title: Fabrication of granular activated carbons derived from spent coffee grounds by entrapment in calcium alginate beads for adsorption of acid orange 7 and methylene blue.
abstract: Biomass-based granular activated carbon was successfully prepared by entrapping activated carbon powder derived from spent coffee grounds into calcium-alginate beads (SCG-GAC) for the removal of acid orange 7 (AO7) and methylene blue (MB) from aqueous media. The dye adsorption process is highly pH-dependent and essentially independent of ionic effects. The adsorption kinetics was satisfactorily described by the pore diffusion model, which revealed that pore diffusion was the rate-limiting step during the adsorption process. The equilibrium isotherm and isosteric heat of adsorption indicate that SCG-GAC possesses an energetically heterogeneous surface and operates via endothermic process in nature. The maximum adsorption capacities of SCG-GAC for AO7 (pH 3.0) and MB (pH 11.0) adsorption were found to be 665.9 and 986.8mg/g at 30°C, respectively. Lastly, regeneration tests further confirmed that SCG-GAC has promising potential in its reusability, showing removal efficiency of more than 80% even after seven consecutive cycles.
authors: Center for Water Resources Cycle Research, Korea Institute of Science and Technology, 5 Hwarang-ro 14-gil, Seongbuk-gu, Seoul 02792, South Korea.
authors: Kyung-Won
authors: KW
authors: Jung
authors: Center for Water Resources Cycle Research, Korea Institute of Science and Technology, 5 Hwarang-ro 14-gil, Seongbuk-gu, Seoul 02792, South Korea.
authors: Brian Hyun
authors: BH
authors: Choi
authors: Future Environmental Research Center, Korea Institute of Toxicology, 17 Jeigok-gil, Munsan, Jinju, Gyeongsangnam-do 52834, South Korea.
authors: Min-Jin
authors: MJ
authors: Hwang
authors: Center for Water Resources Cycle Research, Korea Institute of Science and Technology, 5 Hwarang-ro 14-gil, Seongbuk-gu, Seoul 02792, South Korea.
authors: Tae-Un
authors: TU
authors: Jeong
authors: Center for Water Resources Cycle Research, Korea Institute of Science and Technology, 5 Hwarang-ro 14-gil, Seongbuk-gu, Seoul 02792, South Korea. Electronic address: khahn@kist.re.kr.
authors: Kyu-Hong
authors: KH
authors: Ahn
mesh_terms: D000327:Adsorption; D000464:Alginates; D001391:Azo Compounds / Q000737:chemistry; D001557:Benzenesulfonates / Q000737:chemistry; D018533:Biomass; D002244:Carbon; D002606:Charcoal / Q000138:chemical synthesis*; D003069:Coffee / Q000737:chemistry*; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D008751:Methylene Blue / Q000737:chemistry
chemical_list: D000464:Alginates; D001391:Azo Compounds; D001557:Benzenesulfonates; D003069:Coffee; D006603:Hexuronic Acids; D002606:Charcoal; D002244:Carbon; D020723:Glucuronic Acid; C014722:2-naphthol orange; D008751:Methylene Blue
keywords: Acid orange 7; Activated carbon; Adsorption; Calcium-alginate beads; Methylene blue; Spent coffee grounds