Tao Du

Using one waste to tackle another: preparation of a CO2 capture material zeolite X from laterite residue and bauxite.

In this work, zeolite X, a benchmark adsorbent for carbon capture, has been successfully prepared from low cost waste minerals namely laterite residue and bauxite using alkali fusion process followed by hydrothermal treatment. The structure and morphology of the as-synthesized zeolite X were verified and characterized with a range of experimental techniques such as X-ray diffraction, scanning electronic microscopy and infrared spectroscopy. The surface area and (N2 and CO2) gas adsorption isotherms of this product were found comparable to that of commercial ones, demonstrating the effectiveness of synthesizing zeolite X from laterite and bauxite. Further improvement of the product purity was also accomplished by optimizing the process conditions.

Preparation of zeolite NaA for CO2 capture from nickel laterite residue

Zeolite NaA was successfully prepared from nickel laterite residue for the first time via a fusion-hydrothermal procedure. The structure and morphology of the as-synthesized zeolite NaA were characterized with a range of experimental techniques, such as X-ray diffraction, scanning electronic microscopy, and infrared spectroscopy. It was revealed that the structures of the produced zeolites were dependent on the molar ratios of the reactants and hydrothermal reaction conditions, so the synthesis conditions were optimized to obtain pure zeolite NaA. Adsorption of nitrogen and carbon dioxide on the prepared zeolite NaA was also measured and analyzed. The results showed that zeolite NaA could be prepared with reasonable purity, it had physicochemical properties comparable with zeolite NaA made from other methods, and it had excellent gas adsorption properties, thus demonstrating that zeolite NaA could be prepared from nickel laterite residue.

Measuring the Decoupling Progress in Developed and Developing Countries

The relationship between economic development and the ecological environment is the key to sustainable development of human society. With the rapid economic development, the demand for resources has increased dramatically, which has led to problems such as depletion of resources and environmental pollution. Therefore, the relationship between resource use and economic growth needs to be studied to formulate corresponding resource use policies to facilitate the sustainable development of human society. This paper uses the resource decoupling indicators to study the decoupling condition of domestic material consumption (DMC) and material footprint (MF) indicators of three BRICS countries and three OECD countries from 1990 to 2015. Resources include biomass, non-metallic minerals, fossil fuels, and metal ores. Based on the results from these cases, we find that developed countries have a better decoupling condition than developing countries in the DMC level, but there is not much difference between developed and developing countries at the MF level. The developing countries’ decoupling condition of MF is better than that of DMC, while the developed countries’ decoupling condition is opposite. This study also emphasizes the importance of developing decoupling policies by selecting an appropriate resource use indicator.

Adsorption of carbon dioxide and water vapor on fly-ash based ETS-10

CO2 capture from humid flue gas is always costly due to the irreplaceable pretreatment of dehydration in current processes, which creates an urgent demand for moisture-insensitive adsorbents with considerable CO2 uptakes as well as remarkable H2O tolerances. In the present work, the microporous titanium silicate molecular sieve ETS-10 was synthesized with coal fly ash as the only silica source. The as-synthesized ETS-10 was characterized by X-ray diffraction, scanning electronic microscopy and infrared spectroscopy to verify its crystal morphology, in which neither impurity nor aggregation was observed. The following CO2 adsorption experiments on the thermal gravimetric analyzer demonstrated its similar CO2 adsorption capacity yet dramatical adsorption kinetics among some other microporous materials, e.g., potassium chabazite. These specific properties consequently guaranteed its favorable CO2 adsorption capacity even at high temperatures (1.35 mmol/g at 393 K) and shortened the breakthrough time of single CO2 flow to less than 20 s. In CO2/H2O binary breakthrough experiments, the as-obtained ETS-10 still maintained excellent CO2 uptake of 0.81 mmol/g at 323 K, regardless of the presence of water vapor, making it a promising substitute for direct CO2 separation from humid flue gases at practical conditions of post-combustion adsorption.

An optimal trapdoor zeolite for exclusive admission of CO2 at industrial carbon capture operating temperatures

High purity molecular trapdoor chabazite with an optimal Si/Al ratio (1:9) was prepared from fly ash. Gas adsorption isotherms and binary breakthrough experiments show dramatically large selectivities for CO2 over N2 and CH4, which are the highest among physisorbents at operating temperatures suitable for postcombustion carbon capture and natural gas separations.

Research on Raw Material Consumption and its Socioeconomic Divers of Shenyang

Chinas resource consumption has been increased rapidly with the development of economy. As one of Chinas most important industrializing cities, Shenyang faces even severer situation of resource restriction. It is important to analyze Raw Material Consumption (RMC) of Shenyang and its socioeconomic divers before designing future environmental and economic plans. In this study, we calculate the RMC of Shenyang during 2002-2012, and then use Structural Decomposition Analysis (SDA) to find the driving factors of it. Results show that RMC of Shenyang was increased by 160% from 93 million tons to 247 million tons during the studied period. Construction and heavy manufacture sectors contributed the most to the resource consumption. In terms of driving factors, final demand level was the most significant one, and production structure partly impeded the increasing of RMC. It is suggested that more attention should be paid to construction investment and improvement of production structure to control the increase of resource use.

Research on the separation process model of pressure swing adsorption for CO 2 /N 2 with zeolite molecular sieve

The model of pressure swing adsorption separation process for CO2 with zeolite molecular sieve is established in this paper. The pressure swing adsorption system of CO2 is simulated with mass, gas and energy balance equations. The CO2 adsorption isotherm is fitted by Dual-site Langmuir equation. The recovery rate, productive rate and energy of the separation process is designed. Finally, the model is validated by CO2 of power plant flue gas with zeolite A and zeolite A+X. The result data of experiment and model simulation shows that our model is reliable in simulating the CO2/N2 pressure swing adsorption separation process with zeolite molecular sieve.