Comparative study on the inhibiting mechanism of inhibitor with primary amine groups and quaternary ammonium groups for sodium bentonite

Shale hydration and swelling is the main obstacle to the development of shale gas utilizing water-based drilling fluids(WBDFs).In this work,the inhibition mechanism of alkylammonium inhibitor and alkylamine inhibitor adsorbed on sodium bentonite(Na+Bent)are investigated using infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),X-ray diffraction(XRD),zeta potential,particle size distribution tests,and thermogravimetry analysis(TGA).The results suggest that HTB and HMD can be inserted into the interlamination of Na+Bent and minimize the basal spacing compared to hydrated Na+Bent.HTB and HMD are inserted between the Na+Bent layers in a single-layer tiled manner and replace the sodium ions that are firmly fixed between the layers.Eventually,water molecules are removed from the interlayer Na+Bent.The interaction between the quaternary ammonium group and Na+Bent is more significant than between the primary amine group and Na+Bent.The inhibition performance suggests that HTB inhibits Na+Bent hydration and swelling more substantially than other inhibitors,indicating that the inhibition performance of the two quaternary ammonium groups is greater than that of the two primary amine groups.Therefore,HTB can be used as intercalation inhibition in WBDFs and has tremendous application value.

Research on anti-corrosion property of rare earth inhibitor for X70 steel

Three kinds of rare earth nitrates were adopted to sodium molybdate to get three kinds of LnN-M compounded inhibitors （La（NO3）3＋Na2MoOa（LaN-M）, Ce（NO3）3＋Na2MoOn（CeN-M）, Pr（NO3）3＋Na2MoO4（PrN-M））. The combination of weight-loss method and the electrochemical test, was used to evaluate and analyze the corrosion inhibition efficiency of these LnN-M inhibitors to make the research on their corrosion inhibition performance, and the sequential order of their performance was found as follows： CeN-M〉 LaN-M〉PrN-M, among which, the inhibition efficiency of CeN-M for the X70 steel could reach 98.21%. The synergism parameters were calculated by weight-loss method, these computational data indicated that the synergistic effect between rare earth nitrates and sodium molybdate was obvious and significant. Surface morphology, chemical composition and phase components of the precipitation films were tested for discussing the mechanism of LnN-M inhibitors. The outer electronic configuration of the lanthanide was found to have an important influence on the inhibition efficiency. The CeN-M inhibitor was discovered to have the best inhibition effect with the amorphous cerium oxides. The results of this research revealed that the precipitation films formed on the surface of the steel samples had a crucial influence on the inhibition efficiencies after adding LnN-M inhibitors.