Low-cost adsorbents from bio-waste for the removal of dyes from aqueous solution

• Published in: Environmental science and pollution research international Vol. 20; no. 6; pp. 4111 - 4124
• Main Authors: Manoj Kumar Reddy, P., Mahammadunnisa, Sk, Ramaraju, B., Sreedhar, B., Subrahmanyam, Ch
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.06.2013; Springer Nature B.V
• Subjects: Activated carbon; Activation; Adsorbents; Adsorption; Aquatic Pollution; Aqueous solutions; Atmospheric Protection/Air Quality Control/Air Pollution; Bioremediation; Carbon - chemistry; Color removal; Coloring Agents - chemistry; Coloring Agents - isolation & purification; Dyes; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Fourier transforms; Functional groups; Hydrogen Peroxide; Hydrogen-Ion Concentration; Industrial wastes; Infrared spectroscopy; Kinetics; Methylene blue; Methylene Blue - chemistry; Methylene Blue - isolation & purification; Nitric acid; Photoelectron Spectroscopy; Pollutants; Polystyrene resins; Research Article; Rice; Solutions; Studies; Surface chemistry; Temperature; Textiles; Thermodynamics; Waste materials; Waste Water Technology; Water Management; Water Pollutants, Chemical; Water Pollution Control; Water Purification - economics; Water Purification - methods; India; Rice husk; Adsorption; Surface analysis; Activated carbon; Peanut shell; Methylene blue
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-012-1360-8

Activated carbons (ACs) were developed from bio-waste materials like rice husk and peanut shell (PS) by various physicochemical activation methods. PS char digested in nitric acid followed by treatment at 673 K resulted in high surface area up to ∼585 m 2 /g. The novelty of the present study is the identification of oxygen functional groups formed on the surface of activated carbons by infrared and X-ray photoelectron spectroscopy and quantification by using temperature programmed decomposition (TPD). Typical TPD data indicated that each activation method may lead to varying amounts of acidic and basic functional groups on the surface of the adsorbent, which may be a crucial factor in determining the adsorption capacity. It was shown that ACs developed during the present study are good adsorbents, especially for the removal of a model textile dye methylene blue (MB) from aqueous solution. As MB is a basic dye, H 2 O 2 -treated rice husk showed the best adsorption capacity, which is in agreement with the acidic groups present on the surface. Removal of the dye followed Langmuir isotherm model, whereas MB adsorption on ACs followed pseudo-second-order kinetics.