title: Arsenate adsorption onto iron oxide amended rice husk char.
abstract: In this study, rice husks were charred at 550 °C in a partially sealed ceramic vessel for 30minutes to create a high specific surface area (SSA) rice husk char (RHC). The RHC was then amended with iron oxides using dissolved ferric nitrate, Fe(NO3)3⋅9H2O, to provide a surface chemistry conducive to arsenic adsorption. The 550 °C iron oxide amended rice husk char's (550 IOA-RHC's) SSA was nearly 2.5 orders of magnitude higher and the arsenate adsorptive level was nearly 2 orders of magnitude higher than those reported for iron oxide amended sand, thus indicating a positive relationship between post-amendment SSA and arsenate adsorptive levels. Rice husks were then charred at temperatures ranging from 450 °C to 1050 °C to create an even higher SSA material, which might further increase arsenate adsorptive levels. The 950 °C RHC was chosen for amendment due to its high SSA and feasibility of being produced in the field. Once amended, the 950 °C iron oxide amended rice husk char (950 IOA-RHC) improved the arsenate adsorption capacity by thus confirming a positive relationship, though not a linear relationship, between post-amendment SSA and arsenic adsorptive capacity. Further study demonstrated that post-amendment mesoporous volume and mesoporous surface area appear to be better indicators of arsenic adsorptive capacity than SSA or iron content.
authors: University of Oklahoma, School of Civil Engineering & Environmental Science, 202W Boyd St, Rm 334, Norman, OK 73019, USA. Electronic address: crisco123@gmail.com.
authors: Christopher O
authors: CO
authors: Cope
authors: University of Oklahoma, School of Civil Engineering & Environmental Science, 202W Boyd St, Rm 334, Norman, OK 73019, USA. Electronic address: dswebste@gmail.com.
authors: Damon S
authors: DS
authors: Webster
authors: University of Oklahoma, School of Civil Engineering & Environmental Science, 202W Boyd St, Rm 334, Norman, OK 73019, USA. Electronic address: sabatini@ou.edu.
authors: David A
authors: DA
authors: Sabatini
mesh_terms: D000327:Adsorption; D001149:Arsenates / Q000032:analysis* / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry*; D012275:Oryza / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry; D018508:Water Purification / Q000379:methods*
chemical_list: D001149:Arsenates; D005290:Ferric Compounds; D014874:Water Pollutants, Chemical; C000499:ferric oxide; C025657:arsenic acid
keywords: Adsorption; Arsenic; Iron oxide; Pore size; Rice husk char; Surface area