FORMULATION OF SOL-GEL COATING WITH ADDITION OF SPORA Bacillus sp. AND BIOSURFACTANT AS AN INHIBITION AGENT FOR THE BIOCOROSION OF ST-37 STEEL IN COOLING WATER SYSTEM APPLICATION

• Main Author: Karima, Ahdina
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/41323
• Institution: Institut Teknologi Bandung

Cooling tower is a building structure that functions in transferring heat from recirculating water to the atmosphere. This system has a unique atmosphere, namely 25-35oC, this condition is suitable for microbial growth and can form biofilms. Biofilms can accelerate corrosion on metal surfaces. Corrosion in cooling towers can cause three main problems, namely tool failure, loss of heat transfer efficiency and loss of structural integrity in walls and basins. One prevention of biocorrosion is with silica-based sol-gel coating. In long-term applications, additional corrosion inhibitor components such as bacterial spores or other organic components are needed to improve corrosion inhibiting properties. One of the bacteria that has the potential as a corrosion inhibiting agent is Bacillus sp. which can produce antimicrobial biosurfactants. In addition, biosurfactant Bacillus sp. Was used in this study. directly as an additional sol-gel component. This study aims to determine the formulation and effect of the addition of biosurfactant Bacillus sp. and Bacillus sp. spores. on sol-gel coating on biofilm formation and ST-37 steel corrosion resistance level which was incubated 60 days in water cooling. The viability test of spores in sol-gel was carried out by the ALT method and fluorescence microscope. Analysis of biofilm formation was carried out by the ALT method, while the level of resistance and corrosion rate by electrochemical method. In this study, a sol-gel formulation was successfully carried out with the composition of TEOS: GPTMS: Amino-PDMS of 10: 6: 4 (v / v) with an aging time of 8 hours. The viability of Bacillus sp. Spores. in a silica sol-gel system of 20.8%. In addition, sol-gel coating can inhibit biofilm formation in ST-37 steel. This is evidenced by the decrease in the number of biofilms found in the treatment of sol-gel and sol-gel + biosurfactant. Based on the results of measurements of resistance and corrosion rate, the highest level of corrosion resistance was obtained in the treatment of silica + biosurfactant, ie 13741.12 ? cm2. This is also in line with the lowest corrosion rate compared to other treatments, 0.11863 mpy. From the results of the study it can be concluded, that sol-gel with the addition of biosurfactant is more effective in inhibiting biofilm formation and corrosion of metals ST-37.