Anaerobic removal of linear alcohol ethoxylates

Abstract

The present paper deals with a laboratory-scale study of anaerobic treatment of two commercial mixtures (LS2, LT7) of alcohol ethoxylates with 8±14 carbon atoms and 2 and 7 ethoxy groups. Tests were carried out in batch, with a 2 g l À1 single dose, and in semibatch, with daily 0.2 g l À1 doses. The behaviour of the tested mixtures was di erent: anaerobic sludge adsorption was the main removal process for LS2, while adsorption was less signi®cant and biodegradation was more important for LT7. These di erences appeared to be mainly related to the ethoxy portion length determining the extent of biodegradability and adsorption. Ó

Determination of dodecanol and ethoxylated fatty alcohols from environmental samples using diatomaceous earth as a green sorbent for solid-phase extraction

“…The highest recovery rates, in the rage of 102-121%, were obtained for C 12 than three ethoxyl groups methanol was a more efficient eluent compared to chloroform. In this case the obtained recovery rates ranged from 98% for C 12 EO [8][9] to more than 100% for the remaining ethoxylates comprising more than three ethoxyl groups.…”

“…Acetone, ethyl acetate, chloroform were of analytical grade (purchased from POCh, Gliwice, Poland). All individual AEs C 12 EO x (x = 1, 2, 3,4,5,6,7,8,9) and C 12 OH used as standards were purchased from Sigma-Aldrich (St. Louis, MO, USA). All standards were of high purity grade (˃98%).…”

“…The composition of those mixtures depends on the biodegradation mechanisms. In case when ‘central fission’ is the main maim mechanism, the resulting products include free alcohol and free ethoxylated glycols with different amount of ethoxyl groups in the chain . If the concentration of ethoxylated alcohols with a lower amount of ethoxyl groups is increased in comparison to the initial mixture, then the terminal shortening of the ethoxyl chain is most likely the major mechanism .…”

“…Article Related Abbreviations: AE, Fatty alcohol ethoxylate; C 12 EO x , ethoxylated dodecanol; C 12 OH, dodecanol; DE, diatomaceous earth; PIC, phenyl isocyanate; C 12 EO 1-9 , ethoxylated dodecanol containing 1-9 ethoxy groups In case when 'central fission' is the main maim mechanism, the resulting products include free alcohol and free ethoxylated glycols with different amount of ethoxyl groups in the chain [8,9]. If the concentration of ethoxylated alcohols with a lower amount of ethoxyl groups is increased in comparison to the initial mixture, then the terminal shortening of the ethoxyl chain is most likely the major mechanism [10].…”

Methanogenic potential of an anaerobic sludge in the presence of anionic and nonionic surfactants

“…The linear (unbranched) ethoxylated alcohol known as AE (or LAE), belongs to the commercially significant chemical group of nonionic surfactants (NIS) (Mezzanotte et al, 2002). The AE is usually found in various environments, ranging from 0.9 mg L À1 in activated sludge systems (Morrall et al, 2006) to 1300 mg kg À1 in river sediments (Cavalli et al, 2000).…”