Design, synthesis, and evaluation of bio-based surfactants for industrial cleaning applications

Thesis Abstract

The extensive reliance on synthetic surfactants in industrial cleaning has raised significant environmental and health concerns due to their non-biodegradability, toxicity, and the depletion of fossil resources, necessitating the development of sustainable alternatives. This study aims to design, synthesize, and evaluate bio-based surfactants derived from renewable plant oils for use in industrial cleaning applications, thereby contributing to the advancement of environmentally friendly cleaning agents. The specific objectives include (i) identifying suitable renewable raw materials through a comprehensive review of bio-based surfactant literature; (ii) synthesizing novel surfactant candidates via eco-friendly chemical pathways such as esterification and amidation; (iii) characterizing the chemical structures and purity using Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and gas chromatography-mass spectrometry (GC-MS); (iv) evaluating their surface-active properties, including critical micelle concentration (CMC), surface tension, emulsification capacity, and foaming efficiency; and (v) assessing their cleaning efficacy and biodegradability compared to commercial synthetic surfactants. A mixed-methods research design was employed, combining laboratory experimental synthesis and characterization with field-based performance testing. The population consisted of synthesized bio-based surfactants and commercial control counterparts. A sample size of thirty surfactant formulations was prepared using factorial design to optimize synthesis parameters, with subsequent testing performed on standardized industrial soils and dirt simulants. Data collection instruments included FTIR, NMR, GC-MS for chemical characterization; tensiometry and emulsification tests based on ASTM standards for surface activity; and cleaning efficacy assessments through quantitative weight loss and visual cleanliness ratings. Biodegradability was measured according to OECD guidelines using respirometric tests. Data analysis involved descriptive statistics, Analysis of Variance (ANOVA) for comparing surface-active properties and cleaning performance, and regression analysis to model relationships between chemical structure and functional efficacy, utilizing SPSS and MATLAB software. Expected findings indicate that the newly synthesized bio-based surfactants exhibit lower CMC values, enhanced emulsification, and comparable or superior cleaning efficiency relative to synthetic counterparts, coupled with higher biodegradability scores exceeding 70%, thereby confirming their environmental compatibility. The structural elucidation is anticipated to reveal effective incorporation of fatty acid chains from plant oils, leading to optimized wetting and soil removal capacities. These results are expected to reveal a positive correlation between molecular structure parameters, such as chain length and functional group type, with surface activity and biodegradability. This research makes a significant contribution to the scientific knowledge base by providing a comprehensive framework for sustainable surfactant development, highlighting eco-friendly synthesis routes, and establishing clear performance benchmarks aligned with environmental standards. The findings promote the adoption of renewable raw materials in industrial cleaning formulations, fostering green chemistry principles and reducing environmental footprints. The study concludes that bio-based surfactants derived from plant oils are viable, effective, and sustainable alternatives to conventional synthetic surfactants, urging industrial stakeholders to integrate these bio-based agents into cleaning regimes. Based on these outcomes, the study recommends further optimization of synthesis processes for large-scale production, detailed life cycle assessments to quantify environmental benefits, and extended testing under diverse industrial conditions to enhance commercial applicability. Future research should explore the potential for functional modifications to tailor bio-based surfactants for specialized cleaning tasks, including antimicrobial and anti-corrosion properties, which will expand their utility across various industrial sectors.