The use of biosurfactants to remediate soils contaminated by hydrocarbons and crude oil is a new technology. For example, cascara produced by Pseudomonas aeruginosa removed a large amount of oil from the Alaskan gravel. VanDyke et al. found that from contaminated sand and mud, the rhamnolipids produced by Pseudomonas aeruginosa can increase the recovery of hydrocarbons by 25% to 70% and 40% to 80%, respectively. Similarly, treatment of sandy soils with biosurfactants produced by Pseudomonas aeruginosa resulted in 56% and 73% recoveries of aliphatic and aromatic hydrocarbons, respectively.
Anionic surfactants have excellent performance in decontamination, but they are often used in combination with nonionic surfactants to obtain better deinking effects. Anionic surfactants have good foaming properties and degreasing properties, while nonionic surfactants exhibit a non-ionic state in aqueous solution and have high stability. When the non-ionic surfactant and anionic surfactant are used together, the colloidal particles will be negatively charged, and the same charge will repel each other, forming a stable dispersion system, which is conducive to the separation and removal of ink and fiber.
The source of raw materials for alkyl glycoside surfactants has expanded from petroleum to coal, oil shale, microorganisms and industrial waste liquids.
For example, gas oil produced by coal hydrocracking or creosote produced by coal tar fractionation is an ideal raw material for the preparation of sulfonate surfactants due to its rich aromatic components; Rock oil, because it is rich in nitrogen-containing compounds, is an important raw material for cationic surfactants; biosurfactants obtained from microbial metabolism products can be used for oil displacement; lignosulfonate obtained from waste liquids of paper mills can be used Surfactants are produced by alkylation and oxidation for treatment of formations, etc.
By expanding the source of surfactant raw materials and reducing the cost of surfactants, the large demand for surfactants in oil fields can be met.
According to whether the alkyl glycoside can be ionized and the nature of the charge of the active ion after ionization, surfactants can be divided into four types: nonionic, anionic, cationic, and amphoteric. Non-ionic and anionic types are mostly used in metal degreasing cleaning agents.
In order to express the size of the hydrophilic and lipophilic abilities of a certain surfactant and the power balance between the two, the lipophilic and hydrophilic balance value H.L.B is often introduced. A small H.L.B value indicates that the surfactant has strong lipophilicity to oily dirt, and poor water solubility, which is often difficult to rinse; a large H.L.B value indicates that this type of surfactant has a strong hydrophilic ability. Good water solubility, but not conducive to the adsorption at the two-phase interface.