Abstract
This work focused on evaluating the adsorptive removal of crude oil using a nano-intermediate based on magnetite nanoparticles supported on activated carbon synthesized from spent coffee grounds and the subsequent catalytic oil decomposition to recover by-products and regenerate the support material. The magnetite nanoparticles were synthesized by the co-precipitation method and were used as active phases on prepared activated carbon. The amount of crude oil adsorbed was determined by adsorption isotherms. In addition, dynamic tests were performed on a packed bed to evaluate the efficiency of the removal process. Thermogravimetric analysis and mass spectrometry were used to evaluate the catalytic powder and the quantification of by-products. Contrasting the results with commercial carbon, the one synthesized from the coffee residue showed a greater affinity for the oil. Likewise, the adsorption capacity increased by doping activated carbon with magnetite nanoparticles, obtaining an efficiency greater than 10%. The crude oil decomposition was carried out successfully by thermal cracking, obtaining a 100% removal. The gas produced after decomposition contains light hydrocarbons such as C2H4 and CH4 and shows a decrease in polluting species such as CO and CO2, leading to greater environmental sustainability of the process.
Highlights
There is substantial water production during hydrocarbons extraction, attaining nine barrels of water per barrel of crude oil [1,2]
activated carbon modified with magnetite nanoparticles (ACM)
Where H is the inverse of adsorption affinity, K the crude oil selfassociation over the material surface, Qm is the maximum amount adsorbed, CE is the crude oil concentration at the equilibrium from the solid–liquid equilibrium (SLE) fitting, Ψ and ξ are constants, R (J mol−1 K−1 ) is the universal gas constant, and K1 −K0 are related to the 0 is the enthalpy, ∆S0 is the values of enthalpy and entropy, respectively; Further, ∆Hads ads entropy, ∆Gads is the change of the Gibbs free energy of the adsorption process
Summary
There is substantial water production during hydrocarbons extraction, attaining nine barrels of water per barrel of crude oil (water cut ≥ 0.9) [1,2]. This work focused on developing activated carbon from coffee residues—spent coffee grounds—considering the importance of reusing these resources, and their surface modification with magnetite nanoparticles, to improve their adsorptive and catalytic properties This is the first time a nano-intermediate with these characteristics has been designed to remove crude oil from O/W emulsions. This work is envisioned to open a new landscape for the fabrication of materials from agro-industrial waste, with more significant oil adsorptive capacity, and that require a lower temperature in the decomposition process by thermal cracking (pyrolysis) reactions, which implies a recovery of total activated carbon and possible use of gases (CO, H2 , CH4 )
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