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The new reagent N-methyl-N-((((4-chlorophenyl)diazenyl)thio)carbonothioyl)aniline (L) was synthesized via the reaction of sodium N-methyl-N-phenyldithiocarbamate with 4-chlorobenzenediazonium salt. The reagent was identified with many techniques, such as CHNS elemental analysis, UV-vis spectroscopy, FTIR spectroscopy, mass spectroscopy, 1H-NMR, and 13C-NMR spectroscopy. The Fe(II) ion was utilized to create a metal complex by reacting 2 mol of reagent with 1 mol of iron(II) chloride. Two approaches that were utilized for M:L ratio determination are mole ratio and Job methods. All of these refer to the 1:2 ratio for the complex. The solid complex was prepared and identified with the previous techniques, and additional electrical molar conductivity, and magnetic susceptibility measurements. A tetrahedral structure for the prepared complex was suggested based on spectroscopic measurements and elemental analysis results. Cloud point extraction was created for the preconcentration and separation of Fe(II) in drug samples by forming a rich phase using Triton X-114 at 80 °C temperature and pH 5 measurements utilizing flame atomic absorption spectroscopy and UV-vis spectrophotometer at λmax 635 nm. The calibration curve of Fe(II) was linear in the extent of 0.2–1.0 μg/mL with r2 of 0.996. The detection limit and quantification are 0.0504 and 0.1530 μg/mL.

Magnetic ion-imprinted polymers (MIIPs) are an innovative material that combines the selectivity of ion imprinting with the ease of separation provided by magnetic properties. Recent advancements in MIIPs have shown that they have higher selectivity coefficients compared to non-imprinted materials. The synthesis of MIIPs involves creating specific recognition sites for target ions in magnetic nanomaterials. Various nanomaterials, such as graphene oxide, carbon nanotubes, and silica, have been incorporated into the IIPs to improve their analytical performance for different environmental applications, including metal extraction, monitoring, detection, and quantification. This review stresses the need to develop new monomers with a high affinity for the target analyte and to find supporting materials with groups that facilitate the effective removal of the target analyte. It also explores the influence of experimental parameters on metal determination. [ABSTRACT FROM AUTHOR]

Phosphate is a vital element necessary for the growth and development of plants, making it a crucial element in agricultural fertilizers. Extracting phosphate from wastewater for recovery aligns with the principles of a circular economy by closing the loop on nutrient cycles. Instead of viewing wastewater as a waste product, treating it as a resource for recovering valuable nutrients like phosphate promotes a more sustainable and efficient use of resources. In this study, the phosphate from synthetic wastewater was pre-concentrated by a continuous flow forward osmosis membrane system to facilitate effective precipitation. The pre-concentration feasibility of forward osmosis was studied by changing the draw concentration, feed concentration, feed pH, and flow rate of the feed solution. With the optimum operational parameters in batch mode such as pH of 7, the draw solute concentration of 0.4 M MgSO4, the feed and draw flowrate of 0.7 L/min and 0.3 L/min, the phosphate concentration was increased from 30 mg/L to 525 mg/L after 60 min, the average osmotic flux and reverse solute flux was 2.7 L/m2/h and 0.43 g/m2/h, respectively. As operated with continuous mode, the final phosphate concentration was increased four times, the average osmotic flux was higher with 8.1 L/m2/h and the reverse solute flux was 0.86 g/m2/h, which could improve the efficiency of calcium phosphate crystallization in precipitation/ crystallization reactors. This integrated system, which includes forward osmosis as a pretreatment method followed by a precipitation process, is technically possible for application on a larger scale as a circular economy approach.

A fast and accurate identification of Listeria monocytogenes. A new quartz crystal microbalance (QCM) aptasensor was designed for the specific and rapid detection of L. monocytogenes. Before detection of the target bacterium from samples in the QCM aptasensor, a magnetic pre-enrichment system was used to eliminate any contaminant in the samples. The prepared magnetic system was characterized using ATR-FTIR, SEM, VSM, BET, and analytical methods. The saturation magnetization values of the Fe3O4, Fe3O4@PDA, and Fe3O4@PDA@DAPEG particles were 57.2, 40.8, and 36.4 emu/g, respectively. The same aptamer was also immobilized on the QCM crystal integrated into QCM flow cell and utilized to quantitatively detect L. monocytogenes cells from the samples. It was found that a specific aptamer-magnetic pre-concentration system efficiently captured L. monocytogenes cells in a short time (approximately 10 min). The Fe3O4@PDA@DA-PEG-Apt particles provided selective isolation of L. monocytogenes from the bacteria-spiked media up to 91.8%. The immobilized aptamer content of the magnetic particles was 5834 µg/g using 500 ng Apt/mL. The QCM aptasensor showed a very high range of analytical performance to the target bacterium from 1.0 × 102 and 1.0 × 107 CFU/mL. The limit of detection (LOD) and limit of quantitation (LOQ) were 148 and 448 CFU/mL, respectively, from the feeding of the QCM aptasensor flow cell with the eluent of the magnetic pre-concentration system. The reproducibility of the aptasensor was more than 95%. The aptasensor was very specific to L. monocytogenes compared to the other Listeria species (i.e., L. ivanovii, L. innocua, and L. seeligeri) or other tested bacteria such as Staphylococcus aureus, Escherichia coli, and Bacillus subtilis. The QCM aptasensor was regenerated with NaOH solution, and the system was reused many times. [ABSTRACT FROM AUTHOR]

Mineral deposits have shown decreasing ore grade and increasing complexity, which has led mining projects to experience increased capital and operating costs. Preconcentration is an alternative to minimize such costs. Notwithstanding the resulting rise in ore grade and reduction in feed mass, the generated tailings may contain significant amounts of the material of interest. In order to improve the mineral liberation at this stage, selective comminution proposes to explore different comminution mechanisms. This investigation compared three different crushing methods (jaw crusher, impact crusher, and high-pressure roller mill) for three different types of ores and the response of their products to pre-concentration, using a gravity method that was evaluated through heavy-liquid separation of the -6.35+3.35 mm crushed fraction. This fraction represents approximately 15% of the total sample, and is used as an indication of the gangue rejection potential for the -12+1.18 mm fraction. Copper and polymetallic ores showed good pre-concentration results for this size range at laboratory scale, with metallurgical recoveries greater than 90% and a rejection of over 20% of mass. Iron ore showed a 97% metallurgical recovery and 10% mass rejection. The impact crusher proved to be the best option for selective comminution for the polymetallic ore, with the highest metallurgical recovery. Finally, no significant differences were observed when using any of the three crushing mechanisms for the copper and iron ore. [ABSTRACT FROM AUTHOR]

This research used a simple and efficient liquid-phase microextraction method based on deep eutectic solvents for preconcentration and spectrophotometric determination of purpurin (1, 2, and 4-trihydroxyanthraquinone) dye. The choline chloride-acetic acid DES with a molar ratio of 1:2 was synthesized and used with 1-Decanol as the extraction solvent. The influence of effective parameters on the extraction efficiency, including the type and volume of extracting solvents, pH of sample solution, the molar ratio of DES components, and sodium chloride salt concentration were studied, using the response surface method. The highest extraction percentage (>95%) was obtained at pH = 5.5, 550 mg/L of sodium chloride, 350 and 500 µL of DES, and 1-Decanol solvents, respectively. The effect of different ions and dyes on the extraction efficiency was examined and the results indicated that the method has an acceptable selectivity. The present process was linear in the concentration range of 5.0 × 10-7 to 2.0 × 10-5 mol/L of purpurin, with a detection limit of 2.7 × 10-7 mol/L, preconcentration factor of 100, and a relative standard deviation of 3.13%. Finally, to test the applicability of the proposed method, it was investigated for the uptake of purpurin from various water samples, successfully. [ABSTRACT FROM AUTHOR]

Hg isotope analysis in samples from background regions is constrained by the presence of low Hg concentration and therefore requires a pre-concentration method. Existing Hg pre-concentration methods are constrained by long sample processing time and limited sample loading capacity. Using foliar samples as a test case, an optimized Hg pre-concentration method is presented that involves the microwave-assisted digestion of samples for Hg isotope analysis with the addition of a pre-digestion step. Microwave-digested foliar samples and CRMs were transferred to an impinger, reduced with SnCl2, and collected in a 2.25 mL concentrated inverse aqua regia (3:1 HNO3:HCl, v/v). This resulted in an optimal acid concentration in the solution ideal for analysis on MC-ICP-MS. The time for purging with Hg-free N2 was optimized to 30 min and the efficiency of the pre-concentration method was tested using a combination of approaches. Tests performed on pure reagents and matrix of foliar samples spiked with 197Hg radiotracer showed recoveries averaging 99 ± 1.7% and 100 ± 3.0%, respectively. Mercury at concentrations as low as 1.83 ng g−1 was pre-concentrated by digesting aliquots of foliage samples in individual digestion vessels. Recoveries following their pre-concentration averaged 99 ± 6.0%, whereas recoveries of 95 ± 4.7% and 95 ± 2.5% were achieved for NIST SRM 1575a (pine needle) and reagents spiked with NIST SRM 3133, respectively. Analysis using multicollector-ICP-MS showed low fractionation of δ202Hg during sample pre-concentration with no significant mass-independent fractionation. The proposed method is a relatively simple and robust way to prepare Hg samples for Hg isotopic analysis and is suitable even for complex biological matrices. [ABSTRACT FROM AUTHOR]

The Balzhe rare earth deposit, located in Inner Mongolia, China, is a complex deposit that also contains niobium and zirconium. However, it remains undeveloped. One notable challenge is the low grades of the main valuable minerals, including xinganite, zircon, niobite, ilmenorutile, pyrochlorite, eschynite, monazite, and bastnaesite. These minerals are either weakly magnetic or associated with ilmenite, a paramagnetic mineral. To overcome this, a high-intensity magnetic method can be employed to separate these valuable minerals from the gangue minerals, thereby generating enriched products to lower the cost of the following flotation. In this study, the first step involved utilizing a high-intensity magnetic separation to enrich particles in different size fractions. It was observed that the size fraction of −0.5 + 0.02 mm was particularly suitable for effective separation. Subsequently, staged magnetic pre-concentration was conducted to obtain products with varying specific magnetization coefficients. To optimize the applied magnetic field intensity, a combination of a high-intensity magnetic separator and a superconducting magnetic separator was employed at different magnetic induction intensities. This proposed technique not only reduces reagent costs but also enhances the operational efficiency of subsequent flotation processes. By implementing this approach, it is anticipated that the Balzhe rare earth deposit can be effectively processed, overcoming the challenge of low-grade valuable minerals. This would contribute to improved economic viability and operational efficiency in the extraction of rare earth elements, niobium, and zirconium from the deposit. [ABSTRACT FROM AUTHOR]

The Balzhe rare earth mine, renowned for its rich reservoirs of niobium, zirconium, and rare earth elements, poses a unique challenge due to its diverse and interbedded mineral composition. Despite the abundance of these elements, their valuable grade remains notably low, falling short of economic thresholds. To this end, pre-concentration of valuable minerals to discard gangue minerals before flotation would be an economical option. In response, this study delves into the feasibility of gravity-induced pre-concentration, aiming to segregate valuable minerals from gangue for subsequent flotation processes. Conducting float-and-sink tests on varied particle sizes (-2+0.5 mm, -0.5+0.074 mm, and -0.074+0.02 mm) within heavy liquids of specific gravities (ranging from 2.55 to 2.85), the study reveals the effectiveness of gravity separation. Notably, particles sized -2+0.5 mm and -0.074+0.02 mm demonstrated superior separation performance over the -0.5+0.074 mm fraction. Comparative analysis of diverse gravity separation equipment unveiled compelling results. The dense medium cyclone separator showcased impressive recovery rates and high-grade concentrates of Nb2O5, ZrO2, and total rare earth oxides (TREO) at 0.34%, 8.20%, and 0.41%, respectively, surpassing the sand table's performance for -2+0.5 mm particles. Conversely, for -0.5+0.074 mm particles, the shaking table exhibited optimal separation efficiency, yielding grades of Nb2O5, ZrO2, and TREO at 0.37%, 4.08%, and 0.44%, with substantial recovery values. Ultimately, the Knelson centrifugal separator proved most effective for -0.074+0.02 mm particles, yielding notable grades and recoveries of Nb2O5, ZrO2, and TREO. This study underscores the promising potential of gravity-induced pre-concentration techniques for enhancing the recovery of valuable elements from the complex Balzhe rare earth ore, offering critical insights into optimizing mineral extraction processes. [ABSTRACT FROM AUTHOR]

Hazelnut shell biosorbent immobilized on Amberlite XAD-4 polymer resin as solid phase extraction method was developed and used for preconcentration of Cu(II) and Cd(II) ions from aqueous solutions. Concentrations of analytes in solutions were determined by Flame Atomic Absorption Spectrometry after extraction with column technique. Functional groups of nutshell biosorbent immobilized on resin were characterized by Fourier transform infrared spectrometry. Optimized critical parameters for preconcentration of Cu2+ and Cd2+ ions from sample solutions with nutshell immobilized on the resin were the pH value of solution, type of eluent solutions, the flow rate of sample solution, quantities of nutshell biosorbent, Amberlite XAD-4 resin, and enrichment factors, respectively. Detection limits of Cu2+ and Cd2+ ions found were 0.29 µg L-1 and 0.25 µg L-1, respectively. The method proposed was applied for determinations of Cu2+ and Cd2+ ions in standard reference material (BCR-670 aquatic plant sample) for accuracy and applied to real water samples such as wastewater and Van lake water. At the 95% confidence level, relative standard deviations (RSDs) were found as 1.44% for Cd2+ and 1.21% for Cu2+ ions with three replicate measurements. [ABSTRACT FROM AUTHOR]

Abstract Mineral deposits have shown decreasing ore grade and increasing complexity, which has led mining projects to experience increased capital and operating costs. Preconcentration is an alternative to minimize such costs. Notwithstanding the resulting rise in ore grade and reduction in feed mass, the generated tailings may contain significant amounts of the material of interest. In order to improve the mineral liberation at this stage, selective comminution proposes to explore different comminution mechanisms. This investigation compared three different crushing methods (jaw crusher, impact crusher, and high-pressure roller mill) for three different types of ores and the response of their products to pre-concentration, using a gravity method that was evaluated through heavy-liquid separation of the -6.35+3.35 mm crushed fraction. This fraction represents approximately 15% of the total sample, and is used as an indication of the gangue rejection potential for the -12+1.18 mm fraction. Copper and polymetallic ores showed good pre-concentration results for this size range at laboratory scale, with metallurgical recoveries greater than 90% and a rejection of over 20% of mass. Iron ore showed a 97% metallurgical recovery and 10% mass rejection. The impact crusher proved to be the best option for selective comminution for the polymetallic ore, with the highest metallurgical recovery. Finally, no significant differences were observed when using any of the three crushing mechanisms for the copper and iron ore.

The carcinogenic and teratogenic properties of mercury have driven the necessity for the development of highly sensitive methods capable of detecting even trace amounts of the element. In response to this need, an analysis technique has been established for mercury ions, employing preconcentration methods utilizing filter paper modified by silver nanoparticles (AgNPs) and 3-Amino propyl trimethoxy silane (APTMS). This method allows for the detection of mercury ions through the voltammetry technique, ensuring accurate and reliable results. Upon conducting analyses using this method, it was found that the tested cosmetic samples were free from Hg2+ ions, indicating the absence of mercury contamination in the cosmetics under investigation. The correlation coefficient derived from the graph of the analysis results stands at an impressive value of 0.9976, affirming the strong relationship between the measured concentrations and the actual mercury content. Additionally, the method demonstrates excellent sensitivity, as evidenced by the low limit of detection (LOD) value of 0.0483 mM and the limit of quantification (LOQ) value of 0.1611 mM.

the thallium concentration in water is very low but highly toxic and susceptible to the interference of co-existing ions in water. The pre-concentration and accurate detection technology of trace Thaium are summarized. The research progress of various methods for removing thallium from water is summarized. At present the emergency treatment of excessive thorium in drinking water is mainly to strengthen flocculation' and the removal of thallium in wastewater is mainly by adsorption' and the current trend is to develop highly selective' efficient and recyclable adsorbents. The deficiency of the removal capacity of a single method is pointed out' and the prospect of the development of efficient coupling technology is presented ' with a view to its application in drinking water. [ABSTRACT FROM AUTHOR]

We present five new sorbents for the evaluation of the pre-concentration of L-carnitine. The sorbents were obtained from copolymerization between butylmethacrylate (BuMA) and ethylene dimethacrylate (EDMA), which were physically modified on their surface by each one of the five synthetized resorcinarenes of variable chain length studied, with long-chain resorcinarenes exhibiting better fixation on the copolymer. The characterization of the synthesized resorcinarenes was done using FTIR-ATR, 1H NMR, 13C NMR, and mass spectrometry, while characterization of the sorbents was done using FTIR-ATR and scanning electron micrography (SEM). The molecular interaction between L-carnitine and the synthesized resorcinarenes was studied in DMSO via 1H-NMR spectroscopy and, in the gas phase, via electrospray ionization-mass spectrometry (ESI-MS). The results showed that the short-chain resorcinarenes underwent a stable interaction with the neurotransmitter. Once the sorption of resorcinarenes on the copolymer was accomplished, the best parameters for the evaluation of the L-carnitine preconcentration were established. The solution tests were carried out through LC/MS analysis, obtaining better results for L-carnitine absorption with the short-chain resorcinarenes such as tetra(ethyl)calix[4]resorcinarene and tetra(propyl)calix[4]resorcinarene. [ABSTRACT FROM AUTHOR]

In the process of iron ore beneficiation, a considerable amount of iron was lost to the tailings, resulting in the waste of resources and environmental pollution. In this study, an innovative technology of pre-concentration followed by suspension magnetization roasting and low-intensity magnetic separation (PSRM) was used to recover iron from iron tailings. The iron grade of the roasted feed ores was increased from 15.68% to 33.19% by pre-concentration process. Subsequently, the suspension magnetization roasting was performed to transform the weak magnetic minerals into magnetite, and magnetite concentrate was obtained via low-intensity magnetic separation. The effects of feeding rate, roasting temperature, reducing gas CO flow rate, and fluidizing gas N2 flow rate during suspension magnetization roasting were investigated, and the pilot-scale equipment was conducted for 72 h continuously under the optimum roasting conditions. The phase transformation and magnetic property variations of the minerals before and after roasting were analyzed by X-ray diffractometer (XRD) and vibrating sample magnetometer (VSM), respectively. The results showed that an iron concentrate with iron grade of 63.04% and total iron recovery of 48.40% was obtained under the optimum roasting conditions: feeding rate of 111.70 kg/h, roasting temperature of 550°C, CO flow rate of 4.0 m3/h, and N2 flow rate of 2.0 m3/h. The hematite and siderite in tailings were transformed into magnetite with an average magnetic conversion rate of 86.46%. This innovative PSRM technology provides an important reference for the resource utilization of solid waste and the recovery of iron from iron tailings. [ABSTRACT FROM AUTHOR]

For the first time, copper oxide–coated glass beads (CuO-GBs) were fabricated using physical vapor deposition (PVD) technology for sequestrating Pb2+ ions from solution is addressed. Compared to other coating procedures, PVD offered high-stability uniform CuO nano-layers attached with 3.0-mm glass beads. Heating of copper oxide–coated glass beads after deposition was rather necessary to achieve the best stability of the nano-adsorbent. Detection of nano-size copper oxide on the beads was made by FTIR (intense peak at 655 cm−1 for CuO bond stretching) and XRF (Cu peak at 8.0 keV). Scanning electron micrographs taken at high magnification power indicated the presence of CuO in nano-range deposited over glass beads. The maximum deposited amount of CuO on the beads was 1.1% and accomplished at the following operational conditions: internal pressure 10–5 mmHg, Ar flow rate 8.0 mL/min, voltage 84 V, pre-sputtering time 20 s, total sputtering time 10.0 min, and post-heating temperature 150 °C for 3 h. A univariate analysis indicated that the optimum Pb2+ uptake by CuO-GBs from solution was achieved at pH 7.0–8.0, 7 beads/50 mL, 120-min contact time, and 15-mg/L initial concentration. Kinetic data for Pb2+ uptake was best presented by a pseudo–second-order model with a relative prediction error of 3.2 and 5.1% for GBs and CuO-GBs, respectively. On the other hand, Pb2+ equilibrium isotherms at 25 °C were fairly presented by the Langmuir model, and the predicted saturation values were 5.48 and 15.69 mg/g for GBs and CuO-GBs, respectively. CuO and CuO-GBs had similar Pb2+ saturation values (~ 16 mg/g), although the latter demonstrated 4 times faster kinetic, thanks to fixation CuO on glass beads. Moreover, the chemical stability of copper oxide–coated glass beads was tested under different conditions. Recycling of copper oxide–coated glass beads was also investigated, and 90% of the surface was recovered using 0.01-M HNO3. [ABSTRACT FROM AUTHOR]

In this study, a superconducting high gradient magnetic separation (S-HGMS) technology was used to separate and extract quartz from sea sand. Under optimal conditions (i.e., a magnetic flow ratio of 0.085 T·s/m, slurry flow velocity of 400 ml/min, and pulp concentration of 40 g/L), the SiO2 grade increased from 79.45% of the raw material to 91.35% of quartz concentrate, and the removal rate of Al and Fe reached 91.97% and 82.10%, respectively. Weakly magnetic particles in sea sand were selectively transformed to tailings, and the pre-concentration of quartz was achieved under a high magnetic field intensity. The high magnetic field intensity and mineral magnetic differences were the critical factors influencing the magnetic separation of quartz from sea sand. The S-HGMS technology achieved effective pre-concentration of quartz from sea sand, reducing the handling capacity and providing a high-quality material for subsequent quartz refinement processes. [ABSTRACT FROM AUTHOR]

The technological and mineralogical characterization of gold ores faces several obstacles due to the low contents, occurrence in micrometric grains, possible nugget effect and anomalous occurrence. In order to increase the concentration in content and mass of the phases of interest and gold-bearing minerals, pre-concentration operations have been applied in studies to characterize the forms of occurrence and associations of gold by analyzing scanning electron microscopy images. The use of mineral separation using heavy liquids and hydroseparation systems, such as the Mozley table and elutriation, allows the concentration of high specific weight minerals in a more agile operation, with high recovery of the minerals of interest and with greater ease of standardization and control operational. In this study, the densitary pre-concentration was evaluated for three samples of gold ores of different grades by elutriation, heavy liquid and Mozley table. Elutriation was the procedure that presented the best performance in relation to gold recovery and enrichment in the five granulometric ranges studied. [ABSTRACT FROM AUTHOR]

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• High voltage pulse pre-concentration was compared between two generators. • A gold-copper ore was tested. • Different pre-concentration efficiencies were observed. • Likely caused by differences in the selective breakage of high-grade rocks. High Voltage Pulse (HVP) enabled ore pre-concentration can potentially provide large energy savings and the ability to upgrade low-grade ores for the mining industry. Two types of pulse generator systems commonly used in HVP breakage are Marx generators and pulse transformers. This initial assessment compares the pre-concentration performance of a SelFrag Lab Unit (utilising a Marx generator) and a custom-built HVP machine (employing a pulse transformer) from Huazhong University of Science and Technology (HUST). Eight sets of experimental results using the two generator systems were collected. Two approaches were taken to analyse the data; a trendline approach using all eight sets of data, and a single-point comparison approach with matched specific energy inputs. The results show that there are significant differences in pre-concentration efficiencies with the HUST machine performing better. To elucidate the potential causes, the degree of size reduction (t 10), breakage probability, and selective breakage were investigated for the two generator systems. It is likely that the efficiency of selective breakage is one of the major causes, with the HUST machine presenting better results at selectively breaking high-grade particles and consuming less energy. Additionally, the two generator systems have different energy per discharge levels; the effect of this difference should be investigated in future work. [ABSTRACT FROM AUTHOR]

While unrefined sugar/jaggery consumption has various health benefits, unsustainable and inefficient production processes can negatively impact the environment and health. This study proposes a novel, sustainable approach to jaggery production using solar energy. The primary concentration is done in a VARS system, followed by the secondary concentration in a solar still field at low temperatures to maintain jaggery quality. The study presents experimental observations from the developed inclined solar still with external reflectors to preheat and concentrate the juice. In the absence of sun, the solar still field functions as an evaporation-condensation unit under auxiliary heating. By connecting several solar stills in series, the energy requirements from the PTC field can be reduced. The system is capable of producing a by product of distilled water, amounting to 169.78 kg/day, under varying solar radiation in April at Chennai, India. The overall energy efficiency of the system is 48.31 % under solar load, and 63.05 % under auxiliary heating. The system also leads to enhancement in CO 2 mitigations, amounting to around 3134.7 tons of CO 2 from dry bagasse combustion. Due to the added revenue from distilled water production, the system's payback period is reduced to as low as 4.89 years, depending on product selling price. • Sustainable, energy efficient solution for jaggery production using solar energy. • Two-stage pre-concentration of sugar cane juice at lower temperatures to retain quality. • Secondary pre-concentration of juice using evaporation-condensation unit leading to additional byproduct. • Experimental investigations on concentrated inclined solar still handling sugarcane juice. • Reduced economic payback period of system due to distillate byproduct. [ABSTRACT FROM AUTHOR]

• UAE is the most advanced method used today for the extraction of kaempferol. • The best extraction yield for kaempferol was achieved (under reflux). • HPLC remains immeasurably the most robust approach for quantification. • Kaempferol is primarily sourced from the Asteraceae and Fabaceae families. • Among plant flavonoids, kaempferol is a potent health benefits. As a naturally widely-occurring dietary, cosmetic, and therapeutic flavonoid, kaempferol has gained much consideration for its nutritional and pharmaceutical properties in recent years. Although there have been performed a high number of studies associated with different aspects of kaempferol's analytical investigations, the lack of a comprehensive summary of the various methods and other plant sources that have been reported for this compound is being felt, especially for many biological applications. This study, aimed to provide a detailed compilation consisting of sources (plant species) and analytical information that was precisely related to the natural flavonoid (kaempferol). There is a trend in analytical research that supports the application of modern eco-friendly instruments and methods. In conclusion, ultrasound-assisted extraction (UAE) is the most general advanced method used widely today for the extraction of kaempferol. During recent years, there is an increasing tendency towards the identification of kaempferol by different methods. [ABSTRACT FROM AUTHOR]

Biosurfactants can be potentially used in food, cosmetics, pharmaceuticals, and environmental remediation because of their biodegradability and low toxicity. However, it is very challenging to recover biosurfactants from fermented broth as they are temperature-sensitive and present at dilute concentrations. This study aims to develop an alternative process that uses cloud point extraction (CPE) to recover lipopeptides biosurfactant from cell-free broth of Bacillus sp. GY19. The nonionic surfactant, Triton X-100, was selected as the aqueous-based solvent for CPE. Under the optimal conditions lipopeptides concentration in Triton X-100 was 23,000 mg/L, which is 14.8-folds higher than that in cell-free broth. Lipopeptides and Triton X-100 exerted a positive synergistic effect in reducing the critical micelle concentration of mixed micelles with a β value of −1.9. This could be considered a co-benefit of using CPE for biosurfactant recovery. Two techniques for back extraction of lipopeptides after the CPE process were proposed. Silica gel 60 selectively adsorbed Triton X-100 with 44% removal, while maintaining lipopeptides recovery at 86%. Cold acetone precipitation could remove 99% of Triton X-100 by precipitating lipopeptides. However, a 1%(w/v) SDS solution had to be used to re-solubilize the dehydrated lipopeptide [ABSTRACT FROM AUTHOR]

Direct ceramic microfiltration (DCMF) is an effective technology to pre-concentrate organic matter (OM) for the subsequent anaerobic energy-recovering processes and a fast, cost-effective, easy treatment process for municipal wastewater. The major problem in DCMF is the rapid fouling of the membrane. In this study, to maximize OM recovery rates and prevent membrane fouling, the DCMF process was alternately paired with dosing of a cationic polyacrylamide (PAM) flocculant and chemically enhanced primary sedimentation (CEPS). The DCMF process tested in three stages: (i) optimization of flocculant concentration (0.5, 1, 1.5, and 2 mg/L PAM) and dosing point, (ii) optimization of operational conditions (pH, filtration/backwash duration, flux, and recovery rate) to control membrane fouling, and (iii) long-term operation of the DCMF process. The influence of PAM dosage points on DCMF fouling behavior was explored, and system operating parameters in terms of OM recovery and TMP change were optimized. The CEPS + DCMF setup was discovered to be a potential option for overcoming fouling. The highest chemical oxygen demand (COD) was 520 ± 20 mg/L in the concentrated wastewater using CEPS + DCMF experiments for 0.5 mg/L PAM. The highest OM pre-concentration was achieved at 90% recovery rate. After the optimization, COD concentration in the concentrate of the DCMF process reached 822 mg/L for the long-term (20 days) operation. The net potential energy production was calculated as 0.28 kWh/m3 considering the theoretical COD of 1432 mg/L in the concentrate stream. As a novel approach, the CEPS + DCMF process can be used in place of conventional municipal wastewater treatment processes due to its acceptable OM removal performance, simple operation, small footprint, and potential energy generation. [ABSTRACT FROM AUTHOR]

A new high-efficiency pre-enrichment technology was studied for the recovery of non-ferrous metals from waste rock of mining stripping in Yunnan Dulong.The process mineralogy results showed that the waste rock contains about 0.1% Sn, and the associated relationship of the different valuable minerals was relatively simple.The tin-containing stripped waste rock were divided into four size fraction (-120-+25,-25-+5,-5-+0.5 and-0.5 mm). The photoelectric concentrator was used for pre-enrichment recovery for-120-+25 mm size fraction.The coarse jig was used for pre-concentration recovery for-25-+5 mm size fraction.The fine-grain jig was used for pre-concentration and recovery for the-5-+0.5 mm size fraction. Pre-enrichment recovery was carried out by spiral concentrator for the-0.5 mm size fraction.By using different beneficiation processes and combined equipment to pre-enrich tin-containing waste rock with different size fraction, the obtained concentrate products had a tin grade of 0.29% with a recovery of 56.82%,and the enrichment ratio was 2.74.The new technology of pre-enrichment is of great significance to the security of strategic tin resources, the improvement of comprehensive utilization of tin resources, and prolonging the service life of mines. [ABSTRACT FROM AUTHOR]

To achieve the utilization of the abandoned ultrafine ilmenite (−20 μm) produced in the titanium magnetite processing plant in Panzhihua, the superconducting high-gradient magnetic separation (SMS) technology was proposed in this study. After optimizing the conditions of magnetic intensity, feeding and pulsation, an SMS concentrate with TiO2 grade of 16.03% and TiO2 recovery of 66.39% was obtained through one roughing–one cleaning pre-concentration flowsheet. The specific magnetic force and magnetic force were calculated and analysed to illustrate the pre-concentration mechanism, and the results revealed that the combination of high magnetic field and strong pulsating resulted in the effective pre-concentration of the ultrafine ilmenite in the SMS process. In addition, the magnetic force analysis indicated that the high magnetic intensity and high magnetic gradient are the key factors of the SMS technology. Furthermore, the EDS-Mapping detection certified that the ultrafine ilmenite was concentrated from the gangue minerals using SMS technology.

Synthesis, characterization, and application of 3‐pyridinecarbaldehyde immobilized on MCM‐41 (Py−N‐MCM‐41) was studied. Trace analysis and pre‐concentration of copper ions in water samples was done by Py−N‐MCM‐41as an adsorbent prior to flame atomic absorption spectrometry. X‐ray diffraction of calcined MCM‐41 exhibited that is characteristic of the mesopores silica with hexagonal symmetric structure. Fourier transform infrared spectrum of the Py−N‐MCM‐41demonstrated the existence of functional groups and N2 adsorption‐desorption showed Brunauer‐Emmett‐Teller surface area of 770 m2 g−1 and pore diameter of 2.42 nm. After 30 min stirring, Cu2+ was extracted at pH 5–7. The highest adsorption capacity of the Py−N‐MCM‐41 was 135 μg mg−1. Based on the lowest quantity of acid to strip the ions from adsorbent, the technique's pre‐concentration factor was 30. The relative standard deviation (C=40 ng mL−1, n=5) was 2.9 % and detection limit was 1.6 ng mL−1. An acceptable consistency was observed between the measured amounts of Cu2+ by the thermal and proposed pre‐concentration approaches in different water samples, suggesting high accuracy of the technique. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents have become interested green materials for microextraction applications. In this study, a novel deep eutectic solvent have been formed by combination of thiomalic acid and ferric chloride in ethylene glycol medium, which then used for liquid–liquid microextraction of trace chromium from water samples. The microextraction process is donated the name of deep eutectic solvent-liquid liquid microextraction (DES-LLME). The microextraction procedure was optimised by evaluating the effect of pH, amount of deep eutectic solvent and sample volume. The optimum recoveries for chromium were achieved at pH 7.0, 200 µL of deep eutectic solvents, and sample volume up to 40 mL, with limits of detection and quantification of 1.18 µg·L−1 and 3.54 µg·L−1 respectively. By validating the DES-LLME with TMDA-53.3 fortified water reference materials, the chromium recovery was 99%. [ABSTRACT FROM AUTHOR]

Nanozymes offer many advantages such as good stability and high catalytic activity, but their selectivity is lower than that of enzymes. This is because most of enzymes have a protein component (apoenzyme) for substrate affinity to enhance selectivity and a non-protein element (coenzyme) for catalytic activity to improve sensitivity. The synergy between molecularly imprinted polymers (MIPs) and nanozymes can mimic natural enzymes, with MIP acting as the apoenzyme and nanozyme as the coenzyme. Despite researchers' attempts to associate MIPs with nanozymes, the full potential of this combination remains not well explored. This study addresses this gap by integrating Fe 3 O 4 -Lys-Cu nanozymes with peroxidase-like catalytic activities within appropriate MIPs for L-DOPA and dopamine. The catalytic performance of the nanozyme was improved by the presence of Cu in Fe 3 O 4 -Lys-Cu and further enhanced by MIP. Indeed, the exploration of the pre-concentration property of MIP has increased twenty-fold the catalytic activity of the nanozyme. Moreover, this synergistic combination facilitated the template removal process during MIP production by reducing the extraction time from several hours to just 1 min thanks to the addition of co-substrates which trigger the reaction with nanozyme and release the template. Overall, the synergistic combination of MIPs and nanozymes offers a promising avenue for the design of artificial enzymes. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel approach was proposed to separate Mg and RE ions in ion-adsorption type RE ore leaching liquor by combining RE ions complexation and UF processes. • Using Gly as the complexing agent, the process could increase RE ion concentration from 101 to 3940 mg/L and enhance RE/Mg separation factor from nearly 0 to 36.4. • The novel strategy significantly improved the RE precipitation process, resulting in an 8% increase in RE recovery and a 2.8-fold enhancement in RE purity. • This study will introduce innovative ideas and methods for efficiently recovering RE from leaching liquor by the novel approach. Taking advantage of the environmentally-friendly properties of a magnesium salt leaching agent, magnesium oxide (MgO) was used as a precipitant to enrich rare earth (RE) from leaching liquor in the magnesium salt system. This approach not only tackles the issue of ammonia–nitrogen pollution but also enables efficient magnesium recycling. However, due to the high concentration of magnesium ions and the low concentration of RE ions in the leaching solution, the precipitation kinetics of RE concentrates are sluggish, leading to low RE purity in the resulting precipitated product. In this work, we proposed a novel strategy that combines complexation-ultrafiltration (UF) pre-concentration with subsequent MgO precipitation to enhance the hydrolysis of MgO, promoting the precipitation of RE. We further improved the RE enrichment efficiency by optimizing membrane type, complexing agent selection, concentration levels, precipitation temperature, and MgO dosage. Under the conditions of concentrating the leaching solution using optimal UF membrane and employing glyphosate as the complexing agent, the RE ions concentration increased from 101 to 3940 mg/L, and we successfully separated magnesium ions with a separation factor of 36.4. A comparison between direct MgO precipitation and the pre-concentration approach revealed an 80 % reduction in precipitation time and an 80 % decrease in MgO usage with pre-concentration. Furthermore, this combined process led to an 8 % increase in RE recovery and a 2.8-fold enhancement in RE purity, and similar results were obtained when using actual mine leaching solutions. Additionally, the glyphosate present in the UF permeate and the precipitated mother liquor can be efficiently reclaimed through resin adsorption. This proposed process holds significant potential for engineering applications aimed at enriching RE. [ABSTRACT FROM AUTHOR]

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Quality control in agricultural products has always been noticed. In the present study, a new pre-concentration technique for the determination of Tartrazine (TZ) in saffron samples by employing Fe3O4/Graphene oxide-COOH as an adsorbent is presented. Fe3O4/Graphene oxide-COOH was prepared and characterized by scanning electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FT-IR). After extraction, the TZ concentration was measured by the UV-Vis spectrophotometer. The important factors for pre-concentration such as sample pH, amount of adsorbent, contact time and eluent volume were examined and optimum conditions were obtained. The new proposed spectrophotometric method shows good dynamic range of 0.02 to 10 mg/L (R2>0.996) for TZ with a limit of detection (LOD) of 0.01 mg/L after pre-concentration. This method was applied to the analysis of TZ in saffron samples and recovery values and enrichment factor were found as 94% and 5, respectively. Finally, 5 saffron samples were spiked with TZ and analyzed with new spectrophotometric methods, and results compared by HPLC as a standard method. The results of the t-test showed that there is no significant difference between the two methods.

Abstract The mining sector has a fundamental financial and economical role in the country where it practices these activities. In addition to employment creation and social-cultural development, the mining sector brings economic growth to the country. However, the sector is facing challenges due to COVID-19, incidents involving tailings dam facilities, rising energy costs, low grade ore deposits, restrictions in mining regulations and access to the available resources. Currently sensor-based sorting (SBS) is well known and applied worldwide in the food, recycling, grain separation industries, and processing of metals, such as diamond, gold, platinum, and feldspar. In the mining industry, ore sorting technology can result in significant improvement in ore quality by removing gangue, uplifting grades, reducing cost reduction and recovering minerals. In this article, we discuss the ore sorting test work and modeled cost-benefit analysis (CBA) for refractory gold ore at Córrego do Sítio Mineração, based on the test results and operating parameters.

The release of antibiotics into the environment from agricultural industries has received tremendous attention in recent years. Nonpoint source contamination of the terrestrial environment by these compounds can result from fertilisation of agricultural soils with manure. The presence of antibiotics and their metabolites in manure may pose a threat to agro-ecosystems. This may result in the emergence of antibiotic resistance bacteria in humans through the food chain and this is a major concern globally at the moment. Therefore, monitoring of manure for antibiotic residues is of vital importance in order to assess the risks of environmental pollution to human health by these drugs. Several sample pre-treatment techniques have been developed for the extraction of antibiotic residues from complex matrices including manure over the years. Despite new developments in recent years in separation science where the common trend is miniaturisation and green approaches, solid-phase extraction is still the most widely used technique in the extraction of antibiotics from agricultural wastes such as manure. In view of this, the aim of this review was to give a critical overview of studies that have been conducted in the past 6 years on the extraction of antibiotic residues from manure employing solid-phase extraction based on Oasis HLB and Strata-X. Adsorption mechanisms of these sorbents were also briefly discussed. [ABSTRACT FROM AUTHOR]

Abstract This article evaluates the efficiency, benefits and limitations of pre-concentration by density separation for process mineralogy studies of low-grade gold ore. The pre-concentration by density aims to generate a product with a high content of gold and to maximize the number of gold-bearing particles characterized, thereby increasing the representativity and reducing the number of polished sections to be analyzed. Pre-concentration by density was carried out for a low-grade sulfide gold ore (0.96 ppm) from the north of Brazil. The sample was ground to below 1.7 mm, sieved down to 0.037 mm and subjected to density separation, amalgamation of the heavy product and cyanide leaching of all products. Gold was assessed in each product to evaluate the separation recovery and distribution. The finer the particle size, the higher the gold distribution in the heavy product, due to a higher degree of liberation of gold and sulfides; these values varied from 65% to 84% in fractions below 0.60 mm and decreased from 40% to 13% in the coarser fractions. Regarding gold distribution, fractions finer than 0.84 mm indicates a notable increase on gold recovery by amalgamation, indication higher surface exposure.

In this study, a new and simple column-mode separation method has been proposed for the pre-concentration and removal of trace amounts of thallium(III) (Tl) from water samples. The procedure was based on sorption of Tl(III) ions by a solid phase extraction column filled with 4-[(2-hydroxy, 3-methoxy benzylidine)4-amino]1,2,4-treeazol-5-thione on microcrystalline naphthalene. The determination was performed directly using flame atomic absorption spectrometry (FAAS) method. The main factors affecting the extraction recovery were investigated and optimized. The interference effect of various ions on the determination of Tl(III) was also studied. In optimum conditions, the precision of the proposed method for sample solutions containing 0.2 µg/mL of Tl(III) was 2.0%, and the enrichment factor was found to be 35. The proposed method was evaluated and employed for pre-concentration and removal of Tl(III) from spiked natural (Tap and well) and industrial water samples.

Mining companies are actively looking for new and innovative techniques which can significantly reduce operational costs and processing carbon footprint. The high voltage pulse (HVP) is a novel technology with the potential to be applied in the mineral processing industries which provides enhanced liberation, pre-weakening and pre-concentration benefits for raw material. This paper reviews in detail the HVP working principles and the work devoted to the aforementioned three applications. In addition, major challenges affecting the industrial uptake of the HVP technique are also discussed in the context of HVP fragmentation specific energy consumption, machine wear, cost of water processing and machine throughput limitations. HVP selectivity in between particles is accentuated in this review and believed to have good prospects for industrial uptake due to its capability to achieve selective fragmentation and selective weakening effects for the mineralised particles. Finally, the paper is enclosed with an outlook of HVP future development. The general scheme of the MP test method. [Display omitted] • Review on high voltage pulse (HVP) application in the mineral processing industry is presented. • HVP working principle and the theory of the dielectric breakdown are critically reviewed. • HVP applications in mineral liberation, pre-weakening and pre-concentration are emphasized. • Challenges affecting industrial uptake of HVP technique are discussed. • HVP selectivity in between particles is accentuated and believed to have good potential for industrial uptake. [ABSTRACT FROM AUTHOR]

Waste dyes such as Congo red at certain levels can damage the environment because of toxicity and may cause malfunctioning of the liver, kidneys, and nerves. Therefore, this study aims to analyze optimum pH, concentration, particle size of the adsorbent, and the eluent flow rate on the adsorption of Congo red by Napa soil (NS). The results showed optimum pH of 6, an initial concentration of 20 mg/L, and a particle size of 75 µm and the optimum flow rate of the eluent of 40 drops/minute. Furthermore, the determination of adsorption at the optimum condition of the NS as adsorbent without treatment (fresh) has a higher capacity than the purified Napa soil. The absorption capacity was 0.37 mg/g and 0.25 mg/g, and desorption at the optimum condition (recovery column) showed that the highest percentage is by using ethanol. Besides reducing the concentration of the Congo red dye and determining the absorption capacity of the adsorbent, the other aim of the adsorbent application is for pre-concentration. The results showed that the number of concentrated Congo red dye is equal to 0.11 mg/g. [ABSTRACT FROM AUTHOR]

The mining industry is facing increasingly lower grades, which intensifies the need to reduce costs. The depletion of orebodies close to the surface has pushed the mining industry to progressively explore and extract deposits through underground mining. One approach that is receiving more attention is the application of pre-concentration systems prior to introducing the extracted materials to the main processing plant. Integration of pre-concentration systems into mining operations particularly in underground mines can significantly increase the sustainability and efficiency of operations. This paper reviews the technical concepts of this integration and presents a new mathematical formulation for underground cut-off grade determination, which should play an important role in resource utilisation and strategic planning in any operation. The proposed formulation is implemented on an underground operation to illustrate the impacts and advantages of underground pre-concentration integration. The outputs of this study prove the economic potential of pre-concentration systems in reduction in cut-off grade and increasing NPV. Article Highlights: A comprehensive and updated review of technical concepts in integration of pre-concentration systems in underground operations. Introducing a novel method for underground cut-off grade determination for increasing the sustainability of underground mines. Implementation and investigation of pre-concentration systems in an underground mine, followed by potential benefits and future directions. [ABSTRACT FROM AUTHOR]