Qin Zhong

Preparation of nanosheet Fe-ZSM-5 catalysts, and effect of Fe content on acidity, water, and sulfur resistance in the selective catalytic reduction of NOx by ammonia

Direct synthesis of nanosheet Fe-ZSM-5 catalysts and their use for selective catalytic reduction (SCR) of NOx by ammonia were studied. XRD, BET, SEM, EPR, and NH3-TPD were used to understand the properties of catalysts with different iron loading. XRD confirmed the presence of the ZSM-5 crystal phase, and there was no Fe2O3 phase on the surface of the crystals. SEM showed the Fe-ZSM-5 catalysts comprised microspheres made up of nanosheets. EPR indicated that the iron was present as isolated Fe3+and FeOx oligomers uniformly dispersed throughout the crystals. NH3-TPD indicated that Fe-ZSM-5 (20,1:1) had maximum acid sites and density at approximately 250 and 450xa0°C, respectively. Fe-ZSM-5 (20,1:1) had the highest activity in the SCR reaction with NH3. It was also confirmed that Fe-ZSM-5 (20,1:1) had excellent resistance to SO2 and H2O under the SCR reaction conditions. The effects of water vapor and SO2, iron loading, and the Si/(Fexa0+xa0Al) ratio were also investigated for these catalysts.

Foaming of Homogeneous Polypropylene and Ethylene-Polypropylene Block Copolymer Using Supercritical Carbon Dioxide

A new process was used to foam homogeneous polypropylene (HPP) and ethylene-polypropylene block copolymer (CPP). Many different foaming behaviors of these two kinds of PP were observed. The HPP and CPP were characterized by Differential Scanning Calorimetry (DSC), and Capillary Rheometry. We find that the melt shear viscosity of CPP is more sensitive to the temperature variation than that of HPP, thus leading to larger change of cell diameter of CPP with foaming temperature. Cell size of CPP is the result of competition between cell nucleation and cell growth. When the saturation pressure is lower or higher than 25 MPa, cell nucleation or cell growth plays a dominant role, which leads to the increase or decrease of cell size, respectively. Because of its low melting temperature and crystallinity, cell diameter of CPP increases with the infiltration temperature increasing, which is opposite to those of HPP. And at the foaming temperature of 152°C or 158°C, cell diameter of CPP increases or decreases with an increase in foaming time, while that of HPP decreases with foaming time increasing at both foaming temperatures.

Orthogonal Design Study on Factors Affecting Foaming Behaviors of Polypropylene and Polypropylene/Nano-Calcium Carbonate Nanocomposites

A new process was used to foam polypropylene (PP) and its nanocomposites with supercritical carbon dioxide (SC-CO2) as the foaming agent. Orthogonal designs were carried out for the first time to optimize experimental conditions and investigate the interactions among the foaming temperature, saturation pressure, m infiltration temperature and foaming time. Results showed that the foaming temperature and saturation pressure had the most important impact on the cell diameter and expansion ratio, respectively. The optimal experimental conditions of PP and nanocomposites were different. The cell density was more relative to the cell diameter comparing with the expansion ratio. The results of analysis of variance indicated that only foaming temperature influenced the cell diameter of PP significantly, there were almost no interactions among those factors.

Acid Endurance and Sorption of Zn2+ of Anaerobic Granular Sludge Acclimated by Flue Gas Pretreatment Wastewater

With the aim to use anaerobic granular sludge, the methanogenic activity inhibition and recovery of anaerobic granular sludge from an industrial anaerobic reactor (s1) were investigated by measuring the methane volume at low pH. A lab-scale upflow anaerobic sludge blanket (UASB) reactor was inoculated with s1.s1 was used to remove Zn2+ in wastewater. The results show that activity of s1 is similar when the pH value is 6.5 to 7.0. The methane volume is obviously decreased when the pH value is 6.0. The activity is completely inhibited when the pH value is 4.5. The activity is fully recovered when the pH is above 6.5 and hardly recovers when the pH fell to 4.5. The main Zn2+ removal mechanism is chemical adsorption.

Foaming of Polystyrene with Supercritical Carbon Dioxide

General Purpose Polystyrene (GPPS) and High Impact Polystyrene (HIPS) were foamed with supercritical carbon dioxide in the batch foaming process. Foaming behaviors of GPPS and HIPS were investigated. The cell diameters and cell densities of GPPS and HIPS vary strangely with foaming conditions and can be explained by the classical nucleation. The competition between cell growth and cell nucleation is used to explain these strange foaming behaviors. The glass transition temperature (Tg) almost remains constant with the foaming temperature rising.

Purification of Polyether Polyols Made by Double Metal Cyanide Catalysis

Purification of polyether polyols made by double metal cyanide catalysis was studied. The removal effect of residual double metal cyanide in the polyols by the methods of adsorption and precipitation-filtration is characterized by the residual concentration of the zinc and cobalt ions which is measured by Inductively Coupled Plasma Atomic Emission Spectrometry. Compared with precipitation-filtration, the method of adsorption was more practical and efficient for the purification of the polyols. And the optimum kind and amount of the adsorbent were obtained. The results showed that the combination of chelating fiber and attapulgus clay was the most favorable for the removal of zinc and cobalt ions and the appropriate weight ratio of chelating fiber and attapulgus clay was 1:1. The total concentration of zinc and cobalt ions can be reduced to lower than 1×10-6. And the amount of the adsorbent added was 3.33% by the weight of the polyether polyols. Also through Scanning Electron Spectroscopy the morphology of the chelating fiber was characterized before and after adsorption. The functional groups on the surface of the fiber could be coordinated with the catalyst attached to the polyol polymer chains to form the separable insoluble particles.

Selective Catalytic Reduction of NOx by Ammonia over Fe-ZSM-5 Catalyst

Fe-ZSM-5 catalysts were synthesized by hydrothermal method under different levels of iron loading. The result of XRD and TG/DTA showed that Fe-ZSM-5 catalysts were successfully obtained after calcination at 550 °C. The effects of Si/(Fe+Al) and Fe/Al ratio on the SCR performance of Fe-ZSM-5 catalyst were investigated in a simulated flue gas. When Si/(Fe+Al)=20 and Fe:Al=20 Fe-ZSM-5 catalyst showed excellent catalytic activity. Under the condition of 210 °C, [NH3]/[NO] of 1.2, [O2] of 6 vol%, [NOx] of 900×10-6, Si/(Fe+Al)=20 and Fe/Al=1, NOx conversion exceeds 98%. Besides, Fe-ZSM-5 catalyst was excellently resistant to SO2 and H2O in the SCR reaction.

Experimental Research on Flue Gas Desulfurization with Ethylenediamine

Experiments were performed on the packed tower with 150mm diameter and 2800mm high to study the wet flue gas desulfurization continuously. The results shows that the suitable conditions for the SO2 absorption process of 0.3mol•L-1 ethylenediamine/phosphoric acid and ethylenediamine/boric acid solutions: pH value was 6.0～7.0, liquid-gas ratio was 0.82L•m-3. The import SO2 concentration and the flue gas flow were separately at 500×10-6～3100×10-6 and 110m3•h-1～150m3•h-1, the desulfurization efficiency exceeded 97%. Under the same conditons, ethylenediamine/boric acid has a better desulfurization and was more suitable for the flue gas desulfurization in a wider fluctuation.

Study on the Simultaneous Removal of SO2 and NO by I2 Solution

Experiments for studying simultaneous removal of SO2 and NO from simulated flue gas, with I2 solutions as the absorbent, Fe3+ as the catalyst ,were investigated in a self-designed bubble reactor, while various influencing factors on the removal efficiencies examined.The maximum desulfurization and denitrification efficiency achieved is 100% and 69.9%, respectively.