Simultaneous biosorption of nickel and cadmium by the brown algae Cystoseria indica characterized by isotherm and kinetic models
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Biosorption is an effective way of extracting heavy metal ions from aqueous solutions of various compositions. The brown algae, Cystoseria indica, when treated with sodium chloride, demonstrates significant capacity to extract cadmium and nickel, simultaneously, from aqueous solutions. The batch system was running over wide ranges of initial metal ion concentrations (5–150 mg/L), pH (2–6), adsorbent mass (1–4 g/L), and contact times (20–300 min), at a temperature of 25 °C. The results obtained when applying the system in these conditions exhibit higher removal capacities for cadmium than nickel. The optimal conditions of the biosorption process were found as the adsorbent mass of 1 g/L, initial concentration of adsorbates of 100 mg/L and pH of 6. The equilibrium data obtained are better described by the extended-Freundlich isotherm for nickel and cadmium. The maximum biosorption of nickel and cadmium in binary-metal-component system were 18.17 and 55.34 mg/g, respectively. The kinetic data derived from these experiments were evaluated with pseudo-first-order, pseudo-second-order and intra-particle-diffusion kinetic models. Kinetic examination of the equilibrium data derived from these models suggest that the adsorption of nickel and cadmium both follow the intra-particle-diffusion kinetic model.
KeywordsBrown algae Cadmium nickel extraction Biosorption
Heavy metals constitute significant contaminants in the oceans, in terrestrial water courses and industrial wastewaters. Typically, pollution related to heavy metals is associated with various industries such as batteries, mining, nuclear reactors, oil refineries, and agriculture. Nickel and cadmium are two of the most common heavy-metal contaminants, derived particularly from oil refining, textiles manufacture, batteries, paints, and coatings . The presence of heavy metals in the environment causes damage to many species in the biosphere, including adverse human health impacts and ecosystem disruption [2, 3]. Soluble heavy metal components are not biodegradable and they tend to accumulate in living organisms as well as oceans, lakes, and rivers . Common methods used to separate heavy metals from industrial wastewaters include chemical precipitation, filtration, reverse osmosis, membranes, ion exchange and adsorption . There are a variety of treatment processes deployed to remove heavy metal ions from the environment, but these, typically, are associated with expensive running costs . Consequently, there is an urgent requirement to develop more-effective and low-cost processes to remove heavy metals from aqueous solutions .
Several biomass-based heavy-metal extraction methods have been proposed. A large quantity of materials has been investigated as biosorbents for the removal of metals or organics extensively. The tested biosorbents can be basically classified into the following categories: bacteria (Bacillus subtilis), fungi (Rhizopus arrhizus), yeast (Saccharomyces cerevisiae), algae, industrial wastes, agricultural wastes and other polysaccharide materials . Biosorption technology is well known for providing practically-feasible methods for removing heavy metal from the environment .
A number of studies have demonstrated that among biosorbents, marine algae, especially the brown algae, are excellent biosorbent for heavy metals . The carboxylic group is known to be the key acidic functional group in the brown algae . This is because of the carboxylic groups constitute the highest percentage of titratable sites in dried brown algae biomass. It is the existence of these active sites that provides the capacity of brown algae to adsorb heavy metals . As brown algae occur in abundance in the biosphere there is the potential to exploit them as cost-effective biosorbents . Despite their valuable biosorbent properties for extracting and recovering heavy metals, brown algae have the potential to cause secondary pollution . Organic substances (e.g., alginate) released as the brown algae biosorption processes proceed are potential pollutants that can hinder their use industrial applications. Moreover, there is the potential for leaching to occur as biosorption proceeds, thereby removing key adsorptive components of brown algae causing degradation their biosorption capacity .
The Gulf of Oman is considered as one of the main ecological capitals with the highest biological diversity. Macroalgae is found in the northern coast of the Gulf of Oman is known as the wealthiest sources of macroalgae. Brown algae (Cystoseria indica) are vital groups of bioactive complexes in the northern coast of the Gulf of Oman. These algae (C. indica) are reputation due to their high density and richness in the region, growth in large sizes and valuable combinations such as alginic acid, iodine vitamins, and minerals. The Gulf of Oman is used for fisheries, aquaculture activities, import and export, economy, urbanization, and industries Heavy metals discharging into the marine ecosystem of the Gulf of Oman have possible to negatively affect marine organism .
Here, the surface of brown algae (Cystoseria indica), derived from the Oman Sea is treated with sodium chloride to increase the stability of its biosorbent components. The effects of the initial concentrations of nickel and cadmium on the biosorbent performance of Cystoseria indica are established and the optimal conditions of the biosorption process were found. Biosorption equilibrium data are evaluated using extended-Langmuir and extended-Freundlich isotherms. The biosorption mechanism is also investigated in terms of its kinetic reaction characteristics at optimum concentrations over a range of contact times.
Materials and preparations
A set of aqueous metal solutions displaying various concentrations of cadmium (Cd) and Nickel (Ni) were established by diluting cadmium nitrate (Cd (NO3)2·4H2O) and nickel nitrate (Ni (NO3)2·6H2O) with distilled water. The pH of the solutions was adjusted using HCl (0.1 N) and NaOH (0.1 N) to achieve the desired values.
Cystoseria indica samples were gathered from the coastal area of the Oman Sea, Iran. The algal samples were initially washed with deionized water to remove surface contaminants and impurities (e.g. sand and salt). Clean algal samples were then dried by exposure to the sun for 24 h. Dried algal samples were then crushed and subsequently sieved to a particle size of 0.5–1.0 mm. The sieved samples were then washed with deionized water and desiccated in an oven at 70 °C for 24 h. The samples were then subjected to surface alkaline treatment with sodium chloride (NaCl), which, as demonstrated by Brierley , disrupts the cell walls of algae potentially exposing additional functional groups to which metal ions are able to bind (Brierley protocol) [16, 17].
Unlike continuous system, the batch adsorption process is running without input and output.
Adsorption is monolayer;
All the active sites are equivalent and the adsorption process is uniform; and,
The adsorption of a molecule by a free site does not depend on the occupied neighboring sites.
Optimized adsorption isotherm parameters of nickel and cadmium calculated for single-component system with algae Cystoseria indica at 25 °C
Kf (mg/g) (L/mg)
A higher R2 (i.e. closer to 1.0) indicates a better fitting curve.
Results and discussion
Characterization of C. indica
Effect of pH
Effect of biosorbent dosage
Effect of contact time
Effect of temperature
Effect of initial concentration
Tests were conducted to compare the adsorption performance of Cystoseria indica with respect to nickel and cadmium. An initial concentration of nickel of 60 mg/L was set in three containers. In one of those containers, the initial concentration of cadmium was set at 30 mg/L, in the second container it was set at 60 mg/L, and in the third container it was set at 130 mg/L. The measured adsorption of nickel by Cystoseria indica was 17.5, 9.6 and 5 mg/L, respectively in the first, second and third containers. For comparison purposes, an initial concentration of cadmium of 60 mg/L was set in another three containers. In one of those containers the initial concentration of nickel was set at 30 mg/L, in the second container was set at 60 mg/L, and in the third container it was set at 130 mg/L. The measured adsorption of cadmium by Cystoseria indica was 35, 20.6 and 10.1 mg/L, respectively in the first, second and third container. These observations suggest that Cystoseria indica clearly has a tendency to adsorb significantly more cadmium than nickel. Adsorption is believed to occur at several functional groups within algae, including carboxyl, sulfonic acid and alginate . There may also be other functional groups in Cystoseria indica that are involved in the adsorption of both metal ions. Figures 7 and 8 display the synergistic effect in the binary system by which cadmium is more successful adsorbed at active sites by Cystoseria indica. The alginic acid component, present in alginate within the cell walls of Cystoseria indica and other brown algae, has been suggested as the reason for the higher cadmium adsorption potential [29, 38]. Metallic behavior in multi-component systems is believed to strongly depend on the physical and chemical characteristics of the adsorbent that, in turn, affects the equilibrium behavior of the biosorption processes. The number and type of ions, the concentration of each component ion, pH, and the isotherm models considered will determine the equilibrium constants [39, 40, 41].
Optimum isotherm parameters of binary-metal-component systems for adsorption of nickel and cadmium using Cystoseria indica treated with NaCl (pH = 6, contact time 4 h, temperature 25 °C, impeller speed 175 rpm)
Adsorption process kinetics
Comparison between adsorption rate constant, the estimated qe and the coefficients of determination associated with pseudo-first-order, pseudo-second-order and intra-particle diffusion kinetic models applied to nickel and cadmium adsorption by Cystoseria indica at 25 °C
The consequences achieved in this study can be related with to some others reported in the works Comparing uptake capacities of brown marine algae obtained for metal concentrations in the liquid phase similar to that used in the present study, have shown that In spite of some differences in the experimental conditions, cadmium, and nickel uptake capacities are close to those obtained by other researchers. The accumulation profiles obtained for the different brown algae species show that the metal uptake is rather fast, and more than 75% of the total uptake occurs within the first 20 min and then no further significant adsorption is observed [31, 44].
This research was supported by Islamic Azad University branch of North Tehran (2018–2019).
MK carried out heavy metal sampling, heavy metal solution analyses, and data organization. AH, MK, DAW and NM participated in interpreting the obtained results and organizing the manuscript. All authors read and approved the final manuscript.
The authors declare that they have no competing interests.
- 13.Montazer-Rahmatia MM, Rabbania P, Abdolalia A, Keshtkarb AR (2011) Kinetics and equilibrium studies on biosorption of cadmium, lead, and nickel ions from aqueous solutions by intact and chemically modified brown algae. J Hazard Mater 185(1):401–407. https://doi.org/10.1016/j.jhazmat.2010.09.047 CrossRefGoogle Scholar
- 24.Wang C, Boithias L, Ning Z, Hana Y, Sauvage S, Sanchez-Perez JM, Kuramochi K, Hatano R (2016) Comparison of Langmuir and Freundlich adsorption equations within the SWAT-K model for assessing potassium environmental losses at basin scale. J Agric Water Manag 180(PartB):205–211. https://doi.org/10.1016/j.agwat.2016.08.001 CrossRefGoogle Scholar
- 29.Mudhoo A, Garg VK, Wang S (2012) Heavy metals: toxicity and removal by biosorption. In: Lichtfouse E, Schwarzbauer J, Robert D (eds) Environmental chemistry for a sustainable world, pp 379–442Google Scholar
- 34.Liu Y, Cao Q, Luo F, Chen J (2009) Biosorption of Cd2+, Cu2+, Ni2+ and Zn2+ ions from aqueous solutions by pretreated biomass of brown algae. J Hazard Mater 163:931–938. https://doi.org/10.1016/j.jhazmat.2008.07.046.18755544 CrossRefPubMedGoogle Scholar
- 35.Abdulrazzaq H, Jol H, Husni A, Abu-Bakr R (2014) Characterization and stabilisation of biochars obtained from empty fruit bunch, wood, and rice husk. J Bioresour 9:2888–2898Google Scholar
- 39.Volesky B, Naja GM (2011) Biosorption for industrial application. Biosorption process fundamentals and a pilot design. Biosorption Ind Appl 6:25. https://doi.org/10.1016/B978-0-08-088504-9.00399-8 CrossRefGoogle Scholar
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