title: Treatment technologies and mechanisms for three odorants at trace level: IPMP, IBMP, and TCA.
abstract: Odour episodes caused by algal metabolites are gaining more and more attention in recent years. Besides geosmin and 2-methylisoborneol (MIB), 2-isopropyl-3-methoxypyrazine (IPMP), 2-isobutyl-3-methoxypyrazine (IBMP), and 2,4,6-trichloroanisole (TCA) have emerged to be important off-flavour sources. Their low odour threshold concentrations (several ng ·L(-1)), which are even lower than those of MIB and geosmin, pose challenges for treatment strategies. Hence, a practical and efficient mitigation technology is needed. The possible practical technologies, including powdered activated carbon (PAC) adsorption and oxidation by chlorine and potassium permanganate, were investigated. The results indicated that chlorine and potassium permanganate oxidation of the three odorants were unfeasible while PAC adsorption was effective. As for adsorption, TCA, followed by IBMP and IPMP, was most easily removed by PAC. The Freundlich model could well describe the adsorption isotherm data. The adsorption capacities for IPMP, IBMP, and TCA were described as follows: [Formula: see text], [Formula: see text], and [Formula: see text]. For five earthy/musty odorants including geosmin and MIB, octanol/water partition coefficient, molecular weight, and polarizability all promoted adsorption while aqueous solubility showed a negative influence. The hydrophobic interaction was believed to be the dominant force in the adsorption mechanism while the π-electron interaction enhanced adsorption when a benzene ring was present. This result could be used to predict the adsorption performance of emerging odorants.
authors.affiliation: a School of Environment , Tsinghua University , Beijing 100084 , People's Republic of China.
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.affiliation: a School of Environment , Tsinghua University , Beijing 100084 , People's Republic of China.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Lin
authors.affiliation: a School of Environment , Tsinghua University , Beijing 100084 , People's Republic of China.
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.affiliation: a School of Environment , Tsinghua University , Beijing 100084 , People's Republic of China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: a School of Environment , Tsinghua University , Beijing 100084 , People's Republic of China.|b Changping Water Authority of Beijing , Beijing 102200 , People's Republic of China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Li
authors.affiliation: a School of Environment , Tsinghua University , Beijing 100084 , People's Republic of China.
authors.forename: Xiaojian
authors.initials: X
authors.lastname: Zhang
authors.affiliation: a School of Environment , Tsinghua University , Beijing 100084 , People's Republic of China.
authors.forename: Chao
authors.initials: C
authors.lastname: Chen
mesh_terms: D000327:Adsorption; D000840:Anisoles / Q000032:analysis* / Q000302:isolation & purification; D002244:Carbon / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D009812:Odorants / Q000032:analysis* / Q000517:prevention & control; D011719:Pyrazines / Q000032:analysis* / Q000302:isolation & purification; D018508:Water Purification
chemical_list: D000840:Anisoles; D011719:Pyrazines; C024267:2-isopropyl-3-methoxypyrazine; C110228:2,4,6-trichloroanisole; D002244:Carbon; C034376:2-isobutyl-3-methoxypyrazine
keywords: IBMP; IPMP; adsorption; mechanisms; odour