Removal of Trace Cu2+ from Water by Thermo-Modified Micron Bamboo Charcoal and the Effects of Dosage

Abstract

Chronic copper intoxication via drinking water induces diseases and physiological toxicity. Bamboo charcoal has been applied in the treatment of copper (Cu2+) in water. However, the adsorption by micron bamboo charcoal (MBC) of trace Cu2+ in tap drinking water and the underlying factors behind it have not been sufficiently reported. In this study, to improve the adsorption by MBC of trace levels of Cu2+ in drinking water, MBC was thermo-modified and characterized. Through batch experiments, the adsorption equilibrium was analyzed, and isotherm models were simulated. The removal rates and the optimization were investigated through a general full factorial design including the thermo-modified temperature (MT), initial concentration (C0), and dosage. The results indicated that the thermo-modification significantly improved the removal by MBC of Cu2+ at trace level C0. The satisfactorily low level of 0.12 ± 0.01 mg⋅L−1 was achieved in the range of C0 from 0.5 to 2.0 mg⋅L−1 within the short contact time of 0.5 h. The processes conformed to the Freundlich and Langmuir adsorption isothermal models at a C0 lower than 4.0 mg⋅L−1 and higher than 8.0 mg⋅L−1. The correlation between C0 and dosage played an important role in the removal of Cu2+. This work proposes the application of the ecofriendly material MBC and an optimization mode in the removal of trace Cu2+ from tap drinking water. It is also revealed that the positive and negative correlation and the “critical point” of the removal rate with dosage depend on the initial concentrations.