The corrosion inhibition of thiadiazole derivatives for brass in natural seawater has been evaluated by potentiodynamic polarisation and electrochemical impedance spectroscopic techniques. It was found that the inhibition efficiency of the thiadiazole derivatives, namely, 2-amino-5-ethyl-1,3,4- thiadiazole(AETD), 2-amino-5-ethylthio-1,3,4-thiadiazole(AETTD) and 2-amino-5-tert-butyl-1,3,4- thiadiazole (ATBTD) increases with increase in concentration. The adsorption of thiadiazole derivatives on brass surface exposed to inhibitor-containing solutions was confirmed using SEM/EDX spectra and FT-IR spectra. Adsorption of these inhibitors on brass surface followed Langmuir adsorption isotherm. ICP-AES analysis confirms that dezincification was minimized to a greater extent in the presence of these inhibitors.

Structural parameters of silica gels synthezid by the standard methods and by the method of rapid deposition have been studied. It has been shown that the proposed method of silica gel deposition allows to obtain homogeneously porous samples, including the mesoporous samples. It has been established that silicas obtained by the proposed method have a higher absorption capasity and a more narrow pore size distribution on effective radii. The new methods of hydroxide deposition opens wide opportunites for synthesis of adsorbents and catalysts with predetermined structure.

The present study was carried out to investigate the potential of cement hydrated at various time intervals for the removal of excess F− from aqueous solution by using batch adsorption studies. The influence of different adsorption parameters, viz. effect of adsorbent dose, initial concentration, pH, interfering ions and contact time were studied for their optimization. It was observed that the adsorbent exhibited reasonably significant F− removal over a wide range of pH. The presence of carbonate and bicarbonate ions in aqueous solution were found to affect the F− removal indicating that these anions compete with the sorption of F− on adsorbent. The equilibrium adsorption data were fitted well for both the Freundlich and Langmuir isotherms and the adsorption capacities were calculated. Comparative studies for F− removal in simulated and field water show relatively higher F− removal in simulated water. XRD and SEM patterns of the hydrated cement were recorded to get better insight into the mechanism of adsorption process. From the experimental results, it may be concluded that HC was an efficient and economical adsorbent for F− removal.