Magnetic Hyperbranched Molecular Materials for Treatment of Oily Sewage Containing Polymer in Oilfield Compound Flooding

Abstract

With the continuous improvement in oilfield development and the application of tertiary oil recovery technology, the water content of oilfield-produced fluids has gradually increased, and a large number of oilfield sewage with complex components has also been produced after oil–water separation, and effective treatment is urgently needed. ASP flooding sewage contains alkali, various surfactants, polymers, microemulsion oil droplets, and solid impurities, which are difficult to be effectively treated by traditional water treatment agents and methods. In this study, aminopropyl triethoxysilane (APTES) was used to modify the nano-Fe3O4 coated with tetraethyl silicate (TEOS). The product was used as the ferromagnetic nano-core for the iterative reaction of Michael addition and ester amidation to synthesize a magnetic hyperbranched polyamide amine, and its performance in the treatment of ASP flooding wastewater was evaluated experimentally. For the preparation of APTES-modified Fe3O4@SiO2 (FOSN) product, TEOS was coated over Fe3O4 in an ethanol aqueous solution environment and then APTES was added dropwise. The first-generation branched product (1-FSMN) was obtained by the reaction of FOSN and methyl acrylate graft product (FOSN-M) with ethylenediamine, and the highest yield was 93.7%. The highest yield of the second-generation branched product (2-FSMN) was 91.6%. In this study, a composite flooding wastewater sample from a block in the Bohai oilfield was taken. The suspended solids content was 143 mg/L, the oil content was 921.09 mg/L, the turbidity was 135 NTU, and the zeta potential was −47 mV. The third-generation hyperbranched polymer (3-FSMN) and its quaternary ammonium salt (3-FSMN-Q) performed best in the appropriate dosage range, with the highest oil removal rate of 97%, suspended solid removal rate of 90.3%, turbidity reduction rate of 86.6% and zeta potential reduction rate of 88%. For 3-FSMN and its quaternary ammonium salt, the gravity/magnetic PAC compound treatment experiment was carried out. In the settlement time of only 5 min, 3-FSMN/PAC and 3-FSMN-Q/PAC can achieve the maximum oil removal rate of 87.1% and suspended solids removal rate of 87.3% for polymer containing wastewater from ASP flooding, and 86.3 and 86.0% for 120 mg/L. Its treatment capacity was much better than that of common treatment agent combination (CPAM/PAC).

Synthesis and Application of Ion-Exchange Magnetic Microspheres for Deep Removal of Trace Acetic Acid from DMAC Waste Liquid

“…Firstly, super-paramagnetic Fe 3 O 4 was coated with a silica layer using a sol-gel method, resulting in excellent stability and easy surface modification of iron oxide due to the hydrophilic properties of the silica shell. Secondly, TEOS was selected as the coupling agent, and N-[3-(Trimethoxysilyl)propyl]-N,N,N-trimethylammonium chloride as a functional monomer, a layer of quaternary ammonium (QA) was modified on the surface of Fe 3 O 4 @SiO 2 through a condensation hydrolysis reaction, to form the resulting Fe 3 O 4 @SiO 2 @N(CH 3 ) 3 + [ 21 ]. Thirdly, the –N(CH 3 ) 3 + groups of the nanocomposite were freely exposed to the surrounding solution and interacted with the specific targets, such as acetic acid or other ions in solution, via ion exchange [ 22 ] (bottom of the figure).…”

Preparation and Application of Magnetic Composites Using Controllable Assembly for Use in Water Treatment: A Review

“…In the treatment of oily wastewater, the effectiveness of the process is influenced by factors such as the van der Waals forces, oil viscosity, pore shape, and hydrophobic interactions between the oil and the adsorbent. Magnetic composites have proven to be effective in treating oily wastewater due to their high active sites, terminal functional groups, high interfacial activity, controllable viscosity, and strong ferromagnetism [103,104].…”

Branched Polymers: Synthesis and Application

“…Fu's group prepared magnetic hyperbranched polyamide amines with different branching degrees, amino contents, and their corresponding hyperbranched molecular terminal quaternary ammonium salts by grafting polymer chains on the magnetic Fe 3 O 4 nanoparticle surface; these hybrids were employed in wastewater treatment. 93 The hyperbranched polyamide amines could diffuse in oil droplets and agglomerate emulsified oil droplets into large droplets, which afforded convenient oil separation with the help of an external magnetic field. It was found that with the same concentration of the hyperbranched polymer surfactant, the higher the branching degree of the hyperbranched polyamide amines and the more amino content, the better the oil removal and flocculation.…”

“…The application of branched polymers in biomedicine has been summarized previously, , and we will not further discuss it here. In the following, we mainly introduce the applications of branched polymers in solid polymer electrolytes for Li batteries, ,− coatings and membranes, − surfactants, − and hydrogels. − …”

“…In this Perspective, we discuss some of their general synthesis methods based on the structural classification of branched polymers and stimulate the valid synthesis of well-defined branched polymers. Furthermore, we summarize several potential applications of branched polymers on solid polymer electrolytes for Li batteries, ,− coatings and membranes, − surfactants, − and hydrogels − based on their intrinsic characteristics, such as good solubility, low viscosity, and high fraction of terminals. Finally, we also speculate about possible directions for the synthesis and application of branched polymers.…”