Metal Extraction Efficiency Research Articles

A Comprehensive Review of the Advancement in Recycling the Anode and Electrolyte from Spent Lithium Ion Batteries

Owing to the increasing pressure on the ecological effect of solid waste disposal and developing the need for disposal of the corresponding hazardous metals, recovery of spent lithium ion batteries (LIBs) has gain worldwide attention in recent years. Much work has been done in this regard in the past few decades, and several new, interesting, and unique methods have been developed to recycle the cathode, anode, and electrolyte. Therefore, time has come to summarize the highlights in this emerging area to facilitate young researchers. In this review, starting from the current market demand and commercial value of lithium ion batteries, we have summarized the most recent progress in the direction of recycling the cathode and anode materials and electrolyte. At the beginning, an overview of the recycling techniques is presented to grasp understanding of the topic. Later, laboratory and industrial investigations and implementation are reviewed with emphasis on anode (graphite) and electrolyte recovery. Life cycle assessment of end-of-life LIB recycling, limitations, and future efforts have also mentioned to focus on improving the efficiency of metal extraction and separation with the sustainable and systematic recycling of spent lithium ion batteries.

Plant metal concentrations in Theobroma cacao as affected by soil metal availability in different soil types

Beans of cacao (Theobroma cacaoL.) are used to produce a variety of chocolate products. Bioaccumulation of metals at toxic levels through the consumption of contaminated products has been identified as a health concern in humans. Both metal diversity and concentration as well as their interactions in the soil influence essential and non-essential metal uptake in plants; but the effects of these on bioaccumulation of metals in cacao is not understood across diverse soil types. In this study eight metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) were investigated in 12 soil subgroups belonging to four soil orders across 15 locations in Trinidad, with the aim to investigate the effect of soil metal diversity and concentration on metal bioaccumulation in cacao. Soil metals were extracted using five methods (aqua regia, DTPA, Mehlich 3, nitric acid, and water). Cacao leaf metal concentrations were determined using the USEPA 3052 method. Metal extraction efficiency ranged between methods with aqua regia ≥ nitric acid > Mehlich 3 ≥ DTPA ≥ water across all metals. The soil extraction method that best predicted cacao leaf metal concentrations varied with the metal – Mehlich 3 or DTPA for Cd, Ni, Zn; aqua regia, Mehlich 3, or nitric acid for Pb, and water for Mn. A stepwise regression analysis showed that plant metal concentration can be predicted using soil physicochemical characteristics as well as the concentration of metals in the soil. The importance of soil type on cacao leaf metal bioaccumulation is discussed.

МЕХАНОХИМИЧЕСКАЯ ТЕХНОЛОГИЯ ДОБЫЧИ МЕТАЛЛОВ ИЗ ХВОСТОВ ОБОГАЩЕНИЯ

Актуальность и цель исследования. Цель исследования –установить взаимосвязь параметров технологии выщелачивания с эффективностью извлечения металлов. Статья посвящена проблеме совершенствования технологии извлечения металлов из продуктов первичной переработки металлических руд в рамках направления безотходной утилизации хвостов переработки. Ее актуальность обусловлена тем, что в настоящее время прослеживается глобальная тенденция – переход к «устойчивым геотехнологиям», одним из направлений которой является расширение сферы использования техногенного сырья, а опыт безотходной утилизации хвостов сравнительно мал. Методика исследования. В экспериментах применена единая методика технологического процессас математическим планированием. Для формирования поверхности регрессии в трехмерном виде использована процедура алгоритмов строгой интерполяции. Результаты. Приведены результаты экспериментального обоснования возможности выщелачивания металлов из минеральных отходов из хвостов обогащения с использованием дезинтегратора российского производства. Область эффективного применения технологий утилизации некондиционного металлосодержащего минерального сырья определена моделированием технологических и экономических показателей с учетом стоимости каждого из компонентов выщелачиваемого раствора, а также затрат, связанных с увеличением продолжительности технологического процесса. Показано, что эффективность утилизации хвостов обогащения зависит от масштабов использования технологии выщелачивания на этапах от добычи до металлургического передела, а концепт эффективности новой технологии состоит в получении дохода от увеличения количества товарной продукции за счет утилизации некондиционного по содержанию металлов исходного сырья. Определено, что комплексность использования недр можно повысить путем выделения большей доли металлов в процессе выщелачивания хвостов обогащения в дезинтеграторе. Выводы. Реализация технологии обеспечивает вовлечение в производство омертвленных минеральных ресурсов и создает новую сырьевую базу для устойчивого развития отечественного горно-металлургического комплекса. Рекомендовано дальнейшие исследования параметров безотходного выщелачивания металлов сосредоточить в области выявления совместного влияния доли раствора и массового содержания реагентов в обогащаемой пульпе на эффективность процесса.

Controlling factors on nickel uptake by plants growing on Ni-laterites: A case study in biogeochemical exploration from the Mazayejan area, SW Iran

Nickel bearing soils derived from serpentinized ultramafic rocks are widely exposed as two parallel zones in Bavanat region along the Sedimentary Zagros Orogenic (SZO) and Metamorphic Sanandaj-Sirjan (MSS) belts. These laterites in the Mazayejan area of the Northern zone are divided into two groups; the in situ soils found mainly in the east, and the transported soils which are common in the west of the study area. The maximum Ni concentration of the studied soils is 1787 μg g−1. The main vegetation types of the area include open shrub lands and semi-desert steppes. Many soil characteristics in the study area are quite variable, such as Mg/Ca ratio, exchangeable metal fraction, extraction efficiency (EF), pH, organic content (OM), texture, and cation exchange capacity (CEC) as well as seasonal variation of Ni availability and metal transfer to plants. This study indicated that low Mg/Ca ratio (0.1–2.3 μg g−1), high carbonate content (up to 42.8 wt%) and very low exchangeable Ni fraction (0.01–0.34 μg g−1) result in low uptake of nickel by plants. Low EF, but high pH and OM result in Ni fixation in the soils, and consequently low Ni transfer factor to plants. Clay textured soils with high CEC (10.5 wt%) are characterized by the lowest transfer coefficient of Ni from soil to plant, due to the stronger adsorption of Ni in the soils. Ni concentration in living tissues change with the season, the leaves of the same plants investigated in autumn contain more Ni than in spring. As a result, plant sampling in autumn should be preferred for nickel exploration when using biogeochemical and other methods such as Ni phytoextraction, by selected plants.

Effect of Soil Washing Solutions on Simultaneous Removal of Heavy Metals and Arsenic from Contaminated Soil

In this study, we investigated the feasibility of using a solution of sulfuric acid and phosphoric acid as an extraction method for soil-washing to remove Cu, Pb, Zn, and As from contaminated soil. We treated various soil particles, including seven fraction sizes, using sulfuric acid. In addition, to improve Cu, Pb, Zn, and As removal efficiencies, washing agents were compared through batch experiments. The results showed that each agent behaved differently when reacting with heavy metals (Cu, Pb, and Zn) and As. Sulfuric acid was more effective in extracting heavy metals than in extracting As. However, phosphoric acid was not effective in extracting heavy metals. Compared with each inorganic acid, As removal from soil by washing agents increased in the order of sulfuric acid (35.81%) < phosphoric acid (62.96%). Therefore, an enhanced mixture solution using sulfuric acid and phosphoric acid to simultaneously remove heavy metals and As from contaminated soils was investigated. Sulfuric acid at 0.6 M was adopted to combine with 0.6 M phosphoric acid to obtain the mixture solution (1:1) that was used to determine the effect for the simultaneous removal of both heavy metals and As from the contaminated soil. The removal efficiencies of As, Cu, Pb, and Zn were 70.5%, 79.6%, 80.1%, and 71.2%, respectively. The combination of sulfuric acid with phosphoric acid increased the overall As and heavy metal extraction efficiencies from the contaminated soil samples. With the combined effect of dissolving oxides and ion exchange under combined washings, the removal efficiencies of heavy metals and As were higher than those of single washings.

The Effects of Water Recycling on Flotation at a North American Concentrator—Part 1

Water chemistry and its impact on mineral processing operations are not well understood and often not adequately monitored. CanmetMINING, as part of its water management research program, has been involved in a project initiated to identify opportunities for improving water recovery, water treatment, and recycling in the mining and mineral processing operations. One of the main objectives of this work is to evaluate and assess water chemistry and identify factors that impact mineral recovery, concentrate grade, and metal extraction efficiencies in order to understand and mitigate negative impacts of water recycling and improve process efficiency. In collaboration with a North American concentrator, CanmetMINING has been involved in assessing the water chemistry in the mill and evaluating water recycling options for select process streams to reduce fresh water intake and maximize recycling. The overall goal of the project is to investigate options for water recycling (increase the thickener overflow recirculation from thickener overflow tank) without affecting nickel and copper metallurgy. The results of the sampling campaigns showed that the water chemistry of the streams was fairly consistent throughout the year with no significant seasonal variations. The laboratory tests illustrated that when higher quantities of thickener overflow from thickener overflow were used, the nickel + copper grade versus nickel recovery curves shifted towards lower values. These observations were observed for the plant water samples obtained in April, June and August 2019.

Evaluation of the Extraction Efficiency of Heavy Metals (Pb, Cd, Cu) in Soil–Bayberry System

ABSTRACT This study focused on the efficiency of three chemical extractions (two single procedures, using EDTA or CaCl2 as a reactant, and a sequential chemical extraction) for selected metals (Pb, Cd, Cu) in real agricultural soils, which are different from most researchers using artificial deployment of contaminated soil. The total concentration of metals in soils is frequently insufficient to ascertain environmental risk. Soil washing based on chemical extraction with inorganic and organic acids, bases, surfactants, chelating agents, and redox agents has been widely applied to estimate the mobility of metals. Our results clearly showed that the applied sequential extraction procedure is less aggressive than EDTA for the studied elements. For estimation of metal mobility in real agricultural soils, EDTA leaching is better adapted for Cu, whereas the sequential extraction procedure is better suited for Pb. Different extractants should be used to assess the environmental risk of different soils, rather than to unify the established methods. The validation of the practicability of the method should be based on actual soil rather than artificial deployment of contaminated soil.

Mesophilic bioleaching performance of copper, cobalt and nickel with emphasis on complex orebodies of the Democratic Republic of Congo: a review of dynamic interactions between solids loading, microbiota activity and growth

The copper, cobalt and nickel ores are still currently mined in the world. Its complex mineralogy creates extraction challenges by means of conventional metallurgical methods. Meanwhile, dealing with mesophilic strains in leaching process requires a compromise between solid loading and microbiota activity and growth. That is why, the influence of solid loading with fine or coarse particulates, the cell disturbance during the metal–microbes interactions depending upon the influence of gangue nature as well as metallic ions concentration on bacterial tolerance and the chemical and biological pathways involved in bioleaching mechanism of complex ores are summarised in detail in this paper. The current trends in mechanism research and diverse discovered set of microbiota and bacterial population coupled with bacterial adaptation methods contribute to optimise and improve the metals leaching performance and knowledge. In addition, the different existing complex mineralogical structures elaborate a main indirect mechanism with two different transitory mechanisms, before metal is converted into metal sulphate as wealthily explained in this comprehensive review. More data for cost analysis concomitant with extraction efficiency of metals using mesophilic bioleaching process are needed. However, it does not mean that other options are excluded in order to set a bio-hydrometallurgical chain. In fact, to consider also the concentration and purification of the pregnant leaching solution via phase separation and solvent extraction will be helpful. This obeys to the idea of option trees, where possible options are then systematically gaged with respect to critical criteria.

Closing the phosphorus cycle: Multi-criteria techno-economic optimization of phosphorus extraction from wastewater treatment sludge ash

The presence of heavy metals in concentrations above legal limit values is one of the main obstacles preventing closure of the phosphorus (P) cycle through directly applying wastewater treatment sludge ash as a fertilizer. Therefore, an alternative procedure is proposed to recover the valuable P from the sludge ash via wet chemical extraction. This comprehensive study uses several inorganic and organic acids, chelating agents and an alkaline solution to establish optimal and cost-effective conditions for wet P extraction from sludge ash. The optimization takes into account co-extraction of the following heavy metals: Cd, Cr, Cu, Ni, Pb and Zn. Design of experiments results show extraction liquid concentration, liquid/solid ratio and contact time all affect P and heavy metal extraction efficiency, both individually and through interaction. In addition, type of extraction liquid and pH at the end of the extraction procedure also affect P and heavy metal extraction efficiency. Combining results of XRD and SEM-EDX analysis with extraction data shows that at a pH <2, both Ca- and Al-phosphates in the ash dissolve easily. However, at slightly higher pH only Ca-phosphates dissolve well and at alkaline pH only Al-phosphates. The best trade-off between high P extraction, low heavy metal co-extraction and low operational costs is obtained with H2SO4 (0.5 N, 10 ml/g, 120 min) and oxalic acid (0.5 N, 12.8 ml/g, 120 min). H2SO4 outperforms the other extraction liquids in terms of extraction liquid costs per kg P extracted, whereas extraction with oxalic acid results in the lowest heavy metal co-extraction, thus reducing the downstream processing costs. None of the extraction liquids considered is appropriate for heavy metal removal prior to P extraction due to loss of P and insufficient heavy metal removal.

Influence of Acids on Extraction Efficiency of Zirconium and Rare Earth Metals in Eudialyte Concentrate Leaching

The influence of nitric, sulfuric and chlorohydric acids on the morphology, composition of elements, structural and chemical transformation of mineral surface and leaching of eudialyte concentrate is studied using a set of the modern analytical techniques. Specific features are revealed in the nature and degree of eudialyte decomposition under the influence of different acids. These features affect the intensity of removal of basic cations of Al, Na, Ca, Mg, K, Ti, Mn, Fe, Sr and Zr from the mineral surface. The behavior and regular patterns in the formation of silica gel and secondary phases during dissolution of eudialyte concentrates are examined. Sulfuric acid, which ensures the highest extraction of Zr and rare earth metals in pregnant solution, contributes to maximum formation of silica gel and considerable quantity of gypsum and insoluble sulfates, which results in high loss of Zr and rare earth metals. The use of nitric and chlorohydric acids reduces the loss of Zr and rare earth metals by 2-5 times.

Chelator-assisted washing for the extraction of lead, copper, and zinc from contaminated soils: A remediation approach

Chelators have proven to be effective extractants in soil washing and represent a suitable remediation technology for potentially toxic elements (PTEs) from contaminated sites. In this paper, the extraction of lead (Pb), copper (Cu), and zinc (Zn) from contaminated real and reference soils using both biodegradable (EDDS and HIDS) and persistent (EDTA and DTPA) chelators was investigated. Different metal–chelator complex formation constants, pH, extraction temperature, and mechanochemical energy were tested. The PTEs were extracted at a relatively higher rate under acidic to neutral conditions (pH 5 and 7), with the greatest extraction being observed at pH 5. The metal extraction efficiencies of the chelators for the real sample at pH 5 were as follows: Pb – EDTA > DTPA > EDDS > HIDS; Cu – DTPA > EDTA > EDDS > HIDS; and Zn – DTPA > EDTA > HIDS > EDDS. The data suggested that EDDS was more effective than HIDS for Cu and Zn extraction in neutral to slightly alkaline solutions, as well as at raised temperature. Furthermore, EDTA washing using mechanochemical agitation was found to enhance the removal efficiency of Cu and Zn. Sequential chemical extraction showed that the apparent metal mobilities were reduced by soil washing. EDTA and DTPA appeared to offer greater potential than the biodegradable chelators in extracting metals from the relatively mobile carbonate- and Fe–Mn oxide-bound fractions. The residual fraction of Pb displayed considerable stability (≥70%), and was not entirely amenable under washing treatments, and hence could be considered non-bioavailable and non-toxic.

Bioleaching approach for extraction of metal values from secondary solid wastes: A critical review

Bioleaching (microbial leaching), being an economical and environmental friendly process, is investigated extensively for metal extraction from secondary solid wastes, viz., electronic wastes, spent catalyst, sludge, slag and fly ash. Bioleaching using acidophiles is routed through generation of ferric (Fe III) and sulphuric acid. Other microbes such as the fungi carryout bioleaching by acidolysis,complexolysis (generation of organic acids), redoxolysis and bioaccumulation method. The cyanogenic microbes in particular possess the ability to extract metal(s) by producing hydrogen cyanide. The bioleaching process is achieved by one-step, two-step and spent medium-step in batch mode or by continuous mode reported to be promising on quantitative extraction of various metals (Ni, Co, Mo, V, Fe, Zn, Cu, Cr, Cd, W, Pb and Mn). Enhanced metal extraction can be accomplished by implementing pretreatment methods like, adding a catalyst, prior adaptation of microbes, bioleaching followed by bioleaching or chemical leaching, ultrasound, and also by optimising the process parameters. Additionally, the use of small size waste particles, low pH, low solid concentration and higher operating temperature could also enhance metal leaching to considerable extent. The review compiles extensive studies on treatment of secondary solid wastes employing chemolithotrophs (acidophiles) and organotrophs (fungi and cyanogens) for metal extraction. The mechanism of bioleaching, candidate microbes, metal extraction efficiency, operational strategies and process improvement are extensively reviewed, discussed and reported.

Improvement of magnetic solvent extraction using functionalized silica-coated Fe3O4 nanoparticles

The application of hydrophobic magnetic nanoparticles functionalized with long carbon chain molecules, such as oleic acid, in the solvent extraction process results in a faster phase disengagement and does not affect the extraction and stripping percentages of cobalt with Cyanex 272, as has been reported in previous studies. However, the chemical stability of this organic phase is limited by its applicability only in contact with aqueous solutions of pH ≥ 2.0. Aiming to overcome such an operational constraint, this study proposed the use of nanoparticles coated with silica and functionalized with a long carbon-chain silane (OTS) in the solvent extraction process. Due to the silica-layer coating of the magnetic core of magnetite and maghemite, such nanoparticles became stable when in contact with aqueous solutions of high acidity of up to 2 mol/L. The proposed nanoparticles were characterized by transmission electron microscopy, X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, and magnetic analysis. Their effect on the solvent extraction of cobalt with Cyanex 272 was investigated using magnetic fluids with different concentrations (0, 10, 20, and 30 g/L of magnetic nanoparticles). It was also observed that, under the conditions studied in this work, the presence of these magnetic nanoparticles did not interfere in the efficiency of metal extraction and stripping. Moreover, the time for the phase disengagement can be reduced by a factor of 25 when compared to the process without magnetic nanoparticles.

Changes in heavy metal mobility and availability in contaminated wet-land soil remediated using lignin-based poly(acrylic acid).

To mitigate the serious ecological problems and risks to human health that are posed by heavy metals in the soil, it is important to enhance the efficiency of heavy metal extraction by washing contaminated soil using chemical methods. Secondary pollution of soil by chemical chelating agents has, however, brought a new threat to the environment. Here, we describe a biodegradable LBPAA (lignin based poly(acrylic acid)) composite that was designed as a chelating agent to wash soil contaminated with Cu2+, Zn2+, Cd2+ and Pb2+ ions. Extraction and ion transfer of heavy metal ions by the LBPAA composite improved the remediation rate of contaminated soil during water leaching. After washing five times, the LBPAA-assisted elution process reduced the amount of Cu2+, Zn2+, Cd2+ and Pb2+ ions in contaminated soil to 22.57%, 52.60%, 13.63% and 17.95%, respectively. These values are 2.39-fold, 5.04-fold, 5.04-fold and 1.31-fold, respectively, better than elution with deionized water. Additionally, LBPAA is able to sequester Cd2+ and Pb2+ ions from the contaminated soil and transfer them to the eluent. In summary, this work provides a safe, environmentally friendly and sustainable remediation strategy for heavy metal-contaminated soil and demonstrates a new application for lignin in the field of soil remediation.

The Sorption Activity of a Cellulose–Fullerene Composite Relative to Heavy Metal Ions

Cellulose was modified via impregnation of a polymer sample with a solution of C60 nanocarbon particles in o-xylene. The sorption kinetics of Cu(II), Ni(II), and Cd(II) ions from an aqueous environment on cellulose and composite material is studied. There is an increase in extraction efficiency of metals with a fullerene-containing sorbent compared with that of initial polymer. Quantitative characteristics of sorption kinetics are found for metal ions in the framework of models of pseudo-first- and pseudo-second-order reactions. The equilibrium sorption of Cu(II) ions on cellulose and composite is described with different isotherms, which is due to different mechanisms of interaction of metal ions with initial cellulose and composite.

Influence of Acids on Extraction Efficiency of Zirconium and Rare Earth Metals in Eudialyte Concentrate Leaching

Influence of Acids on Extraction Efficiency of Zirconium and Rare Earth Metals in Eudialyte Concentrate Leaching

Combination of Ultrasonication and Induced Emulsion Breaking for Efficient Extraction of Wear Metals from Lubricating Oils with Inductively Coupled Plasma–Mass Spectrometry Determination

This work proposed a procedure based on combining the advantages of ultrasonic extraction and extraction induced by emulsion breaking techniques to enhance the extraction efficiency of metals (Fe, Cu, Cr, Ni and Pb) from oil samples. In the first part, extraction induced by emulsion breaking used to analyse composition and contaminants of lubricating oils. It is found that differences and diversities in oil samples leads to difficulty in separation of the aqueous phase from oil, which gives low metals recovery. In the second part, the oil samples were analyzed using the combination procedure, where all extraction phases were completely separated. A circulation bath was used as separation medium, which provided a clearer aqueous part. The oil phase is completely separated from the aqueous phase and two phases are stable for hours without any interference between them. In comparison with previous works that did not collect more than 75%, the proposed method collects almost 95% of the aqueous phase for further inductively coupled plasma mass spectrometry analysis.

Identification of Surface Processes in Individual Minerals of a Complex Ore through the Analysis of Polished Sections Using Polarization Microscopy and X-ray Photoelectron Spectroscopy (XPS)

Understanding the changes of a mineral during ore processing is of capital importance for the development of strategies aimed at increasing the efficiency of metal extraction. This task is often difficult due to the variability of the ore in terms of composition, mineralogy and texture. In particular, surface processes such as metal re-adsorption (preg-robbing) on specific minerals are difficult to evaluate, even though they may be of importance as the re-adsorbed material can be blocking the valuable mineral and negatively affect the extraction process. Here, we show a simple yet powerful approach, through which surface processes in individual minerals are identified by combining polarization microscopy (MP) and X-ray photoelectron spectroscopy (XPS). Taking as an example a silver-containing polymetallic sulfide ore from the Peruvian central Andes (pyrite-based with small amounts of galena), we track the changes in the sample during the course of cyanidation. While polarization microscopy is instrumental for identifying mineralogical species, XPS provides evidence of the re-adsorption of lead on a pyrite surface, possibly as lead oxide/hydroxide. The surface of pyrite does not show significant changes after the leaching process according to the microscopic results, although forms of oxidized iron are detected together with the re-adsorption of lead by XPS. Galena, embedded in pyrite, dissolves during cyanide leaching, as evidenced by PM and by the decrease of XPS signals at the positions associated with sulfide and sulfate. At the same time, the rise of a lead peak at a different position confirms that the re-adsorbed lead species cannot be sulfides or sulfates. Interestingly, lead is not detected on covellite surfaces during leaching, which shows that lead re-adsorption is a process that depends on the nature of the mineral. The methodology shown here is a tool of significant importance for understanding complex surface processes affecting various minerals during metal extraction.

Oxidative leaching of a sulfidic flue dust of former copper shale processing with focus on rhenium

The investigation aims at a hydrometallurgical processing approach for an environmentally hazardous material called “Theisenschlamm”, which is a flue dust of former copper shale processing in Germany. Besides eliminating the negative environmental impact, processing of this material would also be a contribution to a circular economy, since it contains about 16 wt.-% zinc, 14 wt.-% lead, minor amounts of copper and tin, as well as valuable elements of strategic economic importance, such as rhenium, molybdenum and germanium. The mainly sulfidic matrix of the Theisenschlamm was characterised using scanning electron microscopy in combination with QEMSCAN software. Leaching of Theisenschlamm in acidic and alkaline media, as well as the effect of oxidising agents, was studied in order to extract zinc, copper, rhenium, germanium and molybdenum. In both sulphuric acid and sodium hydroxide solutions, the addition of oxidising agents (hydrogen peroxide and ozone) improved metal extraction efficiencies significantly. The leaching system sulphuric acid/hydrogen peroxide was investigated in more detail, with focus on the optimisation of rhenium extraction and its effect on the extraction efficiencies of the other target elements. Response surface methodology was applied with respect to H2SO4 concentration (0.1–1.2 mol/L), H2O2 concentration (0.1–2.8 mol/L) and solid:liquid ratio (40–150 g/L). This study shows that oxidative leaching enables the extraction of zinc, copper, rhenium, germanium and molybdenum from this sulfidic material. In terms of rhenium extraction, a low acid concentration is favourable; however, lowering the acid concentration results in a reduced yield of other target elements (e.g. molybdenum).

Removal of toxic metals from canola oil by newly synthesized calixarene-based resin

This study describes the synthesis, characterization, and application of a new $p-$sulfonatocalix[4]arene-based silica resin (calix-resin 5) for the extraction of selected metals, namely Pb, Cd, Co, Ni, Cu and Fe, from canola oil. Synthesis, morphology, purity, and elemental composition of calix-resin 5 were analyzed by FT-IR spectroscopy, scanning electron microscopy, and energy-dispersive spectroscopy. The metal extraction efficiency of calix-resin 5 was evaluated through the batch-wise method with a flame and graphite furnace atomic absorption spectrometer following the wet acid digestion procedure. The results obtained showed that the newly fabricated adsorbent material calix-resin 5 is an efficient adsorbent and exhibits great potential as an alternative adsorbent for the extraction of selected Pb, Cd, Co, Ni, Cu, and Fe in canola oil metal extraction as compared to conventional clay or pure silica.