Rice straw-derived adsorbent for the removal of carbofuran from aqueous solution
Ken-Lin Chang, Chao-Heng Tseng, Chih-Cheng Chen, Jun-Hong Lin, Jung-Feng Hsieh, Yin Wang, Feng Zhao, Yi-Hsuan Shih, Zhen-jiao Xing, Shui-Tein Chen
In this study, we transformed waste biomass (rice straw) into activated carbon using a two-stage process with potassium hydroxide (KOH) as an activator; we then evaluated the capacity of this activated carbon to adsorb carbofuran and thereby remove it from aqueous solution during waste water treatment. Activated carbon removes carbofuran rapidly and effectively because of its high surface area and an adsorptive capacity (296.52 mg/g) that is significantly higher than that of all other recently developed adsorbents. The difference between the initial activated carbon and the carbofuran-loaded adsorbent was characterized by Scanning electron microscopy (SEM), Element analysis (EA) and Fourier transform infrared (FTIR). The surface area and average pore diameter of the adsorbent were 1304.8 m2/g and 23.9 Å, respectively. The effects of various adsorption parameters, such as the initial carbofuran concentration, contact time, temperature and pH, on carbofuran adsorption were studied in a batch system. The maximum adsorptive capacity of activated carbon (296.52 mg/g) for carbofuran was found at 90 min, 30 °C, 100 mg/L adsorbent, 180 rpm and 200 mg/L initial carbofuran concentration. Equilibrium adsorption isotherms (Langmuir, Freundlich and Temkin) and kinetics were investigated. The Langmuir model fit the experimental results better than either the Freundlich or Temkin model, and a pseudo-second-order equation was successfully used to represent the results of the kinetic studies. This study demonstrates that rice straw based adsorbent is a very effective adsorbent for the adsorption of carbofuran from bodies of water.
Key words：Rice straw, Carbofuran, Activated carbon, Adsorption isotherm, Kinetics
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Journal：New Carbon Materials
