Advancing models of bubble-particle contact times: A comprehensive review of flotation attachment efficiency prediction.

Bubble-particle attachment is a fundamental process in flotation, critical for determining separation efficiency, based on surface hydrophobicity and many other aspects of colloid and surface chemistry. This review examines and refines models of contact time - encompassing collision, sliding, and attachment interactions - to quantify attachment efficiency in flotation systems. It begins by exploring the underlying colloidal physics of bubble-particle collision and sliding interactions during attachment, emphasising the velocity components of particles at bubble surfaces, including water flow and particle settling.

Arbuscular Mycorrhizal Fungi Drive Organo-Mineral Association in Iron Ore Tailings: Unravelling Microstructure at the Submicron Scale by Synchrotron-Based FTIR and STXM-NEXAFS.

Arbuscular mycorrhizal (AM) fungi play an important role in organic matter (OM) stabilization in Fe ore tailings for eco-engineered soil formation. However, little has been understood about the AM fungi-derived organic signature and organo-mineral interactions at the submicron scale. In this study, a compartmentalized cultivation system was used to investigate the role of AM fungi in OM formation and stabilization in tailings.

Biomining for sustainable recovery of rare earth elements from mining waste: A comprehensive review.

Rare earth elements (REEs) are essential for advanced manufacturing (e.g., renewable energy, military equipment, electric vehicles); hence, the recovery of REEs from low-grade resources has become increasingly important to address their growing demand.

Enhancing shear strength and handleability of dewatered clay-rich coal tailings for dry-stacking.

Mineral tailings dams pose high pollution risks to the environment and catastrophic failures. Dry stacking has been identified as a promising alternative to mitigate these risks and offers various benefits to the mining industry but lacks systematic research outcomes. To facilitate dry stacking, coal tailings slurries were dewatered using either filtration or centrifugation methods, resulting in a semi-solid form (cake) that can be safely disposed of.

Probing interfacial water structure induced by charge reversal and hydrophobicity of silica surface in the presence of divalent heavy metal ions using sum frequency generation spectroscopy.

Hypothesis: Adsorption of divalent heavy metal ions (DHMIs) at the mineral-water interfaces changes interfacial chemical species and charges, interfacial water structure, Stern (SL), and diffuse (DL) layers. These molecular changes can be detected by probing changing orientation and hydrogen-bond network of interfacial water molecules in response to changing local charges and hydrophobicity.

Experiments: Sum-frequency generation (SFG) spectroscopy was used to probe changes in vibrational resonances of interfacial OH vs.

Unravelling in-situ hardpan properties and functions in capping sulfidic Cu-Pb-Zn tailings and forming a duplex soil system cover.

Developing alternative approaches to cap and rehabilitate the large areas of tailings landscapes is critical for sustainable development of mining industry. This study revealed the potential of an in-situ hardpan-based duplex soil system as an un-conventional approach to rehabilitate sulfidic Cu-Pb-Zn tailings. Under a shallow silicious soil cover, a massive and consistent hardpan horizon had been formed in-situ at the surface layer of tailings across the trial area, which physically separated root zones (i.

Biochar mediated uranium immobilization in magnetite rich Cu tailings subject to organic matter amendment and native plant colonization.

Organic matter (OM) amendments and plant colonization can accelerate mineral weathering and soil formation in metal mine tailings for ecological rehabilitation. However, the weathering effects may dissolve uranium (U)-bearing minerals (e.g.

Chemodiversity of Dissolved Organic Matter and Its Molecular Changes Driven by Rhizosphere Activities in Fe Ore Tailings Undergoing Eco-Engineered Pedogenesis.

Dissolved organic matter (DOM) plays an important role in soil structure and biogeochemical function development, which are fundamental for the eco-engineering of tailings-soil formation to underpin sustainable tailings rehabilitation. In the present study, we have characterized the DOM composition and its molecular changes in an alkaline Fe ore tailing primed with organic matter (OM) amendment and plant colonization. The results demonstrated that microbial OM decomposition dramatically increased DOM richness and average molecular weight, as well as its degree of unsaturation, aromaticity, and oxidation in the tailings.

Co-solidification of bauxite residue and coal ash into indurated monolith via ambient geopolymerisation for in situ environmental application.

Bauxite residues generated from alumina refineries worldwide have accumulated to more than 4 billion tons, at an annual increment of ~ 0.15 billion tons. It is imperative and urgent for the alumina sector to develop field-operable disposal solutions for rapid and cost-effective stabilisation of alkaline bauxite residues (BR) in the storage facility to minimise/prevent potential environmental risks.

Organic Matter Amendment and Plant Colonization Drive Mineral Weathering, Organic Carbon Sequestration, and Water-Stable Aggregation in Magnetite Fe Ore Tailings.

The formation of water-stable aggregates in finely textured and polymineral magnetite Fe ore tailings is one of the critical processes in eco-engineering tailings into soil-like substrates as a new way to rehabilitate the tailings. Organic matter (OM) amendment and plant colonization are considered to be effective in enhancing water-stable aggregation, but the underlying mechanisms have not yet been elucidated. The present study aimed to characterize detailed changes in physicochemistry, Fe-bearing mineralogy, and organo-mineral interactions in magnetite Fe ore tailings subject to the combined treatments of OM amendment and plant colonization, by employing various microspectroscopic methods, including synchrotron-based X-ray absorption fine structure spectroscopy and nanoscale secondary ion mass spectroscopy.

Rhizosphere modifications of iron-rich minerals and forms of heavy metals encapsulated in sulfidic tailings hardpan.

Hardpan caps formed after extensive weathering of the top layer of sulfidic tailings have been advocated to serve as physical barriers separating reactive tailings in depth and root zones above. However, in a hardpan-based root zone reconstructed with the soil cover, roots growing into contact with hardpan surfaces may induce the transformation of Fe-rich minerals and release potentially toxic elements for plant uptake. For evaluating this potential risk, two representative native species, Turpentine bush (Acacia chisholmii, AC) and Red Flinders grass (Iseilema vaginiflorum, RF), of which pre-cultured root mats were interfaced with thin discs of crushed hardpan minerals in the rhizosphere (RHIZO) test.

Molecular Screening of Nasopharyngeal Carcinoma: Detection of LMP-1, LMP-2 Gene Expression in Vietnamese Nasopharyngeal Swab Samples.

Objective: This study aimed to characterize the expression of LMP-1, LMP-2 in clinical swab samples in order to find out the potential molecular based biomarker for NPC diagnosis and screening, which could offer a chance in development of rapid method for NPC diagnosis in Vietnamese population. Materials and Methods: A total of 93 nasopharyngeal carcinoma swab samples and 100 healthy nasopharyngeal swab samples were collected to evaluate LMP-1, LMP-2 expression by Real-time reversed PCR. Results: we figured out the significant association between the expression of LMP-1 (counting for 48.

3D Bombax-structured carbon nanotube sponge coupling with AgPO for tetracycline degradation under ultrasound and visible light irradiation.

A novel photocatalytic carbon nanotube sponge with three-dimensional Bombax-structure was fabricated by a facile chemical vapor deposition followed by in situ ion-exchange approach. The as-prepared sponge achieved both high-efficiency adsorption and photocatalysis towards antibiotics, which can remove up to 90% of tetracycline within an hour. The morphology and mechanism of the photocatalytic CNT sponge were explored by multiple measures.

Zinc and lead encapsulated in amorphous ferric cements within hardpans in situ formed from sulfidic Cu-Pb-Zn tailings.

Hardpans are massively indurated layers formed at the top layer of sulfidic tailings dams, which develop cementation structures and result in heavy metal immobilization. However, the micro-structural and complex forms of the cementing materials are not fully understood, as well as the mechanisms by which Zn and Pb are stabilized in the hardpans. The present study deployed synchrotron-based X-ray fluorescence microscopy (XFM) to have characterized the cementing structures, examined the distribution of Fe, Zn and Pb, and obtained laterally-resolved speciation of Zn within the hardpans using fluorescence X-ray absorption near-edge structure (XANES) imaging.

Microstructural characteristics of naturally formed hardpan capping sulfidic copper-lead-zinc tailings.

A massive and dense textured layer (ca. 35-50 cm thick) of hardpan was uncovered at the top layer, which capped the unweathered sulfidic Cu-Pb-Zn tailings in depth and physically supported gravelly soil root zones sustaining native vegetation for more than a decade. For the purpose of understanding functional roles of the hardpan layer in the cover profile, the present study has characterized the microstructures of the hardpan profile at different depth compared with the tailings underneath the hardpans.

Efficient Binding, Protection, and Self-Release of dsRNA in Soil by Linear and Star Cationic Polymers.

Double stranded RNA (dsRNA) exhibits severe degradation within 3 days in live soil, limiting its potential application in crop protection. Herein we report the efficient binding, protection, and self-release of dsRNA in live soil through the usage of a cationic polymer. Soil stability assays show that linear poly(2-(dimethylamino)ethyl acrylate) can delay the degradation of dsRNA by up to 1 week while the star shaped analogue showed an increased stabilization of dsRNA by up to 3 weeks.

Analytical Model for Diffusive Evaporation of Sessile Droplets Coupled with Interfacial Cooling Effect.

Current analytical models for sessile droplet evaporation do not consider the nonuniform temperature field within the droplet and can overpredict the evaporation by 20%. This deviation can be attributed to a significant temperature drop due to the release of the latent heat of evaporation along the air-liquid interface. We report, for the first time, an analytical solution of the sessile droplet evaporation coupled with this interfacial cooling effect.

Overcoming Surfactant-Induced Morphology Instability of Noncrosslinked Diblock Copolymer Nano-Objects Obtained by RAFT Emulsion Polymerization.

RAFT emulsion polymerization techniques including polymerization-induced self-assembly (PISA) and temperature-induced morphological transformation (TIMT) are widely used to produce noncrosslinked nano-objects with various morphologies. However, the worm, vesicle and lamellar morphologies produced by these techniques typically cannot tolerate the presence of added surfactants, thus limiting their potential applications. Herein we report the surfactant tolerance of noncrosslinked worms, vesicles, and lamellae prepared by RAFT emulsion polymerizations using poly(di(ethylene glycol) ethyl ether methacrylate---(2-hydroxypropyl) methacrylamide) (P(DEGMA--HPMA)) as a macromolecular chain transfer agent (macro-CTA).

Red mud carbonation using carbon dioxide: Effects of carbonate and calcium ions on goethite surface properties and settling.

Carbonation using CO appears as an attractive solution for disposing of red mud suspensions, an aluminum industry hazardous waste since it also offers an option for CO sequestration. Here we report the novel findings that CO together with Ca can significantly affect the surface properties and settling of goethite, a major component of red mud. Specifically, their effects on the goethite surface chemistry, colloidal interaction forces and settling in alkaline solutions are investigated.

Microbial nanowires - Electron transport and the role of synthetic analogues.

Unlabelled: Electron transfer is central to cellular life, from photosynthesis to respiration. In the case of anaerobic respiration, some microbes have extracellular appendages that can be utilised to transport electrons over great distances. Two model organisms heavily studied in this arena are Shewanella oneidensis and Geobacter sulfurreducens.

Characterization of hard- and softwood biochars pyrolyzed at high temperature.

A wide range of waste biomass/waste wood feedstocks abundantly available at mine sites provide the opportunity to produce biochars for cost-effective improvement of mine tailings and contaminated land at metal mines. In the present study, soft- and hardwood biochars derived from pine and jarrah woods at high temperature (700 °C) were characterized for their physiochemical properties including chemical components, electrical conductivity, pH, zeta potential, cation-exchange capacity (CEC), alkalinity, BET surface area and surface morphology. Evaluating and comparing these characteristics with available data from the literature have affirmed the strong dictation of precursor type on the physiochemical properties of the biochars.

Extremely High Phosphate Sorption Capacity in Cu-Pb-Zn Mine Tailings.

Elevated inorganic phosphate (Pi) concentrations in pore water of amended tailings under direct revegetation may cause toxicity in some native woody species but not native forbs or herb species, all of which are key constituents in target native plant communities for phytostabilizing base metal mine tailings. As a result, Pi sorption capacity has been quantified by a conventional batch procedure in three types of base metal mine tailings sampled from two copper (Cu)-lead (Pb)-zinc (Zn) mines, as the basis for Pi-fertiliser addition. It was found that the Pi-sorption capacity in the tailings and local soil was extremely high, far higher than highly weathered agricultural soils in literature, but similar to those of volcanic ash soils.

Copper and zinc adsorption by softwood and hardwood biochars under elevated sulphate-induced salinity and acidic pH conditions.

Biochar adsorption may lower concentrations of soluble metals in pore water of sulphidic Cu/Pb-Zn mine tailings. Unlike soil, high levels of salinity and soluble cations are present in tailing pore water, which may affect biochar adsorption of metals from solution. In the present study, removal of soluble copper (Cu) and zinc (Zn) ions by soft- (pine) and hard-wood (jarrah) biochars pyrolysed at high temperature (about 700 °C) was evaluated under typical ranges of pH and salinity conditions resembling those in pore water of sulphidic tailings, prior to their direct application into the tailings.

Effect of energy source, salt concentration and loading force on colloidal interactions between Acidithiobacillus ferrooxidans cells and mineral surfaces.

The surface appendages and extracellular polymeric substances of cells play an important role in the bacterial adhesion process. In this work, colloidal forces and nanomechanical properties of Acidithiobacillus ferrooxidans (A. f) interacted with silicon wafer and pyrite (FeS2) surfaces in solutions of varying salt concentrations were quantitatively examined using the bacterial probe technique with atomic force microscopy.