The removal of toxic metals from liquid effluents by ion exchange resins. Part V: Nickel(II)/H+/Dowex C400

Francisco José Alguacila,*

a Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Avda. Gregorio del Amo 8, 28040 Madrid, Spain

*Corresponding author:



The cationic exchange resin Dowex C400 was used to remove nickel(II) from aqueous solutions of different pH values and under various experimental conditions: stirring speed of the aqueous solution/resin system, temperature, resin dosage and aqueous ionic strength. The selectivity of the resin was investigated against the presence of various metals in the aqueous solution, and the removal of nickel(II) from aqueous solutions was also compared with results obtained using multiwalled carbon nanotubes or functionalized (carboxylic groups) multiwalled carbon nanotubes as adsorbents. According to batch experimental data, best fit of the results is obtained with the Freundlich model, whereas the ion exchange process is best explained by the pseudo-first order model. Experimental data fit well to the moving boundary controlled model. Elution of the nickel(II) loaded onto Dowex C400 resin is fully possible using acidic solutions.



La eliminación de metales tóxicos presentes en efluentes líquidos mediante resinas de cambio iónico. Parte V: níquel(II))/H+/Dowex C400. Se ha empleado la resina de intercambio catiónico Dowex C400 en la eliminación de níquel(II) de disoluciones acuosas de distintos valores de pH y en varias condiciones experimentales: velocidad de agitación del sistema acuoso/resina, temperatura, dosificación de la resina y disoluciones acuosas de distinta fuerza iónica, investigándose la eliminación del níquel de medios acuosos que contenían varios metales, así como las posibilidades de la resina frente a la utilización de otros potenciales adsorbentes como son los nanotubos de carbono de pared múltiple y los nanotubos de carbono de pared múltiple funcionalizados con grupos carboxílicos. Los resultados experimentales indican que la carga del níquel(II) en la resina responde al modelo de Freundlich, mientras que los modelos cinéticos y de control indican que el proceso de intercambio catiónico responde al modelo de pseudo-primer orden y núcleo recesivo. La elución del níquel(II) se realiza con disoluciones acidas.


Submitted: 28 March 2017; Accepted: 12 May 2017; Available On-line: 27 November 2017

Citation/Citar como: Alguacil, F.J. (2017) “The removal of toxic metals from liquid effluents by ion exchange resins. Part V: Nickel(II)/H+/Dowex C400”. Rev. Metal. 53(4): e105.

KEYWORDS: Dowex C400; Liquid effluents; Multiwalled carbon nanotubes; Nickel(II); Removal

PALABRAS CLAVE: Dowex C400; Efluentes líquidos; Eliminación; Níquel(II); Nanotubos de carbono de pared múltiple

ORCID ID: Francisco J. Alguacil (

Copyright: © 2017 CSIC. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) Spain 3.0.




Though nickel is considered a hazardous element, there is not a clear evidence that soluble nickel salts alone are responsible for cancer, or whether when they appeared in conjunction with insoluble nickel form. In fact, this element does not appear in the list of harmful elements in primary and secondary drinking water standards (USEPA, 2017).

The overall consideration of nickel toxicology has lead to a recent number of reports about the removal of this metal from aqueous solutions using different technologies (El-Bahy and El-Bahy, 2016; Guan et al., 2016; Jain et al., 2016; Melo et al., 2016; Otrembska and Gega, 2016; Taha et al., 2017; Yousef et al., 2016; Zhang and Chen, 2016; Moghbeli et al., 2017). Next in the series of articles published by the author about the use of ion exchange technology in the removal of toxic metals (Alguacil, 2002; Alguacil et al., 2002; Alguacil, 2003; Alguacil, 2017), the present work reports about the use of the cationic exchange resin Dowex C400 on the removal of nickel(II) from aqueous solutions and under various experimental conditions, and different mathematical models were used to fit the various aspects in relation of the cationic exchange process.


Dowex C400 (Fluka) having the characteristics shown in Table 1 were used to investigate the removal of nickel(II) from solutions. Other chemical used in the investigation were of AR grade, whereas the experimental procedure used here was the same as described in previous works (Alguacil, 2002; Alguacil et al., 2002; Alguacil, 2003; Alguacil 2017). The multiwalled carbon nanotubes presented the characteristics described elsewhere (Alguacil et al., 2016), whereas the carboxylic functionalized multiwalled carbon nanotubes were obtained from the Aldrich catalogue, ref. 755125.

Table 1. Characteristics of Dowex C400 resin
Active group Sulfonic in H+ form
Matrix Crosslinked styrene-DVB
Particle form and mean size Spheres, 410 μm

All the loading experiments were carried out using 200 mL of the aqueous solution, 800 rpm and 20 ºC, except when these variables were investigated.

Metals in solution were analysed by AAS spectrometry, whereas metals load in the resin was calculated by the mass balance.


3.1. Nickel loading onto the resinTOP

Being Dowex C400 a cationic exchanger, in which the sulfonic group is the active one, the equilibrium which describes the removal of nickel(II) from the solutions in the 0-5 pH range is represented by (Eq. (1)):

where, R is the non-reactive part of the resin, and r and aq represented the resin and the aqueous solution, respectively.

In batch ion exchange-adsorption experiments, the stirring speed could play a key-role in the performance of the system, since the correct stirring speed allows to gain a maximum in the metal loaded in the corresponding solid resin-adsorbent; however, this variable is often neglected in many scientific reports (AlOmar et al., 2017; Drasinac et al., 2017; Kim and Kwak, 2017; Ogden et al., 2017; Wang and Liu, 2017). In the present work, aqueous solutions containing 0.01 gL-1 Ni(II) at pH 5 was put into contact with 0.5 gL-1 of the resin, and the system was stirred at different stirring speeds ranging 200-1000 rpm. Results obtained from this set of experiments are shown in Fig. 1. The maximum in adsorption loading is reached in the 800-1000 rpm range, and thus, the thickness of the aqueous solution layer reached a minimum and a maximum in nickel(II) uptake is accomplished.

Figura 1. Influence of stirring speed on nickel loaded onto the resin.


The influence of the temperature on metal load onto the resin was investigated using a resin dose of 0.25 gL-1 and aqueous solution of 0.01 gL-1 Ni(II) at pH 5. The results from Table 2 showed that the values of the nickel distribution coefficient, defined as (Eq. (2)):

Table 2. Influence of the temperature on nickel(II)l loadinga
T (ºC) D (Lg-1) log D
20 156 2.2
40 794 2.9
60 3996 3.6
a Time: 5 h

where [Ni]r and [Ni]aq represented the nickel(II) concentrations at equilibrium in the resin and in the aqueous solution, respectively, increases as the operational temperature increases.

Thermodynamic parameters were estimated using conventional relationships, indicating that the reaction is endothermic (ΔHº 65 kJmol-1), and ΔSº and ΔGº are 111 kJmol-1K and 33 kJmol-1, respectively. The positive ΔGº value indicated that the exchange process is not spontaneous, and the also positive ΔSº value is an indication of increasing randomness at the liquid-resin interface during the exchange process.

The influence of the aqueous pH, ranging 0-5, on metal load onto the resin was investigated using 0.25 gL-1 of resin and an aqueous solution containing 0.01 gL-1 Ni(II). As can be seen seen from Fig. 2 and Table 3, the pH of the aqueous solution has little influence in the metal uptake in the pH range 1-3, though some decrease in the metal load can be observed as the pH shifted to more acidic values. However, this nickel uptake completely falls off when the pH of the solution reached values near 0, although this behaviour will be useful (see below) when the nickel(II) elution is considered.

Table 3. Influence of pH on metal uptake
pH Ni(II) (mgL-1) Ni(II) (mg.g-1)
5 0.25 39.0
3 0.4 38.4
1 0.5 38.0
0 9.6 1.6
Resin: 0.25 gL-1

Figura 2. Influence of the aqueous pH on nickel removal from solution.


The influence of the resin dosage on nickel uptake onto the resin was also investigated, when the resin dosage was changed between 0.5 and 0.05 gL-1, and the results obtained are summarized in Table 4. As it is expected, nickel adsorption increases with the resin dosage until reaching, under the present experimental conditions, a metal uptake in the 110 mg.g-1 range.

Table 4. Influence of resin dosage on metal uptake
Resin (gL-1) [Ni(II)] (mgL-1) [Ni(II)] (mg.g-1)
0.5 0.03 19.9
0.25 0.25 67.2
0.13 1.6 67.2
0.05 4.5 110.0

The aqueous ionic strength is another experimental variable which could influence the metal loading onto the resins, and its effect on the present system was investigated by the use of different concentrations of lithium chloride in the aqueous solution. After 3 h of contact between 0.25 gL-1resin and an aqueous solution containing 0.01 gL-1Ni(II), the results presented in Table 5 showed a continuous decrease in the percentage of nickel uptake, or nickel concentration in the resin, as the aqueous ionic strength is increased, being this a point to consider when real solutions need to be treated since they have normally ionic strengths greater than zero.

Table 5. Metal uptake at various aqueous ionic strengths
I (M) aNi(II) uptake (%) aNi(II) uptake, (mg.g-1)
1 - -
0.5 0.9 0.37
0.25 15.0 6.0
0.13 40.5 16.2
0 93.4 37.4
aAfter 3 h

It is important to remark that when real solutions are considered is that very often the targeted metal is accompanied by a miriade of other metals, thus, the selectivity of the present system is next investigated using binary solutions containing nickel(II) and another metal in equimolar concentrations. Values of metal distribution coefficients (see Eq. (2)) and separation factors β, calculated as in Eq. (3), are shown in Table 6:

Table 6. Performance of Dowex C400 resin in binary solutions at 1:1 molar metals relationship
System Elements pair D (L g-1) βNi/M
1 Ni(II) 196 0.99
  Mn(II) 198  
2 Ni(II) 196 0.98
  Cu(II) 199  
3 Ni(II) 196 2.6
  Co(II) 75.9  
4 Ni(II) 196 8.7
  Zn(II) 22.6  
5 Ni(II) 196 <0.005
  In(III) >40000  
Aqueous solution: 0.17 mmolL-1 each metal at pH 5. Resin dosage: 0.25 gL-1. Temperature: 20 ºC. Time: 5 h

It can be seen from this Table 6, that the separation of nickel(II) from the accompanying metals, β>1, is only possible in the case of zinc(II) and cobalt(II), being manganese(II) and copper(II) more or less equally loaded onto the resin than nickel(II) (not separation possible here), whereas indium(III) is by far loaded preferably to nickel (β<1). It is worth to mention here that in all the experiments using binary solutions, the loading curve versus time for nickel(II), as represented in Fig. 3, always responded to the same pattern and with practically the same quantitative results for each time, which also corresponded to the data obtained when only nickel(II) is present in the aqueous solution (nickel uptake of 39 mg.g-1 at equilibrium versus 39.2 mg.g-1 for binary solutions) this means that apparently the population or crowding effect showed in other separations technology, i.e. liquid membranes, did not appear here (Alonso et al., 2006).

Figura 3. Nickel(II) loaded onto the resin from binary solutions.


It is worth to brief mention here, that when the population or crowding effect, in a given system, appeared, it means that the value of the metal uptake of a target element in, i.e. the binary solution, decreased in comparison with the same value obtained when the given element is alone in solution.

The performance of Dowex C400 was compared with results obtained in the removal of nickel(II) by other smart adsorbents like multiwalled carbon nanotubes (MWCN) and carboxylic functionalized multiwalled carbon nanotubes (C-MWCN) are. Results for these series of experiments are shown in Table 7. At the present experimental conditions, the resin has a better performance, in terms of nickel removal from the aqueous solution, that either type of carbon nanotubes tested in this work.

Table 7. Comparison of nickel exchanger-adsorbents
Exchanger-adsorbent Ni uptake (mg g-1)
Dowex C400 19.9
MCN <1.0
CMCN 4.4
Aqueous solution: 0.01 gL-1 Ni(II) at pH 5. Resin or carbon nanotubes dosage: 0.5 gL-1.
Temperature: 20 ºC. Time: 5 h

The adsorption data were used to examine their fit to the Langmuir or Freundlich models (Alguacil et al., 2016). The results of these tests show that the adsorption is best fit to the Freundlich model (r2: 0.993):

with 1/n 0.33 and ln Kf 4.1. In the above equation, [Ni]r,e and [Ni]aq,e represented the nickel concentrations at equilibrium in the resin and in the aqueous solution, respectively, whereas Kf is a Freundlich constant.

Adsorption or exchange kinetics was also evaluated. The pseudo-first and pseudo-second order rate equations, Eqs. (5 and 6), respectively:

were used to estimate their fit to the experimental data. In the above equations, [Ni]r,e represented the nickel concentration in the resin at equilibrium, [Ni]r,t represented the metal concentration in the resin at an elapsed time, t is the elapsed time and k1 and k2 are the respective rate constant for each model. Numerical results, Table 8, showed that the kinetics is slightly best explained within the pseudo-first order model.

Table 8. Results of the numerical calculations of the adsorption kinetics models.
Model r2 Constant rate
Pseudo-first order 0.993 k1= 1.4x10-2 min-1
Pseudo-second order 0.991 k2= 4.9x10-4 g mg-1 min-1

Moreover, the exchange process was evaluated by the use of the models described elsewhere (López Díaz-Pavón et al., 2014). Results of the experimental data fitting to the models, showed that the rate law governing (best fitting) the nickel exchange within the resin is a liquid-solid phase reaction which includes a moving boundary process described by:

with rate constant k 3.5x10-3 min-1 and r2 0.988. In the above equation, the fractional attainment to the equilibrium, F, was calculated by the next relationship:

where, [Ni]r,t and [Ni]r,e are the nickel concentrations in the resin at and elapsed time t and at equilibrium, respectively.

3.2. Metal elution from the loaded resinTOP

As it is mentioned above, and since nickel is poorly loaded onto the resin at pH values in the zero range, it seemed logical the use of mineral acids to accomplish both the nickel elution from the resin and the resin regeneration in the same step. Results obtained from these series of experiments are summarized in Table 9. It can be seen, that, under the same experimental conditions, a slightly best percentage of nickel elution is obtained when sulphuric acid solution is used as eluant, whereas the change in the amount of resin/volume of eluant solution also slightly influenced the percentage of nickel recovered from the loaded resin (98.5% versus >99%). These results lead to obtain aqueous solutions with concentrations, at least, one magnitude order greater than the original aqueous feed (0.1 gL-1 in the eluted solution versus 0.01 gL-1 in the original feed). Beside the elution of nickel, the use of these acidic solutions result in the resin regeneration by shifting the equilibrium shown in Eq. (1) to the left.

Table 9. Results of elution experiments
Eluant Resin (mg) Solution volume (mL) Ni(II) eluted (%) Ni(II) (mg L-1)
HCl 1M 0.1 25 91.3 56.4
H2SO4 1M 0.1 25 98.5 60.9
H2SO4 1M 0.1 12.5 >99 123-124
Time: 1 h


The removal of nickel(II) from aqueous solutions, in the 1-5 pH range, can be successfully done using the resin Dowex C400, however, at zero pH this removal falls off, the increase of the aqueous ionic strength also decreases the metal uptake onto the resin. The endothermic exchange process (between H+ from the resin and Ni2+ from the solution) is best explained by the moving boundary model, being the kinetics best explained by the pseudo-first order kinetic rate.
From binary solutions, nickel(II) can be separate from cobalt(II) and zinc(II), almost equally uptake onto the resin than manganese(II) and copper(II), whereas indium(III) is best loaded onto the resin than nickel. In any case, the uptake of nickel onto the resin is independent of the accompanying metal in the solution and also almost equal to that when only nickel is present in this solution (at 0.25 gL-1resin dosage, nickel uptake of 39.2 mg.g-1 from binary solutions versus 39 mg.g-1 for nickel monoelemental solution).
With respect to nickel removal from solutions, the performance of Dowex C400 resin is better than that of the multiwalled carbon nanotubes or carboxylic functionalized multiwalled carbon nanotubes.


To the CSIC (Spain) for support. To Mr. J.M. Medina for assistance in part of the experimental work.



Alguacil, F.J. (2002). The removal of toxic metals from liquid effluents by ion exchange resins. Part II: cadmium(II)/sulphate/Lewatit TP260. Rev. Metal. 38 (5), 348–352.
Alguacil, F.J. (2003). The removal of toxic metals from liquid effluents by ion exchange resins. Part III: copper(II)/sulphate/Amberlite 200. Rev. Metal. 39 (3), 205–209.
Alguacil, F.J. (2017). The removal of toxic metals from liquid effluents by ion exchange resins. Part IV: chromium(III)/H+/Lewatit SP112. Rev. Metal. 53 (2), e093.
Alguacil, F.J., Coedo, A.G., Dorado, T., Padilla, I. (2002). The removal of toxic metals from liquid effluents by ion exchange resins. Part I: chromium(VI)/sulphate/Dowex 1x8. Rev. Metal. 38 (4), 306–311.
Alguacil, F.J., López, F.A., Rodríguez, O., Martinez-Ramirez, S., García-Díaz, I. (2016). Sorption of indium (III) onto carbon nanotubes. Ecotox. Environ. Safe. 130, 81–86.
Alonso, M., López-Delgado, A., Sastre, A.M., Alguacil, F.J. (2006). Kinetic modeling of the facilitated transport of cadmium (II) using Cyanex 923 as ionophore. Chem. Eng. J. 118 (3), 213–219.
AlOmar, M.K., Alsaadi, M.A., Jassam, T.M., Akib, S., Hashim, M.A. (2017). Novel deep eutectic solvent-functionalized carbon nanotubes adsorbent for mercury removal from water. J. Colloid. Interf. Sci. 497, 413–421.
Drasinac, N., Erjavec, B., Drazic, G., Pintar, A. (2017). Peroxo and gold modified titanium nanotubes for effective removal of methyl orange with CWPO under ambient conditions. Catal. Today 280 (Part 1), 155–164.
El-Bahy, S.M., El-Bahy, Z.M. (2016). Síntesis and characterization of polyamidoxime chelating resin for adsoprtion of Cu(II), Mn(II) and Ni(II) by batch and column study. J. Environ. Chem. Eng. 4 (1), 276–286.
Guan, Q.-J., Sun, W., Zhou, G,.Y., Liu, J.-P., Yin, Z.-G. (2016). Recovery of cobalt and nickel in the presence of magnesium and calcium from sulfate solutions by Versatic 10 and mixtures of Versatic 10 and Cyanex 301. T. Nonferr. Metal. Soc. China 26 (3), 865–873.
Jain, C.K., Malik, D.S., Yadav, A.K. (2016). Applicability of plant based biosorbents in the removal of heavy metals: a review. Environ. Proc. 3 (2), 495–523.
Kim, J., Kwak, S.-Y. (2017). Efficient and selective removal of heavy metals using microporous layered silicate AMH-3 as sorbent. Chem. Eng. J. 313, 975–982.
López Díaz-Pavón, A., Cerpa, A., Alguacil, F.J. (2014). Processing of indium(III) solutions via ion exchange with Lewatit K-2621 resin. Rev. Metal. 50 (2), e010.
Melo, D.D.Q., Vidal, C.B., Medeiros, T.C., Raulino, G.S.C., Dervanoski, A., Pinheiro, M.D.C., Nascimento, R.F.D. (2016). Biosorption of metal ions using a low cost modified adsorbent (Mauritia flexuosa): experimental design and mathematical modeling. Environ. Technol. 37 (17), 2157–2171.
Moghbeli, M.R., Khajeh, A., Alikhani, M. (2017). Nanosilica reinforced ion-exchange polyHIPE type membrane for removal of nickel ions: Preparation, characterization and adsorption studies. Chem. Eng. J. 309, 552–562.
Ogden, M.D., Moon, E.M., Wilson, A., Pepper, S.E. (2017). Application of chelating weak base resin Dowex M4195 to the recovery of uranium from mixed sulfate/chloride media. Chem. Eng. J. 317, 80–89.
Otrembska, P., Gega, J. (2016). Separation of nickel(II) and cadmium(II) ions with ion-exchange and membrane processes. Sep. Sci. Technol. 51 (15-16), 2675–2680.
Taha, A.A., Shreadah, M.A., Heiba, H.F., Ahmed, A.M. (2017). Validity of Egyptian Na-montmorillonite for adsorption of Pb2+, Cd2+ and Ni2+ under acidic conditions: Characterization, isotherm, kinetics, thermodynamics and application study. Asia-Pac. J. Chem. Eng. 12 (2), 292–306.
USEPA (2017). Reports National primary and secondary drinking water standards. (checked 6 september 2017).
Wang, Y., Liu, R. (2017). Comparison of characteristics of twenty-one types of biochar and their ability to remove multi-heavy metals and methylene blue in solution. Fuel Process. Technol. 160, 55–63.
Yousef, N.S., Farouq, R., Hazzaa, R. (2016). Adsorption kinetics and isotherms for the removal of nickel ions from aqueous solutions by an ion-exchange resin: application of two and three parameters isotherm models. Desalin. Water Treat. 57 (46), 21925–21938.
Zhang, J., Chen, Y. (2016). Uptake of Fe(III), Ag(I), Ni(II) and Cu(II) by salicyl acid-type chelating resin prepared via surface-initiated atom transfer radical polymerization. RSC Adv. 6 (73), 69370–69380.

Copyright (c) 2017 Consejo Superior de Investigaciones Científicas (CSIC)

Licencia de Creative Commons
Esta obra está bajo una licencia de Creative Commons Reconocimiento 4.0 Internacional.

Contacte con la revista

Soporte técnico