title: Recovery of gallic acid from gallic acid processing wastewater.
abstract: In this paper, an extraction technology has been investigated to recover gallic acid (GA) from GA processing wastewater. The effects of phase ratio and pH on the extraction behaviour of tributyl phosphate (TBP)/kerosene were investigated using TBP as the extractant and kerosene as the diluent. Our results showed that using 30% TBP, equilibrium was reached in 1 min. Extraction yields could be improved by increasing the phase ratio (organic phase:aqueous phase). The optimum pH values for the extraction and stripping processes were 3 and 6-9, respectively. The different GA concentrations had no noticeable effects on the distribution ratio between the organic phase and the aqueous phase during the extraction and stripping processes. The extraction yield that resulted from using the six-stage concentrating extraction was greater than 93%, with a phase ratio of 1:1 and an initial pH of 0.6. The GA concentration in the four-stage stripping liquor was greater than 100 g L(-1). Overall, the results indicated that the recovery of GA from GA processing wastewater is feasible using the methods described in this paper.
authors.affiliation: a School of Metallurgy and Environment , Central South University , Changsha 410083 , Hunan , People's Republic of China.
authors.forename: Yundong
authors.initials: Y
authors.lastname: Wu
authors.forename: Kanggen
authors.initials: K
authors.lastname: Zhou
authors.forename: Shuyu
authors.initials: S
authors.lastname: Dong
authors.forename: Wei
authors.initials: W
authors.lastname: Yu
authors.forename: Huiqing
authors.initials: H
authors.lastname: Zhang
mesh_terms: D003247:Conservation of Natural Resources; D005707:Gallic Acid / Q000302:isolation & purification*; D007648:Kerosene; D010755:Organophosphates / Q000737:chemistry; D013816:Thermodynamics; D062065:Wastewater
chemical_list: D005707:Gallic Acid; D007648:Kerosene; D010755:Organophosphates; D062065:Wastewater; C009524:tributyl phosphate
keywords: TBP; extraction; gallic acid; stripping; wastewater