Copper(II) Adsorptive Removal from Solutions with Sunflower Straw-Modified by Phosphoric Acid

Abstract:

Straw active carbon was manufactured from sunflower straw by phosphoric acid. The adsorption was studied by considering the effects of various parameters on the removal rate of Cu2+ such as the dosage of absorbent, adsorption time, temperature and pH. The results showed that the absorbent was efficient, the removal ratio of Cu2+ up to 98.3% with an adsorbent dosage of 16 g•L-1, a pH of 6.0, at 25°C and absorption time of 4 hours. The Langmuir and Freundlich equations can describe the adsorption equilibrium well. The negative values of the adsorption enthalpy △H and the absolute values>42 kJ•mol-1 indicate the exothermic chemical adsorption character. The negative changes in free energy (△G) indicate that the adsorption is a spontaneous process, The negative values of the adsorption entropy △S indicate the more restricted mobility of the Cu2+ on the carbon surface than in solution.

• Periodical: Advanced Materials Research (Volumes 518-523)
• Pages: 159-163
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.518-523.159
• Online since: May 2012
• Authors: Li Ping Chen, Yi Wen Duan, Jing Xia Zhang
• Keywords: Active Carbon, Adsorption, Copper, Sunflower Straw, Thermodynamic

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