Reduction of calcium carbonate (CaCO 3 ) scale formation on the equipment surface is essential in a wide variety of industrial fields. In this work, polydopamine/polytetrafluoroethylene (PDA/PTFE) coating prepared by the simple immersion on stainless steel (SS) surfaces was developed to suppress the CaCO 3 scale adhesion. The PDA/PTFE-coated surface showed the higher hydrophobicity (water contact angle = 133.50 ) and lower surface free energy (11.92 mN/m) than the stainless-steel surface. The scale inhibiting rate of the coated surface was up to 76.8% after 12-hour immersion in the CaCO 3 solution in comparison with the untreated SS. More bubbles were observed on the PDA/PTFE-coated surfaces, and the number of bubbles increased with increasing solution temperature leading to less area for the scale adhesion. As a result, the PDA/PTFE coated surfaces have the higher antiscale ability at the higher solution temperature. Furthermore, the stripping and electrochemical corrosion tests demonstrated that the PDA/PTFE coating has the better stability and anticorrosion ability. The PDA/PTFE coating with the superior properties has potential application for the long-lasting reduction of the scale formation.

The poly(ethyleneimine) (PEI)-functionalized organic-inorganic hybrid silica was prepared by a hydrothermal-assisted surface grafting technique. Static adsorption experiment results showed that PEI-functionalized hybrid silica had high static adsorption capacity of 68.1 mg g À1 , which was 1.3 times as much as that of the sorbents by conventional heating method. PEI-functionalized hybrid silica displayed stable adsorption ability for Pb(II) ions in the range of pH 4-8. An equilibrium state was reached within 30 min. Freundlich and Langmuir adsorption isotherm models were used to fit the equilibrium data, and it was found that the Langmuir adsorption model provided good fit. Kinetic studies indicated that the adsorption followed a pseudo-second-order model. Various thermodynamic parameters, such as ΔG o , ΔH o and ΔS o , were evaluated with results indicating that this system was a spontaneous and endothermic process. The results indicated that PEIfunctionalized hybrid silica could be employed as an effective material for the adsorption of Pb(II) ions from aqueous solutions.