Palygorskite (PG) supported La1-xSrxMnO3 catalysts were fabricated by copreripitation. The catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), specific surface area (SSA) and H2 temperature programmed reduction (H 2-TPR). Catalytic activity for VOCs was examined by using toluene as a model compound. The results show that the surface area as well as mechanical strength of catalysts increase substantially after catalysts loaded in PG. XRD patterns show that after calcination at 700 0C, PG as a support in 9% LaMn03/PG and 9% La0.7Sr0.3MnO3/PG was transformed into amorphous phase and the morphology was not destroyed. It was well established that the main reductive components are factually Mn(III) or Mn(IV) oxides in catalysts based on the results of TPR. It was also found that Mn(IV) increases while Mn(III) reduces responding with the increasing amount of Sr. Toluene conversion rate of as-preparedμ% La1-xSr xMnO3/PG increases with the increasing values of x and μ when x=0-0.3 and μ = 3-9%. Toluene can be converted completely at 285 0C by 9% La0.7Sr0.3MnO3/PG catalyst while no significant change was observed after addition on the doping and loading amount of Sr. During a 100 h stability experiment of 9% La 0.7Sr0.3MnO3/PG catalyst, toluene removal was found to be above 95%.
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The mineralogical characteristics of palygorskite from the Lower Miocene Euphrates Formation and the Middle Miocene Fat.ha (Lower Fars) succession in north and northwestern Iraq were studied by X-ray diffraction (XRD), Infrared spectroscopy (IR) and scanning electron microscopy (SEM) with EDAX analysis. Palygorskite is the common clay mineral in the rocks studied, together with small amounts of illite, chlorite, and kaolinite, in addition to various amounts of quartz, feldspar, dolomite and calcite. It is believed that most of the clay minerals are detrital in origin, except palygorskite, which is formed by authigenesis in evaporitic environments. Marl beds of the Euphrates Formation were deposited in a lagoonal, relatively saline environment, suitable for the neoformation of palygorskite. The Fat.ha Formation is composed mainly of an evaporitic sequence. It consists of numerous shallowing-upward cycles of alternating mudrock, limestone, gypsum and/or anhydrite and halite in the basin centre. This depositional environment favours the authigenic formation of palygorskite and partly its diagenetic formation by transformation of precursor clays, mainly smectite and mixed-layer illite-smectite, as revealed by scanning electron microphotographs.
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