Corrosion inhibition of heat exchanger tubing material (titanium) in MSF desalination plants in acid cleaning solution using aromatic nitro compounds

The inhibition impact of aromatic nitro compounds on the corrosion of heat exchanger tubing material (titanium tubes) in MSF desalination plants in acid cleaning solution (1.0 M sulfuric acid) was explored. Corroborative results between chemical and electrochemical (EIS) methods have been reported. FTIR and SEM analysis were further used to characterize the morphology and the nature of the film adsorbed on the titanium surface. The study informed that the maximum corrosion rate of titanium (0.260 mg cm−2 h−1) was obtained in 1.0 M sulfuric acid at 298 K. Aromatic nitro compounds act as effective corrosion inhibitors for titanium in acid cleaning solution. The efficiency of these compounds boosts with concentration and diminishes with temperature. The aromatic nitro compounds exhibit a maximum inhibition efficiency of 73.0% (NI), 82.6% (NII) and 94.6% (NIII) at 600 ppm. They form a good protective layer on titanium surface through their adsorption. The adsorption of aromatic nitro compounds on titanium surface obeys Langmuir model. The performance of these compounds decreases in sequence: (NI) < (NII) < (NIII).