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a Number of published documents by year and b co-occurrence network of the keywords ("Flotation" AND "Biosurfactants" OR "natural surfactant") from Scopus database, for better interpretation of the color figure, the reader could refer the web version of this article
Source publication
The transition of the mineral processing sectors, which depend mainly on various petroleum-origin chemicals, to the green industry based on the production of greener materials and the reduction of carbon footprints, is mandatory due to the growing concerns regarding the extensive environmental impact of the mining industry. In this context, biologi...
Citations
... Additionally, most of the commercial flotation reagents are known for their hazardous manufacturing processes, thus, the emerging wave of clean biobased flotation reagents is attracting interest (Abdalla et al., 2018;Huang et al., 2019;Wang et al., 2022). Attempts for reaching even better results in phosphate flotation while preserving the environment are persisting (Dong et al., 2020;El-Bahi et al., 2023;Oulkhir et al., 2022;Yang et al., 2021). In a previous work, olive, nigella, and flaxseed oils were tested for their ability to produce well-performing flotation reagents . ...
Calcium minerals are the main constituents of most sedimentary phosphate ores. These include apatite, calcite,
and dolomite. Owing to the similar surface properties of these minerals, their selective flotation is notably
intricate. Fatty acids are the mostly employed collectors in calcium minerals flotation. The performance of fatty
acids and their selectivity towards minerals depends on their hydrocarbon chain’s length, unsaturation number
and type, as well as their comprised polar and nonpolar functional groups, amongst others. In the present work,
ricinoleic (RA) and erucic acid (EA)’s collecting ability and affinity towards apatite, calcite, and dolomite were
investigated. These fatty acids were biobased; extracted from castor and mustard oils respectively. Their performance was monitored alongside two different conventional collectors for an effective evaluation. The castor
and mustard oils were characterized and saponified. The critical micellar concentration of the yielded soaps and
the commercial collectors was determined, and their chemistry was analyzed. In the framework of fundamental
studies, the four collectors were made in contact with pure fluorapatite, calcite, and dolomite. Zeta potential,
surface chemistry, and wettability assessments confirmed the adsorption of the fatty acids on the mineral surfaces. The biobased collectors’ adsorption at the surface of the three minerals was important yet less selective
than the conventional ones. Flotation tests conducted on a sedimentary phosphate ore have affirmed the
applicability of the castor oil derived collector in calcite and dolomite flotation (in the presence of phosphoric
acid as an apatite depressant). The castor oil collector was able to selectively recover excellent carbonate concentrates, while surpassing the performance of the tested conventional collectors.
... Foaming agents, which act as surfactants, shape the surface properties of bubbles, mitigating their tendency to coalesce. Meanwhile, modifiers function as reagents that fine-tune the collectors' performance by augmenting their selectivity, thereby regulating the flotation conditions (Oulkhir et al. 2023 ). ...
Abstract
Aim
To assess the effectiveness of Bacillus subtilis strain LN8B as a bio-collector for recovering pyrite (Py) and chalcopyrite (CPy) in both seawater (Sw) and deionized water (Dw), and to explore the underlying adhesion mechanism in these bioflotation experiments.
Materials and methods
The bioflotation test utilized B. subtilis strain LN8B as the bio-collector through microflotation experiments. Additionally, frother methyl isobutyl carbinol (MIBC) and conventional collector potassium amyl xanthate (PAX) were introduced in some experiments. The zeta potential (ZP) and Fourier Infrared Spectroscopy (FT-IR) was employed to explore the adhesion mechanism of Py and CPy interacting with the bio-collector in Sw and Dw. The adaptability of the B. subtilis strain to different water types and salinities was assessed through growth curves measuring optical density. Finally, antibiotic susceptibility tests were conducted to evaluate potential risks of the bio-collector.
Results
Superior outcomes were observed in Sw where Py and CPy recovery was approximately 39.3 ± 7.7% and 41.1 ±5.8%, respectively, without microorganisms’ presence. However, B. subtilis LN8B potentiate Py and CPy recovery, reaching 72.8 ± 4.9% and 84.6 ± 1.5%, respectively. When MIBC was added, only the Py recovery was improved (89.4 ± 3.6%), depicting an adverse effect for CPy (81.8 ± 1.1%). ZP measurements indicated increased mineral surface hydrophobicity when Py and CPy interacted with the bio-collector in both Sw and Dw. FT-IR revealed the presence of protein-related amide peaks, highlighting the hydrophobic nature of the bacterium. The adaptability of this strain to diverse water types and salinities was assessed, demonstrating remarkable growth versatility. Antibiotic susceptibility tests indicated that B. subtilis LN8B was susceptible to 23 of the 25 antibiotics examined, suggesting it poses minimal environmental risks.
Conclusions
The study substantiates the biotechnological promise of B. subtilis strain LN8B as an efficient sulfide collector for promoting cleaner mineral production. This effectiveness is attributed to its ability to induce mineral surface hydrophobicity, a result of the distinct characteristics of proteins within its cell wall.
... Flotation is a widely used mineral processing technique for concentrating valuable mineral elements, including REEs, based on their distinct physical and chemical properties, such as surface charge, hydrophobicity, and surface complexation, distinguishing them from undesirable ores constituents. This technique requires using surfactants (from biological or chemical origins), particularly depressants and collectors (Oulkhir et al., 2022;Shetty et al., 2020). These surfactants encompass fatty acids, hydroxamic acids, and phosphoric esters (Dhar et al., 2021). ...
... These surfactants have selective binding properties to the surfaces of minerals containing REEs or REEs ions. This selective binding allows for the targeted separation of REEs from other undesirable elements in the ore, thereby enhancing the purity of the obtained REEs fraction (Marion et al., 2020;Oulkhir et al., 2022). Bioflotation using bioreagents offers the potential to reduce the toxicity issues associated with chemical collectors and depressors, as they are naturally more biodegradable and can also be produced at a lower cost than synthetic chemicals. ...
... Substrate availability: The availability and nature of the carbon and nitrogen sources in the growth medium can impact the biosynthesis of lipopeptide biosurfactants (Ndlovu et al., 2017). Variation in the substrate composition can lead to changes in precursor availability and subsequently affect the structure of the lipopeptide molecule (Oulkhir et al., 2023). Extraction and purification methods: The choice of extraction and purification methods can also influence the structure of lipopeptide biosurfactants. ...
... Further research could explore the specific interactions between lipopeptides and different plant surfaces to elucidate the underlying molecular mechanisms involved in wettability alteration. This could involve techniques such as surface analysis, spectroscopy, or molecular modeling to gain insights into the interactions at the molecular level (Oulkhir et al., 2023). In conclusion, wettability alteration of plant surfaces by lipopeptide biosurfactants involves mechanisms such as reduction in contact angle, formation of thin films, and modification of surface roughness (Sreedharan et al., 2023). ...
... The increase in public awareness of environmental pollution has an impact on research on the application of biological methods for mineral separation. The number of publications related to mineral flotation and flocculation using agents of biological origin is increasing, as presented in Figure 1 and also reported by Oulkhir et al. [3], indicating a growing interest in the development of new ecological process approaches. ...
... Appropriate control of these processes offers the possibility of using microbes and bio-based compounds in flotation or flocculation [6]. The main factors influencing the biomodification of the solid surface in mineral beneficiation have been described in detail [3,7] and include the particle size, the pulp density of the mineral suspension, bacterial cell concentration, the contact time of the bacteria with a mineral substrate, pH, the nutrient composition of the medium, surface potential, and surface charge. ...
... Variations in the bacterial cell attachment to the mineral surface depicted in Figure 2 include the following: (i) reversible adhesion, which occurs via weak van der Walls forces; (ii) immobilisation, when bacteria anchor to the surface with cell structures, that is, pilli or exopolymers, which attach them irreversibly; and (iii) biofilm, when multilayered cells accumulate on the surface and produce extracellular polymeric substances (EPS) [14]. The main factors influencing the biomodification of the solid surface in mineral beneficiation have been described in detail [3,7] and include the particle size, the pulp density of the mineral suspension, bacterial cell concentration, the contact time of the bacteria with a mineral substrate, pH, the nutrient composition of the medium, surface potential, and surface charge. ...
Increasing environmental concern forces the reduction in the share of synthetic surfactants in the production of various industries, including mineral processing, by replacing them with more environmentally friendly compounds of biological origin. Several studies on the use of biosurfactants in mineral processing are currently available in the literature, but they contain limited information related to the physicochemistry of these processes. Therefore, this review aims to summarise publications from the last decade related to the role of microorganisms and their metabolic products in mineral surface modification applied in mineral processing. Theoretical principles of bacteria–mineral interactions are presented. Salt-type, sulphide, and oxide minerals were discussed with greater attention to the physicochemistry of biosurfactant–mineral interactions, such as the wettability and surface charge. The advantages and disadvantages of using bacterial cells and surface-active microbial compounds were proposed. The trends and challenges of biomodification in flotation and flocculation were discussed.
... However, because of its bitter taste, the seed's external layer is a waste that must be disposed of before quinoa consumption [5]. This biowaste has been reported to be an excellent source of saponins and secondary metabolites, notably polyphenols, phytosterols, and flavonoids [8,9]. ...
... Physical adsorption of MB on the lignocellulosic biomass surface can occur through electrostatic attraction, ion exchange, or/and hydrogen bonding [96]. Chemical adsorption, on the other hand, is attributed to a chemical reaction between the functional groups of biomasses and the MB to form a high-energy covalent bond [9]. According to the FT-IR, the carboxyl peak was weakening, which implies that the carboxyl group plays an essential role in MB biosorption. ...
ynthetic toxic dyes from liquid wastes can be harmful for living organisms and the environment, even at low concentrations. This research investigated the utilization of the Chenopodium quinoa pericarp bio-waste (QBW) after saponin glycosides extraction as biosorbent in the removal of methylene blue (MB) dye as a model contaminant from aqueous solution. QBW was successfully modified by chemical (sulfuric acid) and thermal (pyrolysis) treatments. The biosorbent was characterized by FTIR, TGA, BET, Zeta Potential, SEM/EDX, and contact angle analysis to get further insight into the adsorbent’s behavior and to propose a suitable biosorption mechanism. Batch experiments were explored to study the effect of various parameters on MB removal efficiency, including contact time, adsorbent quantity, initial concentration, and process temperature. The optimum conditions for QBW biosorption of MB were at neutral pH and contact time of 60 min. The maximum adsorption capacity of the biosorbent (QBW-II), which demonstrated the highest MB removal efficiency in the biosorption test was 193.802 ± 4.365 mg.g−1. The kinetic and isotherm study of MB dye biosorption revealed that the pseudo-second-order model and Langmuir isotherm were the best fit. Thermodynamic parameters for the biosorption showed that the process was spontaneous and exothermic. Our findings demonstrate that QBW has a high potential to be used as an environmentally friendly and promising bio-sorbent to effectively remove organic contaminants from aqueous systems.
... The quintessential examples are xanthates [5,6] and amines [7]. Therefore, there is a growing trend to extend the share of green reagents in flotation [8][9][10][11]. The adjective "green," or "eco-friendly," implies that the reagents comply across their life cycle with a set of principles of green chemistry, including production from renewable feedstocks, minimization of hazards, and benign degradation after the use [12,13]. It has been suggested that the true "greenness" of collectors should be measured over four major life cycle stages, (i) manufacturing, (ii) storage and transportation, (iii) usage and processing, and (iv) post-usage and processing, for which most reagents are still unavailable [14]. ...
... At the same time, there is very limited knowledge about the potential of biosurfactants as green collectors, not to mention a general framework that classifies biosurfactants in terms of the minerals that they can float [8,9,11,13,32]. ...
The separation of fine mineral particles, especially using environmentally friendly approaches, is one of the main problems in the processing of low-grade ores and the re-processing of mining tailings. This work assesses the potential of biosurfactants as collectors in the flotation of ultrafine (smaller than 20 μm) particles of hematite and malachite. As biosurfactants, we test acetylated acidic (ac-ASL) and lactonic sophorolipids (ac-LSL). In addition, n-dodecyl-β-D-maltoside (DDM) is used as a model non-ionic alkyl disaccharide surfactant, and sodium oleate (NaOl) is used as a reference. The biosurfactants are characterized using surface tension and foam analysis. The interaction of the minerals with the surfactants is characterized using zeta potential, solubility, and single-mineral flotation. The collecting properties of the surfactants are compared for the ultrafine (− 20 μm) and coarser (38–90 µm) particle size in the two-mineral flotation of hematite and malachite against quartz. The ultrafine particle size improves the grade in the oleate flotation of hematite, as well as the grades in the DDM flotation of hematite and malachite, which is explained by the weak interactions of the metal oxides with fatty acids and DDM. At the same time, the flotation with ac-LSL and ac-ASL is highly tolerant to the ultrafine particle size. These results indicate that biosurfactants are an interesting alternative to conventional petroleum-based surfactants in the flotation of Fe and Cu oxides. Moreover, a proper selection of surfactants can help combat the problem of fines.
Graphical Abstract
... Recently, the use of natural fibers in the development of bio-composites has attracted more attention of researchers, which may provide access to additional high value applications [9][10][11][12][13][14]. The development of reinforced thermoplastic polymers using cellulose fibers has brought several challenges, such as low compatibility between the hydrophilic cellulose and hydrophobic polymers [15]. ...
The aim of this work is the valorisation of bagasse cane by-product for the development of a new bio-composite based on Polypropylene (PP) reinforced with diferent cellulose derivatives. In this study, the efect of fber’s chemical surface treatments on the thermal and mechanical performance of PP was investigated, in particular, a comparison between three chemical treatments (alkali, bleaching, and coupling agent). Bio-composite materials were prepared using twin-screw extrusion followed by injection molding by mixing PP pellet with 5 to 10 Wt.% of raw bagasse cane (RBC), alkali bagasse cane (ABC) and cellulose microfbers (CMF), as well as CMF with Styrene-(ethylene-butene)-styrene three-block co-polymer grafted with maleic anhydride (SEBS-g-MA) as coupling agent. Overall, the thermal analysis reveals that the addition of fbers reduces the thermal stability of the reinforced PP. The mechanical results show an improvement in the values of Yung’s modulus, tensile strength and hardness of the reinforced PP compared to neat PP. However, a remarkable decrease was obtained in elongation at break and toughness for all reinforced composites compared to neat PP. These fndings clearly show the advantages in the use of thermoplastic matrix reinforced with cellulosic fbers.
The quest for sustainable mining processes has directed research towards environmentally friendly alternatives to conventional beneficiation practices, with biosurfactants emerging as a viable option due to their lower environmental impact. This study reviews the application of biosurfactants as bioreagents in mineral flotation, exploring their production, their mechanisms of action, and the sustainability benefits they offer. Methods include a decade-long text mining analysis of relevant literature, utilizing software tools like Zotero on platforms like Web of Science to extract and analyze data. The results underscore the growing interest in biosurfactants over the last ten years, highlighting their increasing relevance in industrial applications such as mineral flotation, where they replace synthetic surfactants. Particularly, biosurfactants have shown effectiveness in enhancing the froth flotation process, leading to more efficient mineral recovery while mitigating environmental harm. In conclusion, the adoption of biosurfactants in mineral processing not only aligns with sustainability goals but also demonstrates potential improvements in operational efficiency, offering a dual benefit of environmental protection and enhanced resource recovery.
