Addition Of Hydrolyzed Polyacrylamide Research Articles

Effect of partially hydrolyzed polyacrylamide (HPAM) on the bacterial communities of wetland rhizosphere soils and their efficiency in HPAM and alkane degradation.

The effect of partially hydrolyzed polyacrylamide (HPAM) on structure and function of rhizosphere soil bacterial communities in constructed wetlands has been largely underinvestigated. In this study, we compare the effect of 250, 500, and 1000mg/L of HPAM on bacterial community composition of Phragmites australis associated rhizosphere soils in an experimental wetland using MiSeq amplicon sequencing. Rhizosphere soils from the HPAM-free and the 500-mg/L-exposed treatments were used for laboratory experiments to further investigate the effect of HPAM on the soil's degradation and respiration activities. Soils treated with HPAM showed differences in bacterial communities with the dominance of Proteobacteria and the enrichment of potential hydrocarbon and HPAM-degrading bacteria. CO2 generation was higher in the HPAM-free soils than in the HPAM pre-exposed soil, with a noticeable increase in both soils when oil was added. The addition of HPAM at different concentrations had a more pronounced effect on CO2 evolution in the HPAM-pre-exposed soil. Soils were able to degrade between 37 ± 18.0 and 66 ± 6.7% of C10 to C30 alkanes after 28days, except in the case of HPAM-pre-exposed soil treated with 500mg/L where degradation reached 92 ± 4.3%. Both soils reduced HPAM concentration by 60 ± 15% of the initial amount in the 500mg/L treatment, but by only ≤ 21 ± 7% in the 250-mg/L and 1000-mg/L treatments. In conclusion, the rhizosphere soils demonstrated the ability to adapt and retain their ability to degrade hydrocarbon in the presence of HPAM.

Dilational Rheological Properties of Surfactants at the Crude Oil-Water Interface: The Effect of Branch-Preformed Particle Gels and Polymers.

The interfacial properties of a heterogeneous composite flooding system containing a surfactant fatty alcohol polyoxyethylene carboxylate (C12EO3C), branched-preformed particle gel (B-PPG), and polymer partly hydrolyzed polyacrylamide (HPAM) at the crude oil–water interface were investigated by a dilational rheology method. The results demonstrated that the C12EO3C molecules can form an elastic interfacial film with certain strength at the crude oil–water interface. The addition of HPAM to the C12EO3C solution has a detrimental effect on the interfacial film formed by C12EO3C molecules, leading to a decrease in the dilational modulus and an increase in the phase angle. Moreover, the addition of B-PPG to the C12EO3C solution also disrupts the stability and strength of the interfacial film of C12EO3C. In particular, linear HPAM with a lower steric hindrance is more likely to insert into the interfacial film of C12EO3C; thus, HPAM possesses a stronger destruction ability for the interfacial film of C12EO3C than B-PPG. When HPAM is compounded with B-PPG, a superimposed effect exists to cause more severe disruption for the interfacial film. The heterogeneous composite flooding system not only enhances oil recovery by increasing the viscosity of the bulk phase but also weakens the interfacial film to facilitate the post-treatment of the recovered crude oil. Thus, the heterogeneous composite flooding system exhibits promising prospects in practical application.

New insights into the interaction between asphaltene and hydrolyzed polyacrylamide at the oil-water interface based on emulsion stability

Asphaltene and hydrolyzed polyacrylamide (HPAM) are important components for stabilizing polymer-containing oil water/sludge in oilfield. In this study, the effects of asphaltenes concentration, HPAM concentration, pH, oil/water ratio and salinity on the storage stability and shear rheology of the emulsions were investigated. The results showed that the addition of HPAM could change the emulsion type from W/O to O/W, and the shear modulus of the emulsions stabilized by HPAM and asphaltenes were 10 times lower than that of asphaltenes emulsions. As the pH increased from 4 to 11, the emulsion type changed from W/O to O/W and the shear modulus of the emulsion decreased by 2 orders of magnitude. The addition of inorganic salts destroyed the asphaltene interfacial film and reduced the stability of the emulsion. The interaction of amide and carboxylic acid groups in HPAM molecules with asphaltenes was investigated through interfacial properties. The carboxylic groups and amide groups of HPAM molecules could interact with the interfacial active components of asphaltenes and formed a carboxyl-asphaltene-amide complex unit, which made the asphaltene molecules “anchorage” on the HPAM molecular chain. This study is intended to provide a theoretical basis for the efficient and environmentally friendly treatment of polymer-containing oil water/sludge in oilfield.

Dynamic interfacial tensions of sulfobetaine and polymers solutions: Effect of structures

To facilitate the understanding of the intrinsic mechanism responsible for the IFTs of betaine solutions, partly hydrolyzed polyacrylamide (HPAM) and hydrophobically modified polyacrylamide (HMPAM) were employed to investigate their effect on IFTs of different betaine solutions against decane using a spinning drop interfacial tensiometer. Moreover, the effects of oleic acid on the IFTs of betaine-polymer systems were also studied. The results show that the water-soluble polymers (HPAM) form the mixed adsorption film with alkyl sulfobetaine (ASB) molecules and prevent the hydrophilic groups of ASB from lying flat, which produces a minimum IFT with aging time. Besides, the hydrophobic HMPAM forms mixed micelle-like interfacial associations with ASB molecules, which results in a stronger disruption tendency for the interfacial film. The branched xylyl substituted alkyl sulfobetaine (BSB) molecules will form a tight interfacial film, therefore HPAM can’t insert into the interfacial film easily. Meanwhile, steric hindrance makes it difficult to form interfacial aggregates with HMPAM. Thus, the addition of HPAM and HMPAM polymers has little influence on the IFTs in the BSB system. The mixed adsorption of oleic acid and betaine molecules results in a significant decrease in IFTs, especially for BSB. However, in the ASB-polymer system, HPAM forms mixed adsorption film with ASB molecules and hinders the adsorption of oleic acid, accordingly IFTs change little. In contrast, the hydrophobic interaction of HMPAM promotes the adsorption of oleic acid, so the synergistic effect reduces IFTs to some extent. In the BSB-polymer system, the strong synergistic effect between oleic acid and BSB molecules is disrupted by polymers, which results in a significant increase in IFTs. The relevant results are helpful for the design of novel and efficient chemical flooding systems.

Synergetic effect of asphaltenes extracted from polymer containing oil sludge and HPAM at water/toluene interface

The interaction between asphaltenes and hydrolyzed polyacrylamide (HPAM) at the oil-water interface is the key factor leading to the stability of polymer-containing wastewater/oil sludge in the oilfield. In this study, the asphaltenes extracted from polymer-containing oil sludge were systematically characterized and the interaction between asphaltenes and HPAM at the toluene/water interface was studied. We found that asphaltenes had a moderately aromatic structure and a large number of fatty chains. There was a strong π-π stacking interaction among asphaltenes molecules. Asphaltenes and HPAM could reduce the interfacial tension of oil/water, increase the interfacial dilatational modulus, and enhance the stability of emulsion synergistically. Both the asphaltenes concentration and the HPAM concentration affected the interfacial stability. With the changes of the two components concentrations, there was a synergistic or competitive effect between asphaltenes and HPAM at the toluene/water interface. At low concentrations of asphaltenes (Casphaltenes = 100 ppm) the addition of HPAM (CHPAM = 300 ppm) reduced the interfacial tension by 0.52 ± 0.17 mN/m, improved the dilatational modulus by 7.75 ± 0.4 mN/m (the growth rate was 57.33%), asphaltenes molecules and HPAM molecules co-adsorbed on toluene/water interface. For the high concentration of asphaltenes (Casphaltenes = 500 ppm), the addition of HPAM (CHPAM = 300 ppm) rarely reduced the interfacial tension, a few increased the dilatational modulus by 0.69 ± 0.15 mN/m, asphaltenes molecules competed with HPAM molecules to adsorb on toluene/water interface. The presence of HPAM in the aqueous phase changed the emulsion from water-in-oil type (W/O) to oil-in-water type (O/W). The increase of asphaltenes and HPAM concentration is beneficial to the increase of emulsion interfacial film strength (the addition of HPAM increased the yield stress of emulsion interfacial film by 22 times) and the enhancement of emulsion storage stability of 100% maximum. These results provided a theoretical foundation for treating polymer-containing oil sludge in oil fields.

Impacts of partially hydrolyzed polyacrylamide (HPAM) on microbial mats from a constructed wetland treating oilfield produced water

Constructed wetlands have been successfully used in the treatment of produced water brought to the surface in large quantities during oil extraction activities. However, with the increasing use of partially hydrolyzed polyacrylamide (HPAM) in enhancing oil recovery, the impacts of HPAM on the biological processes of wetlands is still unknown. Microbial mats in wetlands play a key role in hydrocarbon degradation. Here, we compared the bacterial communities of four wetland microbial mats after flooding with different concentrations of HPAM. Two mats (i.e. the HPAM-free and the 500 ppm HPAM pre-exposed mats) were selected to further investigate the effect of HPAM on respiration and biodegradation activities. The field mats exhibited clear differences in their bacterial community structure, where Cyanobacteria and Alphaproteobacteria became dominant in the presence of HPAM. In the laboratory experiments, the generated CO2 by the HPAM-free and the 500 ppm HPAM pre-exposed mats did not vary significantly when HPAM was added, although CO2 values were slightly higher in the presence of oil. Both mats were still able to degrade between 15 ± 14.4 to 50 ± 13.0% of C10 to C30 alkanes in 28 days, and this degradation was not affected by HPAM addition. The HPAM concentration decreased by 22–34% of the initial amount after 28 days of incubation in the HPAM-free mat, versus only 7–18.4% decrease in the 500 ppm HPAM pre-exposed mat. We conclude that the wetland microbial mats seem to have become well adapted to HPAM and could maintain their respiration and hydrocarbon degradation activities.

Polymer-assisted modification of metal-organic framework MIL-96 (Al): influence of HPAM concentration on particle size, crystal morphology and removal of harmful environmental pollutant PFOA

A new synthesis method was developed to prepare an aluminum-based metal organic framework (MIL-96) with a larger particle size and different crystal habits. A low cost and water-soluble polymer, hydrolyzed polyacrylamide (HPAM), was added in varying quantities into the synthesis reaction to achieve >200% particle size enlargement with controlled crystal morphology. The modified adsorbent, MIL-96-RHPAM2, was systematically characterized by SEM, XRD, FTIR, BET and TGA-MS. Using activated carbon (AC) as a reference adsorbent, the effectiveness of MIL-96-RHPAM2 for perfluorooctanoic acid (PFOA) removal from water was examined. The study confirms stable morphology of hydrated MIL-96-RHPAM2 particles as well as a superior PFOA adsorption capacity (340 mg/g) despite its lower surface area, relative to standard MIL-96. MIL-96-RHPAM2 suffers from slow adsorption kinetics as the modification significantly blocks pore access. The strong adsorption of PFOA by MIL-96-RHPAM2 was associated with the formation of electrostatic bonds between the anionic carboxylate of PFOA and the amine functionality present in the HPAM backbone. Thus, the strongly held PFOA molecules in the pores of MIL-96-RHPAM2 were not easily desorbed even after eluted with a high ionic strength solvent (500 mM NaCl). Nevertheless, this simple HPAM addition strategy can still chart promising pathways to impart judicious control over adsorbent particle size and crystal shapes while the introduction of amine functionality onto the surface chemistry is simultaneously useful for enhanced PFOA removal from contaminated aqueous systems.

Removal of sodium oleate from synthetic manganese leaching solution by coagulation-dissolved air flotation

The coagulation-dissolved air flotation for removal of sodium oleate (NaOL) from synthetic manganese leaching solution was focused in this study. It indicates that partially hydrolyzed polyacrylamide (HPAM), NaOL dosage and pH have a multiple effect on the removal efficiency of NaOL. The results represents a significant removal efficiency of 97.6% NaOL was achieved under the optimal conditions of coagulation-dissolved air flotation by dosage of 20 mg/L HPAM and 30 mg/L NaOL, pH 8.0. Solution pH has a significant effect on the distribution of oleate species and Mn2+ species. The addition of HPAM facilitates the formation of OL− micelle and the decrease of critical micelle concentration (CMC). Oleate species primarily exist, containing Mn(OL)2(s), OL− and HOL(aq). HPAM could cause the Zeta potential of NaOL to shift negatively. HPAM could decrease CMC of NaOL and lead to a transition from three dimensional network structure to lamellar structure. NaOL can be removed by coagulation-dissolved air flotation through the adsorption and bridge effect of HPAM chains on the floating bubble surface.

Heavy oil recovery by surface modified silica nanoparticle/HPAM nanofluids

Recent studies showed that the presence of dispersed nanoparticles (NPs) can increase the efficiency of polymer flooding. The network structure of polymer/NP hybrid dispersion has a significant impact on oil recovery. In this work, the surface of SiO2 NPs was modified by chemical grafting of octyltriethoxysilane (SiO2-OTES), oleic acid (SiO2-OAA) and stearic acid (SiO2-SAA) in an attempt to stimulate higher degree of interaction with partially hydrolyzed polyacrylamide (HPAM). Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) spectroscopy were employed to characterize the modified silica NPs. In addition, ζ-potential, cryo-scanning electron microscopy (cryo-SEM), and linear and nonlinear rheology were used to evaluate the characteristics of the hybrid dispersion of HPAM/unmodified and modified SiO2 NPs. ζ-potential measurements showed that the addition of HPAM improved the colloidal stability of the modified and unmodified SiO2 NPs dispersed in deionized (DI) water. Moreover, the addition of HPAM reduced the size of the NP aggregates by effective steric repulsion. Small and large shear oscillatory deformation results showed that SiO2-OTES NPs improved the HPAM network significantly. Nevertheless, HPAM/NPs network formed with all the different SiO2 NPs severely decreased the intra-cycle shear-thickening behavior of the polymer. Lastly, the addition of 0.2 wt% SiO2-OTES NPs to the HPAM solution increased the ultimate oil recovery from 71.4% to 75.7% OOIP.

Adsorption behavior of hydroxypropyl guar gum onto montmorillonite and reducing adsorption in the reservoir

Hydroxypropyl guar gum (HPG) is a kind of thickener commonly used in the field of oilfield chemistry. The adsorption behavior of HPG onto Montmorillonite (Mt) was investigated in this article. The maximum adsorption amount of HPG on Mt. was 3.6 mg/g at the HPG concentration of 2 g/L. The effect of pH, temperature, salts, alcohols and hydrolyzed polyacrylamide (HPAM) on adsorption behavior was revealed. The results showed that adsorption capacity increased with pH ranging from 3 to 13. The adsorption capacity was slightly influenced at temperature from 20 °C to 60 °C. The adsorption amount decreased at the presence of NaCl, KCl, CaCl2 or MgCl2, while it increased with addition of Na2SO4 or Na3PO4. The adsorption capacity was found no change at the presence of monobasic alcohol, while it significantly increased with the increasing concentration of polybasic alcohol. The adsorption density reduced with the addition of HPAM. Scanning electron microscope (SEM) and X-ray Diffraction (XRD) confirmed that adsorption behavior occurred on the exterior surface of Mt. Besides, the adsorption was attributed to Van der Waals' forces and electrostatic interaction. The Fourier Transform infrared spectroscopy (FTIR) showed that adsorption behavior occurred on Mt. surface via physisorption rather than chemisorption. The adsorption behavior of HPG on Mt. surface obeyed the Langmuir adsorption isotherm which showed that the adsorption was monolayer adsorption. The adsorption mechanism would be characterized as exterior surface adsorption, physical adsorption and monolayer adsorption.

Effect of partially hydrolyzed polyacrylamide on the solution and foam properties of sodium alcohol ether sulfate

The solution and foam properties of systems composed of sodium alcohol ether sulfate (AES) and partially hydrolyzed polyacrylamide (HPAM) at different concentrations were investigated. The addition of HPAM could increase the surface tension of AES solutions caused by the decrease of surfactant adsorption density at the air-water surface. The viscosity of the AES/HPAM systems were determined by the HPAM concentration. With the increase in AES concentration, the foam generation time and bubble size first decreased and then reached a plateau, while the initial liquid volume of the foam increased first and then reached a plateau. The inflection occurred at an AES concentration of 0.1 wt%, which is higher than the critical micelle concentration (CMC). This is because the air-water surface area increased dramatically during foam generation, which makes surfactant surface density unsaturated at the CMC. Only a higher surfactant concentration could maintain the saturation of surface adsorption density. The addition of HPAM could improve the foamability and enlarge the bubble size at low AES concentrations, because the increased bulk viscosity and the hydrogen bonds between AES molecules and HPAM chains stabilized bubble films and reduced the breakdown of large bubbles. The increase of HPAM concentration would always improve the liquid-carrying capacity and decrease the drainage rate of the foam. These findings indicate that it is possible to use low concentrations of foaming agents and improve foam properties by adding water-soluble polymer in field applications.

Effect of partially hydrolyzed polyacrylamide on emulsification stability of wastewater produced from polymer flooding

Abstract In this work, the effect of partially hydrolyzed polyacrylamide (HPAM) on the oil–water interfacial properties of produced water from polymer flooding (PWPF) was investigated. In addition, this study investigated the effects of three fiocculants (polyaluminium chloride PAC, cationic polymer FO4800SH, and nonionic polymer 402) on the stability of PWPF. The experimental results demonstrate that the addition of HPAM enhances the emulsion stability by increasing viscosity, zeta potential, interfacial tension and interfacial dilational viscoelasticity. The molecular weight and hydrolysis degree of HPAM have no significant influences on these properties. The stability of PWPF can be enhanced by increasing HPAM concentration. Dependency of frequency and concentration was observed for the interfacial dilational viscoelasticity. With the addition of HPAM, the dilational viscoelasticity not only increases with HPAM concentration but runs through a maximum at a concentration of 300 mg/L. As the oscillating frequency increases, the dilational modulus and dilational elasticity increase but the dilational viscosity decreases. The three flocculants can reduce the stability of the emulsion by considerably decreasing the absolute value of zeta potential of oil droplets. FO4800SH has a greater ability than PAC and 402 to separate oil from the emulsion. But the demulsification efficiencies of the three flocculants are not satisfactory because of the presence of HPAM residue. Further research is needed to find more efficient methods to achieve excellent performance of oil–water separation towards PWPF.

Effect of laponite particles on the emulsion stability of produced water from polymer flooding

In many oilfields, produced water from polymer flooding was more difficult to be treated than produced water from water flooding. The results of simulated experiment showed that the partly hydrolyzed polyacrylamide (HPAM) was present in the produced water, which stabilized the oil droplets in produced water. The addition of HPAM decreased oil–water interfacial tension and increased the viscosity of produced water, the emulsion stability was enhanced when the concentration of HPAM was below 500 mg/L. As the concentration of HPAM was high enough, the flocculating ability of the HPAM caused small oil droplets to coalesce into bigger ones. The addition of laponite particles to simulated polymer flooding water caused the zeta potential and interfacial tension of oil droplets to decrease rapidly, and the formation of stable oil–mineral aggregates (OMA) structures was observed when the concentration of laponite particles was below 150 mg/L. When the concentration of laponite particles was further increased, the zeta potential of oil droplets remained stable, the oil–water interfacial tension increased slightly, and large oil–mineral aggregates formed. These results caused the produced water to become unstable. The concentration of laponite particles determined the emulsion stability of the produced water. It was found that the synergetic effects of the laponite particles and the HPAM enhanced the emulsion stability of the produced water from polymer flooding. The electrostatic repulsion and steric stabilization effect are the main stabilization mechanisms in the polymer flooding water. • Laponite particles were used as model solid particles of natural clays. • Laponite particles significantly affect the emulsion stability. • Synergy of polymer and laponite particles enhance the emulsionstability. • Electrostatic repulsion and steric stabilization are the main mechanisms.

Micro-constituants, oligoéléments et peptides bioactifs : leurs effets en pathologie cardio-métabolique

In many oilfields, produced water from polymer flooding was more difficult to be treated than produced water from water flooding. The results of simulated experiment showed that the partly hydrolyzed polyacrylamide (HPAM) was present in the produced water, which stabilized the oil droplets in produced water. The addition of HPAM decreased oil–water interfacial tension and increased the viscosity of produced water, the emulsion stability was enhanced when the concentration of HPAM was below 500 mg/L. As the concentration of HPAM was high enough, the flocculating ability of the HPAM caused small oil droplets to coalesce into bigger ones. The addition of laponite particles to simulated polymer flooding water caused the zeta potential and interfacial tension of oil droplets to decrease rapidly, and the formation of stable oil–mineral aggregates (OMA) structures was observed when the concentration of laponite particles was below 150 mg/L. When the concentration of laponite particles was further increased, the zeta potential of oil droplets remained stable, the oil–water interfacial tension increased slightly, and large oil–mineral aggregates formed. These results caused the produced water to become unstable. The concentration of laponite particles determined the emulsion stability of the produced water. It was found that the synergetic effects of the laponite particles and the HPAM enhanced the emulsion stability of the produced water from polymer flooding. The electrostatic repulsion and steric stabilization effect are the main stabilization mechanisms in the polymer flooding water.

Adhesion of Single Polyelectrolyte Molecules on Silica, Mica, and Bitumen Surfaces

In a recent study (Energy Fuels 2005, 19, 936), a partially hydrolyzed polyacrylamide (HPAM) was used as a process aid to recover bitumen from oil sand ores. It was found that HPAM addition at the bitumen extraction step not only improved bitumen recovery but also enhanced fine solids settling in the tailings stream. To understand the role of HPAM, single-molecule force spectroscopy was employed for the first time to measure the desorption/adhesion forces of single HPAM molecules on silica, mica, and bitumen surfaces using an atomic force microscope (AFM). Silicon wafers with an oxidized surface layer and newly cleaved mica were used, respectively, to represent sand grains and clays in oil sands. The force measurements were carried out in deionized water and in commercial plant process water under equilibrium conditions. The desorption/adhesion forces of HPAM obtained on mica, silica, and bitumen surfaces were approximately 200, 40, and 80 pN in deionized water and approximately 100, 50, and 40 pN in the plant process water, respectively. The measured adhesion forces together with the zeta potential values of these surfaces indicate that the polymer would preferentially adsorb onto clay surfaces rather than onto bitumen surfaces. It is the selective adsorption of HPAM that benefits both bitumen recovery and tailings settling when the polymer was added directly to the bitumen extraction process at an appropriate dosage.

Synergetic Role of Polymer Flocculant in Low-Temperature Bitumen Extraction and Tailings Treatment

This paper presents a preliminary study on the synergetic effect of a polymer flocculant, derived from hydrolyzed polyacrylamide (HPAM), on both bitumen extraction and tailings treatment as applied to oil sands. Bitumen extraction experiments and tailings settling tests were carried out with the addition of HPAM directly in the bitumen extraction process. To understand how the polymer affects bitumen recovery and tailings treatment, the long-range interaction and adhesion forces between bitumen and solids (clay and silica) and between clay and silica were measured using an atomic force microscope (AFM). Our study clearly demonstrated a synergetic role of HPAM in processing poor oil sand ores, which are characterized by high clay fines content. The addition of HPAM at an appropriate dosage not only improved bitumen liberation and recovery but also increased the tailings settling rate. Such improvements were attributed to the selective flocculation of clay fines by HPAM, which was supported by the AFM data. On the basis of the results of the present study, it is suggested to directly add HPAM into the bitumen extraction process, rather than to tailings, to facilitate both bitumen recovery and tailings treatment in production operations.