A new efficient forest biowaste as biosorbent for removal of cationic heavy metals

Bioresource Technology 175 (2015) 629–632

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Short Communication

A new efficient forest biowaste as biosorbent for removal of cationic heavy metals Namgyu Kim, Munsik Park, Donghee Park ⇑ Department of Environmental Engineering, 1 Yonseidae-gil, Wonju 220-710, South Korea

h i g h l i g h t s  Among various forest biowastes, chestnut bur was screened as efficient biosorbent.  The biosorbent had 34.77 mg/g of Cd(II) uptake and 74.35 mg/g of Pb(II) uptake.  Biosorption rate of Pb(II) was 3.12 times higher than that of Cd(II).  This study is the first report showing the high potential of chestnut bur as biosorbent.

a r t i c l e

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Article history: Received 9 July 2014 Received in revised form 14 October 2014 Accepted 18 October 2014 Available online 25 October 2014 Keywords: Biosorption Biosorbent Forest biowaste Chestnut bur Heavy metal

a b s t r a c t Among various forest biowastes, chestnut bur had the highest uptake values of Cd(II) and Pb(II), and these values were higher than those of agricultural biowastes used as comparable biosorbents. This study is the first report showing the high potential of chestnut bur as biosorbent for the removal of cationic heavy metals. Pseudo-second-order equation satisfactorily described the biosorption behaviors of both metals. Biosorption rate of Pb(II) was 3.12 times higher than that of Cd(II). Langmuir model could fit the equilibrium isotherm data better than Freundlich model. The maximum uptake capacities of Cd(II) and Pb(II) were determined to be 34.77 mg/g and 74.35 mg/g, respectively. FTIR study showed that carboxyl group on the biosorbent was involved in biosorbing the cationic metals. In conclusion, abundant and cheap forest biowastes, especially chestnut bur, is a potent candidate for efficient biosorbent capable of removing toxic heavy metals from aqueous solutions. Ó 2014 Elsevier Ltd. All rights reserved.

1. Introduction The use of biosorbents for removal of toxic heavy metals or for recovery of valuable metals from aqueous solutions is one of the most recent developments in environmental and bioresource technology (Park et al., 2010). The major advantages of this technology over conventional ones are its low cost, high efficiency, the minimization of chemical sludges, regeneration of biosorbent, and the possibility of metal recovery. The first challenge faced by biosorption researchers is to select the most promising types of biomass from extremely large pool of available and inexpensive biomass (Park et al., 2010). For this reason, many researchers have investigated the biosorptive capacities of various biomasses (Park et al., 2005; Salman et al., 2013; Seo et al., 2013).

⇑ Corresponding author. Tel.: +82 33 760 2435; fax: +82 33 760 2571. E-mail address: [email protected] (D. Park). http://dx.doi.org/10.1016/j.biortech.2014.10.092 0960-8524/Ó 2014 Elsevier Ltd. All rights reserved.

Biosorbents primarily fail into the following categories: bacteria, fungi, algae, industrial wastes, agricultural wastes, natural residues, and other biomaterials (Park et al., 2010). There are many review papers that have quantitatively compared the hundreds of biosorbents reported thus far in the literature (Vijayaraghavan and Yun, 2008). According to the literature reviews, however, there are few studies on the use of forest biowastes as biosorbents (Arshad et al., 2008; Dundar et al., 2008). When choosing biomass, for large-scale industrial uses, the main factor to be taken into account is its availability and cheapness. Considering these factors, forest biowastes are potent candidates for biosorbent having low cost and high efficiency. In this study, various forest biowastes, such as bark, chestnut bur, sawdust, pinecone, pine needle and pine-nut cone, were examined as biosorbents for the removal of cationic metals, i.e. Cd(II) and Pb(II). Kinetic and isotherm experiments were conducted to evaluate biosorptive rate and capacity of the biosorbent. To calculate the maximum uptake of each metal, Langmuir equation was used as isotherm model.

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2. Methods

Table 1 Cd(II) and Pb(II) uptake of forest and agricultural biowastes.

2.1. Preparation of raw biomass

Biomass

Forest biowastes used in this study were bark, chestnut bur, sawdust, pinecone, pine needle and pine-nut cone. As comparative materials, agricultural biowastes such as corncob, cornhusk, rice husk and rice straw were used. These materials were collected from mountain and farmland located in Wonju, Korea. Each biowaste was washed with deionized–distilled water several times and then dried in an oven at 100 °C for 24 h. The resulting dried biowastes were ground and sieved to a particle size of 500– 1000 lm. To evaluate the biosorptive potential of the native biowastes, any pretreatment method was not used in this study. The sieved particles were then stored in a desiccator, until being used as biosorbent in subsequent batch experiments.

Forest biowastes

Bark Chestnut bur Sawdust Pinecone Pine needle Pine-nut cone

Agricultural biowastes

Corncob Cornhusk Rice husk Rice straw

2.2. Batch experiments Cationic metal solutions were prepared by dissolving analytical grade Cd(NO3)24H2O (Samchun, Korea) and Pb(NO3)2 (Kanto, Japan) in deionized–distilled water. Each batch experiment was performed by bringing into contact 0.4 g of biosorbent with 200 mL of a metal solution of known concentration in a 230 mL bottle. In experiment for screening a new excellent biosorbent, 2 g/L of each biosorbent was contacted with 100 mg/L of Cd(II) or Pb(II) solution at pH 4.0. Effect of pH was investigated with chestnut bur as biosorbent at pH 2, 2.5, 3, 3.5 and 4. Kinetic and isotherm studies were conducted with chestnut bur at pH 4.0. The bottles were horizontally agitated on a shaker at 200 rpm for 6 h under room temperature (20–25 °C). In all batch experiments, the solution pH was maintained at the desired value using a 1 M HCl or 1 M NaOH solution. Samples were intermittently removed from the bottles to analyze Cd(II) or Pb(II) concentration, following appropriate dilution with deionized–distilled water. It was confirmed from three independent replicates that the batch experiments were producible within at most 5% error. 2.3. Analysis After being filtered through a 0.45 lm membrane, Cd(II) or Pb(II) concentration of the samples were measured using inductively coupled plasma-atomic emission spectrometer (ICP/IRIS, Thermo Jarrell Ash Co., USA). Infrared spectrum of native biomass of chestnut bur was obtained using a Fourier transform infrared spectrometer (Vertex 70, Bruker).

Cd(II) uptake (mg/g)

Pb(II) uptake (mg/g)

9.31 16.18 5.46 4.29 6.65 10.92

25.89 42.36 15.45 15.17 25.86 27.16

5.87 5.08 6.56 9.34

23.86 23.20 16.59 32.66

study. Rice straw was the most efficient biosorbent among agricultural biowastes (Table 1). Agricultural biowastes have been well studied by many researchers due to its low cost and availability in nature (Li et al., 2007; Salman et al., 2013; Sud et al., 2008). They have showed the high potential of agricultural biowastes as biosorbent for the removal of toxic heavy metals. However, there are relatively few studies on the use of forest biowastes as biosorbents (Park et al., 2008, 2011; Zou et al., 2013). To sum up, forest biowastes, especially chestnut bur, is a potent candidate for biosorbent because it had higher uptake value with respect to cationic metals, compared with agricultural biowastes (Table 1). This study is the first one reporting the application of chestnut bur which is abundant and cheap as biosorbent for the removal of heavy metals. 3.2. Effect of pH on metal biosorption by chestnut bur For evaluating the potential of biosorbent for metal removal, it is very important to investigate the removal efficiency of a given biosorbent for the target metal. Metal uptake can involve different types of biosorption processes that are affected by various physical and chemical factors, and these factors determine the overall biosorption performance of a given biosorbent (Park et al., 2010). Among various factors which affect metal uptake rate, specificity for the target metal, and the quantity of target removed, solution pH has been known to be the most important regulator of the biosorption process. The pH affects the solution chemistry of metal itself, the activity of functional groups on the biosorbent, and the competition with coexisting ions in solution (Vijayaraghavan and Yun, 2008). Fig. 1 shows the uptake of each metal by chestnut bur according to the solution pH. The experiments were conducted below pH 4 in

3. Results and discussion 50

Six kinds of forest biowastes, which are abundant in Korea, were tested as biosorbents for the removal of cationic metals. For comparable experiment, four kinds of agricultural biowastes were used in this study (Table 1). Uptake of cationic metal by each biosorbent was dependent on both biosorbent type and metal species. In all cases, the uptake of Pb(II) were higher than that of Cd(II). In the case of bark, it had 9.31 mg/g of Cd(II) uptake and 25.89 mg/g of Pb(II) uptake. Pine needle showed 3.9 times of Pb(II) uptake compared with Cd(II) uptake. It has been well known that Pb(II) adsorbs on biosorbents more easily than Cd(II) does (Sud et al., 2008; Vijayaraghavan and Yun, 2008). Among the forest biowastes, chestnut bur had the highest uptake values of both Cd(II) and Pb(II); the former was 16.18 mg/g, the latter 42.36 mg/g. These values were higher than those of agricultural biowastes used in this

40

Uptake(mg/g)

3.1. Screening of a new efficient biosorbent from forest biowastes

Cd Pb

30 20 10 0 1.5

2.0

2.5

3.0

3.5

4.0

4.5

pH Fig. 1. Effect of pH on the removal of Cd(II) and Pb(II) by chestnut bur (experimental condition: biomass dosage = 2 g/L, metal concentration = 100 mg/L).

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order to eliminate hydroxide precipitation of metals. Pb(II) hydroxide and Cd(II) hydroxide were formed above pH 4.5 and 5.5 in this study, respectively (data not shown). Uptake of each metal by the biosorbent was dependent on both solution pH and metal species. In all pHs, the uptake of Pb(II) were higher than that of Cd(II). At pH 2, Cd(II) was not adsorbed on the biosorbent, but Pb(II) was remarkably adsorbed up to 8.45 mg/g. As the pH increased, the uptake values of both metals were increased. This phenomenon has been known to be due to the low activity of functional groups on the biosorbent and the competition of hydrogen ions for the adsorption sites with cationic metals (Seo et al., 2013; Shin et al., 2014; Zou et al., 2013).

lated by mechanistic or empirical models; the former can explain and represent the experimental behavior, while the latter do not explain the mechanism, but can reflect the experimental curves (Vijayaraghavan and Yun, 2008). Fig. 3 shows the equilibrium isotherm curves of Cd(II) and Pb(II) by chestnut bur at pH 4. Among various isotherm models which have been introduced in the literatures (Park et al., 2010), Langmuir model having two parameters was chosen to describe equilibrium adsorption behaviors of each metal, which has been able to fit the experimental data of adsorption reactions reasonably well (Patkool et al., 2014; Salman et al., 2013; Yun et al., 2001). General form of Langmuir model can be represented as follows:

3.3. Kinetic study of metal biosorption by chestnut bur

q¼

Kinetic study gives detailed information on adsorbate uptake rate and rate-controlling step. Thus it is essential in determining the optimum contact time for successful batch biosorption process. Fig. 2 shows the biosorptive removal of Cd(II) and Pb(II) by chestnut bur at pH 4. Biosorption of both metals proceeded up to approximately 95% within 4 h, and the equilibrium state could be reached after 9 h of contact time. To quantitatively describe kinetic behavior of Cd(II) and Pb(II) during the biosorption process, various adsorption kinetic equations were used to fit the batch kinetic data. Similar to previous studies (Ho, 2006; Kim et al., 2014; Salman et al., 2013; Shin et al., 2014; Shirzad-Siboni et al., 2013), the pseudo-second-order equation satisfactorily described the removal behaviors of both metals, as shown in Fig. 2. The integrated form of pseudo-second-order equation can be expressed as:

where qm is the maximum metal uptake (mg/g) and b is the ratio of adsorption/desorption rate related to energy of adsorption. qm and b were calculated from the slope and intercept of the linear plot of Ce/ q versus Ce. High values of the correlation coefficient (R2) meant that Langmuir model could fit the experimental data better than Freundlich model whose values were below 0.98. The maximum uptake capacities of Cd(II) and Pb(II) were 34.77 mg/g and 74.35 mg/g, respectively. According to few studies in which forest biowastes were used for metal removal, the maximum uptakes of Pb(II) by poplar tree sawdust (Li et al., 2007) and African beech sawdust (Abdel-Ghani et al., 2013) were reported as 21.05 mg/g and 1.059 mg/g. Compared with these results, chestnut bur is a good candidate for cheap biosorbent capable of removing toxic heavy metals from aqueous solution.

t 1 1 ¼ þ t qt k2 q2e qe

3.5. Removal mechanism of cationic metal by chestnut bur

ð1Þ

where k2 (g/mg h) and qe (mg/g) are the rate constant and the equilibrium uptake for the pseudo-second-order equation, respectively. The parameters could be calculated from the intercept and slope of the linear plot of t/qt versus t. The correlation coefficient (R2) values of the pseudo-second-order equation were higher than 0.999. According to the calculated values of rate constant (k2), Pb(II) was adsorbed onto the biosorbent 3.12 times faster than Cd(II). Equilibrium uptake of Pb(II) was 2.23 times higher than that of Cd(II); the former was 48.2 mg/g, the latter 21.6 mg/g. 3.4. Isotherm study of the metal biosorption by chestnut bur

qm bC e 1 þ bC e

ð2Þ

There are many types of biosorbents derived from various forms of raw biomass, including bacteria, fungi, algae and natural biomaterials. The complex structure of raw biomass implies that there are many ways, by which these biosorbents remove various pollutants, but these are not yet fully understood (Park et al., 2010; Vijayaraghavan and Yun, 2008). To characterize functional groups of biosorbents is important for the understanding of the mechanisms by which these remove pollutants. Fourier transformed infrared spectroscopy (FTIR) was used for it in this study. As shown in Fig. 4, the FTIR spectrum of native chestnut bur displayed many absorption peaks, indicating the complex nature of the biomass. The broad absorption peak around 3430 cm1 is indicative of the

Quantification of metal uptake by biosorbent is fundamental for the evaluation of its potential. Metal uptake can be easily calcu-

Fig. 2. Kinetics of Cd(II) and Pb(II) removal by chestnut bur (experimental condition: biomass dosage = 2 g/L, metal concentration = 100 mg/L, solution pH = 4.0). Symbols represent experimental data and continuous lines represent the predicted values modeled by pseudo-second order equation.

Fig. 3. Equilibrium isotherms of Cd(II) and Pb(II) by chestnut bur at pH 4 (experimental condition: biomass dosage = 2 g/L, metal concentration = 50, 100, 200, 300, 400 mg/L). Symbols represent experimental data and continuous lines represent the predicted values modeled by Langmuir isotherm equation.

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Acknowledgements

Absorbance (-)

This work was financially supported by Kangwon Green Environment Center through R&D project, and partially by the Human Resource Development Project for Energy From Waste & Recycling. References

4 4000 0

35 500

300 00

2500 2 0

20 000

150 00

1000 0

50 00

Fre equenc cy (c cm-11) Fig. 4. Fourier transform infrared absorption spectra of the chestnut bur.

existence of bonded hydroxyl group. The peak observed at 2900 cm1 can be assigned to the CH group. The spectrum also displayed the absorption peaks at 1650 cm1 and 1750 cm1 corresponding to the stretching band of the carboxyl double bond from carboxyl functional group. The phosphate group showed some characteristic absorption peaks around 1150 cm1 (P@O stretching) and 1050 cm1 (POH stretching and/or POC stretching) (Kang et al., 2013; Yun et al., 2001). Considering pKH values of the functional groups, carboxyl group was regarded as a main biosorption site which played a significant role in the cationic metal removal under the given experimental condition (i.e., solution pH 2–4). Many researchers have showed the importance of carboxyl group on native biomass in biosorbing cationic ions under weak acidic conditions (Kang et al., 2013; Sud et al., 2008; Yun et al., 2001; Zou et al., 2013). 4. Conclusions Of various forest biowastes, chestnut bur was screened as a potent candidate for biosorbent capable of removing cationic heavy metals efficiently. The biosorbent in the native form of chestnut bur had 34.77 mg/g of Cd(II) uptake and 74.35 mg/g of Pb(II) uptake; these values were higher than those of agricultural biomass which have been considered as good biosorbents by many researchers. Therefore, abundant and cheap chestnut bur must be one of potent candidates that can be used to manufacture commercial biosorbent having low cost and high efficiency.

Abdel-Ghani, N.T., El-Chaghaby, G.A., Helal, F.S., 2013. Simultaneous removal of aluminum, iron, copper, zinc, and lead from aqueous solution using raw and chemically treated African beech wood sawdust. Desalin. Water Treat. 51, 3558– 3575. Arshad, M., Zafar, M.N., Younis, S., Nadeem, R., 2008. The use of need biomass for the biosorption of zinc from aqueous solutions. J. Hazard. Mater. 157, 534–540. Dundar, M., Nuhoglu, C., Nuhoglu, Y., 2008. Biosorption of Cu(II) ions onto the litter of natural trembling poplar forest. J. Hazard. Mater. 151, 86–95. Ho, Y.-S., 2006. Review of second-order models for adsorption systems. J. Hazard. Mater. 136, 681–689. Kang, Y.L., Poon, M.Y., Monash, P., Ibrahim, S., Saravanan, P., 2013. Surface chemistry and adsorption mechanism of cadmium ion on active carbon derived from Garcinia mangostana shell. Korean J. Chem. Eng. 30, 1904–1910. Kim, J.-H., Park, J.-A., Kang, J.-K., Son, J.-W., Yi, I.-G., Kim, S.-B., 2014. Characterization of quintinite particles in fluoride removal from aqueous solutions. Environ. Eng. Res. 19, 247–253. Li, Q., Zhai, J., Zhang, W., Wang, M., Zhou, J., 2007. Kinetic studies of adsorption of Pb(II), Cr(III) and Cu(II) from aqueous solutions by sawdust and modified peanut husk. J. Hazard. Mater. 141, 163–167. Park, D., Yun, Y.-S., Jo, J.H., Park, J.M., 2005. Effects of ionic strength, background electrolytes, heavy metals, and redox-active species on the reduction of hexavalent chromium by Ecklonia biomass. J. Microbiol. Biotechnol. 15, 780– 786. Park, D., Ahn, C.K., Kim, Y.M., Yun, Y.-S., Park, J.M., 2008. Enhanced abiotic reduction of Cr(VI) in a soil slurry system by natural biomaterial addition. J. Hazard. Mater. 160, 422–427. Park, D., Yun, Y.-S., Park, J.M., 2010. The past, present, and future trends of biosorption. Biotechnol. Bioprocess Eng. 15, 86–102. Park, D., Yun, Y.-S., Lee, D.S., Park, J.M., 2011. Optimum condition for the removal of Cr(VI) or total Cr using dried leaves of Pinus densiflora. Desalination 271, 309– 314. Patkool, C., Chawakitchareon, P., Anuwattana, P., 2014. Enhancement of efficiency of activated carbon impregnated chitosan for carbon dioxide adsorption. Environ. Eng. Res. 19, 289–292. Salman, M., Athar, M., Farooq, U., Nazir, H., Noor, A., Nazir, S., 2013. Microwaveassisted urea-modified sorghum biomass for Cr(III) elimination from aqueous solution. Korean J. Chem. Eng. 30, 1257–1264. Seo, H., Lee, M., Wang, S., 2013. Equilibrium and kinetic studies of the biosorption of dissolved metals on Bacillus drentensis immobilized in biocarrier beads. Environ. Eng. Res. 18, 45–53. Shin, W.-S., Kang, K., Kim, Y.-L., 2014. Adsorption characteristics of multi-metal ions by red mud, zeolite, limestone, and oyster shell. Environ. Eng. Res. 19, 15–22. Shirzad-Siboni, M., Jafari, S.-J., Farrokhi, M., Yang, J.K., 2013. Removal of phenol from aqueous solutions by activated red mud: equilibrium and kinetics studies. Environ. Eng. Res. 18, 247–252. Sud, D., Mahajan, G., Kaur, M.P., 2008. Agricultural waste material as potential adsorbent for sequestering heavy metal ions from aqueous solutions – a review. Bioresour. Technol. 99, 6017–6027. Vijayaraghavan, K., Yun, Y.-S., 2008. Bacterial biosorbents and biosorption. Biotechnol. Adv. 26, 266–291. Yun, Y.-S., Park, D., Park, J.M., Volesky, B., 2001. Biosorption of trivalent chromium on the brown seaweed biomass. Environ. Sci. Technol. 35, 4353–4358. Zou, W., Bai, H., Gao, S., Li, K., 2013. Characterization of modified sawdust, kinetic and equilibrium study about methylene blue adsorption in batch mode. Korean J. Chem. Eng. 30, 111–122.