Co-pyrolysis Oily Sludge And Biomass Waste To Prepare Activated Carbon

Oily sludge is one of solid wastes generated from petroleum industry and a large amount of oily sludge is accumulated in the world every year.Biomass waste also increases every year.At present,there are limited studies on the preparation of activated carbon from the mixture of industrial waste and agricultural waste.In addition,the organic matter adsorption mechanism of activated carbon needs further research.In this paper,three typical biomass waste,including walnut shell,coconut shell and cottonwood sawdust was mixed with oily sludge respectively to prepare activated carbon.Co-pyrolysis characteristics of oily sludge and biomass were studied and activated carbon from the mixture was prepared.The adsorption capacity of phenol and sulfamethoxazole?SMZ?on activated carbon was researched.The work provided a new idea for the utilization of waste resources and for the preparation of high quality activated carbon from the mixture of industrial waste and biomass materials.The major results are presented as following:?1?The analysis of pyrolysis characteristics of oily sludge and walnut shell showed that alkali metals such as K in biomass promoted the conversion of light components to heavy components in oily sludge,so that more carbon in oily sludge was fixed.The pyrolysis rate increased due to the char produced from walnut shell,which was a catalyst for the decomposition of oily sludge.The products of oily sludge from fast pyrolysis were mainly hydrocarbons?97%?.However,products of walnut shell from fast pyrolysis were mainly oxygen-containing organic matters and hydrocarbons were only about 4.1%.The products of the mixture of oily sludge and walnut shell from fast pyrolysis contained 86.7%hydrocarbons and in which aromatic hydrocarbons were32.9%.The content of esters,aldehydes,ketones,furans,halogenated hydrocarbons and heterocyclic compounds were 0%.The oxygen-containing organic matters in walnut shell converted to aliphatic hydrocarbon and aromatic hydrocarbons by condensation,deoxidation and condensation reactions because of the catalytic effect from oily sludge ash.Macromolecular hydrocarbons in oily sludge were decomposed under catalyze cracking and gasification effect from alkali-metal elements such as K in walnut shell;?2?Using K₂CO₃ as activator to prepare the mixture of oily sludge and biomass based activated carbon by one-step activation and two-step activation method.The results showed that:the yield and the specific surface area of the activated carbon prepared by one-step activation were higher.Texture morphology of the mixute-based activated carbon was more similar to that of biomass-based activated carbon.The mesropore porosity of the mixture-based activated carbon was almost 2 times of that of biomass-based activated carbon and the specific surface area was almost 10 times of that of oily sludge-based activated carbon.The pore diameter distribution was from 0.5-5 nm.Among the mixture-based activated carbon,the activated carbon prepared from oily sludge and walnut shell by one-step activation had the largest specific surface area?1342 m²/g?,which was more than twice of that by two-step activation method.More content of C-O and lower C=O functional groups in the mixture-based activated carbon;?3?The research on the adsorption capacity of activated carbon on phenol and SMZ showed that:phenol adsorption capacity was mainly influenced by microporous prosity and effective pore diameter was 0.9-2.2 nm;SMZ adsorption of activated carbon was influenced by micropore and mesopore and effective pore diameter was 1.5-3 nm.The adsorption capacity of SMZ was better than that of phenol.Among the mixture-based activated carbon,the activated carbon prepared from the mixture of coconut shell and oily sludge by one-step activation had the highest adsorption capacity of phenol,which was 200.6 mg/g.The activated carbon prepared from the mixture of walnut shell and oily sludge by one-step activation had the highest adsorption capacity of SMZ,which was 361.9 mg/g.The adsorption was controlled by chemical adsorption maily and the adsorption rate was related to both of film diffusion and intraparticle diffusion.The specific surface area and electron acceptor-donor interaction played major roles in the adsorption mechanism and?-?electron coupling and solvent effects made a little difference.