Exopolysaccharides from Rhizobium pusense as bioinhibitor on mild steel corrosion in 0.5 N sulphuric acid medium exploration of biofilm, adsorption, mechanistic insights
Year: 2026
Type: article
Abstract: Extracellular polymeric substances (EPS) are complex mixtures of saccharides that contribute to the structure of biofilm environments via the formation of microbial aggregates. The biofilm-forming ability of the Rhizobium pusense (R.P) culture on corrosion inhibition of mild steel (MS) in 0.5 N sulphuric acid (H₂SO₄) was studied using spectral, analytical, and electrochemical techniques. EPS-biofilm exhibits the highest percentage of MS corrosion inhibition efficiency of 89.07% in 2.5 mL of inhibitor concentration and the deviations of inhibition efficiency while changing the temperatures were studied. The obtained IE, % value (89.07%) at 298 K in 0.5 N H₂SO₄ containing 2.5 mL concentration of R.P is accordance with the inhibition efficiency values (IE= 85.86% and 89.25%) obtained for the same concentration by electrochemical impedance (EIS) and polarizations studies. Tafel polarization study reveals that the R.P exhibits a mixed type of inhibition against MS in 0.5 N H₂SO₄. The R.P adsorption on the MS surface follows physisorption and obeys the Langmuir isotherm model. Surface analysis (FE-SEM, AFM), UV–visible, FTIR, and GC-MS studies confirmed the interaction between the inhibitor and MS surface and supports the biofilm formation in this study. Based on the experimental data, a suitable electrostatic attraction-based adsorption mechanism between R.P and active mild steel surface in 0.5 N H₂SO₄ was discussed.
Source: Next Materials
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,280
OpenAlex ID: W7148646624