Dilute HNO3 Solution Research Articles

Effect of alkali metal nitrates on palladium dissolution in nitric acid solutions

Hydrometallurgical unit operations are typically used to recover palladium (Pd) from its ores and secondary resources with high selectivity owing to their low energy consumption, cost effectiveness, and volume flexibility. Herein, diluted HNO3 solutions with added nitrate salts were used to dissolve Pd powders. Moreover, solutions of nitrates with same valency cations (such as HNO3, LiNO3, NaNO3, KNO3, CsNO3, and NH4NO3) and same period cations (such as NaNO3, Mg(NO3)2, and Al(NO3)3) were used to reveal the involved beneficial effects of the nitrates on the Pd dissolution in an environment friendly way with low acidity of the solutions. Among all added alkali metal nitrates, LiNO3 resulted in the highest Pd dissolution efficiency, which was attributed to the higher dissociation constant of LiNO3, resulting in a higher concentration of free nitrate and hence a higher oxidation potential of the overall system. The dissolution process was systematically investigated to determine the optimal temperature (353 K), LiNO3 and HNO3 concentrations (6 and 1 mol L−1, respectively), stirring speed (500 rpm), and reaction time (5 h). These optimal conditions yielded a dissolution efficiency of 99.6%. Notably, as the reaction proceeded, the Pd powder surfaces corroded to form numerous holes, indicating that internal diffusion control also affected Pd dissolution.

How to overcome the difficulty in assaying Ni in biodiesel samples? Extraction induced by microemulsion breaking and square wave adsorptive stripping voltammetry could be the answer

Herein, a simple, green, and relatively inexpensive approach to determine nickel (Ni) in biodiesel samples by square wave adsorptive cathodic stripping voltammetry (SWAdCSV) is presented. A method based on the accumulation of Ni as Ni(II)-dimethylglyoxime (Ni(II)(HDMG)2) on the glassy carbon electrode was carried out in a solution containing the aqueous phase extract (APhEx) obtained from an extraction induced by microemulsion breaking (EIMB), which was achieved by adding a few microliters of ultrapure water to a microemulsion composed of biodiesel, n-propanol and a diluted HNO3 solution. The LOD and LOQ were 0.2 μg L−1 and 0.8 μg L−1, respectively, and the accuracy was evaluated by recovery assays of spiked samples and by analyzing a standard reference material. Results obtained from a comparative method (HR-CS GF AAS) were also used for this evaluation. The method was applied to biodiesel samples produced from different feedstocks. To the best of the authors knowledge, it is the first time that: 1) Ni in biodiesel is determined by a voltammetric method; 2) EIMB is applied to extract Ni from this matrix and 3) this type of sample preparation method is used with adsorptive stripping voltammetry.

Determination of yttrium in phosphorus powder from fluorescent lamps by microwave-induced optical emission spectrometry (MIP OES) after ultrasound-assisted extraction.

In this work, we propose a novel method for yttrium determination by microwave-induced optical emission spectrometry (MIP OES). It is based on the ultrasound-assisted extraction of yttrium with a diluted HNO3 solution and was applied to yttrium determination in phosphorus powder from fluorescent lamps. The method was optimized employing a multivariate strategy, based on a Box-Behnken design, taking into account three experimental factors: mass of the sample (25 to 75 mg), sonication time (15 to 165 min) and HNO3 concentration in the extractant solution (2.0 to 6.0 mol L-1). According to the data obtained in the optimization process, only the sonication time and the HNO3 concentration had an influence on the extraction of yttrium from the samples. The data also indicated that yttrium must be strongly linked to the matrix, since its quantitative extraction was only possible when using the maximum values of the two factors. Therefore, under optimized conditions, we could quantitatively extract yttrium from 75 mg of sample using a 6 mol per L HNO3 solution and a sonication time of 165 min. The limits of detection and quantification for the method were 0.4 and 1.2 μg g-1, respectively, and the intermediary precision (three days) was 14%. The concentration of Y in the analyzed samples varied from 5.37 ± 1.82 to 298 ± 31 μg g-1, and recoveries of 91.0 ± 34.6 and 106 ± 23% were obtained in comparison to total digestion. The results obtained by the proposed method were not statistically different (at the 95% confidence level) from those obtained after the total digestion of the samples when applying the Student's t-test.

Gas-Liquid Interfacial Plasma engineering under dilute nitric acid to improve hydrophilicity and OER performance of nickel foam

The world has been moving rapidly to find new eco-friendly energy sources. Water electrolysis consists of two reactions of Oxygen Evolution Reaction (OER) and Hydrogen Evolution Reaction (HER), whereas the OER is considered the rate-limiting step. The most commercialized electrode for OER in the alkaline electrolyte is Ni foam, but its original surface is hydrophobic. It is possible to accelerate the adsorption and desorption process of reactants and products during OER by adding hydrophilic functional groups such as –OH on the surface of Ni foam. In this study, a novel Gas-Liquid Interfacial Plasma (GLIP) engineering at room temperature was successfully applied to modify the Ni foam surface dilute (1 ​M) HNO3 solution. At a current density of 400 ​mA ​cm−2, GLIP-treated Ni foam electrodes at 1 ​M HNO3 concentrations showed OER overpotentials of 458 ​mV. Among all, GLIP with 1 ​M HNO3 treatment of 30 ​min showed 129 ​mV less overpotential than the nickel foam before treatment. In summary, GLIP can be justified as an environmentally friendly and efficient surface treatment to improve the wettability and OER performance of Ni-based electrodes in water electrolysis.

Properties and Hydrolysis Behavior of Celluloses of Different Origin.

The present paper is a fundamental study on the physicochemical properties and hydrolysis behavior of cellulose samples differing in origin: bacterial, synthetic, and vegetal. Bacterial cellulose was produced by Medusomyces gisevii Sa-12 in an enzymatic hydrolyzate derived from oat-hull pulp. Synthetic cellulose was obtained from an aqueous glucose solution by electropolymerization. Plant-based cellulose was isolated by treatment of Miscanthus sacchariflorus with dilute NaOH and HNO3 solutions. We explored different properties of cellulose samples, such as chemical composition, degree of polymerization (DP), degree of crystallinity (DC), porosity, and reported infrared spectroscopy and scanning electron microscopy results. The hydrolysis behavior was most notable dependent on the origin of cellulose. For the bacterial cellulose sample (2010 DP, 90% DC, 89.4% RS yield), the major property affecting the hydrolysis behavior was its unique nanoscale reticulate structure promoting fast penetration of cellulases into the substrate structure. The study on enzymatic hydrolysis showed that the hydrolysis behavior of synthetic and Miscanthus celluloses was most influenced by the substrate properties such as DP, DC and morphological structure. The yield of reducing sugars (RS) by hydrolysis of synthetic cellulose exhibiting a 3140 DP, 80% DC, and highly depolymerization-resistant fibers was 27%. In contrast, the hydrolysis of Miscanthus-derived cellulose with a 1030 DP, 68% DC, and enzyme-accessible fibers provided the highest RS yield of 90%. The other properties examined herein (absence/presence of non-cellulosic impurities, specific surface, pore volume) had no considerable effect on the bioconversion of the cellulosic substrates.

Evaluation of Partial Digestion as a Strategy for Elemental Analysis of Inorganic Samples by Inductively Coupled Plasma–Optical Emission Spectrometry (ICP OES)—A Proof of Concept Study

This study discusses the application of microwave-assisted sample preparation for inorganic samples using concentrated or diluted HNO3 solutions followed by determination of Al, Ca, Cu, Cr, Fe, K, Mg, Mn, Na, Ni, P, Pb, S, Si, and Zn using inductively coupled plasma–optical emission spectrometry (ICP OES). Aiming the total digestion (reference procedure), samples were decomposed in a heating block using a mixture of 2 mL of 40% v v−1 HF and 5 mL of 14 mol L−1 HNO3. Four digestion mixtures composed by (1) 14, (2) 7.0, (3) 4.0, and (4) 2.0 mol L−1 HNO3 plus 3 mL of concentrated H2O2 were evaluated as alternatives for microwave-assisted digestion of six inorganic samples (partial digestion). Considering all evaluated procedures, quantitative recoveries were obtained applying reference and partial digestion procedures. Therefore, the use of HNO3 dilute solutions as an alternative for HF is a feasible procedure for quantitative analysis of zinc oxide, kaolin, zinc residue, and zinc sulfide. However, tailored procedures must be taken into consideration, since quantitative determination depends on digestion mixture, sample matrix, and analytes.

Gravimetric and data analysis of the corrosion resistance behaviour and inhibition of C26000 brass in dilute HNO3 solution

The corrosion resistance of as-received and heat treated C26000 brass (annealed and quenched) was evaluated by gravimetric analysis in 0.5 M, 1 M, 1.5 M, 2 M, 2.5 M, 3 M and 3.5 M HNO3 solution. Generally, corrosion rate of C26000 increased with increase in HNO3 concentration and varies significantly with respect to observation time. Results showed that heat treatment has no influence on the corrosion resistance of the brass heat treated brass compared to the as-received sample. Application of garlic extracts in HNO3 solution at 0.5 M significantly decreased the corrosion rate of C26000 60% concentration with inhibition value of 79.46%. The garlic extract exhibited significant concentration dependent behaviour and its inhibition performance varies with observation time. Statistical evaluation showed the standard deviation values of as-received and heat treated C26000 varied with respect to mean inhibition data. However, variation increased with HNO3 concentration due to thermodynamic instability with respect to observation time. In the presence of the garlic extracts, the high standard deviation values at the lowest and highest garlic concentration signify significant variation with observation time and thermodynamic instability. Evaluation through analysis of variance shows HNO3 concentration and observation are statistically irrelevant to the corrosion rate output of as-received and heat treated C26000. In the presence of garlic extracts only the extract concentration is statistically relevant with value of 90.52%.

Selective recovery of rare earth elements with ligand-functionalized polymers in fixed-bed adsorption columns

Rare earth elements (REE) are a group of valuable metals with growing demand and broad applications. Mineral ores, the traditional sources of REE, require significant capital investment and their refinement has been a source of environmental contamination. Industrial fluids and natural REE-bearing liquids are potential alternative sources for these metals. This work investigated the performance and REE selectivity of polymer resin beads functionalized with N,N-bis(phosponomethyl)glycine (BPG) for extraction of REE from saline solutions in fixed-bed adsorption columns. Competitive batch adsorption experiments were conducted with various metals (Nd, Gd, Ho, Al, Fe, Co, Ni, Ba, Pb, Th, and U) and the BPG-functionalized resins were up to 137 times more selective for REE than aminated resins. In column experiments, the BPG-functionalized resins preferentially adsorbed heavier metals and REE were strongly retained in the functionalized column, taking 270 times longer than the amine column to reach 10% breakthrough and 128 times longer to reach 50% breakthrough. REE bound to the BPG-functionalized resins were recovered with a dilute HNO3 solution, yielding REE concentrations up to 236 times higher than the influent feedstock. This work provides new insight into the operational performance of novel functionalized adsorbents for recovery of REE from saline fluids.

Residual and ecological risk assessment of heavy metals in fly ash from co-combustion of excess sludge and coal

Co-combustion of municipal excess sludge (ES) and coal provides an alternative method for disposing ES. The present study aims to investigate the residual and ecological risk of heavy metals in fly ash from co-combustion of ES and coal. The total concentration and speciation distribution of heavy metals, characterization of SEM, EDX, XRD and leaching test were carried out to assess the fly ash in this study. The results showed that the total concentrations of Cu, Zn and Mn were higher than others in fly ash, and most heavy metals were concentrated in fine particles. For Cd, Cr and Pb, the percentages of speciation of F4 and F5 were all over 90%, suggesting the relatively lower leaching toxicity. The leaching percent of all heavy metals was lower than 5% by two diluted HNO3 solutions for fly ash. The potential ecological risks increased with the decrease of particle size of fly ash, and Cd accounted for the main fraction for ecological risk despite of lower concentration in comparison to other measured heavy metals.

Study on synthesis of mesoporous carbon from MOF-199 metal-organic framework as potential adsorbent

Porous carbon material is one of the most common and very important for various applications thank to its high surface area and adsorption capability. In this study, mesoporous carbon was prepared by thermal decomposition of copper-based metal-organic framework MOF-199 under inert atmosphere and followed by immersing in diluted HNO3 solution in order to remove metal/metal oxide and activation of the resultant porous carbon. Scanning electron microscopy (SEM) revealed that as-prepared material remained intact octahedral morphology of pre-pyrolysis MOF structure, and product has spongy structure with specific surface area of 375 m2/g as measured using N2 adsorption isotherm (BET), which can be employed as an effective adsorbent.

Pretreatments of Non-Woody Cellulosic Feedstocks for Bacterial Cellulose Synthesis.

Pretreatment of biomass is a key step in the production of valuable products, including high-tech bacterial cellulose. The efficiency of five different pretreatment methods of Miscanthus and oat hulls for enzymatic hydrolysis and subsequent synthesis of bacterial cellulose (BC) was evaluated herein: Hydrothermobaric treatment, single-stage treatments with dilute HNO3 or dilute NaOH solution, and two-stage combined treatment with dilute HNO3 and NaOH solutions in direct and reverse order. The performance of enzymatic hydrolysis of pretreatment products was found to increase by a factor of 4−7. All the resultant hydrolyzates were composed chiefly of glucose, as the xylose percentage in total reducing sugars (RS) was 1−9%. The test synthesis of BC demonstrated good quality of nutrient media prepared from all the enzymatic hydrolyzates, except the hydrothermobaric treatment hydrolyzate. For biosynthesis of BC, single-stage pretreatments with either dilute HNO3 or dilute NaOH are advised due their simplicity and the high performance of enzymatic hydrolysis of pretreatment products (RS yield 79.7−83.4%).

Reversed-Phase Dispersive Liquid-Liquid Microextraction (RP-DLLME) as a Green Sample Preparation Method for Multielement Determination in Fish Oil by ICP-OES

A new and simple method for Cd, Fe, Mn, Ni, Pb, and Zn determination in fish oil by inductively coupled plasma optical emission spectrometry (ICP-OES) was developed using reversed-phase dispersive liquid-liquid microextraction (RP-DLLME) for sample preparation. The RP-DLLME method was based on the simultaneous extraction and pre-concentration of analytes in fish oil, using 10.0 g of sample preheated (75 °C), with the addition of a dispersant/extractant mixture (n-propanol/diluted HNO3 solution). After stirring and centrifugation (5600g, 10 min), the aqueous phase was used for analyte determination. The RP-DLLME method was performed using only 700 μL of n-propanol and 300 μL of 2.0 mol L−1 HNO3 solution. The recoveries for Cd, Mn, Ni, and Zn using the spikes of 100 and 500 μg kg−1 ranged from 86.4 to 93.4% and 90.4 to 97.3%, respectively. For Fe and Pb, the recoveries ranged from 85.7 and 90.0% and 85.3 and 94.4% for the same spikes. The limits of quantification (LOQs) were 0.41, 1.98, 0.33, 0.35, 1.52, and 1.39 μg kg−1 for Cd, Fe, Mn, Ni, Pb, and Zn, respectively. The proposed RP-DLLME sample preparation method allowed analyte extraction for further determination by ICP-OES using a small amount of diluted HNO3 solution avoiding applying a sample decomposition step. The extract was suitable for direct introduction in the ICP-OES equipment and reached LOQs values lower than similar methods from literature. Finally, the proposed analytical method was viable and this is the first application of RP-DLLME for animal source fat combined with ICP-OES determination.

Evaluation of torrefied poplar-biomass as a low-cost sorbent for lead and terbium removal from aqueous solutions and energy co-generation

Two low-cost renewable poplar-based materials were manufactured in this work for energy production and as sorbents for lead and terbium removal from aqueous effluents. Torrefaction was used as a pretreatment process for conditioning the raw biomass. Two different operating conditions were used in the multiple-hearth furnace of the torrefaction pilot-plant: i) 250 °C; ii) 280 °C, with residence times of 75 min and 60 min, respectively. The raw and torrefied biomasses have been characterized using SEM-EDX, FTIR, TGA, XRD and elemental analyses (C, H, N, S, O); an increase of the torrefaction severity, results in an increase of the carbon/oxygen ratio and in a greater mass loss (21% at 250 °C, and 53% at 280 °C). The torrefaction had a positive impact on the sorption of metals, it allowed the increase of lignin content of the manufactured materials, and it allowed the storage of the sorbents for longer time with reduced moisture content. The equilibrium studies were performed in batch system and the experimental data were described with the Sips equation. The maximum sorption capacity was found as 30 mg g−1 for lead and 9.4 mg g−1 for terbium (at pH 4). The kinetic profiles were fitted using the pseudo-second order rate equation. The regeneration of the sorbent was demonstrated by three sorption-desorption cycles using dilute HNO3 solution (0.1 M) as eluent for metal recovery.

A kinetic and mechanistic study of adsorptive removal of metal ions by imidazole-functionalized polymer graft banana fiber

Chemically modified fibrous bio-adsorbent extracted from banana trunk was synthesized for potential application in adsorption of heavy metal from wastewater. Glycidyl methacrylate (GMA) polymer graft was first introduced onto the fiber through electron beam irradiation technique. GMA-grafted fiber was subsequently functionalized with imidazole (IMI) group through epoxide ring-opening reaction where amine density of 2.00 mmol/g was achieved. The adsorbent was characterized with Scanning Electron Microscopy (SEM), Fourier Transformed Infrared Spectroscopy (ATR-FTIR), and Thermogravimetric Analyzer (TGA). An extensive kinetic and mechanistic study on the adsorptive removal of metal ions (Cu2+, Pb2+ and Zn2+) by IMI-functionalized GMA-grafted banana fiber is presented. The effects of pH and initial concentration on adsorption capacity were investigated. The adsorption data were correlated with pseudo-first and second order model and the isotherms were analyzed with Langmuir and Freundlich model in order to explain the kinetics and adsorption mechanisms of different metal ions. The thermodynamic studies revealed that the adsorption process for metal ions was exothermic. We also demonstrated that the IMI-GMA-grafted fiber can be regenerated using dilute HNO3 solution, and can be recycled up to 10 times while maintaining satisfactory adsorption performance. Lastly, the chemically modified bio-sorbent was used to treat a local domestic sewage water.

Investigation of electrochemical capacitance of 18k nanoporous current collector incorporated MnO2

This paper deals with the fabrication of super capacitor electrode material employing a facile etching process followed by electrodeposition. Nanoporous gold current collector has been fabricated by chemically dealloying commercially available 18k gold having a composition of 74% Au, 24% Cu and 2% Ag, with dilute HNO3 solution. Electrochemically deposited MnO2 over the prepared porous Au electrode exhibits a very high specific capacitance value of 670 Fg-1 which is about 1.65 times greater than that of MnO2 coated over unetched Au electrode (407 Fg-1). Etched and unetched MnO2 coated electrode materials are characterized using XRD, XPS, FESEM with EDAX and AFM. Electrochemical characterization of the obtained hybrid material is evaluated by running several cyclic voltagramms using electrochemical workstation. In contrast to the MnO2 coated unetched Au hybrid electrode system, nanoporous AuMnO2 electrode displays higher phase angle (79°) and lower time constant (2 ms) derived from the bode plot suggesting a better capacitance value. The high specific capacitances offered with good charge/discharge rates at a potential window of 0–0.8 V, in the scan rate of 100 mV/s for 1000 cycles, exhibiting high-energy storage density of 32.56 wh/kg and 53.6 wh/kg and power density of 366 w/kg and 603 w/kg for un-etched and etched electrodes respectively.

Desalination Performance of Modified Multiwall Carbon Nanotubes

Modified multiwall carbon nanotubes (MWCNTs) were used as the electrodes of flow–through capacitor for the desalination, which were cost–cutting, energy–saving, and enviromnent–friendly and could be expected to be an altemative technology for reverse osmosis membrane for sea water desalination. Investigated by transmission electron microscope (TEM) and nitrogen adsorption/desorption for modified MWCNTs, it was confirmed that after modification treatment by immersion in diluted HNO3 solution with ultrasonic and then milling by ball at a high velocity, the metal catalyst particles at the tip of MWCNTs disappeared, the MWCNT length became short, the cap at the tip of nanotube was opened, the internal surface area could be effectively used, leading to the increase of the specific surface area and pore volume, and thus MWCNTs modified by that method had the best desalination performance. This modification technique is simple and the efficiency is high.

Acidification with nitric acid improves chemical characteristics and reduces phytotoxicity of alkaline chars

Charred organic matter is recently receiving attention for its potential use as soilless growth medium. However, depending on its origin and on the manufacturing technology, it can result toxic for plants. This fact implies that a detoxifying treatment ought to be devised in order to reclaim char in this way. We have studied three materials which combine these factors: two pyrolyzed biochars, one from forest waste (BCH-FW) and another from olive mill waste (BCH-OMW), and one hydrothermally carbonized hydrochar from forest waste (HYD-FW). These materials are suspicious of phytotoxicity due to their high pH, high salinity, or presence of organic toxics. For these new materials, it is mandatory to select fast and reliable bioassays to predict their potential phytotoxicity. In order to achieve this goal water extracts of the three chars were subjected to bioassays of seed germination and bioassays of seedling growth in hydroponic conditions. The biochar from olive mill waste and the hydrochar, but not the biochar from forest waste, showed considerable phytotoxicity as seed germination and plant growth were negatively affected (e.g. BCH-OMW reduced seed germination by 80% and caused early seedling death). In order to adjust pH and electrical conductivity for plant growth, treatments of acidification and salt leaching with optimal diluted HNO3 solutions (0.3 N, 0.2 N, and 0.75 N for BCH-OMW, BCH-FW, and HYD-FW, respectively) as calculated from titration curves, were conducted. The acid treatment reduced electrical conductivity in BCH-OMW (from 9.2 to 4.5 dS m−1), pH (maximum in BCH-FW from 9.6 to 6.2) and water soluble carbonaceous compounds (maximum in HYD-FW from 5969 to 2145 mg kg−1) in the three chars, and increased N content (maximum in BCH-OMW from 50 to 6342 mg kg−1) in the three chars. Bioassays on acid-treated chars demonstrated the absence of phytotoxicity and even stimulation of seedling growth over the control (increase of 86% and 56% for BCH-FW and HYD-FW, respectively). We conclude that acidification of chars with diluted HNO3 is a viable technique to conform chars to standards for plant growth purposes.

Microwave-Assisted Oxidation of Organic Matter Using Diluted HNO3 under O2 Pressure: Rationalization of the Temperature Gradient Effect for Acid Regeneration

Oxidation using diluted HNO3 solution is dependent on reactions taking place in the gas phase, resulting in HNO3 regeneration, thus allowing sub stoichiometric reactions (16.7 mmol of C oxidized with 10.4 mmol of HNO3). Reactions for HNO3 regeneration are dependent on temperature gradient along reaction vessel. Thermographic images were obtained of external vessel wall after 2.5, 5 and 7.5 min of heating. Temperature inside reaction vessel was directly measured using a sapphire thermocouple in four different depth (3, 6, 12 and 16 cm). Reactions under inert atmosphere (7.5 bar Ar) were evaluated and normally presented higher temperature gradient than that performed with O2 pressure, since HNO3 regeneration reactions are exothermic. A better understanding of the regeneration of HNO3 and the dependence on the whole reaction vessel temperature in this system was possible combined to residual carbon content and residual acidity measurements to estimate the extent of organic matter oxidation.

Preparation of a Reduced Graphene Oxide @ Stainless Steel Net Electrode and Its Application of Electrochemical Removal Pb(II)

A novel RGO@SSN electrode prepared by directly electrodepositing reduced graphene oxide (RGO) on stainless steel net (SSN) was applied to remove Pb(II) from the aqueous solution. The RGO@SSN electrode exhibits substantial apparent current densities and the presence of RGO on SSN affects the morphology of deposited crystal. After electrochemical treatment with RGO@SSN for 200 min, the Pb(II) removal efficiency of Pb(II) solution (1000 mg L−1) gets to 97.2%, which is promoted by 12.0% compared to that with the SSN treatment. The removal rate of RGO@SSN is 4.45 times higher than that of SSN. The polarization resistance is promoted by 55.3 and 89.5% in 0.1 M NaCl and 0.1 M HCl solution, respectively, indicating stronger protection against corrosion. Moreover, the RGO@SSN electrode can be efficiently recycled in dilute HNO3 solution. These results suggest that RGO@SSN electrode possesses a good potential to be applied for the treatment of Pb(II) in wastewater.

Investigating essential and toxic elements in Antarctic macroalgae using a green analytical method

A systematic study for the determination of essential and toxic elements (such as As, Cd, Cu, Mn, Ni, Pb, V and Zn) in Antarctic macroalgae species (Desmarestia anceps, Iridaea cordata, Palmaria decipiens and Pyropia endiviifolia) was performed. For this purpose, a green sample preparation method combined with a high-sensitivity detection technique (inductively coupled plasma mass spectrometry) was used. By using the microwave-assisted digestion combined with ultraviolet radiation (MW-UV) method, 700 mg of macroalgae were digested using a diluted HNO3 solution (2 mol L−1). The accuracy was evaluated by analysis of certified reference materials of aquatic plant (BCR 060) and apple leaves (NIST 1515). Agreement with reference or informed values for all analytes ranged from 94 to 106%, except for As and Mo in BCR 060. The results were also compared with those obtained by the reference method, which did not present a significant difference (t test, 95% confidence level). Based on the results, analysed samples showed considerable variations in regards to the concentrations of Zn, Ni and Mn. Moreover, a relatively high concentration of As in Desmarestia anceps and Pyropia endiviifolia was observed. The results for most of the analytes in Antarctic macroalgae were in agreement with other studies that have been published in literature. In addition, the proposed method was suitable for determining toxic and essential elements in Antarctic macroalgae reducing reagent consumption and waste generation, which is in agreement with the green chemistry recommendation.