1. Scale-up Modelling of the Adsorption of a Basic Dye onto a Novel Clay-papaya Combo Adsorbent
Adedoyin O. Adedapo1*, Cynthia O. Nnamdi2, Adewuyi Adewale 2, Martins O. Omorogie2, Kayode O. Adebowale1, Bamidele I. Olu-Owolabi1, Augustine E. Ofomaja3 , Andreas Taubert 4 , Emmanuel I. Unuabonah2
1Department of Chemistry, Faculty of Sciences, University of Ibadan, Nigeria.
2Environmental and Chemical Processes Research Laboratory, Department of Chemical Sciences, Redeemer's University, Nigeria, PMB 3005, Mowe, Ogun State, Nigeria
3Biosorption and Water Treatment Research Laboratory, Department of Chemistry, Faculty of Applied and Computer Science, Vaal University of Technology, P. Bag X021,
Vanderbiljpark 1900, South Africa. 4Institute of Chemistry, University of Potsdam, D Potsdam-Golm, Germany.
ABSTRACT
METHODOLOGY
DESORPTION STUDY
CONCLUSION
Experimental data suggests that increasing initial dye concentration, bed height and temperature increased breakthrough adsorption capacity of HYCA adsorbent for the MB dye. This invariably led to a decrease in the over all rate of adsorption of MB dye. On the contrary, increasing flow rate was found to reduce same because of the short residence time of MB dye molecule in the bed which reduces the time for interaction between the MB dye and the adsorbent.
A low-cost Clay-Papaya combo adsorbent, HYCA, was prepared from a combination of carica papaya seeds and kaolinite clay. HYCA breakthrough adsorption capacity was mg/g for the adsorption of MB dye in a pilot scale fixed bed reactor. The AdDesignSTM software was used to successfully predict the breakthrough curve and scale-up performance of Methylene Blue dye adsorption onto the HYCA adsorbent. The Pore and Surface Diffusion Model described experimental data better than the Constant Pattern Homogeneous Surface Diffusion Model. From economic assessment, the Pore and Surface Diffusion Model predicted that 1 kg of HYCA can effectively treat 1.45 m3 of water containing 1 mg/L of MB dye (with a treatment objective of 50 L g/ µ MB dye) in effluent solution in 9 h 35 min with run time of ca.15 h in a day including time for five regeneration cycles.
It was also predicted that the presence of other organic pollutants in low concentrations reduces the brea
kthrough adsorption capacity of HYCA by 10%. The cost of preparing 1kg of HYCA adsorbent was calculated to ≈ $ 6.31 vs. ≈ $ 31.25/kg for medium quality commercial activated carbon.
Keywords: Hybrid Clay; Cationic dye; Methylene blue; Breakthrough; Adsorption; Regeneration; Pore and Surface Diffusion Mode
Dyes, broadly used as colouring agents pose a major threat to living things because the chemicals used for production are usually highly toxic, carcinogenic and can be explosive[1]. Textile, cosmetics, pulp mill, leather, dye production, printing, food, and plastics factories dump huge quantities of dye effluents into water bodies, hence, a means of effective removal of these coloured pollutants from the wastewater are inevitable [2]
Removal of color from waste effluents is environmentally important because even a small quantity of dye in water can be toxic and highly visible. There is a constant need of a process that can effectively remove these dyes[3,4]. Methylene Blue (MB) dye was chosen as a model because it strongly interacts with many solids and is often used as a model compound for the adsorption cationic organic compounds in aqueous solution.
CLAY
Carica papaya
seeds
HYCA
Effect of Flow Rate Effect of Varying Bed Heights
Effect of Initial Dye Concentration Effect of Temperature
Change in Flow rate
Change in the Weight of the Adsorbent
Change in Initial Dye Concentration
Change in Temperature
DISCUSSION OF RESULTS
INTRODUCTION
[1] E.I. Unuabonah, G.U. Adie, L.O. Onah, O.G. Adeyemi (2009). Multistage optimization of the adsorption of Methylene Blue Dye onto defatted Carica papaya seeds, Chem. Eng. J. 155:
[2] C.-H. Weng, Y.-T. Lin, T.-W. Tzeng (2009). Removal of methylene blue from aqueous solution by adsorption onto pineapple leaf powder, J. Hazard. Mater. 170: 417–424.
[3] K.O. Adebowale, I.E. Unuabonah, B.I. Olu-owolabi (2005). Adsorption of some heavy metal ions on sulfate- and phosphate-modified kaolin, Appl. Clay Sci. 29: 145– 148.
[4] Kundu, S., Gupta, A.K., (2007). As (III) removal from aqueous medium in fixed bed using iron oxide-coated cement (IOCC): experimental and modeling studies. Chem. Eng. J. 129:
REFERENCES