Plastics floatability: effect of saponin and sodium lignosulfonate as wetting agents

Pita, Fernando; Castilho, Ana

doi:10.1590/0104-1428.01419

Cited by 9 publications

(6 citation statements)

References 24 publications

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“…Quartz crystal microbalance (QCM), spectroscopic ellipsometry, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy have been suggested as alternatives for investigating the adsorption of lignosulfonates on solids [87][88][89]. Contact angle measurements can provide information on the effect on lignosulfonates on wettability of a solid surface [90,91]. Moreover, the zeta potential of suspensions and emulsions provides information about the adsorption and stabilization mechanism of lignosulfonate dissolved in the continuous (aqueous) phase [32,92,93].…”

Section: Analytical Techniques For Lignosulfonate Characterizationmentioning

confidence: 99%

A Critical Review of the Physicochemical Properties of Lignosulfonates: Chemical Structure and Behavior in Aqueous Solution, at Surfaces and Interfaces

Ruwoldt¹

2020

Surfaces

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Lignosulfonates are bio-based surfactants and specialty chemicals, which are generated by breaking the near-infinite lignin network during sulfite pulping of wood. Due to their amphiphilic nature, lignosulfonates are used in manifold applications such as plasticizer, dispersant, and stabilizer formulations. Function and performance are determined by their behavior in aqueous solution and at surfaces and interfaces, which is in turn imposed by the chemical make-up. This review hence summarizes the efforts made into delineating the physicochemical properties of lignosulfonates, while also relating to their composition and structure. Lignosulfonates are randomly branched polyelectrolytes with abundant sulfonate and carboxylic acid groups to ensure water-solubility. In aqueous solution, their conformation, colloidal state, and adsorption at surfaces or interfaces can be affected by a range of parameters, such as pH, concentration of other electrolytes, temperature, and the presence of organic solvents. These parameters may also affect the adsorption behavior, which reportedly follows Langmuir isotherm and pseudo second-order kinetics. The relative hydrophobicity, as determined by hydrophobic interaction chromatography, is an indicator that can help to relate composition and behavior of lignosulfonates. More hydrophobic materials have been found to exhibit a lower charge density. This may improve dispersion stabilization, but it can also be disadvantageous if an electrokinetic charge needs to be introduced at solid surfaces or if precipitation due to salting out is an issue. In addition, the monolignol composition, molecular weight distribution, and chemical modification may affect the physicochemical behavior of lignosulfonates. In conclusion, the properties of lignosulfonates can be tailored by controlling aspects such as the production parameters, fractionation, and by subsequent modification. Recent developments have spawned a magnitude of products and technologies, which is also reflected in the wide variety of possible application areas.

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Section: Analytical Techniques For Lignosulfonate Characterizationmentioning

confidence: 99%

A Critical Review of the Physicochemical Properties of Lignosulfonates: Chemical Structure and Behavior in Aqueous Solution, at Surfaces and Interfaces

Ruwoldt¹

2020

Surfaces

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“…However, it is unnecessary to reduce the contact angle of PVC to zero, as the contact angle of PVC is 49 • , which leads to a nearly 100% depression rate [57]. Saponin and sodium lignosulfonate (SL) also influenced PVC flotation by reducing the contact angle [58].…”

Section: Flotation With Surfactantsmentioning

confidence: 99%

Recent Studies and Technologies in the Separation of Polyvinyl Chloride for Resources Recycling: A Systematic Review

Phengsaart,

Julapong,

Manositchaikul

et al. 2023

Sustainability

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Material recycling and thermal treatment are the two most common recycling methods employed for plastic waste management. Thermal treatment for energy recovery is more widely applied compared with material recycling because the latter requires a high efficiency of separation and a high purity of products. Unfortunately, certain plastics like polyvinyl chloride (PVC) are unsuitable for thermal treatment because they contain additives like chloride (Cl−) that have adverse effects on refractory materials used in boilers. As a result of this, mixed plastic wastes containing PVC generally end up in landfills. PVC-bearing mixed plastics, however, remain valuable resources as championed by the United Nation Sustainable Development Goals (UN-SDGs): Goal 12 “Responsible production and consumption”, and their recycling after the removal of PVC is important. In this paper, recent studies (2012–2021) related to the separation of PVC from other types of plastics were systematically reviewed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A total of 66 articles were selected, reviewed, and summarized. The results showed that various separation technologies conventionally applied to mineral processing—selective comminution, gravity separation, magnetic separation, electrical separation, and flotation—have been studied for PVC separation, and the majority of these works (>60%) focused on flotation. In addition, more advanced technologies including sorting and density-surface-based separation were introduced between 2019 and 2021.

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“…2 ml of MIBC (frother agent) was added and conditioned for 2 minutes after the fourth minute of tannic acid conditioning. After tannic acid conditioning, the air valve was opened to release air into the cell and flotation began [5]. Three different flotation tests, (Test 1 (T1), Test 2 (T2) and Test 3 (T3)) were conducted under the following conditions: T1: flotation of CS2 with no tannic acid addition (without depressor conditioning), T2: flotation of CS1 with tannic acid addition (with depressor conditioning) and T3: flotation of CS2 with tannic acid addition (with depressor conditioning).…”

Section: Flotation Testmentioning

confidence: 99%

The Use of Froth Flotation for Selective Separation of Plastic Wastes from Soil

Moro

Dechie

2021

EJENG

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The Use of Froth Flotation for Selective Separation of Plastic Wastes from Soil Kofi Moro and Dorothy A. Dechie Abstract — In recycling of plastics, unless the goal is to form composites or materials having special properties, it is not advisable to mix plastics of different kinds because of the differences in their molecular weights and chain lengths. Hence, there is the need to separate these plastics when they are mixed before recycle can be done. This project investigated the selective separation of Polypropylene (PP), Polystyrene (PS) and Polyethylene terephthalate (PET) plastics out of soils using froth flotation. Pulverized samples were prepared from post-consumer plastic sources (PP, PS and PET) and soil and mixed uniformly to form a composite sample. The composite sample was subjected to froth flotation. Two tests were performed. A first test, where there was no addition of a depressant (tannic acid), and a second test, where there was addition of tannic acid to depress some of the plastics in order to selectively separate them. Recoveries from each test work indicated that, plastics are naturally hydrophobic and can be floated out of soils without modifying their surface properties. However, selective separations of the plastics were achieved when tannic acid was used to modify the surface properties of the plastic types.

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Plastics floatability: effect of saponin and sodium lignosulfonate as wetting agents

Cited by 9 publications

References 24 publications

A Critical Review of the Physicochemical Properties of Lignosulfonates: Chemical Structure and Behavior in Aqueous Solution, at Surfaces and Interfaces

A Critical Review of the Physicochemical Properties of Lignosulfonates: Chemical Structure and Behavior in Aqueous Solution, at Surfaces and Interfaces

Recent Studies and Technologies in the Separation of Polyvinyl Chloride for Resources Recycling: A Systematic Review

The Use of Froth Flotation for Selective Separation of Plastic Wastes from Soil

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