EDTA interfacial chelation Ca^(2+) incorporates superhydrophobic coating for scaling inhibition of CaCO_(3) in petroleum industry

In this paper,the superhydrophobic poly(vinylidene fuoride)/fuorinated ethylene propylene/SiO_(2)/CNTs-EDTA(PFSCEDTA)composite coating was successfully fabricated and applied for anti-scaling performance.The deposition of CaCO_(3) on the surface of the superhydrophobic PFSC-EDTA composite coating reached 0.0444 mg/cm^(2) for 192-h immersion into the supersaturated CaCO_(3) solution,which was only 11.4%that of the superhydrophobic PFSC composite coating.At the interface between the CaCO_(3) solution and the PFSC-EDTA coating,the Ca^(2+)could be frstly chelated by EDTA that was beneft for improving the anti-scaling performance of the superhydrophobic PFSC-EDTA composite coating.In another hand,the addition of EDTA to the CNTs played an important role in fabricating the SiO_(2)-centric and CNTs-EDTA-surrounded multilevel micro-nanostructure in the superhydrophobic PFSC-EDTA composite coating,in favor of maintaining the air flm under the water and the stability of the superhydrophobic surface.The research supplies a new way of improving antiscaling performance of superhydrophobic coating by incorporating the organic chelating agent at the interface and changing the traditional way of scale prevention.

Effect of Preoperative Double-J Ureteral Stenting before Flexible Ureterorenoscopy on Stone-free Rates and Complications

The effect of preoperative Double-J(DJ)ureteral stenting before flexible ureterorenoscopy(FURS)in the treatment for urinary stones was evaluated.We retrospectively enrolled 306 consecutive patients who underwent FURS from Jan.2014 to Dec.2017.All the patients were classified into two groups according to whether they had DJ ureteral stenting before FURS.Baseline characteristics(age,sex,stone location,stone size,surgical success rate,operation time,stone-free rate of the first day after surgery,stone-free rate of the first month after surgery,total complication rate)were compared using Chi-square test for categorical variables and Kruskal-Wallis test for continuous variables.In total,306 patients were included in this study.The group of DJ stenting before FURS included 203(66.3%)patients,and non-DJ stenting before FURS was observed in 103(33.7%)patients.The group of DJ stenting before FURS was significantly associated with a shorter operation time(53.8 vs.59.3 min,P<0.001),a higher stone-free rate of the first day after surgery(69.0%vs.51.5%,P=0.003).However,statistical significant differences were not found in the age,sex,stone location,stone size,surgical success rate,stone-free rate of the first month after surgery(89.2%vs.81.6%,P=0.065)and total complication rate(5.4%vs.9.7%,P=0.161)between the two groups.Preoperative DJ ureteral stenting before FURS could reduce the operation time and increase stone-free rate of the first day after surgery.However,it might not benefit the stone-free rate of the first month after surgery and reduce the complication rate.Preoperative DJ stenting should be not routinely performed.