scholarly journals Evaluation of a Novel Polymeric Flocculant for Enhanced Water Recovery of Mature Fine Tailings

Processes ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 735
Author(s):  
Kyle C. Lister ◽  
Heather Kaminsky ◽  
Robin A. Hutchinson
Keyword(s):  
Hydrolytic Degradation ◽  
Process Water ◽  
Poly Lactic Acid ◽  
Water Recovery ◽  
Water Release ◽  
Anionic Polymers ◽  
Cationic Flocculant ◽  
Mature Fine Tailings ◽  
Fine Tailings ◽  
The Impact

The novel cationic flocculant, poly(lactic acid) choline iodide ester methacrylate (poly(PLA4ChMA)), has been shown to provide improved flocculation of 5.0 wt.% mature fine tailings (MFT) diluted in deionized water compared to commercial anionic polymers, with continued dewatering of the sediment occurring as the polymer undergoes partial hydrolytic degradation. However, the elevated dosages (10,000 ppm) required would make the polymer costly to implement on an industrial scale. With this motivation, the impact of MFT loading and the use of process water is explored while comparing the settling performance of poly(PLA4ChMA) to available commercial alternatives such as anionic FLOPAM A3338. Improved consolidation of 5.0 wt.% MFT diluted with process water could be achieved at reduced dosages (500 ppm) with poly(PLA4ChMA). However, the final compaction levels after polymer degradation were similar to those achieved with the nondegradable commercial flocculants. Flocculation-filtration experiments with undiluted MFT are also conducted to compare the performance of the polymers. Significantly faster rates of water release were observed with the cationic flocculants compared to FLOPAM A3338, but no improvement in the overall tailings compaction was found either before or after poly(PLA4ChMA) degradation. Thus, the improved dewatering observed with poly(PLA4ChMA) in dilute MFT suspensions does not extend to conditions that would be encountered in the field.

Structure Modifications of Hydrolytically-Degradable Polymer Flocculant for Improved Water Recovery from Mature Fine Tailings

2018 ◽  
Vol 57 (32) ◽  
pp. 10809-10822 ◽  
Author(s):  
Georges R. Younes ◽  
Abbigale R. Proper ◽  
Thomas R. Rooney ◽  
Robin A. Hutchinson ◽  
Sarang P. Gumfekar ◽  
...  
Keyword(s):  
Water Recovery ◽  
Degradable Polymer ◽  
Mature Fine Tailings ◽  
Fine Tailings ◽  
Polymer Flocculant

scholarly journals Water-Induced Breaking of Interfacial Cohesiveness in a Poly(lactic acid)/Miscanthus Fibers Biocomposite

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2285
Author(s):  
Nicolas Delpouve ◽  
Hajar Faraj ◽  
Clément Demarest ◽  
Eric Dontzoff ◽  
Marie-Rose Garda ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Hydrolytic Degradation ◽  
Thermomechanical Properties ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
Incomplete Filling ◽  
The Matrix ◽  
High Elongation ◽  
The Impact

The impact of the immersion in water on the morphology and the thermomechanical properties of a biocomposite made of a matrix of poly (lactic acid) (PLA) modified with an ethylene acrylate toughening agent, and reinforced with miscanthus fibers, has been investigated. Whereas no evidence of hydrolytic degradation has been found, the mechanical properties of the biocomposite have been weakened by the immersion. Scanning electron microscopy (SEM) pictures reveal that the water-induced degradation is mainly driven by the cracking of the fiber/matrix interface, suggesting that the cohesiveness is a preponderant factor to consider for the control of the biocomposite decomposition in aqueous environments. Interestingly, it is observed that the loss of mechanical properties is aggravated when the stereoregularity of PLA is the highest, and when increasing the degree of crystallinity. To investigate the influence of the annealing on the matrix behavior, crystallization at various temperatures has been performed on tensile bars of PLA made by additive manufacturing with an incomplete filling to enhance the contact area between water and polymer. While a clear fragilization occurs in the material crystallized at high temperature, PLA crystallized at low temperature better maintains its properties and even shows high elongation at break likely due to the low size of the spherulites in these annealing conditions. These results show that the tailoring of the mesoscale organization in biopolymers and biocomposites can help control their property evolution and possibly their degradation in water.

scholarly journals Use of Multi-Anionic Sodium Tripolyphosphate to Enhance Dispersion of Concentrated Kaolin Slurries in Seawater

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1085
Author(s):  
Williams Leiva ◽  
Norman Toro ◽  
Pedro Robles ◽  
Edelmira Gálvez ◽  
Ricardo Ivan Jeldres
Keyword(s):  
Rheological Properties ◽  
Fine Particles ◽  
Sodium Tripolyphosphate ◽  
Mining Industry ◽  
Chord Length ◽  
Water Recovery ◽  
Reflectance Measurement ◽  
Anionic Charge ◽  
Free Environment ◽  
The Impact

This research aims to analyze the impact of sodium tripolyphosphate (STPP) as a rheological modifier of concentrated kaolin slurries in seawater at pH 8, which is characteristic of copper sulfide processing operations. The dispersion phenomenon was analyzed through chord length measurements using the focused beam reflectance measurement (FBRM) technique, complementing size distributions in unweighted and square-weighted modes. The reduction of the rheological properties was significant, decreasing from 231 Pa in a reagent-free environment to 80 Pa after the application of STPP. A frequency sweep in a linear viscoelastic regime indicated that by applying a characteristic dosage of 0.53 kg/t of STPP, the pulp before yielding increases its phase angle, which increases its liquid-like character. Measurements of the chord length verified the dispersion of particles, which showed an apparent increase in the proportion of fine particles and a reduction of the coarser aggregates when STPP was applied. Measurements of the zeta potential suggested that the high anionic charge of the reagent (pentavalent) increases the electrostatic repulsions between particles, overcoming the effect of cations in seawater. The results are relevant for the mining industry, especially when the deposits have high contents of complex gangues, such as clays, that increase the rheological properties. This increases the energy costs and water consumption needed for pumping the tailings from thickeners to the tailing storages facilities. The strategies that allow for the improvement of the fluidity and deformation of the tailings generate slack in order to maximize water recovery in the thickening stages.

scholarly journals Surface charge modulation of rifampicin-loaded PLA nanoparticles to improve antibiotic delivery in Staphylococcus aureus biofilms

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
David Da Costa ◽  
Chloé Exbrayat-Héritier ◽  
Basile Rambaud ◽  
Simon Megy ◽  
Raphaël Terreux ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Surface Charge ◽  
Treatment Efficacy ◽  
Particle Migration ◽  
Bacterial Biofilm ◽  
Poly Lactic Acid ◽  
Retention Capacity ◽  
The Impact ◽  
Positively Charged ◽  
Antibiotic Delivery

Abstract Background After the golden age of antibiotic discovery, bacterial infections still represent a major challenge for public health worldwide. The biofilm mode of growth is mostly responsible for chronic infections that current therapeutics fail to cure and it is well-established that novel strategies must be investigated. Particulate drug delivery systems are considered as a promising strategy to face issues related to antibiotic treatments in a biofilm context. Particularly, poly-lactic acid (PLA) nanoparticles present a great interest due to their ability to migrate into biofilms thanks to their submicronic size. However, questions still remain unresolved about their mode of action in biofilms depending on their surface properties. In the current study, we have investigated the impact of their surface charge, firstly on their behavior within a bacterial biofilm, and secondly on the antibiotic delivery and the treatment efficacy. Results Rifampicin-loaded PLA nanoparticles were synthetized by nanoprecipitation and characterized. A high and superficial loading of rifampicin, confirmed by an in silico simulation, enabled to deliver effective antibiotic doses with a two-phase release, appropriate for biofilm-associated treatments. These nanoparticles were functionalized with poly-l-lysine, a cationic peptide, by surface coating inducing charge reversal without altering the other physicochemical properties of these particles. Positively charged nanoparticles were able to interact stronger than negative ones with Staphylococcus aureus, under planktonic and biofilm modes of growth, leading to a slowed particle migration in the biofilm thickness and to an improved retention of these cationic particles in biofilms. While rifampicin was totally ineffective in biofilms after washing, the increased retention capacity of poly-l-lysine-coated rifampicin-loaded PLA nanoparticles has been associated with a better antibiotic efficacy than uncoated negatively charged ones. Conclusions Correlating the carrier retention capacity in biofilms with the treatment efficacy, positively charged rifampicin-loaded PLA nanoparticles are therefore proposed as an adapted and promising approach to improve antibiotic delivery in S. aureus biofilms.

scholarly journals Superabsorbent recycling for process water recovery

2021 ◽  
Vol 6 ◽  
pp. 100085
Author(s):  
Sophia Joseph-Soly ◽  
Richmond Asamoah ◽  
Jonas Addai-Mensah
Keyword(s):  
Process Water ◽  
Water Recovery

scholarly journals Poly(Lactic Acid)–Poly(Butylene Succinate)–Sugar Beet Pulp Composites; Part I: Mechanics of Composites with Fine and Coarse Sugar Beet Pulp Particles

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2531
Author(s):  
Rodion Kopitzky
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Sugar Beet ◽  
Cell Structure ◽  
Sugar Beet Pulp ◽  
Poly Lactic Acid ◽  
Butylene Succinate ◽  
Fracture Patterns ◽  
Beet Pulp ◽  
The Impact

Sugar beet pulp (SBP) is a residue available in large quantities from the sugar industry, and can serve as a cost-effective bio-based and biodegradable filler for fully bio-based compounds based on bio-based polyesters. The heterogeneous cell structure of sugar beet suggests that the processing of SBP can affect the properties of the composite. An “Ultra-Rotor” type air turbulence mill was used to produce SBP particles of different sizes. These particles were processed in a twin-screw extruder with poly(lactic acid) (PLA) and poly(butylene succinate) (PBS) and fillers to granules for possible marketable formulations. Different screw designs, compatibilizers and the use of glycerol as a thermoplasticization agent for SBP were also tested. The spherical, cubic, or ellipsoidal-like shaped particles of SBP are not suitable for usage as a fiber-like reinforcement. In addition, the fineness of ground SBP affects the mechanical properties because (i) a high proportion of polar surfaces leads to poor compatibility, and (ii) due to the inner structure of the particulate matter, the strength of the composite is limited to the cohesive strength of compressed sugar-cell compartments of the SBP. The compatibilization of the polymer–matrix–particle interface can be achieved by using compatibilizers of different types. Scanning electron microscopy (SEM) fracture patterns show that the compatibilization can lead to both well-bonded particles and cohesive fracture patterns in the matrix. Nevertheless, the mechanical properties are limited by the impact and elongation behavior. Therefore, the applications of SBP-based composites must be well considered.

Morphological behaviour of poly(lactic acid) during hydrolytic degradation

2008 ◽  
Vol 93 (10) ◽  
pp. 1964-1970 ◽  
Author(s):  
Xiaoqing Zhang ◽  
Maria Espiritu ◽  
Alex Bilyk ◽  
Lusiana Kurniawan
Keyword(s):  
Lactic Acid ◽  
Hydrolytic Degradation ◽  
Poly Lactic Acid

scholarly journals The combined plasticization of jute and tung oil anhydride for jute fiber reinforced poly(lactic acid) composites

2021 ◽  
pp. 096739112110576
Author(s):  
Ying Zhou ◽  
Can Chen ◽  
Lan Xie ◽  
Xiaolang Chen ◽  
Guangqiang Xiao ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Physical And Mechanical Properties ◽  
Complex Viscosity ◽  
Poly Lactic Acid ◽  
Melt Blending ◽  
Sem Images ◽  
Pseudoplastic Fluid ◽  
Tung Oil ◽  
Biodegradable Poly ◽  
The Impact

In this work, novel plasticizing biodegradable poly (lactic acid) (PLA) composites were prepared by melt blending of jute and tung oil anhydride (TOA), and the physical and mechanical properties of PLA/jute/TOA composites were tested and characterized. The impact strength of PLA/jute/TOA composites significantly increases with increasing the content of TOA. The SEM images of fracture surface of PLA/jute/TOA composites become rough after the incorporation of TOA. In addition, TOA changes the crystallization temperature and decomposition process of PLA/jute/TOA composites. With increasing the amount of TOA, the value of storage modulus (E′) of PLA/jute/TOA composites gradually increases. The complex viscosity (η*) values for all samples reduce obviously with increasing the frequency, which means that the pure PLA and PLA/jute/TOA composites is typical pseudoplastic fluid. This is attributed to the formation of crosslinking, which restricts the deformation of the composites.

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