Effect of Ethylene Oxide Group in the Anionic–Nonionic Mixed Surfactant System on Microemulsion Phase Behavior

Empirical Relationship among the Parameters in HLD Equation of Block Polyether Water Clarifier

In this work, the empirical relationship among three apparent parameters in the hydrophilic-lipophilic deviation (HLD) equation was studied to provide help in using the HLD equation to design a block polyether water clarifier for treating produced water in an oilfield. Ten block polyethers (including six linear polyethers and four branched polyethers) were prepared, and their HLD equations were measured. By curve fitting, the empirical relationship among apparent hydrophobicity characteristic (K), apparent characteristic curvature (Cc n ), and apparent temperature coefficient (c t) of block polyether were obtained: K = 9.32c t, Cc n = 18e-24.5K (for linear polyether), and Cc n = 3.7e-20.8K (for branched polyether). By introducing these relationships into the HLD equation and combining an empirical relationship between propylene oxide/ethylene oxide (mole ratio) in a block polyether and K/Ccn, a new block polyether was designed to treat the produced water. The treatment result confirmed the reliability of these empirical relationships. The results expand the practical application of HLD theory and are useful for the development of a block polyether water clarifier.

Field demonstration of in-situ microemulsion flushing for enhanced remediation of multiple chlorinated solvents contaminated aquifer

The remediation of in-situ microemulsion flushing for multiple chlorinated solvents contaminated groundwater is challenging, because different chlorinated solvent has major influence on microemulsion formation and solubilization behaviors. This work was conducted to evaluate the remediation effectiveness for various chlorinated solvents contaminated site and monitor the disturbance of groundwater during in-situ microemulsion flushing process. Groundwater at this site was contaminated with chlorobenzene (MCB), chloroaniline and nitrochlorobenzene. The medium layer was mainly composed of fine and silty sand, with average hydraulic conductivity of 4.97 m/d. Results of this field-scale test indicated in-situ microemulsion flushing successfully enhanced the apparent solubility of various chlorinated solvents. Post-flushing concentration of various chlorinated solvents were 1.33-71.6-fold the concentration of pre-flushing values at 10 sampling locations within the test zone. This field was flushed with 16.8 m3 microemulsion, removing approximately 18.49 kg chlorinated solvents. Besides, a trend in the desorption order of various chlorinated solvents was observed. The least hydrophobic pollutant was flushed first, followed by contaminants of increasing hydrophobicity. In addition, during remediation process, the indexes of groundwater fluctuated insignificantly, indicating the reagent had little disturbance to aquifer. This field work demonstrated the feasibility of in-situ microemulsion enhanced remediation via increasing apparent solubility of multiple chlorinated solvents.