Special Issue "Determination and Extraction of Heavy Metals from Wastewater and Other Complex Matrices"

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Environmental Sciences".

Deadline for manuscript submissions: closed (31 July 2020).

Special Issue Editors

Prof. Dr. Franz Jirsa
E-Mail Website
Guest Editor
Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
Interests: environmental chemistry; heavy metals in the environment; bioaccumulation in aquatic plants and animals; bio indication using fish and other sentinel organisms; ionic liquids for heavy metal removal from natural waters; applications for heavy metal analyses in difficult matrices
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. José A. López-López
E-Mail
Guest Editor
University of Cádiz, Faculty of Marine and Environmental Sciences, Marine Research Institute, Department of Analytical Chemistry, República Saharaui st, 11510 Puerto Real, Spain
Interests: environmental chemistry, heavy metals in the environment, trace metals in marine systems; metal speciation in marine waters; ionic liquids for the extraction of heavy metals; micro-extraction techniques for sample preparation

Special Issue Information

Dear Colleagues,

Heavy metals in complex matrices, such as wastewater and natural waters with high salinity, present several challenges. The analyses of these elements call for intensive sample pretreatment to avoid interferences of matrix components during the analyses or the need for preconcentration of the analyte. On the other hand, the removal of heavy metals from such matrices calls for the development of task-specific methods and materials that show low interaction with matrix components, such as major ions and organic material, and a high specificity towards the targeted metals. For this Special Issue, contributions are welcome that address the development of new methods for analyses and/or removal of heavy metals from wastewater and other complex matrices.

Prof. Franz Jirsa
Prof. José A. López-López
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Applied Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2300 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • heavy metal analyses
  • wastewater
  • hypersaline water

Published Papers (7 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Article
Sensitivity and Calibration of the FT-IR Spectroscopy on Concentration of Heavy Metal Ions in River and Borehole Water Sources
Appl. Sci. 2020, 10(21), 7785; https://doi.org/10.3390/app10217785 - 03 Nov 2020
Cited by 2 | Viewed by 585
Abstract
Heavy metals in water sources can threaten human life and the environment. The analysis time, need for chemical reagents, and sample amount per analysis assist in monitoring contaminants. Application of the Fourier Transform Infrared (FT-IR) Spectroscopy for the investigation of heavy metal elements [...] Read more.
Heavy metals in water sources can threaten human life and the environment. The analysis time, need for chemical reagents, and sample amount per analysis assist in monitoring contaminants. Application of the Fourier Transform Infrared (FT-IR) Spectroscopy for the investigation of heavy metal elements has significantly developed due to its cost effectiveness and accuracy. Use of chemometric models such as Partial Least Square (PLS) and Principle Component Regression Analysis (PCA) relate the multiple spectral intensities from numerous calibration samples to the recognized analytes. This study focused on the FT-IR calibration and quantification of heavy metals (Ag, Cd, Cu, Pb and Zn) in surveyed water sources. FT-IR measurements were compared with the atomic absorption spectrometer (AAS) measurements. Quantitative analysis methods, PCA and PLS, were used in the FT-IR calibration. The spectral analyses were done using the Attenuated Total Reflectance (ATR-FTIR) technique on three river and four borehole water sources sampled within two seasons in QwaQwa, South Africa (SA). The PLS models had good R2 values ranging from 0.95 to 1 and the PCA models ranged from 0.98 to 0.99. Significant differences were seen at 0.001 and 0.05 levels between the PLS and PCA models for detecting Cd and Pb in the water samples. The PCA models detected Ag concentrations more (˂0 mg L−1 on selected sites). Both the PLS and PCA models had lower detection only for Zn ions mostly above 45 mg L−1 deviating from the AAS measurements (<0.020 mg L−1). The FT-IR spectroscopy demonstrated good potential for heavy metal determination purposes. Full article
Show Figures

Figure 1

Article
Prediction of As, Cd, Cr, Hg, Ni, and Se Concentrations in Organic Amendments Using Portable X-ray Fluorescence and Multivariate Modeling
Appl. Sci. 2020, 10(17), 5726; https://doi.org/10.3390/app10175726 - 19 Aug 2020
Cited by 1 | Viewed by 619
Abstract
Portable X-ray fluorescence (pXRF) has been a widely used technique in various applications. However, its use for the analysis of organic amendments (composts, sewage sludges, organic fertilizers) is scarce. In these matrices, concentrations of some elements are below their detection limit. The objective [...] Read more.
Portable X-ray fluorescence (pXRF) has been a widely used technique in various applications. However, its use for the analysis of organic amendments (composts, sewage sludges, organic fertilizers) is scarce. In these matrices, concentrations of some elements are below their detection limit. The objective of this work was to find multiple linear regression equations that were able to predict the aqua-regia-soluble concentrations of the elements As, Cd, Cr, Hg, Ni, and Se using the pXRF readings of other measurable elements as predictor variables. For this, a set of 30 samples of organic amendments (composts, sewage sludges, and organic fertilizers) from the Manure and Refuse Sample Exchange Programme of the Wageningen Evaluating Programs for Analytical Laboratories (MARSEP-WEPAL) was used. Several amendment type-dependent single or multiple linear functions were found based on 1, 2, or 3 predictors. The predictor readings corresponded to the concentration of elements of geogenic (Fe, Si, Ti, Cl, Zr Al, Ca, S, Mn, and Ba), anthropogenic (Zn and Pb), and agricultural (P and K) origin. The regression coefficients of these functions were r = 0.90–0.99; therefore, they allowed for the quantitative determination of the target elements. These results will allow for fast and reliable analysis of organic amendments using pXRF that is valid for quality control in treatment plants. Full article
Show Figures

Figure 1

Article
Electrospark Method in Galvanic Wastewater Treatment for Heavy Metal Removal
Appl. Sci. 2020, 10(15), 5148; https://doi.org/10.3390/app10155148 - 27 Jul 2020
Cited by 5 | Viewed by 830
Abstract
The objective of this research is to improve water treatment use of the electric spark method. Studies on the treatment of multicomponent galvanic effluent by the electric spark method using metal loading (Fe, Al) and low-voltage (up to 1000 V) equipment have been [...] Read more.
The objective of this research is to improve water treatment use of the electric spark method. Studies on the treatment of multicomponent galvanic effluent by the electric spark method using metal loading (Fe, Al) and low-voltage (up to 1000 V) equipment have been carried out. The factors that have the largest influence on the degree of galvanic wastewaters purification are the conditions and parameters of the discharge pulse—an efficiency of approximately 0.8–0.85 has a specific energy, which at moderate concentrations of pollutants can be less than 65 kJ/dm3 (18 kWh/m3)—and the metal loading height. Other variable technological parameters can serve either as scaling tools or as methods for regulating the operation of electrical equipment. The research shows that the degree of purification depends on the specific energy and the height of the metal loading of the reactor, and it weakly depends on the pulse energy and the speed of its input. The concentrations of heavy metals (Zn2+, Cr6++Cr3+, Cu2+) in the treated water are significantly lower than their maximal permissible concentrations. The electric spark method allows us to achieve highly efficient results of wastewater treatment from heavy metals. Full article
Show Figures

Figure 1

Article
The Use of a Two-Dimensional Electrical Resistivity Tomography (2D-ERT) as a Technique for Cadmium Determination in Cacao Crop Soils
Appl. Sci. 2020, 10(12), 4149; https://doi.org/10.3390/app10124149 - 17 Jun 2020
Cited by 5 | Viewed by 1213
Abstract
Cadmium (Cd) is a non-essential heavy metal naturally occurring in the earth’s crust or due to anthropogenic activity. The presence of this metal in cacao farm soils represents a significant issue as levels are now regulated in products derived from cacao beans ( [...] Read more.
Cadmium (Cd) is a non-essential heavy metal naturally occurring in the earth’s crust or due to anthropogenic activity. The presence of this metal in cacao farm soils represents a significant issue as levels are now regulated in products derived from cacao beans (Theobroma cacao L.). Several strategies have been proposed to measure cadmium levels; however, little is known regarding in situ non-destructive and time efficient techniques to analyze Cd contents in both cacao topsoils and subsoils, particularly nearby the root system. Therefore, this research aims to integrate the physical property of soil resistivity to Cd content in cacao soils. Cd hot spots are estimated from resistivity measurements using a two-dimensional electrical resistivity tomography (2D-ERT) technique and correlated to Cd determination using inductively coupled plasma optical emission spectrometry (ICP-OES). To assess the dynamics of soil Cd content the correlation is discussed with other physical chemical parameters of soils (pH, organic matter, Ca, Fe, and P). The study was performed in 27 cacao farms in Colombia. A farm in Santander district proved to have the highest level of Cd using the correlated techniques (2.76 mg·kg−1 Cd and 1815 Ohm·m) followed by farms in Boyacá and Arauca districts (2.6 and 0.66 mg·kg−1 Cd, related to 1616 and 743 Ohm·m, respectively). A high correlation between 2D-ERT and Cd determination (R2 = 0.87) was found. The discussion regarding the soil parameters analyzed suggests that the 2D-ERT technique could be used as a preliminary approach to explore Cd distribution in cacao soils. Full article
Show Figures

Figure 1

Article
Heavy Metal Extraction under Environmentally Relevant Conditions Using 3-Hydroxy-2-Naphthoate- Based Ionic Liquids: Extraction Capabilities vs. Acute Algal Toxicity
Appl. Sci. 2020, 10(9), 3157; https://doi.org/10.3390/app10093157 - 01 May 2020
Cited by 3 | Viewed by 726
Abstract
We investigated the applicability of three task-specific ionic liquids (ILs) as heavy metal extracting agents by contrasting extraction capabilities with algal toxicity. The compounds tested were trihexyltetradecylphosphonium-, methyltrioctylphosphonium- and methyltrioctylammonium 3-hydroxy-2-naphthoates. Experiments were performed to assess if these ILs can provide environmentally safe [...] Read more.
We investigated the applicability of three task-specific ionic liquids (ILs) as heavy metal extracting agents by contrasting extraction capabilities with algal toxicity. The compounds tested were trihexyltetradecylphosphonium-, methyltrioctylphosphonium- and methyltrioctylammonium 3-hydroxy-2-naphthoates. Experiments were performed to assess if these ILs can provide environmentally safe residual concentrations of the target metals after extraction. Both pure water and natural mineral water samples were spiked with 20 µg L−1 of Cu, Ag, Cd, Hg and Pb, respectively. Quantitative extraction (> 99%) of Hg and Ag was achieved. Cu and Hg were below the respective no-observed-effect-concentrations (NOECs) after extraction and Ag below 0.03 µg L−1. Acute toxicity assays were conducted using two freshwater green algae Raphidocelis subcapitata and Tetradesmus obliquus. Growth inhibition and maximum photochemical quantum yield of photosystem II after 72 h were assessed. ILs were less toxic than similar compounds, but still must be classified as acute toxicants for algae. An inhibiting effect on both growth and chlorophyll fluorescence was observed. The leaching of the ILs into the samples remains a limitation regarding their environmental-friendly applicability. Nonetheless, the extremely efficient removal of Cu, Ag and Hg under environmentally relevant conditions calls for further research, which should focus on the immobilization of the ILs. Full article
Show Figures

Graphical abstract

Article
A Coupled Extraction/Re-Extraction Method for the Chemical Speciation of Nickel in Natural Waters
Appl. Sci. 2020, 10(1), 262; https://doi.org/10.3390/app10010262 - 29 Dec 2019
Viewed by 990
Abstract
Chemical fractionation and speciation of metals species in natural waters and its relation with bioavailability have received increased attention in recent years. A simple liquid membranes method, based on coupled liquid extraction and re-extraction processes, is proposed to separate and quantify the species [...] Read more.
Chemical fractionation and speciation of metals species in natural waters and its relation with bioavailability have received increased attention in recent years. A simple liquid membranes method, based on coupled liquid extraction and re-extraction processes, is proposed to separate and quantify the species of nickel present in water samples. A simplex optimization of chemical variables, such as carrier concentration in the organic solution and nitric acid concentration in the receiving solution, was performed and, under optimized conditions, the extraction system was applied to determine nickel species in water samples at natural level concentrations. A linear relationship was established between extraction efficacy and the concentration of dissolved organic carbon in the samples, allowing the separation and determination of labile and non-labile nickel fractions, since the latter was not transported through the organic solution acting as liquid membrane. When the total and labile concentrations of metals were analyzed in real samples with different salinities, no significant differences were found between the results obtained and those from well-established methods. An average relative error of 1.50 and 2.37 was obtained for total Ni concentration and labile fraction, respectively. Finally, a comparison with the theoretical speciation data calculated with the software WinHumic V was successfully performed. Thus, the proposed method allows the simultaneous determination of labile and non-labile nickel fractions, presented as a simple alternative to nickel fractionation in natural waters. Full article
Show Figures

Figure 1

Article
Colorimetric Technique for Antimony Detection Based on the Use of Gold Nanoparticles Conjugated with Poly-A Oligonucleotide
Appl. Sci. 2019, 9(22), 4782; https://doi.org/10.3390/app9224782 - 08 Nov 2019
Cited by 2 | Viewed by 943
Abstract
A simple and rapid positive–negative colorimetric approach to determine the presence of antimony ions based on the use of gold nanoparticles conjugated with oligonucleotide (poly-A sequence) is developed. Colorimetric measurements reveal that the aggregates of modified gold nanoparticles were afforded after adding antimony [...] Read more.
A simple and rapid positive–negative colorimetric approach to determine the presence of antimony ions based on the use of gold nanoparticles conjugated with oligonucleotide (poly-A sequence) is developed. Colorimetric measurements reveal that the aggregates of modified gold nanoparticles were afforded after adding antimony ions, thus changing the solution color from pink to blue. The results of aptamer’s interaction on the gold nanoparticle surface with the target analyte can be detected either by photometry or by the naked eye. The realized assay provides rapid (2 min), sensitive (detection limit 10 ng/mL), specific, and precise (variation coefficient less than 3.8%) detection of antimony (III) in drinking water. Full article
Show Figures

Graphical abstract

Back to TopTop