Applicability of an anionic-nonionic surfactant in p-cresol contaminated soil washing: Finding the optimal mixing ratio
- PDF / 853,307 Bytes
- 10 Pages / 595.276 x 790.866 pts Page_size
- 53 Downloads / 172 Views
RESEARCH ARTICLE
Applicability of an anionic-nonionic surfactant in p-cresol contaminated soil washing: Finding the optimal mixing ratio Ali Mohebban 1 & Peyman Yaghoobzadeh 1 & Saeid Gitipour 1 & Mahdi Abdollahinejad 1 & Reza Maleki Delarestaghi 1 & Mostafa Ramezani 1 Received: 14 August 2019 / Revised: 30 January 2020 / Accepted: 7 September 2020 # Springer Nature Switzerland AG 2020
Abstract In this study, the parameters influencing p-cresol removal efficiency in soil washing method were investigated. Primarily, extraction efficiencies of three Tween series surfactants (Tween 20, Tween 60, Tween 80) with 10 mM concentration were compared. Tween 80 showed the best results since its value (55%) was 4% and 13% higher than that of Tween 60 and Tween 20. The impact of mixed surfactant on extraction rate was examined by employing a mixture of Tween 80 and one anionic surfactant (sodium dodecyl sulfate) with different molar ratio as the main washing solution. The results denoted that the molar ratio of 3:2 (SDS:Tween80) could enhance the extraction rate up to 38% compared to using SDS and Tween 80 alone. Regarding the initial p-cresol concentration in the collected sample, the cleanup level (390 mg/kg) could only be achieved using the mixed-surfactant. Thus, the minimum required surfactant concentrations to hit the target level was calculated to be 3.54 g/L of Tween 80 and 2.105 g/ L of SDS (molar ratio of 0.27 SDS:Tween80). Studying the role of surfactant concentration indicated that its increment from 10 mM to 20 mM, which is way above all the reagents’ critical micelle concentration (CMC), does not affect the removal rate considerably. The same results were obtained comparing the effect of washing time in three different levels (30 min, 60 min and 90 min). However, temperature showed to be a more significant parameter as it could enhance the results up to 20% (for SDS). Keywords Surfactant-Enhanced Remediation . Mixed surfactant . Extraction efficiency . P-cresol . Soil contamination
Introduction Phenolic compounds are among the most concerning environmental pollutants due to their widespread use, refractory in nature and their short and long-term effects on human health [1]. Cresols are isomeric substituted phenols with methyl groups at one of the ortho, meta or para positions relative to the OH-group [2]. These compounds have been categorized by the EPA as Group C, possible human carcinogens [3–5]. P Cresol or 4-methylphenol, as a derivative of phenol and an isomer of cresol has been believed to exert a substantial influence on biological systems in uremia and can cause nervous system depression [6, 7]. The concentrations of cresols in soil and water are usually low. Because of their relatively rapid rate of biodegradation, only in areas where petroleum products were spilled or produced, could higher levels of cresols be detected [8].These
* Ali Mohebban [email protected] 1
Graduate Faculty of Environment, University of Tehran, Tehran, Iran
areas have to be precisely identified and cleared, otherwise the c
Data Loading...
