Calcium ion contamination in water-based drilling fluids (WBDs) dramatically increases filtration volume loss and worsens rheological properties, especially in high-temperature bore holes. This study demonstrated two types of acrylamide polymers as anti-calcium contamination fluid-loss additives in WBDs, including an amphoteric polymer (ADD) synthesized by 2-acrylamide-2-methylpropanesulfonic acid (AMPS), acrylamide (AM), and diallyl dimethylammonium chloride (DMDAAC) and an anionic polymer (AD) synthesized by AMPS and AM. In transmission electron microscopy (TEM) of sodium bentonite (Na-BT)-based mud under 11.1% CaCl2 contamination and 150 °C hot rolling, a typical “star-net” structure was observed between the ADD and Na-BT layers; however, polymer AD could not form such a net structure. Energy-dispersive spectrometry (EDS) analysis of the Na-BT layer indicated that ADD could greatly decrease the amount of Ca2+ on Na-BT layers in comparison to AD. Accordingly, in an American Petroleum Institute (API) filtration test and a rheological test of Na-BT-based mud with 11.1% CaCl2 contamination after 150 °C hot rolling, Na-BT-based mud with 1.5% ADD could maintain an API filtration volume (FLAPI) as low as 9.6 mL, whereas Na-BT-based mud with 1.5% AD maintained a FLAPI of 36 mL. The rheological properties of Na-BT-based mud also showed that ADD could maintain higher viscosity and shear stress than AD, suggesting that amphoteric polymer ADD was suitable for making WBDs more resistant to calcium contamination and high temperature.

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A novel ionic liquid (1-aminoethyl-3-methylimidazolium lysinate, [C 2 NH 2 MIm][Lys]) functionalized with three amino groups had been developed for carbon dioxide (CO 2 ) capture in this work. The CO 2 absorption loading of [C 2 NH 2 MIm][Lys] solution was found to be 1.59 mol CO 2 /mol IL with a concentration of 0.5 mol/L at 313.15 K, which was much higher than that of the most existing dual functionalized ILs. Besides, [C 2 NH 2 MIm][Lys] also owned a good regenerability even after 6 regeneration cycles. According to the results of 13 C nuclear magnetic resonance ( 13 C NMR), CO 2 absorption into [C 2 NH 2 MIm][Lys] solution could be divided into two stages, which began with the formation of carbamate, and followed by the hydration of CO 2 to form carbonate/bicarbonate. Meanwhile, the desorption of the saturated [C 2 NH 2 MIm][Lys] was proven to be a reverse process of the adsorption. Based on the mechanism results, the kinetics of CO 2 capture into [C 2 NH 2 MIm][Lys] solution was investigated by using a double stirred-cell absorber at temperatures ranging from 303 to 333 K. Under the pseudofirst-order regime, the overall reaction rate constants (k ov ) and the forward second-order rate constants (k 2 ) under different concentrations and temperature were obtained, which were both increased considerably as temperature increased. Moreover, the values of enhancement factor (E) were linear with C RNH2 and temperature. The Arrhenius equation of CO 2 absorption was also estimated, and the activation energy was calculated to be 25.5 kJ•mol −1 .

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