A comparative adsorption study with different industrial wastes as adsorbents for the removal of cationic dyes from water

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Abstract

Four adsorbents have been prepared from industrial wastes obtained from the steel and fertilizer industries and investigated for their utility to remove cationic dyes. Studies have shown that the adsorbents prepared from blast furnace sludge, dust, and slag have poor porosity and low surface area, resulting in very low efficiency for the adsorption of dyes. On the other hand, carbonaceous adsorbent prepared from carbon slurry waste obtained from the fertilizer industry was found to show good porosity and appreciable surface area and consequently adsorbs dyes to an appreciable extent. The adsorption of two cationic dyes, viz., rhodamine B and Bismark Brown R on carbonaceous adsorbent conforms to Langmuir equation, is a first-order process and pore diffusion controlled. As the adsorption of dyes investigated was appreciable on carbonaceous adsorbent, its efficiency was evaluated by comparing the results with those obtained on a standard activated charcoal sample. It was found that prepared carbonaceous adsorbent exhibits dye removal efficiency that is about 80–90% of that observed with standard activated charcoal samples. Thus, it can be fruitfully used for the removal of dyes and is a suitable alternative to standard activated charcoal in view of its cheaper cost.

Introduction

Dyes are important water pollutants which are generally present in the effluents of the textile, leather, food processing, dyeing, cosmetics, paper, and dye manufacturing industries. They are synthetic aromatic compounds which are embodied with various functional groups. The worldwide high level of production and extensive use of dyes generates colored wastewaters which cause environmental pollution. The colored dye effluents are generally considered to be highly toxic to the aquatic biota [1] and affect the symbiotic process by disturbing the natural equilibrium through reduced photosynthetic activity due to the coloration of the water in streams. The nonbiodegradable, toxic, and inhibitory nature of spent dye baths has a considerable deleterious effect on the environmental matrix (water and soil). Some dyes are reported to cause allergy, dermatitis, skin irritation, cancer, and mutations in humans [2], [3]. Thus, the removal of dyes from effluents before they are mixed up with unpolluted natural water bodies is important. Several treatment technologies exist for dye removal [4], but the process of adsorption using activated carbon [5], [6], [7], [8] has been found to be an efficient technology for decolorization of wastewater. Though the removal of dyes through adsorption is quite effective, its use is restricted sometimes due to the higher cost of activated carbon and difficulties associated with regeneration. Attempts have therefore been made to utilize natural as well as waste materials as alternative adsorbents. But the utilization of industrial waste materials is of vital concern over the past few years because these wastes represent unused resources and, in many cases, cause serious disposal problems. The aim behind using waste materials as adsorbents is that it will provide a twofold advantage with respect to environmental pollution. First, the volume of waste materials could be partly reduced, and second, the low-cost adsorbent, if developed, can reduce the pollution of wastewaters at a reasonable cost. In view of the low cost of such adsorbents, it would not be necessary to regenerate spent materials. Thus, a number of waste materials from different sources have been investigated with or without treatment as adsorbents for the removal of dyes from wastewater. Recently, Garg et al. [9] have listed materials studied as adsorbents for dye removal from aqueous solutions.

A number of low-cost alternative adsorbents have been explored but they have not been highly successful. In general the limitations of such studies have been

  • (i)

    the surface area of alternative adsorbents developed has been low in most cases, resulting in poor adsorptive power;

  • (ii)

    comparative studies on different adsorbents have not been carried out; and

  • (iii)

    the performance of alternative adsorbents has not been assessed by comparing the results with those obtained on activated carbon.

It is therefore still important to develop low-cost adsorbents with good surface area, which may in turn exhibit good adsorption potential for the removal of aqueous pollutants.

Keeping the above points under consideration, a comparative adsorption study was carried out by us [10] using carbon slurry waste obtained from a fertilizer plant and blast furnace sludge, dust, and slag from steel plant wastes as adsorbents for the removal of two anionic dyes, methyl orange and brilliant blue G. It was found that carbonaceous adsorbent prepared from a fertilizer plant exhibits good potential for the removal of dyes as compared to the other three adsorbents prepared. In order to further test the versatility of the carbonaceous adsorbent, investigations with regard to the adsorption of another class of dyes, cationic dyes, were also undertaken, and two important and widely used cationic dyes, rhodamine B and Bismark Brown R, were studied on all the adsorbents prepared. Further, a comparative study with standard activated charcoal was also carried out and the results are incorporated into the present communication.

Section snippets

Materials

Rhodamine B and Bismark Brown R were procured from S.D. Fine-Chem. Limited (India). The standard activated charcoal sample was obtained from E. Merck. Other reagents used were of AR grade. Double-distilled water was used in preparing solutions throughout these investigations.

Preparation of adsorbents

The adsorbents under investigation have been prepared from fertilizer and steel plant wastes.

Characterization of the prepared adsorbents

The BF sludge, dust, and slag were chemically analyzed and it was found that BF slag is basically inorganic in nature; i.e., it contains mainly inorganic constituents such as silica (32.7%), calcium oxide (31.7%), magnesium oxide (6.8%), and R2O3; R = Fe, Al (22.8%). On the other hand, silica, R2O3 (mainly iron oxide), and carbon (due to the presence of coke particles) are the prominent components of BF dust and sludge. Although the inorganic constituents such as silica (15.8% and 12.7%), R2O3

Conclusions

It is reasonable to conclude from the present investigations on the adsorption of cationic dyes on some adsorbents prepared from industrial wastes that (i) carbonaceous adsorbent possessing an organic nature and consequently having higher surface area and porosity is efficient for the removal of dyes, whereas the other three adsorbents, BF sludge, dust, and slag, possessing inorganic nature resulting in lower surface area and porosity, are poor materials for this purpose; (ii) the adsorption of

References (22)

  • G.E. Walsh et al.

    Environ. Pollut. Ser. A

    (1980)
  • K.G. Bhattacharyya et al.

    J. Environ. Manag.

    (2004)
  • G.M. Walker et al.

    Water Res.

    (1997)
  • G.M. Walker et al.

    Environ. Pollut.

    (1998)
  • J.-M. Chern et al.

    Water Res.

    (2001)
  • V.K. Garg et al.

    Dyes Pigments

    (2004)
  • S.K. Srivastava et al.

    Water Res.

    (1987)
  • G. McKay et al.

    Water Res.

    (1980)
  • K.K. Panday et al.

    Water Res.

    (1985)
  • E. Tutem et al.

    Water Res.

    (1998)
  • Y.S. Ho et al.

    Water Res.

    (1999)
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    Present address: Water Resources and Drinking Water (W+T), Swiss Federal Institute for Environmental Science & Technology (EAWAG), Postfach 611, Ueberlandstrasse 133, CH-8600, Duebendorf, Switzerland.

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