4th International Congress of the European Confederation of
Soil Science Societies (ECSSS).
2-6 July 2012, Bari – Italy.
Removal of Cr (VI) from industrial wastewater using Clay-micelle complex
QURIE M.1,2, KHAMIS M.2, KARAMAN R.3, AYYAD I.2 , SCRANO L.1, BUFO S.A.1
1
PhD Programme “Crop Systems, Forestry and Environmental Sciences”, University of Basilicata, Via dell’Ateneo Lucano 10, 85100, Potenza, Italy. E-mail. [email protected].
2 Department of Chemistry and Chemical Technology, and 3 Faculty of Pharmacy, Al-Quds University, Jerusalem, Palestine.
INTRODUCTION Chromium (VI) is an industrial contaminant in soil and ground water, moreover, it is also well known as carcinogenic
agent (1). Chromium is discharged into environment due to many modern industries like electroplating, tanning, plastic surface coating for
water and oil resistance, pigments and wood preservative (2,3). Several treatment methods (as ion exchange, membrane filtration, reverse
osmosis and adsorption) have been developed to remove chromium form industrial wastewater (4) and there are different adsorbent employed
such as wool (3) activated aluminum and activated carbon (5).
AIM The objective of this study is to investigate the performance of micelle – clay complex (ODTMA- montmorillonite) as adsorbents for
the removal of Cr(VI) from polluted water by systematic evaluation of different parameters involved as pH, initial concentration, contact time
and adsorbents.
MATERIALS AND METHODS
 Micelle-clay complex: (ODTMA-Montmorillonite) was prepared as described in Polubesova et al. (6).
 Batch experiments: This method was carried out to evaluate the effect of pH (2-8), contact time, adsorbent and initial concentration (20200 ppm) on Cr(VI) removal. Furthermore, the Langmuir adsorption isotherms were applied to study the adsorption capacity.
 Column experiments were performed with packing material consisting of 3 g clay micelle complex and 147 g sand, i.e. 1:49 (w/w)
sand/clay micelle complex.
Control
Clay
Complex
Removal %
75
50
25
0
0
1
2
3
4
pH
5
6
7
8
Figure (1)
100
pH 1
pH 6
Removal ( %)
90
80
70
60
50
0
20
40
60
80
100
120
140
160
180
Time (min)
Figure (2)
100
80
Removal %
RESULTS AND DISCUSSION
Effect of pH and different adsorbents: Figure 1 shows that maximum adsorption
for clay micelle complex was observed between pH 1 and pH 3 (98%) and was
extended to higher pH up to 6. It can be also revealed that neither clay nor the
container interfere with adsorption process.
Effect of initial Concentration: Figure 2 shows that the removal efficiency of
Cr(VI) is a function of initial Cr(VI) concentration ranging from 20 mg/L to 200
mg/L in tap water (pH = 7.1). This remarkable result indicates that micelle-clay
complex can effectively remove Cr(VI) without the need of acidification as required
by most of the adsorbents so far employed in the literature. Hence, the new
adsorbent invokes an environmentally friendly method for Cr removal.
Column Experiment: Figure 3 shows the removal efficiency, at different intervals
of time, for solutions having pH values of 1, 2, 4, and 6. The results indicated that
there is a fast adsorption of Cr (VI) from the solution at all pH values and high
removal efficiency (100%) at first fractions.
Adsorption isotherm. The Langmuir equation was applied to quantify the
adsorption process. Figure 4 displays the results with good linearity. The Langmuir
constants Qmax and K were determined from the slope and the intercept of the plot
and their values were 9.61 mg/g and 0.136 L/mg, respectively.
100
60
pH=1
pH=2
pH=4
pH=6
40
20
0
2
4
6
8
10
No. Of Fractions
Figure (3)
3.5
y =0.1044x + 0.7606
R² = 0.9898
3
2.5
CONCLUSION
Ce/Qe
2
 A clay-micelle complex filter could be used as effective adsorbent for the
removal of Cr VI) ions from polluted water at normal pH values.
 The removal efficiency reached 100% when using optimum conditions for
both batch mode and column mode experiments.
1.5
1
0.5
0
0
5
10
15
20
25
30
Ce (mg/L)
Figure (4)
[1] Katz, S. and Salam, H. (1994). The Biological and Environmental Chemistry of Chromium. VCH Published, New York.
[2] Modrogan, C. Costache, C. Orbulet, D. (2007). The first international proficiency testing conference.11th-13th October, 2007. Sinia . Romania.
[3] Manassra, A. Khamis, M. Ihmied, T. ElDakiky, M. (2010). EJEAFChe. 9 (3). 651-663.
[4] Shi L. Zhang X. and Chen Z. (2011). Water research. 45. 886-892
[5] Mor S. Ravindra, K. Bishnoi, N. (2007). Bioresour Technol. Mar; 98(4). 954-957.
[6] Polubesova T., Nir S., Zadaka D., Rabinovitz O., Serban C., Groisman L., and Rubin B. (2005). Environ. Sci. Technol. 39. 2369-2348.
Acknowledgements: This work was supported by the European Union in the framework of the Project “Diffusion of nanotechnology based devices
for water treatment and recycling - NANOWAT” (ENPI CBC MED I-B/2.1/049, Grant No. 7/1997).