Study On Preparation And Adsorption Performance Of Mesoporous Starch Activated Carbons

Mesoporous carbon, as an effective adsorbent shows higher adsorption capacity and faster speed for inorganicions and organic molecules. Compared with resin, silica and zeolite,the advantage of mesoporous carbon are developed pore structure and higher special surface area, moreover, the mesoporous carbon is easy to modify to introduce various chemical groups and displays certain catalytic activity and stability, especially in acid or base solutions. In addition, the mesoporous carbon was widely used in wastewater and air treatment and solvent recovery.As a natural polymer, starch with plenty source and cheap price, has high oxygen content and is easy to modify and polymerize. Recently, the utilization of renewable source is more and more attractive issue; starch as polymers with more oxygen-containing groups is used in different fields.In this work, the soluble starch was used as carbon precursor to prepare the hierarchical mesoporous carbon. FT-IR, SEM, XRD, N2 adsorption and equilibrium adsorption of organic compounds were used to evaluate the pore structure, functional groups, surface morphology and adsorption properties. In this work, starch was selected as carbon precursor to synthesize mesoporous carbon microsphere, the detail result as following:1. Strach carbon could be prepared using the mixture of solubility starch and white starch in presence of hexadecyl trimethyl ammonium bromide.2. Starch microsphere could be synthesized by cross-linking between N,N-methylene bisacrylamide and starch.3. When N,N-methylene bisacrylamide and epichlorohydrin were used as cross-linking, lubricant as oil phase, starch microsphere with better morphology was obtained, carbon microsphere was formed after carbonization.The results showed that there exist layer structure in the resultant carbon material when starch was mixed with white starch and carbonized, the mesopore ranged from 2-3nm to 3-5nm and adsorption capacity for ammonia was about 10.45%(wt%); the ordered macro pore of 1 micrometer appeared when starch was polymerized with MBAA and CTAB, and adsorption capacity for ammonia was 7.61% (wt%). In addition, the starch micro sphere with a diameter around 0.5 micrometers was formed when starch polymerized in lubricates media, and the mesopore located at 4nm-20nm. The sample showed higher adsorption capacities for ammonia about 14.77% and ethanol about 10%, respectively.Both samples displayed similar adsorption capacities for ethanol, acetic acid and ammonia, the adsorption behaviors were related with its pore structure and surface chemical properties.