A new absorbent from chemically modified powder of Bidens pilosa and its characteristics for Cd removal from solutions

Author(s): Zhao, B.; Zhang, J.; He, T.; Guan, A.; Gu, N.; Ouyang, Y.

Bidens pilosa is a harmful invasive plant species in many countries. In this study, a cadmium (Cd) adsorbent for water treatment was developed by modifying the Bidens pilosa powder with chemical agents including hydrochloric acid, hydrogen nitrate, sodium hydroxide, sodium carbonate, sodium bicarbonate and potassium permanganate to test the Cd removal efficiency. Results demonstrated that the modified Bidens pilosa (MBP) powder with potassium permanganate was an effective adsorbent to extract Cd from a solution. To further assess the potential application of the MBP in polluted water, characteristics of the MBP and its related interference ions effect were investigated. Results showed that: 1) the Cd removal efficiency exceeded 97% when the dosage of the MBP was > 1g/L; 2) the Cd removal efficiency remained at about 99% when the initial Cd concentration was < 100 mg/L; 3) the Cd removal efficiency of the MBP was > 95% when the pH ranged from 2.5 to 5.5; 4) more than 90% of Cd in the polluted water was removed by the MBP in 5 minutes and about 100% of Cd was removed after 1 h; 5) the addition of Mg ion had no significant negative effect on Cd removal when the concentration of Mg ion was below 50 mg/L; and 6) the Cd removal efficiency was significantly decreased when the concentration of Zn or Cu ion was 100 mg/L. This study proved that the MBP is an effective absorbent for Cd removal from polluted water. Being a harmful invasive plant, the utilization of the MBP is beneficial to the control of Bidens pilosa. Further study is warranted to investigate the ions competitive effect provided that the MBP is used for wastewater treatment.

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