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Four kinds of π-complexation adsorbents are synthesized via ion exchange method or incipient wetness impregnation method with Amberlyst 35, SBA-15, TUD-1, and KIT-6 as supports, and AgNO 3 as active ingredient. The samples are characterized by N 2 adsorption/desorption. Fourier transformed infrared spectroscopies, transmission electron microscopy, X-ray diffraction spectrum analysis, and coupled plasma optical emission spectrometry are also used as adsorbents for ethylene/ethane adsorptive separation. The results show that the specific surface area and the dispersion of silver ions affect the separation performance of the adsorbent. Ag−Amberlyst 35 has the highest ethylene/ethane selectivity among these adorbents while the adsorbed amounts of ethylene of the three mesoporous silica complexation adsorbents are higher. Adsorption thermodynamics analysis suggests that the interaction of ethylene with adsorbent is a mild chemical adsorption. An adsorption kinetics study indicates that the adsorption of ethylene on silver-supported mesoporous materials is not a simple diffusion-control process. The adsorption behavior of ethylene on the π-complexation adsorbent has an energy barrier in the range of 24−33 kJ/mol. Among the adsorbents in this work, the KIT-6-based adsorbent has the best mass kinetic performance due to its three-dimensional regular interconnected mesoporous structure.

In this paper, the factors related to the morphology of calcium sulfate whisker (CSW) are discussed. Most attention was devoted to the influence of co‐crystallized phosphorus in phosphogypsum—existing in the form of CaHPO4 · 2H2O—on the crystal growth, which was ignored in the preparation of CSW from phosphogypsum in previous research. Methods including X‐ray powder diffraction and scanning electron microscopy were performed to characterize the resultant crystals. The CSWs with uniform morphology were prepared by hydrothermal synthesis with commercial CaSO4 · 2H2O. However, the productions from the pretreatment phosphogypsum by hydrothermal synthesis appeared as irregular crystals with a small length to width ratio, and whisk‐broom‐like crystals were common. The influence of CaHPO4 · 2H2O on the growth of CSW has also been studied. The results showed that CaHPO4 · 2H2O can promote the formation of needle‐like crystals and whisk‐broom‐like crystals at hydration condition. In order to improve the morphology of CSW in a CaSO4 · 2H2O‐CaHPO4 · 2H2O system, substantive condition experiments were carried out, and it finally revealed that Fe3+ was useful for the well‐developed CSW.

The equilibrium solubility of the quaternary system Na + , NH 4 + //SO 4 2−, NO 3 − −H 2 O at 303.15 and 323.15 K was determined by an isothermal dissolution equilibrium method. The weighing bottle method and Abbe refractometer were adopted to measure the density and refractive index of the aqueous liquid phase. The solid-phase invariant points at equilibrium were confirmed by Xray diffractometry. The complete diagrams of equilibrium phase, water content vs J(NO 3 − ) 2 of this quaternary system at 303.15 and 323.15 K were constructed based on experimental data. The phase diagrams demonstrated that the system was a complicated quaternary system at 303.15 and 323.15 K. Five single-salt crystallization zones and four double-salt crystallization zones were found in this system at 303.15 K. Four single-salt crystallization zones and four double-salt crystallization zones were found in this system at 323.15 K.