title: Effects of pH, dissolved organic matter, and salinity on ibuprofen sorption on sediment.
abstract: Ibuprofen is well known as one of the most frequently detected pharmaceuticals and personal care products (PPCPs) in rivers. However, sorption of ibuprofen onto sediment has not been considered in spite of its high Kow(3.5). In this study, the effects of various environmental conditions such as pH (4, 5.3, and 7), the concentrations of dissolved organic matters (0 to 1.0 mM citrate and urea), salinity (0, 10, 20, and 30 part per thousand), and presence of other PPCP (salicylic acid) on ibuprofen sorption were investigated. Linear model mainly fitted the experimental data for analysis. The distribution coefficient (Kd) in the linear model decreased from 6.76 at pH 4 to near zero at pH 7, indicating that neutral form of ibuprofen at pH below pKa (5.2) was easily sorbed onto the sediment whereas the sorption of anionic form at pH over pKa was not favorable. To investigate the effect of dissolved organic matters (DOMs) on ibuprofen sorption, citrate and urea were used as DOMs. As citrate concentration increased, the Kdvalue decreased but urea did not interrupt the ibuprofen sorption. Citrate has three carboxyl functional groups which can attach easily ibuprofen and hinder its sorption onto sediment. Salinity also affected ibuprofen sorption due to decrease of the solubility of ibuprofen as salinity increased. In competitive sorption experiment, the addition of salicylic acid also led to enhance ibuprofen sorption. Conclusively, ibuprofen can be more easily sorbed onto the acidified sediments of river downstream, especially estuaries or near-shore environment with low DOM concentration.
authors: Institute of Livestock Environmental Management, Daejeon, 34065, Republic of Korea. oh@ilem.or.kr.
authors: Sanghwa
authors: http://orcid.org/0000-0003-4356-6955
authors: S
authors: Oh
authors: Department of Environmental Engineering, Kyungpook National University, Daegu, 41566, Republic of Korea.
authors: Won Sik
authors: WS
authors: Shin
authors: Department of Civil Engineering, Kyungpook National University, Daegu, 41566, Republic of Korea.
authors: Hong Tae
authors: HT
authors: Kim
mesh_terms: D000327:Adsorption; D004784:Environmental Monitoring / Q000379:methods*; D063366:Estuaries; D019015:Geologic Sediments / Q000737:chemistry*; D006812:Humic Substances / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D007052:Ibuprofen / Q000032:analysis* / Q000737:chemistry; D056910:Republic of Korea; D045483:Rivers / Q000737:chemistry*; D054712:Salinity; D012995:Solubility; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D006812:Humic Substances; D014874:Water Pollutants, Chemical; D007052:Ibuprofen
keywords: Dissolved organic matter; Ibuprofen; Salinity; Sediment; Sorption; pH