In this study, the typical azo dye methyl orange (MO) was degraded by pyrite (FeS2) activated by hydrogen peroxide (H2O2). When [MO] = 0.1 mM, [FeSJ = 2.0 g/L and [H2O2] = 22 mM, 96.4% MO was removed in 120 min and the TOC removal rate was higher than 50%. HO* was the primary radical responsible for MO degradation, in addition, the acid condition promoted the degradation of MO in the FeS2/H2O2 system. MO in tap water and river water was not effectively degraded, whereas acidification could weaken the inhibitory effect on the FeS2/ H2O2 system to enable the degradation of MO in tap and river water. The OD600 indicated that the solution was environmentally friendly after the reaction, and three degradation pathways of MO were discussed. In summary, Fe(ll) could be dissolved from FeS2, which activated H2O2 to generate Fe(lll) and HO*. FeS2 could reduce Fe(lll) into Fe(ll), thus realizing the Fe(lll)/(ll) cycle and efficiently activating H2O2 to degrade MO.

Lead-free ceramics Ba(Zr xTi1-x)O3 (x = 0.02-0.2) were prepared using a solid-state reaction technique. The structural and electrical properties were systemically investigated. Crystalline structures and microstructures were analyzed by X-ray diffraction and scanning electron microscope (SEM) at room temperature. All the samples possess pure perovskite structure. A small amount of Zr content has great effect on the microstructure of Ba(Zr xTi1-x)O3 ceramics. The homogeneous microstructure with grain size about 30µm is obtained for the sample at x = 0.05. The phase transitions merge together in one peak for the samples at x = 0.10 and the highest dielectric constant 15900 is obtained for the sample at x = 0.15. The Ba(Zr xTi1-x)O3 ceramics at x=0.05 exhibit excellent piezoelectric properties of high d33 = 208 pC/N, k p = 31.5% and Qm = 500.