Study On Preparation And Adsorption Performance Of Hydrophobic Mesoporous Attapulgite-based Absorbents

With the development of modern industry, the serious water pollution becomes a bottleneck problem hindering the economic and social growth in China. Attapulgite(ATP) been applied as adsorption material, however, the rod-like ATP crystals usually pack together closely to form agglomerates, which reduces their adsorption capability due to the decrease of the effective contact areas of the crystals.In this work, mesoporous materials based on ATP were prepared using hole-agent or template method. Followed by treatment with polytetrafluoro-ethylene(PTFE) and polydimethylsiloxane(PDMS) by chemical vapour deposition method(CVD) et al., the wettability of mesoporous ATP-based materials can be tailored to be strong hydrophobic to water while superoleophilic to oil. And a variety of analysis of SEM, XRD, BET, FT-IR, XPS were performed. The separation and selective absorption of organics or oils from water by using mesoporous ATP-based materials, as well as the recycling of mesoporous ATP-based materials were studied in our experiments.The main contents are as follows:1. A new strategy of separation and selective absorption of organics or oils from water by using natural clay-derived absorbent was demonstrated in our experiments. Spongy ATP(SA) with mesoporous structure (average pore diameter of10.749nm and a BET surface area of63.438m2g-1) was successfully synthesized by thermolysis of ATP/polymers nanocomposites. Followed by treatment with PTFE and PDMS, the wettability of the spongy ATP can be tailored to be strong hydrophobic to water while superoleophilic to oil. Due to its mesoporous structure and excellent hydrophobicity, the as-resulted strong hydrophobic and superoleophilic spongy ATP(HSA) shows good selectivity and absorption performance for a wide series of organic solvents and oils.2. PAA templete was carbonized under nitrogen atmosphere at high temperature for preparing a new porous, lipophilic absorbent material, and the porous ATP-based materials(PA) was modified by YDH-151. The modification effect and the mesoporous structure of PA, selective adsorption, recyclable properties of the YDH-151treated PA(OPA) were researched by SEM, BET and FT-IR et al. The results showed that the OPA, with functional spongy structure, lipophilic, and recyclability, possesses excellent and selective adsorption for organic contaminants.3. We have developed a simple method for fabrication of robust, three-dimensional all-inorganic porous ATP monolith(AM) based on natural clay nanocrystals using CaCO3as a hard template. By a simple surface modification with PDMS by CVD, the resulting hydrophilic AM(HAM) can be tuned to be superhydrophobic and superolephilic for selective absorption oils or organics from water. Also, the surface wettability of AM can be reversibly tailored from superhydrophobic to hydrophilic by simple thermal treatment, making it multifunctional absorbent for absorption of oils, organics, and metal ions from water only by simply tuning its surface wettability.Taking advantages of low cost production and easy to scale up, the mesoporous ATP-based materials might be a promising substitute for the conventional absorbent materials and may have great potentials as environmentally friendly absorption for a wide range of applications such as water treatment, oil spills cleanup, and so on. Meanwhile, the results of the thesis may open a new way for value-increment of ATP resources.