الفهرس 
ContentsOnly 14 pages are availabe for public view
 |  | from | 206 |  |  |
| | | from | 206 | | |
Abstract
In the present study activated carbons were prepared to remove mercury from natural gas on the basis of the fact that these sorbents are characterized by unique textural properties and functionalized surface. Activated carbons prepared from three different agricultural wastes (Olive stone, Pistachio nut shells and Date stone). Phosphoric acid‒activated carbons (OP11, OP12 and OP13) were prepared from olive stone as a precursor by soaking precursor with phosphoric acid in the different weight ratio as 1:1, 1:2 and 1:3 (Olive stone : H3PO4) at room temperature. The impregnated samples were carbonized at 600 °C under a flow of nitrogen. Also, PP11, PP12, and PP13 prepared with the same previous procedure. Non‒activated carbon (DC600) was obtained by carbonization of Date stone at 600 °C. Afterwards, steam‒activated carbons (DS40 and DS80) were obtained by gasification a portion of DC600 carbon at 900 °C to burn ‒off (40% and 80%). Afterwards, OPS13 and OPSE13 were prepared by two sulfur impregnation method. The characterization of the prepared activated carbons is of prime importance not only for determining the structure, textural and surface chemistry of the adsorbent but also to understand how modification is related to the changes in these properties and also to the change in the performance of adsorbent. All the prepared solid adsorbent materials were characterized using different classical and advanced techniques such as : ash content, moisture content and thermal gravimetric analysis (thermal characterization), nitrogen adsorption/desorption isotherms, Scanning electron microscopy, high resolution transmission electron microscopy, and X‒ray diffraction (textural characterization), and FTIR, pHPZC, Boehm titration method, Zeta potential and elemental analysis (chemical characterization). The surface area of prepared samples are high and reachs to 1357.5 m2/g for OP13 sample. Also, the adsorption capacity for elemental mercury (Hg°) and total breakthrough time were studied by using a continuous flow system (OPS13 uptake 111.8 mg/g). Thomas and Yoon‒Nelson models used to evaluate the breakthrough results and to scale it up for industrial applications. Moreover, the adsorption of Hg2+ was investigated on samples OP13, PP13 and OPS13.The maximum monolayer capacity (qm) calculated from the Langmuir isotherm reachs to 113.6 mg/g for OPS13 sample. The thermodynamic parameters for Hg2+ adsorption indicated the spontaneous physical adsorption with exothermic nature.