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Copper, lead and zinc removal from metal-contaminated wastewater by adsorption onto agricultural wastes
- Janyasuthiwong, Suthee, Phiri, Sheila M., Kijjanapanich, Pimluck, Rene, Eldon R., Esposito, Giovanni, Lens, Piet N.L.
- Environmental technology 2015 v.36 no.24 pp. 3071-3083
- adsorbents, adsorption, agricultural wastes, bananas, coconuts, copper, cost effectiveness, environmental technology, heavy metals, hydrochloric acid, lead, pH, peanuts, response surface methodology, rice hulls, sawdust, trees, wastewater, zinc
- The use of agricultural wastes (groundnut shell, orange and banana peel, rice husk, coconut husk and Wawa tree saw dust) as potential cost-effective adsorbent for heavy metal removal from wastewater was evaluated. The effect of pH (2.0–6.0), adsorbent dosage (0.6–2.2 g), contact time (10–130 min) and initial concentration (Pb: 5–105 mg/L, Cu and Zn: 2.5–52.7 mg/L) on the metal removal efficiency and uptake capacity were investigated using response surface methodology to optimize the process conditions. Groundnut shell showed a high potential to remove Cu, Pb and Zn from synthetic wastewater. The highest removal efficiencies with groundnut as the adsorbent were 85% at pH 5.0 for Cu and 98% at pH 3.0 for Pb and Zn. The optimum conditions obtained were 2.5 g adsorbent with 40.7 mg/L Cu at pH 4.4 and 64 min contact time, 2.5 g adsorbent with 196.1 mg/L Pb at pH 5.6 and 60 min contact time and 3.1 g adsorbent with 70.2 mg/L Zn at pH 4.3 and 50 min contact time, for Cu, Pb and Zn, respectively. The regeneration of the groundnut shell was possible for a maximum of three cycles using 0.2 M HCl as the desorbing solution without any significant change in the adsorbing efficiency.