Environment-friendly industrial cleaning agents incorporating plant-oil-based raw materials as chlorofluorocarbon (CFC) alternatives

Chlorofluorocarbons (CFCs) are known to cause depletion of the stratospheric ozone layer and to contribute to global warming. For this reason, many researchers are investigating alternative CFCs. In the present study, bio-surfactants incorporating two oils, soy bean and canola, were prepared, and bio-surfactants in water in oil (W/O) and oil in water (O/W) types were produced, respectively. The phase behaviors of the as-prepared lauryl alcohol, caster oil, and oleic acid bio-surfactants were investigated under temperatures ranging from 4 to 60 °C to find the optimal single phase. The bio-surfactants additionally were analyzed for biodegradability, cleaning efficiency, and degree of corrosion of several metals and plastics, taking into due consideration the industrial cleaning process for chemical impurities. For removal of flux (i.e., abietic acid that constitutes most of rosin) from 25 to 60 °C temperature by sonication treatment, first, the biodegradability (%) of the four bio-surfactants, namely the W/O- and O/W-formulated soybean methyl ester (SME) and canola ethyl ester (CEE) types, were determined to be 94.66%, 95.60%, 94.43%, and 93.87%, respectively. Second, the cleaning efficiencies of the four bio-surfactants were 99%, 97%, 58%, and 15%, respectively, under the optimal cleaning conditions. Third, the degrees of maximal corrosion of caster iron and polyvinyl chloride (PVC) by W/O SME, O/W SME, W/O CEE, and O/W CEE were recorded as −0.11/−7.65, −0.44/−5.79, −0.11/−11.80, and −0.12/−2.84 Δmg/cm3, respectively. Compared with trichloroethylene (TCE)'s cleaning performance for oil-contaminated brake pads, the W/O SME bio-surfactant showed better (∼99%) cleaning efficiency in <5 min. Conclusively, the W/O SME bio-surfactant was judged to be a proper CFC alternative for application to industrial cleaning processes.