Carbon quantum dots are fluorescent nanoparticles with various unique properties such as environmental friendliness, high conductivity, low toxicity and high stability. This study aimed to synthesize carbon nanodots (CDs) from chitosan and apply them as a corrosion inhibitor in BIS 2062 carbon steel. CDs were synthesized from chitosan, and their morphological characteristics studied using atomic force microscopy (AFM) and transmission electron micrograph (TEM). The AFM and TEM results showed that the CD had a spherical shape and 2D structure. The FTIR spectroscopy results indicated that the CDs were rich in C=O and C-O functional groups. The UV-Vis spectroscopic analysis showed absorption peaks at 288 and 222 nm. Moreover, the zeta potential was positive. The BIS 2062 carbon steel, which is used for boat building, was coated with CDs, and its electrochemical characteristics were studied through linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). The LSV and EIS results showed that steel coupons coated with 0.05% CD had excellent corrosion resistance. Cyclic voltammetric evaluation using glassy carbon electrode revealed that the oxidation and reduction potential of iron oxide were significantly suppressed due to the coating of CDs. The results highlighted the use of CDs as a corrosion inhibitor and a potential alternative to graphene-based materials.

Biofouling is one of the problems faced by cage aquaculture farmers, and its management is expensive. In this present study, polyethylene aquaculture cage nets were coated with the nano structured oxides of zinc and silicon incorporated with polyaniline. Fourier transform infrared spectroscopy and scanning electron microscope data evidenced that a thick coating of nano particle was formed on polyethylene. The oxides were attached to the quinoid part of polyaniline. The antifouling efficiency of treated cage net was tested by exposing in the Cochin estuary for three months. A webbing treated with 0.01% of each of the nano zinc oxide (ZnO) and silicon dioxide (SiO 2) exhibited the highest biofouling resistance. Reinforcement of nano SiO 2 with ZnO increased biofouling resistance as the former complemented the coating to make the system more efficient.