Oily wastes are the serious environmental hazards in petroleum industry . Solvent extraction has commonly been used to remove oil from these wastes. However, the traditional solvents suffer from challenges such as difficult separation of oil and solvent, and high solvent consumption. Here, oil separation and solvent reuse were well achieved through the phase transition of ionic liquid system (D-230-FA system) between one phase and two phases, which the process procedure was simple. The ionic liquid (D-230-FA) was successfully formed by poly (propylene glycol) bis (2-aminopropyl ether) D-230 and fatty acids, which was demonstrated by 1 HNMR and FT-IR. The acid-basic switchability of the D-230-FA system was studied by pH, FT-IR. The process of separating oil based on the D-230-FA system was studied by SEM, infrared spectrophotometry test, Soxhlet extraction and molecular dynamics simulation. The results show that the D-230-FA system exhibited excellent acid-basic switchability, the extraction rate could reach 97.59 % and the residual oil rate in the solvent was less than 0.1495 %. Thus, the acid-base switchable D-230-FA system will be expected to treated as the effective extractant for sustainable separation of oily wastes.
Ning Gao,Yunbo Wang,Huixin Luo,Yingtong Xu,Jining Liu,Yingwen Chen
The accumulation of oily waste increases annually with the growth in crude oil demand. Its toxicity and high heating value present both opportunities and challenges for treatment technologies. In recent years, the emergence of hydrophobic deep eutectic solvents (HDES) has promoted advancements in low-toxicity extraction processes. Leveraging the advantages of HDES and addressing the challenges posed by real oily sawdust (with a 67.9 % oil content), this study presents a novel green HDES solvent composed of ethyl maltol and fatty acids, accompanied by a corresponding extraction process. At a low temperature of 60 °C, the process achieved impressive results: an oil extraction efficiency close to 86.3 %, a dehydration rate exceeding 92.2 %, and a heavy metal removal rate ranging from 15 % to 75 %. In the exploration of solvents recycling, pH-switching facilitated the deprotonation and protonation of phenol-fatty acid HDES, promoting effective recovery of the oil phase. Even after 5 cycles, the oil extraction rate could still be maintained above 75 %. It is worth noting that the regenerated HDES exhibited greater selectivity for extracting light oil after multiple uses. The total ratio of saturated and aromatic hydrocarbons reached approximately 81.7 %, significantly enhancing the value of the recovered oil. Integrating systematic characterization with the extraction performance, as well as the variation in recovered oil phase components, highlighted the multifaceted effects of introducing ethyl maltol. Specifically, this effect is demonstrated in its ability to enhance the oil phase’s solubility by regulating the intermolecular spacing of HDES, and to impede the dissolution of heavy oil into its gaps by optimizing the local zone through the formation of complexes with HDES and heavy metals.
Oily wastes are easily generated in many processes of exploitation, solvent extraction is the common method for treating the oily waste. However, traditional solvent extractions are difficult to recycle the solvent, and oil is difficult to separated. As a low-volatility solvent, ionic liquid is simple in synthesis, low in cost, so it has good application prospect. In this work, the sustainable separation of oil from oily waste was implemented by using CO 2 -switchable ionic liquids. On the basis of solvent extraction, ionic liquids can reduced losses and costs. The CO 2 -switchable ionic liquids were prepared by poly (propylene glycol) bis(2-aminopropyl ether) D-230 and fatty acids with low volatility at the mole ratio of 1:2. Upon the alternate bubbling CO 2 and N 2, ionic liquids could be transformed alternately from water-miscible state to water-immiscible state. The water-immiscible state was bi-phasic system containing hydrophobic fatty acids and ammonium bicarbonate solution by bubbling CO 2 . Based on the bi-phasic system, the oil (kerosene, paraffin oil and crude oil) could be mixed with fatty acids, and were separated from fatty acids in the hydrophilic state upon N 2 , where the recovery rate of oil was more than 97% and fatty acids was not residual in recovered oil. Treating oily waste, the oil could be extracted from oily waste by the bi-phasic system. The ionic liquids were reused and the oil was separated by bubbling N 2 without extra additives, where the recovery rate of oil from oily waste was more than 85.57%. Due to the simplified process and negligible solvent loss, the economic benefit of recovering per barrel crude oil reached 76.7% of the price of crude oil. Compared with the existing technology , this sustainable separation is simpler, more economical and more environmentally friendly. Hence, it is expected that this sustainable separation based on CO 2 -switchable ionic liquids will meet the development of green separation with low-energy consumption.
危险品化学品经营许可证（带存储）