Water contamination is a severe environmental problem that has detrimental effects on the health of living
organisms. One of the most significant contaminants of water is petroleum films resulting from oil slicks. Using
bio-based surfactants generated from renewable resources or waste can be a sustainable strategy for addressing
such a problem. In such direction, novel groups of bioactive gemini cationic surfactants (5a-d) with benzoimidazole moiety were designed as petro-dispersing and antimicrobial agents using an efficient method. Spectroscopic techniques, including FT-IR, 1
H, and 13C NMR, were utilized to analyze their chemical structures.
Initially, the mixture of free fatty acids was extracted from the dried spent coffee waste using the Soxhlet method
and elucidated by gas chromatography flame ionized detector (GC-FID). It was then esterified with methanol and
followed by the reduction process in abundance of NaBH4 to afford the desired mixed fatty alcohols. Finally, the
resulting mixed fatty alcohols were esterified with monochloroacetic acid to produce mixed fatty acids chloroacetate. In parallel, 1H-benzo[d]imidazole, was synthesized by fusing o-phenylenediamine with formic acid in
the presence of KOH. The resulting compound was then subjected to further treatment with KOH and separately
refluxed with various alkylene glycol bis(2-chloroacetate) (3a-d) to produce 4a-d. Finally, the quaternization
process of the tertiary nitrogen in 4a-d with mixed fatty acids chloroacetate (1) was carried out to obtain the
bioactive gemini cationic surfactants (5a-d) bearing benzo-imidazole moiety. The physicochemical properties of
the extracted oil and the surface-active indices of the synthesized gemini cationic surfactants (GCS) were
elucidated. Also, the antimicrobial indices were investigated using the in vitro disc diffusion method on different
species of bacteria and fungi. The results revealed that GCS (5a-d) compounds showed the highest inhibition
zone diameter (IZD) ranged from 40-36 mm against gram-negative bacteria compared to gram-positive, due to
them to the chemical composition of the quaternary benzo-imidazole moiety. Furthermore, the efficiency of GCS
(5a-d) was determined in dispersing and collecting thin films of petroleum in different types of water. It was
interesting to note that the majority of designed GCSs have shown the highest capabilities in dispersing and
collecting thin films of petroleum from water with a thickness ranging from 0.15 to 0.90 mm. |
