title: Insights into aqueous carbofuran removal by modified and non-modified rice husk biochars.
abstract: Biochar has been considered as a potential sorbent for removal of frequently detected pesticides in water. In the present study, modified and non-modified rice husk biochars were used for aqueous carbofuran removal. Rice husk biochars were produced at 300, 500, and 700 °C in slow pyrolysis and further exposed to steam activation. Biochars were physicochemically characterized using proximate, ultimate, FTIR methods and used to examine equilibrium and dynamic adsorption of carbofuran. Increasing pyrolysis temperature led to a decrease of biochar yield and increase of porosity, surface area, and adsorption capacities which were further enhanced by steam activation. Carbofuran adsorption was pH-dependant, and the maximum (161 mg g-1) occurred in the vicinity of pH 5, on steam-activated biochar produced at 700 °C. Freundlich model best fitted the sorption equilibrium data. Both chemisorption and physisorption interactions on heterogeneous adsorbent surface may involve in carbofuran adsorption. Langmuir kinetics could be applied to describe carbofuran adsorption in a fixed bed. A higher carbofuran volume was treated in a column bed by a steam-activated biochar versus non-activated biochars. Overall, steam-activated rice husk biochar can be highlighted as a promising low-cost sustainable material for aqueous carbofuran removal.
authors.affiliation: Chemical and Environmental Systems Modeling Research Group, National Institute of Fundamental Studies, Kandy, Sri Lanka.
authors.forename: S S
authors.initials: SS
authors.lastname: Mayakaduwa
authors.affiliation: Chemical and Environmental Systems Modeling Research Group, National Institute of Fundamental Studies, Kandy, Sri Lanka.
authors.forename: Indika
authors.initials: I
authors.lastname: Herath
authors.affiliation: Korea Biochar Research Center & Department of Biological Environment, Kangwon National University, Chuncheon, 200-701, Republic of Korea.
authors.forename: Yong Sik
authors.initials: YS
authors.lastname: Ok
authors.affiliation: School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India.
authors.forename: Dinesh
authors.initials: D
authors.lastname: Mohan
authors.affiliation: Chemical and Environmental Systems Modeling Research Group, National Institute of Fundamental Studies, Kandy, Sri Lanka. meththikavithanage@gmail.com.
authors.forename: Meththika
authors.initials: M
authors.lastname: Vithanage
mesh_terms: D000327:Adsorption; D002235:Carbofuran / Q000032:analysis* / Q000737:chemistry; D002606:Charcoal / Q000737:chemistry*; D007700:Kinetics; D012275:Oryza / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry; D018508:Water Purification / Q000379:methods*
chemical_list: D014874:Water Pollutants, Chemical; C540010:biochar; D002606:Charcoal; D002235:Carbofuran
keywords: Activated carbon; Agricultural by-product; Dynamic adsorption; Pesticide; Pyrolysis; Steam activation