Daniel Mitru, Elena Stanescu, Alina Roxana Banciu, Mihai Nita-Lazar
Anionic surfactants
Abstract:
It has been known the surfactants have been used to remove stains from leather,
clothes and household items, particularly from kitchens and bathrooms.
Our studies were carried out during eight months in order to include all the seasons
(July, August 2016 – Summer; September, October 2016 – Autumn; January,
February 2017 – Winter and March, April 2017 – Spring) to detect the variation of
anionic and nonionic surfactants concentration from industrial wastewaters. The
wastewater samples were taken from three sampling points belonging to a subway
maintenance company: Berceni, Militari and Pantelimon.
The total concentration of anionic surfactants in wastewaters was analyzed by
Methylene Blue Active Substances Method (MBAS), and the total concentration of
nonionic surfactants was detected by the method with Dragendorff reagent.
The results showed that anionic and nonionic surfactants concentrations detected in
wastewater samples were less than 0.1 mg/L (under the quantification limit) up to
2.03 mg/L for anionic surfactants and the nonionic surfactants had less than 0.15mg/L
(under the quantification limit) up to 1.72 mg/L. According to the national legislation
(HG 352/2005, NTPA 002, Annex 2/2005), the accepted value of surfactants (as sum
of anionic and nonionic) is less than 25 mg/L.
The results of the study revealed the highest concentration of both anionic and
nonionic surfactants during March, one of the possibilities of this variations could be
the lower level of maintenance in February than the other months. Furthermore, this
change of concentration may be the result of switching the type of organic compound
(detergent) using for the subways cleaning.