Removal of methylene blue from aqueous solutions by chemically modified bamboo

- The carboxyl group and diethylenetriamine modified bamboo was firstly synthesized.
- The absorbent showed the prominent adsorption capacity and strong removal ability.
- The adsorption kinetics was systematically investigated and mechanism was proposed.
- Electrostatic interaction is responsible for the strong adsorption.

Chemically modified bamboo (CMB) was utilized for removing methylene blue (MB) from aqueous media in the present study. The adsorbent was characterized by Fourier transform infrared (FTIR) spectra and elemental analysis, which confirms that carboxyl groups and diethylenetriamine were successfully introduced into the surface of bamboo. The effects of initial MB concentration (100-900 mg L−1), contact time (15-315 min), the pH of the solution (3-10), temperature (298-318 K), adsorbent dosage (0.4-2.6 g L−1) and salt concentration on the adsorption efficiency of CMB towards MB were investigated. It was found that the adsorption of MB in CMB fits Langmuir mode well, and the maximum adsorption capacity of CMB achieved 606 mg g−1 at 298 K, which is much higher than those obtained from previously investigated bioadsorbents. The adsorption kinetics can be described by pseudo-second-order kinetic model, and the adsorption of MB on CMB was an exothermic process. The results of the present study suggest that CMB is an effective biosorbent for removal of organic pollutants from aqueous solutions.