Adsorption of creatinine on porous carbon prepared from rice husk

The adsorption of creatinine (CR, a kind of metabolin in the human body) on the rice husk-based carbons (RHCs) with high specific area was studied. Comparison was made between the CR adsorption on four samples of porous carbon prepared by NaOH activation from rice husk at different activation conditions and two samples of commercial carbon. Meanwhile, the adsorption of CR on the modified carbon surfaces treated with HCl, H2O2, and HNO3, respectively, and calcined at 800 degrees C was investigated. Compared with commercial carbons, it was shown that the RHCs had larger capacity for the adsorption of CR. Generally, the CR adsorption capacity increased after the modification of the carbon surfaces. With regard to the adsorbability towards CR, the porous carbons treated by HCl was the best, the porous carbons treated by HNO3 was the worst, and the one treated by H2O2 was in the middle. The adsorbability of porous carbons after being calcined at high temperature (800 degrees C) was obviously worse. The experiment testified that the adsorption of CR by porous carbons followed the Freundlich equation.