Physically activated charcoal from waste and low-cost biomass: Adsorptive and porosity studies

• Published in: Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering Vol. 52; no. 14; pp. 1341 - 1351
• Main Authors: Kukucka, Miroslav D, Kukucka Stojanovic, Nikoleta M
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 06.12.2017; Taylor & Francis Ltd
• Subjects: Activated carbon; Activated charcoal; Activation; Adsorption; adsorption modeling; Adsorptivity; Biomass; broom grass; Carbon; Carbonization; Charcoal; Charcoal - chemistry; Corn; Free energy; Grasses; Groundwater; Groundwater - chemistry; Humic Substances - analysis; Intrusion; Isotherms; Kinetics; macroporosity; Mercury; Models, Theoretical; Optimization; Organic matter; Porosity; Raw materials; Sawdust; steam activation; Straw; Surface area; Surface Properties; Temperature; Waste Products; Water Pollutants, Chemical - analysis; Water vapor; Wheat; Wood - chemistry; Zea mays; broom grass; adsorption modeling; steam activation; Activated carbon; macroporosity
• ISSN: 1093-4529; 1532-4117
• DOI: 10.1080/10934529.2017.1362305

Different plant raw materials (corn stalk, wheat straw, saw dust, corn cobs, broom grass and Sudan grass) were carbonized and secondary activated in the rotating kiln with the action of water vapor as activation agent under different temperatures and lasting times. Optimum carbonization parameters such as temperature and lasting time were found to be 750°C and 45 min, while optimal conditions for powdered activated carbon obtained by water vapor activation at a temperature of 1,000 C and contact time of 120 min were determined. All obtained activated carbons were distinctly macroporous with mercury intrusion total specific pore volume in the range from 2.04 to 4.86 cm 3 /g for activated carbons originating from sawdust and broom grass, respectively. Activated carbon prepared from broom grass had the largest specific surface area of 1,190 m 2 /g. Freundlich, Langmuir, Dubinin-Radushkevitch and Temkin adsorption isotherm models were applied for groundwater humic matter adsorption modeling. Broom grass-originated activated carbon was found to have excellent adsorption affinities toward natural organic matter with regard to the Langmuir model, with maximum adsorption capacity of 90.1 mg TOC/g. The Freundlich isotherm was best fitted with the obtained experimental data. Adsorption experiment followed a physical process as can be seen from heat of sorption of 118.82 J/mol estimated by the Temkin isotherm model, and mean free energy of 0.158 kJ/mol estimated by the Dubinin-Radushkevitch isotherm model.