Preparation And Application Of Efficient Carbon-Based Adsorbing Material Using Asphaltenes From Unconventional Petroleum

The asphaltenes,a complex mixture,has a lower value because of the utilization difficulty of asphaltene and the negative effects on heavy oil separation process.In this work,the asphaltenes from natural Indonesia asphalt rocks were taken as raw materials for the utilization through pyrolysis.And the efficient carbon-based adsorption material derived from residue by potassium hydroxide was used for adsorbing methylene blue.The Indonesian asphaltenes was converted to gaseous product(36.02%),pyrolytic tar(26.57%)and residual char(37.44%).The gaseous product is mainly composed of methane and hydrogen gas while liquid decomposition product has complex component.The adsorptive properties of product,including the specific surface area and the adsorbing content of MB,were influenced by the quantity of alkali and activation tem-perature.The optimal product could be obtained at the activation temperature of 800℃,with KOH/char ratio at 3:1.This porous carbon material possesses abundant micropores(<2.0nm).The activation experiments were conducted in batch mode to test the influ-ence of the quantity of alkali and reaction temperature on the adsorptive property of product with high surface area(1735 m~2/g).The porous carbon material was suited to the adsorption separation process because of micro-mesoporous structure.Results also show that almost all of the nitrogen atoms stay in the carbon solid during heating with-out releasing to the gas or liquid products and there are abundant heteroatomic groups,including S=O,—OH,—N=,on the activated carbon surface.The adsorption isotherm results of methylene blue on obtained carbon-based ad-sorption material accords with the Langmuir isotherm equation,which suggested that the adsorption was homogeneous.It is also observed that the maximal adsorption ca-pacity was determined to be 556.00 mg/g.The microporous of the adsorbent contrib-uted to fast adsorption equilibrium while the adsorption amount approximately equals to calculative maximal adsorption capacity at high initial concentrations.The actual adsorption kinetics results matching with pseudo-second-order kinetic model and the rate-determining step may be chemical sorption.These results indicated that activated carbon using Indonesia asphaltenes as raw materials has excellent effect for removing methylene blue.Through this study,a recycling technology was obtained by the pyrolysis process for the utilization of oil sand asphaltenes and the preparation process for efficient ad-sorbent materials.This search makes a preliminary exploration of preparing carbon-based materials by asphaltenes.Also,it provides the basic data and a new idea for the subsequent utilization of unconventional petroleum resources.