aluminium oxide modified onion skin wastes: Adsorbent characterization, equilibrium modelling and kinetic studies

Aluminium oxide modified onion skin waste (Al2O3/OSW) was characterized and used for adsorption of metal ions (Pb2+ and Cd2+) in this study, and the relations between sorbent properties and metal ion sorption were investigated. The effects of adsorption process conditions on metal ion removal efficiency, including initial cation concentration, contact time, adsorbent dosage and pH, were examined. The obtained adsorption data were analyzed by various adsorption isotherm and kinetic models. It was found that the optimum values of the initial concentration, contact time, adsorbent dosage and pH were 10 mg/L, 120 min, 1.6 g/L and 6.0, respectively. At these optimum conditions, maximum removal percentages of Pb2+ and Cd2+ were 91.23 and 94.10%, respectively. The isotherm and kinetic studies showed a multilayer adsorbate-adsorbent system with the dominance of the chemisorption mechanism. The study concluded that onion skin waste is a viable, cheap and effective alternative for removing heavy metal ions from water/wastewater.

Optimization of Initial Cation Concentrations for L-Lactic Acid Production from Fructose by Lactobacillus pentosus Cells.

In this study, Box-Behnken design was applied to optimize the initial concentrations of 4 cations for L-lactic acid production from fructose by homologous batch fermentation of Lactobacillus pentosus cells. The optimum initial cation concentrations were obtained as 6.542 mM Mg2+, 3.765 mM Mn2+, 2.397 mM Cu2+, and 3.912 mM Fe2+, respectively. The highest L-lactic acid yield and productivity were obtained as 0.935 ± 0.005 g/g fructose and 1.363 ± 0.021 g/(L × h), respectively, with a maximum biomass concentration of 7.97 ± 0.17 g/L. The effectiveness of the optimization by Box-Behnken design was confirmed based on the small errors between predicted results and experimental results shown as 0.3%, - 0.2%, and - 1.2%, respectively. The quadratic models with high accuracy and reliability can be applied to mathematically forecasted the fermentation performance. After the optimization, the lactic acid yield and productivity were significantly improved by 3.7% and 21.0%, respectively.

Primary biosorption mechanism of lead (II) and cadmium (II) cations from aqueous solution by pomelo (Citrus maxima) fruit peels.

The present work investigates the primary adsorption mechanisms of lead (II) and cadmium (II) cations onto pomelo fruit peel (PFP) from aqueous solution. pH, adsorption time, ion strength, and initial metal cation concentrations, which are factors affecting the uptake of these cations, are investigated. Results show that pH and ion strengths strongly affect the removal of these cations from aqueous solution. Different isotherm adsorption models, such as Langmuir, Freundlich, and Sips, are utilized to fit the experimental data in order to determine the adsorption in nature. The Langmuir monolayer adsorption capacities are found to be 47.18 mg/g for lead (II) and 13.35 mg/g for cadmium (II). Kinetic and thermodynamic studies based on a combination of FT-IR and TG-DSC spectroscopies demonstrate that electrostatic attraction plays a primary adsorption mechanism of lead (II) and cadmium (II) cations onto pomelo fruit peel.

Zinc-induced stress on cells of Halamphora luciae (Bacillariophyceae)

ABSTRACT The aim of the present paper was to study the effect of zinc on the benthic diatom Halamphora luciae. Bioassays using the metal concentration corresponding to the ICzn50 were terminated in two selected endpoints: day 4 (acute phase) and day 9 (chronic phase). A 1.4- and 2.2-fold reduction in Zn2+ with respect to the initial cation concentration was estimated by atomic absorption at days 4 and 9, respectively and was attributed both to precipitation of insoluble carbonates and oxides at alkaline pH and to biosorption. Carrying capacity of Zn-exposed cultures diminished even when growth rate remained unchanged, suggesting some degree of acclimation of the strain to metal stress. Zn stimulated cell bleaching together with the shift into the lipogenic phase, denoted by total lipid quantification and bigger lipid bodies volumes. Lipid peroxidation and phenolic compounds dosage revealed no major metal-induced oxidative stress. On the other hand, metal exposure had an antagonistic effect on the activation of alkaline phosphatase activity after phosphorus starvation. Superoxide dismutase (SOD) activity, cell motility and mucilage secretion were enhanced only during acute exposure. Soluble extracellular polymeric substances (S-EPS) from Zn-exposed cultures denoted a higher heterogeneity in monosaccharide composition. Frustules from metal-exposed cells presented a reduction in areolae diameter together with a lower area:volume ratio of the cells due to the addition of cingular bands.

An electrokinetic perspective into the mechanism of divalent and trivalent cation sorption by extracellular polymeric substances of Pseudomonas fluorescens

Extracellular polymeric substances (EPS) contain a vast number of functional groups which can provide sorption sites for heavy metal cations in solution, however, the mechanisms for the interaction of EPS with various metal cations were not well understood. In this study, the sorption potential of EPS from Pseudomonas fluorescens for different cations was investigated. The changes of electrokinetic properties that occurred on the surface of EPS once they adsorbed these cations were also studied using zeta potential measurements as a function of pH and cation concentration. The adsorption data fitted Freundlich isotherm better than Langmuir and D–R isotherms. The interactions of the cations with EPS were favourable with the separation factor Kr < 1. Under different pH conditions, the zeta potential of EPS in the different cation solution followed the order: Fe(III) (at pH ≤ 5.0) > Al(III) > Cu(II) > Mn(II) > Ni(II)≈Cd(II) > Ca(II) > EPS, while with respect to the initial cation concentration, the zeta potential of EPS was in the order: Fe(III) > Al(III) > Cu(II) > Cd(II) > Ni(II)≈Mn(II)≈Ca(II). The effect of cation sorption on the surface charge of EPS increased with pH as well as cation concentration. The thermodynamic analysis demonstrated that besides the sorption of Fe which was exothermic, all the other cations were adsorbed through an endothermic process. The ΔSads revealed that most of the cations interacted with EPS through the formation of inner-sphere complexes. The ATR-FTIR analyses confirmed that complexation occurred between the cations and functional groups on the surface of EPS. The zeta potential of EPS shifted to positive value direction due to sorption of cations on EPS, indicating that the specific interactions were involved in the sorption process. This study enhances our understanding of EPS aggregation and heavy metal bio-sorption through the electrokinetic mechanism. The results will provide useful references for immobilization of heavy metals and alleviation of Al toxicity in acidic soils.

Theophylline‐loaded pectin‐based hydrogels. II. Effect of concentration of initial pectin solution, crosslinker type and cation concentration of external solution on drug release profile

ABSTRACTA series of drug‐loaded pectin hydrogels were prepared by mixing method in two ion types, Ca+2 or Zn+2, for wound dressing applications and their drug release performances were investigated at pH 6.4 in four different calcium ion concentrations of external solution. Pectin hydrogels were synthesized in three different concentrations of initial pectin solution and theophylline was used as a model drug. Fourier transform infrared spectroscopy, scanning electron microscopy, and atomic force microscopy were used for hydrogel characterization. Additionally, fluid handling capacity, swelling behavior, dehydration rate, dispersion characteristic, dressing pH determination, water vapor permeability, oxygen permeability, surface contact angle, flexibility, mass per unit area, and thickness were determined for selected hydrogels. One of the most valuable contributions of our study is that the concentration of initial pectin solution and calcium ion concentration of external solution are very important parameters to obtain an effective drug release. After evaluating all data, we have shown that flexible and transparent pectin‐based wound dressings can be synthesized as a controlled drug release system. Zinc‐containing hydrogel was antibacterial against Staphylococcus aureus and Escherichia coli but not suitable for cell migration. On the other hand, calcium‐based hydrogel was nontoxic on the fibroblast cells and it had no negative effect on cell migration. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48155.

Adsorption and On-Site Transformation of Transition Metal Cations on Ni-Doped AlOOH Nanoflowers for OER Electrocatalysis

AlOOH has long been used as excellent adsorbent for removal of heavy metal cations from wastewater. Herein we report one-pot synthesis of carboxylic-functionalized Ni-doped AlOOH nanoflowers (AlOOH NFs) with high adsorptive capability toward various transition metal cations, and more importantly, the AlOOH NFs adsorbed with various transition metal cations were for the first time directly used as electrocatalyst for oxygen evolution reaction (OER). By simply manipulating the initial metal cation concentration and their molar ratio, the OER catalytic performance of the resulting catalysts could be modulated. The lowest overpotential at a current density of 10 mA cm–2 prepared from AlOOH NFs adsorbed with FeIII and NiII is 0.32 V in 0.1 M KOH and 0.275 V in 1.0 M KOH. Such AlOOH-supported electrocatalyst demonstrates remarkable stability, which shows no evident increase of the overpotential at 10 mA cm–2 after 2 h of steady electrolysis at an overpotential of 0.42 V. The excellent OER electrocatalytic activ...

Mechanoelectric transduction of ionic polymer-graphene composite sensor with ionic liquid as electrolyte

In this paper, an ionic polymer-graphene film composite (IPGC) sensor comprised of an ionic polymer membrane sandwiched between two graphene electrodes was demonstrated, the mechanoelectrical properties were investigated on home-built experimental setup and a physical mechanoelectrical model that takes ion transportation into account was presented using Comsol Multiphysics software for numerical simulations. Scanning electron microscope observation shows that the graphene electrode is tight coupling with chitosan polymer. Experimental verification indicates that as the frequency of input displacement increases from 2 to 10 Hz, the voltage output increases from 2.95 to 13.56 mV under the peak-to-peak amplitude of sinusoidal vibration of 2 mm. Compared with conventional ionic polymer metal composite (IPMC) sensor, IPGC in this work generates 2.74∼4.52 times higher output voltage, which is attributed to high initial cation concentration (∼4250 mol/m3), and IPGC shows the relatively stable mechanoelectrical property because of the crackless graphene electrode and the stable ionic liquid. Model analysis shows that a fair agreement between the simulated and measured data is achieved and the peak-to-peak amplitude of the generated voltage increases with the increasing frequency in the range from 2 to 10 Hz with the increase rate about 1.2–1.4 mV/Hz. This paper provides the understanding of the mechanoelectrical transduction mechanism and property, which can be used for development of sensors and energy harvesters.

Removal of Cs+ from aqueous solutions by perlite.

Perlite is an abundant mineral that requires minimum processing before use either as raw or expanded perlite, resulting in a low-cost, natural porous material. The application of materials for the removal of radioactive cesium from liquid effluents and contaminated waters is currently of great interest. Perlite has been evaluated in the last years for the sorption of a variety of metals, but it had not been investigated before for removal of Cs+ from contaminated waters. The present work examines the use of perlites from a deposit in Salta, Argentina, for removal of Cs+ from aqueous solutions. The mineral was characterized by means of powder X-ray diffraction, thermal analysis, analysis of specific area, and scanning electron microscopy. The effect of solution pH, presence of concomitant ions, contact time, Cs+ initial concentration, perlite dose, and basic or acidic treatment of the sorbent were studied by batch experiments. Removal increased at high pHs and after treatment with NaOH. Sorption of Cs+ by perlite presented a rapid rise in the first 80min of contact. The selected material (from Pava mine) yielded removal efficiencies of 84 and 89% before and after treatment with NaOH, respectively, for a dose of 30gperlite/L and initial cation concentration of 10mg/L. Our results demonstrate that perlite is a material capable of removing Cs+ from aqueous solutions, even when applied at low doses. These findings are relevant in the context of removal of radioactive Cs isotopes from nuclear effluents and in case of contamination of environmental waters.

Insights into gelation kinetics and gel front migration in cation-induced polysaccharide hydrogels by viscoelastic and turbidity measurements: Effect of the nature of divalent cations

Polysaccharide-based hydrogels were prepared by the diffusion of various divalent cations (X2+) into the polygalacturonate (polyGal) solution through a dialysis membrane. The diffusion of various divalent cations (Mg2+, Ca2+, Zn2+ and Ba2+) was investigated. The polyGal gel growth was studied as a function of the initial cation concentration by both viscoelastic and turbidity measurements. We have demonstrated for the first time that the determination of the spatiotemporal variation of turbidity during the gelation process allowed to study the gel front migration. For Ca-polyGal, Zn-polyGal and Ba-polyGal, the gel front migration was characterized by the presence of a peak at the sol/gel interface. This peak was not observed in the case of Mg-polyGal where the gel was not formed. The apparent diffusion coefficient of the gel front (Dapp) which was calculated from the evolution of this peak increased when the initial cation concentration was increased. Moreover, we have suggested a gelation mechanism based on the presence of a threshold molar ratio R* (=[X2+]/[Galacturonic unit]) in which some point-like crosslinks are precursors of the formation of dimers and multimers inducing the contraction of the gel and thus the formation of the gel front.

C-dots/Fe3O4 magnetic nanocomposite as nanoadsorbent for removal of heavy metal cations

In this work, C-dots/Fe3O4 magnetic nanocomposite as nanoadsorbent was implemented for adsorption of Cu(II), Cr(III) and Pb(II) cations from aqueous solutions. The effect of various parameters on adsorption process of all three mentioned cations such as nanoadsorbent dosage, initial cation concentration, contact time and pH were explored to find the mechanism of adsorption. Different kinetic models including pseudo-first-order, pseudo-second-order, Elovich and intra-particle diffusion kinetic models were used to fit experimental data. In this way, pseudo-second-order model described the kinetic data of all three cations well. Also, equilibrium isotherm studies were examined by application of different conventional isotherms such as Langmuir, Freundlich, Tempkin and Dubinin–Radushkevich models to explain the experimental data. The Freundlich isotherm fitted equilibrium data of all three cations, whereas other models were not fitted well. Results indicate that the adsorption of all three cations is followed by chemisorption mechanism via electrostatic attraction at heterogeneous surface of nanoadsorbent.

Single and competitive adsorptive removal of lead, cadmium, and mercury using zeolite adsorbent prepared from industrial aluminum waste

The removal of Pb2+, Cd2+, and Hg2+, which act as endocrine disruptors, from aqueous solutions was performed using a NaP1-type zeolite synthesized from a hazardous aluminum waste. The effects of parameters such as pH, contact time, adsorbent dose, initial cation concentration, and coexisting cations on the adsorption efficiency and capacity of the adsorbent were evaluated. Single-cation adsorption was found to be a fast process well described by the pseudo-second-order kinetic model. Equilibrium was reached in the first 15 min achieving high removal efficiencies: 98.9%, 93.3%, and 99.3% for Pb2+, Cd2+, and Hg2+, respectively. The removal of the metal cations could occur via a homogeneous and physical adsorption process that was satisfactorily described by the Sips isotherm. The maximum adsorption capacities, obtained from the Sips isotherm model, were 245.75, 4.43, and 0.22 mg/g for Pb2+, Cd2+, and Hg2+, respectively. In multi-cation adsorption, the zeolite presented the greatest affinity for Pb2+ (due to its smallest cationic size) compared with Cd2+ and Hg2+. The Pb2+ removal efficiency remained practically constant in presence of Hg2+ and Cd2+, reaching efficiencies near 100% at very low contact times (<5 min). Thus, this zeolite could become an alternative adsorbent to eliminate heavy metals from waters. A synergic effect on the environmental protection could be achieved: the end-ofwaste condition of a hazardous waste as well as the water decontamination.