لخّصلي

Analyses of various methods for removing pollutants from old lubricants showed that the acid-clay method had the highest environmental risk and the lowest cost.The acid treatment stage of the process can be carried out under atmospheric pressure to remove the acidic products, oxidized polar compounds, suspended particles, and additives in order to decrease these dangerous contaminants from this approach [31].The acid-clay method differs from others in that it is easy to use, requires little upfront investment and little ongoing maintenance [27-29].However, this approach has a number of drawbacks: it also generates a significant amount of pollutants, can't handle current multigrade oils, and is challenging to clean out asphaltic impurities [30].He used phosphoric acid, sulphuric acid, methanoic acid, and acetic acid to treat used motor oil.

Analyses of various methods for removing pollutants from old lubricants showed that the acid-clay method had the highest environmental risk and the lowest cost. Utilizing acid and clay to remediate spent oil is the approach [24,25,26].
To get rid of the smell and black color, they all utilized the clay as an adsorbent. The acid-clay method differs from others in that it is easy to use, requires little upfront investment and little ongoing maintenance [27–29].However, this approach has a number of drawbacks: it also generates a significant amount of pollutants, can't handle current multigrade oils, and is challenging to clean out asphaltic impurities [30].
The acid treatment stage of the process can be carried out under atmospheric pressure to remove the acidic products, oxidized polar compounds, suspended particles, and additives in order to decrease these dangerous contaminants from this approach [31].
According to Princewill and Sunday [32], the high recovery rate of treated lube oil from used lube oil is largely determined by the source of used lube oil, pre-treatment mechanisms, extent of contamination, and acid grade used. He also demonstrated that the amount of adsorbent (clay) used could influence the rate at which contaminants are removed and the method's recovery percentage. Worked on used motor oil in Abu-Elella [26]. He used phosphoric acid, sulphuric acid, methanoic acid, and acetic acid to treat used motor oil. He discovered that methanoic acid, sulfuric acid, and acetic acid all have significant effects on kinematic viscosity, whereas phosphoric acid is unaffected by used lube oil. As a result, he concluded that acetic acid treatment produced better results than formic acid-clay treatment.