title: Characteristics of biochar derived from marine macroalgae and fabrication of granular biochar by entrapment in calcium-alginate beads for phosphate removal from aqueous solution.
abstract: In this work, granular biochar, Laminaria japonica-derived biochar (LB)-calcium alginate beads (LB-CAB), was successfully prepared by dropping a mixture of powder biochar and alginate solution into a calcium chloride solution for phosphate adsorption. Among different marine macroalgae derived biochars, LB exhibited the best performance, showing a phosphate removal rate of 97.02%, which was attributed to its high Ca/P and Mg/P ratios. With increasing pyrolysis temperature up to 600°C, the physicochemical properties of LB became suitable for adsorbing phosphate. Experimental results of kinetics and equilibrium isotherms at different temperatures (10-30°C) showed that the phosphate adsorption process is endothermic and is mainly controlled by external mass transfer and the intraparticle diffusion rate. The maximum adsorption capacity was found to be 157.7mgg(-1) at 30°C, as fitted by the Langmuir-Freundlich model, which is higher than capacities of other powder form of biochars.
authors.affiliation: Center for Water Resources Cycle Research, Korea Institute of Science and Technology, 5 Hwarang-ro 14-gil, Seongbuk-gu, Seoul 02792, South Korea.
authors.forename: Kyung-Won
authors.initials: KW
authors.lastname: Jung
authors.affiliation: Center for Water Resources Cycle Research, Korea Institute of Science and Technology, 5 Hwarang-ro 14-gil, Seongbuk-gu, Seoul 02792, South Korea.
authors.forename: Tae-Un
authors.initials: TU
authors.lastname: Jeong
authors.affiliation: Civil and Environmental Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, South Korea.
authors.forename: Ho-Jeong
authors.initials: HJ
authors.lastname: Kang
authors.affiliation: 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.forename: Kyu-Hong
authors.initials: KH
authors.lastname: Ahn
mesh_terms: D000327:Adsorption; D000464:Alginates / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry*; D002606:Charcoal / Q000032:analysis* / Q000378:metabolism; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D007700:Kinetics; D007795:Laminaria / Q000378:metabolism; D008863:Microspheres; D010710:Phosphates / Q000302:isolation & purification* / Q000493:pharmacokinetics; D012624:Seaweed / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification* / Q000493:pharmacokinetics
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D010710:Phosphates; D014874:Water Pollutants, Chemical; C540010:biochar; D002606:Charcoal; D020723:Glucuronic Acid; D002118:Calcium
keywords: Biochar; Calcium-alginate beads; Laminaria japonica; Marine macroalgae; Phosphate; Pyrolysis