Formation of improved activated carbons from sugarcane bagasse as environmental materials for adsorption of phenolic pollutants

Phenolic pollutants are very toxic and their removal from aquatic resources is very important. Adsorption by activated carbon, AC, is the best method for removal of phenols from solutions. However, the high cost of AC and difficulty of its regeneration after phenol adsorption puts high demand on low price AC materials. Therefore, sugarcane bagasse as a sustainable, bulky and fibrous biomass was selected for the purpose of low-price AC formation for phenols adsorption. Sugarcane bagasse derived activated carbon, BAC, was achieved via an environmental thermo-chemical activation process using ZnCl2 followed by pyrolysis at different temperatures (400-600 degrees C). The formed BAC materials were characterized by elemental analysis, simultaneous TGA-DTA, ATR-FTIR, XRD, Raman spectroscopy, SEM, and nitrogen adsorption/desorption techniques. The BAC materials showed several enhanced characteristics including extra high specific surface area (up to 2046 m(2)/g), improved meso-/microporosity dual system and nanostructured graphitic-like structure composed of few graphene layers. Adsorption removal of phenol as an industrial waste pollutant was investigated from solutions of wide range of concentrations (50-1000 mg/L). The adsorption processes were characterized by (L2) class of adsorption isotherm, Langmuir isotherm model, physical-adsorption thermochemical parameters and pseudo-second-order kinetics. Adsorptions of two other substituted phenols (resorcinol and pyrogallol) were investigated. The adsorption capacity was increased with increasing of intramolecular bonding of the adsorbate in the order of phenol < resorcinol < pyrogallol. The present results emphasized the versatility of the formed BACs as environmentally sustainable adsorbent for phenolic pollutants.