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[Display omitted] The calcium sulfate scale is a common scale in the industrial water system, which is difficult to be removed by common chemical cleaning methods. In this paper, a new phosphorous free of 1,6-Diaminohexane-contained polyaminoamide dendrimers (PAMAM) scale inhibitor with a three-dimensional (3D) branched structure has been developed. The scale inhibition performances of different generations of PAMAM dendrimers (PAMAM-mid, PAMAM-0G, PAMAM-0.5G and PAMAM-1G) are estimated by the static scale inhibition method. Moreover, the effects of the scale inhibitor concentrations and solution temperatures on the CaSO 4 scale inhibition efficiency are thoroughly discussed. Results indicate that the PAMAM-mid and PAMAM-0.5G) exhibit excellent inhibition performance on CaSO 4 precipitation. Especially, the CaSO 4 scale inhibition efficiency of PAMAM-0.5G is above 95% when the dose is 10 mg/L, and the corresponding value is almost 100% when the inhibitor dose is 20 mg/L. In addition, the influence of descaling agents on the crystal and morphology of CaSO 4 scales are studied by XRD and SEM tests. The results show that the scale inhibition ability of the PAMAM molecules mainly inhibits the growth of these crystal planes by adsorption on the surface of the growing crystal. Molecular dynamics simulation results find that the PAMAM-0.5G dendrimer molecule can energetically interact well with three crystal planes of calcium sulfate dihydrate. Finally, the simulation results provide a theoretical guidance to judge the performance of scale inhibitors and synthesize new high-efficiency scale inhibitor. [ABSTRACT FROM AUTHOR]

In this work, N-[2-(3-indolyl)ethyl]-cinnamamide (IA) synthesized from tryptamine (TA) and cinnamic acid was evaluated as green corrosion inhibitor for Q235 steel in 0.5 M HCl solution by weight loss tests, potentiodynamic polarization (PDP) curve and electrochemical impedance spectroscopy (EIS). Gravimetric measurements displayed the maximum inhibition efficiencies of TA and IA at 1.0 mM were up to 92.8% and 97.6%, respectively. PDP and EIS studies revealed they could hinder both hydrogen evolution and metal dissolution reactions and that the inhibiting effect was temperature and concentration dependent. The surface analysis of sample was presented through scanning electron microscope (SEM), energy dispersive spectroscopy (EDX) and atomic force microscope (AFM), which indicated the anti-corrosion ability of Q235 steel in hydrochloric acid was enhanced by the inhibitor. The adsorptive behavior of inhibitors including physisorption and chemisorption obeyed Langmuir isotherm. The inhibition mechanism was elucidated by determining the potential of zero charge (Epzc) at solid/liquid interface. Quantum chemistry calculation provided a theoretical estimate of the reactivities of TA and IA as corrosion inhibitors to ascertain the correlation between the inhibition efficiency and molecular structures. Results of molecular dynamics (MD) simulations confirm that IA shows better inhibitive performance due to higher interaction energy (– 79.1 kJ mol−1for TA and – 144.16 kJ mol−1for IA).

• The doping of Sb-SnO 2 NPs decreases the size of the PPy balls. • Embedding Sb-SnO 2 NPs improves the physical properties of PPy coating. • Sb-SnO 2 /PPy coating is of better anti-corrosion and self-healing ability. • The band gap of SnO 2 NPs increases with the doping of Sb in SnO 2 lattice. Polypyrrole (PPy) coatings were successfully electrosynthesized on the carbon steel by embedding SnO 2 and Sb-SnO 2 nanoparticles (NPs). The associated structural, morphology, hydrophobic, physical properties, anti-corrosion and self-healing performance of these coatings were systematically studied by several tests. XRD results showed that SnO 2 had a tetragonal rutile structure and the lattice parameters indicated that Sb ions were successful substituted into SnO 2 lattice. The average size of SnO 2 NPs was decreased by the incorporation of Sb-SnO 2 NPs, which were found through TEM images. The contact angle test showed that the hydrophobic of PPy coatings was greatly enhanced by the incorporation of Sb-SnO 2 NPs. SEM results revealed that Sb-SnO 2 /PPy coating exhibited a more compact and uniform surface than SnO 2 /PPy coating, hence the physical barrier effect was significantly strengthened. The electrochemical measurements confirmed the excellent anti-corrosion and self-healing ability of Sb-SnO 2 /PPy coating for a long immersion time in HCl solution. The superior anti-corrosion performance of Sb-SnO 2 /PPy coating was ascribed to the synergistic effects of the anodic protection combined with the self-healing effect, the excellent physical barrier effect with compact, smooth and hydrophobic coating surface as well as the formation of p-n junction with decreased charge transfer. [ABSTRACT FROM AUTHOR]

The ionic liquids, 1-vinyl-3-aminopropylimidazolium hexafluorophosphate ([VAIM][PF 6 ]) and 1-vinyl-3-aminopropylimidazolium tetrafluoroborate ([VAIM][BF 4 ]) acted as the corrosion inhibitors. Weight loss measurements showed the corrosion inhibition efficiencies of [VAIM][PF 6 ] and [VAIM][BF 4 ] were 90.53% and 54.01% at 45 °C, respectively. The ILs were mix-type inhibitors. Raising the temperature can have a decreased inhibition efficiency of [VAIM][BF 4 ], while [VAIM][PF 6 ] presented an opposite trend. In addition, [VAIM][PF 6 ] obeyed Langmuir monolayer adsorption isotherm, while [VAIM][BF 4 ] obeyed EI-Awady kinetic-thermodynamic adsorption for blocking active sites. Moreover, Molecular Dynamic Simulations showed that [VAIM][PF 6 ] owned a higher adsorption energy, which may be responsible for the more adsorption groups of [VAIM][PF 6 ]. [ABSTRACT FROM AUTHOR]

To overcome the problems of stagnant activity and vulnerable acid sites, a meticulously tailored tetra-metallic catalyst, ScTiTbAuAPO-5, with an extremely low surface gold atom concentration of 0.02%, has been designed and prepared via one-step hydrothermal crystallization. It exhibits remarkable catalytic activity, leading to the direct condensation of aniline and C═X (X = O, N) blocks without extra assistance. The highest selectivity exceeds 99.00%. The highly dispersed stable metallic sites and the drastic surface polarization are the keys to unique catalytic performances, leading to high acid density and reversed acidity transformation behavior. In this synergistic system, scandium and titanium are the main active components, whereas terbium and gold regulate the acidity and activity via withdrawing electrons. The application of tetra-metallic synergy on the catalysis of C–N bond formation unveils a promising methodology to manipulate the surface acidity of the catalyst with the relativistic effect, dropping the consumption of noble metals simultaneously. The present work also exemplifies the immense potential of the multi-metallic synergistic strategy in green catalysis.

•The Mn/γ-Al2O3nanocatalyst significantly enhanced phenol removal in reaction with ozone.•Protonated surface hydroxyl groups could promote the catalytic ozonation.•The degradation of phenol is affected by the solution pH and the pHpzcof catalysts.•Other active oxygen species could involve in the catalytic ozonation.•A possible mechanism of catalytic ozonation is proposed.