Removal of phenol from aqueous solution using rice straw as adsorbent

Phenol is an environmental pollutant; the present study was conducted to examine the adsorption of phenol by rice straw. For this purpose raw (untreated), physically treated (boiled and dried) and thermally treated (heated at 230 °C for 3 h to produce ash) rice straw were selected to determine phenol removal efficiency at different contact times and adsorbent dosages for 1 and <1 mm rice straw particles. Residual phenol concentrations were determined by colorimetric method. Highest 84 % of phenol removal was observed for thermally treated <1 mm rice straw particle. Equilibrium time was more than four hour. Percentage of removal of phenol increased as the adsorbent dose increase. The removal efficiency increase in the order of: raw rice straw < physically treated < thermally treated (ash) rice straw. Langmuir and Freundlich isotherm was developed for 1 and <1 mm particle size of thermally (ash) treated rice straw. Freundlich isotherm best fit the equilibrium data for 1 mm thermally treated rice straw. The results showed that thermally treated rice straw (ash) can be developed as a potential adsorbent for phenol removal from aqueous solution.