Three polystyrene (PS) resin microspheres supported nanoscale zero-valent iron (nZVI), i.e., nZVI@PS, nZVI@PS-Cl, and nZVI@PS-N, were prepared and characterized by FT-IR, XPS, SEM, EDS, and weighing method. The functional groups on the carriers showed obvious influence on the loading quantity, the micro morphology, and the reduction efficiency of these supported nZVI. The best hybrid reducer was nZVI@PS-N. The load quantity of nZVI was 0.2476 g/g, and some of them were dispersed and the others remained as particles (≤ 50 nm). At optimal reaction conditions, i.e., initial solution pH = 3, 25 °C, 100 r/min stirring, 99% nitrobenzene (NB) in 250 mL 123.1 mg/L NB solution could be totally reduced into AN by 1.31 g fresh nZVI@PS-N within 20 min. The excellent reduction efficiency and fast degradation rate of nZVI@PS-N were mainly attributed to the synergistic effects between the good adsorption property of its carrier and the high reduction activity of nZVI particles. NZVI@PS-N was reproducible and recycled, and 90.6% degradation ratio of NB was till obtained at its seventh recycle. The results showed that nZVI@PS-N had high potential practical application value in the reductive degradation and emergency rescue of nitrobenzene pollutant.
Adopting the Reynolds averaged Navier-Stokes equation and RNG k-ε turbulent model, the unsteady flow in the double channel pump is simulated with sliding mesh technique. Detecting points in the impeller and volute passages are to capture the pressure fluctuation law at different time. The pressure fluctuation around the outlet of the volute is measured by pressure transducer, then the frequency domain pattern under different conditions comes out. With the Fast Fourier transform (FFT) analysis, the pressure changing law of time domain at the outlet of the volute is investigated under different operating conditions. It shows that the pressure fluctuation in the volute differs under different conditions. The pressure changing law obtained by the numerical simulation at the outlet of the volute accords with the measurement results. Also the pressure fluctuation at the outlet of the volute is closely related to the interaction between impeller and volute.
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