Exploring Alternatives to Polyacrylamide: A Comparative Study of Novel Polymers in the Flocculation and Dewatering of Iron Ore Tailings.

Despite being widely used in tailings treatment, polyacrylamide continues to face performance challenges. In this study, two commercial polyacrylamides with different molecular weights were used to flocculate iron ore tailings and their performance was compared with two polymers designed to treat oil sand tailings: poly(vinylbenzyl)trimethylammonium chloride and partially hydrolyzed poly(methyl acrylate) grafted onto ethylene-propylene-diene copolymer backbones. The polyacrylamide with the highest molecular weight performed better than the one with the lowest molecular weight, but its efficiency was still considerably lower than what would be desired for good solid-liquid separation. The new polymer flocculants performed better than the commercially available polyacrylamides but retained high amounts of water in the sediments. This comparison shows that polymers other than polyacrylamide may be used to treat iron ore tailings.

Facile and Efficient Phase-Selective Powder Polymer Organogelator for Oil Spill Remediation.

Phase-selective organogelators that gel oils from oil/water mixtures are useful to remediate oil spills on water. We designed and synthesized polymer organogelators, poly(styrene-co-10-undecenoic acid) with five different 10-undecenoic acid contents that could be added as powders at room temperature to gel oils with different viscosities. The morphologies and mechanical strengths of the gels were investigated using field-emission electron microscopy and rheological measurements, respectively. The gels formed porous fibrillar structures and had high stiffness. Fourier transformm infrared (FTIR) spectroscopy studies of these gels showed that hydrogen bonding and van der Waals forces helped create three-dimensional networks. The straightforward synthesis procedure, room-temperature conditions, and easy powder delivery make poly(styrene-co-10-undecenoic acid) an attractive alternative to existing oil spill response methods.

Polystyrene magnetic nanocomposite blend: An effective, facile, and economical alternative in oil spill removal applications.

Finding an efficient and economical method to remediate oil spills on water is a priority worldwide. In this article, we propose a solution to this problem using polystyrene magnetic nanocomposite blends composed of polystyrene chains grafted on the surface of silica coated on iron oxide nanoparticles and polystyrene. The hydrophobic and oleophilic magnetic polymer nanocomposite collected oil from the water surface quickly and efficiently. However, when the magnetic polymer nanocomposite was blended with polystyrene, the resulting material also absorbed oil efficiently from the water surface. The blending technique made it easier to prepare the absorbent and dramatically decreased its cost. These new absorbents absorbed oil up to 5 times their own weight in only 5 minutes. The excellent hydrophobicity, low density, and easy magnetic separation makes these new absorbents a promising alternative to recover oil from spilled in fresh and marine water.

Development and application of an amylopectin-graft-poly(methyl acrylate) solidifier for rapid and efficient containment and recovery of heavy oil spills in aqueous environments.

Effective oil spill preparedness and response are crucial to ensure environmental protection and promote the responsible development of the petroleum industry. Hence, interest in developing new approaches and/or improving existing oil spill response measures has increased greatly in the past decade. Solidifiers are an attractive and underutilized option to mitigate the effects of oil spills, as they interact with oil to contain the spill, prevent it from spreading, and facilitate its removal from the environment. In this work, we have synthesized an inexpensive and easy-to-make natural-based sorbent, a subclass of solidifiers. Our amylopectin-graft-poly(methyl acrylate) (AP-g-PMA) sorbent is highly oleophilic and hydrophobic, and selectively solidifies diluted bitumen and conventional crude oil from biphasic mixtures of oil and water. The complete solidification of conventional crude oil and diluted bitumen by the AP-g-PMA sorbent occurs within 8 and 32 min, respectively, and even a low solidifier-to-oil ratio of 4% w/w is sufficient to enable complete recovery of diluted bitumen. This innovative natural-based polymeric sorbent may be applied as a key component of oil spill response procedures, especially for heavy oils. The AP-g-PMA sorbent combines the biodegradability and non-toxicity of the amylopectin with the hydrophobicity and oleophilicity of the synthetic polymer poly(methyl acrylate).

Advanced Polymer Flocculants for Solid-Liquid Separation in Oil Sands Tailings.

The generation of tailings as a by product of the bitumen extraction process is one of the largest environmental footprints of oil sands operations. Most of the tailings treatment technologies use polymer flocculants to induce solid-liquid separation. However, due to the complex composition of tailings, conventional flocculants cannot reach the same performance achieved in other wastewater treatments. Over the last couple of decades, the oil sands industry has used acrylamide-based flocculants to treat tailings, achieving major progress in process optimization and integration with mechanical operations, but they still could not reach the required land reclamation targets. Over the last 5 years, the group designed, synthesized, and tested several novel polymer flocculants tailored for oil sands tailings treatment. This feature article communicates recent developments in these innovative polymers. The article first provides a background on tailings generation and treatment, followed by the description of advanced polymer flocculants categorized according to their microstructures such as linear, branched, and graft. The other tailings remediation technologies and one of the initial works on modeling of tailings flocculation is discussed.

Application of solidifiers for oil spill containment: A review.

The need for new and/or improvement of existing oil spill remediation measures has increased substantially amidst growing public concern with the increased transportation of unconventional crudes, such as diluted bitumen products. Solidifiers may be a very good spill response measure to contain and mitigate the effects of oil discharge incidents, as these interact with the oil to limit hydrocarbon release into air and water, prevent it from adhering onto sediment and debris, and could allow for oil recovery and reuse. Solidifiers change the physical state of the spilled oil from liquid to a coherent mass by chemical interactions between the spilled oil and the solidifier. Currently, the use of solidifiers is limited to small spills near shorelines. To extend their use to large-scale spill containment operations, it is necessary to understand the mechanism of solidifier action and to establish consistent criteria for evaluation of their effectiveness. The research effort to date has been focused mainly on gelators and cross-linking agents, with particularly impressive advancements in the areas of phase-selective polymeric and small-molecule gelators. Substantial research efforts are needed to improve solidifier performance and integrate solidifiers as part of spill response procedures, particularly for acute oil spills involving unconventional petroleum products.

Enhanced Flocculation of Oil Sands Mature Fine Tailings Using Hydrophobically Modified Polyacrylamide Copolymers.

Hydrophobically modified acrylamide copolymers dewater oil sands tailings more effectively than anionic polyacrylamide, but the root causes for this enhanced performance have not been investigated systematically. Polyacrylamide-poly(ethylene oxide methyl ether methacrylate) copolymers with different comonomer compositions, hydrophobic chain lengths, and molecular weights to map out these effects systematically are synthetized. Through a statistical design of experiments, it is found out that all three variables above significantly affected flocculation performance and that certain combinations achieve optimal results. The effect of centrifugation on the flocculation and dewatering performance of these polymers is also investigated.

Dewatering Oil Sands Tailings with Degradable Polymer Flocculants.

We synthesized hydrolytically degradable cationic polymers by micellar radical polymerization of a short-chain polyester macromonomer, polycaprolactone choline iodide ester methacrylate (PCL2ChMA) with two polyester units, and used them to flocculate oil sands mature fine tailings (MFT). We evaluated the flocculation performance of the homopolymer and copolymers with 30 mol % acrylamide (AM) by measuring initial settling rate (ISR), supernatant turbidity, and capillary suction time (CST) of the sediments. Flocculants made with trimethylaminoethyl methacrylate chloride (TMAEMC), the monomer corresponding to PCLnChMA with n = 0, have improved performance over poly(PCL2ChMA) at equivalent loadings due to their higher charge density per gram of polymer. However, MFT sediments flocculated using the PCL2ChMA-based polymers are easier to dewater (up to an 85% reduction in CST) after accelerated hydrolytic degradation of the polyester side chains. This study demonstrates the potential of designing cationic polymers that effectively flocculate oil sands tailings ponds, and also further dewater the resulting solids through polymer degradation.