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Adsorption of Congo red dye onto different variants of wastewater sludge
Babongile Masimula and Gcina D Vilakati University of Eswatini, Faculty of Science and Engineering, Department of Chemistry, Private Bag 4 Kwaluseni, Eswatini
This study explores the potential of wastewater sludge as a cost-effective adsorbent for the removal of Congo Red (CR) dye from textile industry effluents. Batch adsorption experiments were conducted to assess the effects of key parameters, including initial dye concentration, adsorbent dosage, contact time, and pH. Preliminary findings indicate that wastewater sludge demonstrates a high capacity for CR dye removal, achieving significant adsorption percentages and reaching equilibrium within 60 minutes without requiring pretreatment. The adsorption process is rapid in the initial phase, with dye molecules occupying active sites within the first few minutes, followed by a slower progression toward equilibrium. However, as CR concentration increases (from 50 ppm to 500 ppm), adsorption efficiency declines, reducing removal rates from 90% to 60%. Conversely, increasing the adsorbent dosage enhances the availability of active sites, leading to improved CR removal, which rises from 51% to 94%, with an optimal dosage of 3 g/L. Although this research is still in its early stages, the results suggest that wastewater sludge has significant potential as an effective and sustainable alternative for the treatment of dye- contaminated water. Key words: Adsorption, Congo red, wastewater sludge Highlights: Synthetic dyes are widely used and are difficult to biodegrade. Wastewater sludge is a promising adsorbent, effective and sustainable alternative to conventional adsorbent for coloured wastewater treatment.
P22
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