Slag-Based Nanomaterial in the Removal of Hexavalent Chromium

2017 ◽  
Vol 17 (01n02) ◽  
pp. 1760013 ◽  
Author(s):  
J. Baalamurugan ◽  
V. Ganesh Kumar ◽  
K. Govindaraju ◽  
B. S. Naveen Prasad ◽  
V. K. Bupesh Raja ◽  
...  
Keyword(s):  
Hexavalent Chromium ◽  
Inductively Coupled Plasma ◽  
Steel Slag ◽  
Steel Production ◽  
Cost Effective ◽  
Alkali Activation ◽  
Surface Hydroxyl ◽  
Chromium Vi ◽  
Wide Range ◽  
Toxic Pollutant

Slag-based nanomaterial is a by-product obtained during steel production and has wide range of components in the form of oxides. In this study, Induction Furnace (IF) steel slag-based application in adsorption of hexavalent chromium is investigated. IF slag has mixture of oxides mainly Fe2O3 and Chromium (VI) a highly toxic pollutant leads to environmental pollution and causes problem to human health mainly, carcinogenetic diseases. Slag-based nanomaterial is characterized using High Resolution Scanning Electron Microscope (HR-SEM) in which the size was around 100[Formula: see text]nm and X-ray Fluorescence (XRF) spectroscopy. Further inductively coupled plasma mass spectroscopy and Fourier transform infrared spectroscopy were used for adsorption studies. Slag activation using NaOH (alkali activation) to the intent of surface hydroxyl ([Formula: see text]OH) group attachment will be a cost-effective process in the removal of hexavalent chromium. Cr(VI) ions are adsorbed on the surface of alkali activated slag material. The core-shell formation of Fe(II)/Fe(III)/Cr(VI) and the adsorption are investigated in detail in the present study.

Determination of Hexavalent Chromium in Environmental Fly Ash Samples by an Inductively Coupled Plasma-Atomic Emission Spectrometer with Ammonium Ion Complexation

1994 ◽  
Vol 48 (9) ◽  
pp. 1111-1117 ◽  
Author(s):  
J. David Hwang ◽  
Wen-Jwu Wang
Keyword(s):  
Fly Ash ◽  
Hexavalent Chromium ◽  
Inductively Coupled Plasma ◽  
Ammonium Hydroxide ◽  
Atomic Emission ◽  
Ammonium Ion ◽  
Inductively Coupled ◽  
Chromium Vi ◽  
Icp Analysis

A method to determine hexavalent chromium in environmental solid waste has been developed by using an ammonium complexation technique in ICP-AES. This method consists of a two-step extraction and the complexation of ammonium ion. An ammonium hydroxide solution was used to extract the chromium(VI) out of the fly ash sample into the solution. Interfering metal ions, such as Pb, Fe, and Zn in the fly ash sample, were effectively removed by extracting them as diethyldithiocarbamate (DDTC) complexes at pH 9.5 into an MIBK (methyl isobutyl ketone) solution. The pH of the aqueous phase of the sample is then transferred and adjusted to 6.0, and the Cr(VI) is extracted as its complex with MIBK prior to the organic ICP analysis. A method detection limit of 50 ng/g or better, as well as spike recoveries of 90 to 110% (at a spike concentration level of 500 ng/g), is obtained when this method is applied to determine chromium(VI) in fly ash samples.

scholarly journals Metal Content in Textile and (Nano)Textile Products

2022 ◽  
Vol 19 (2) ◽  
pp. 944
Author(s):  
Iria Rujido-Santos ◽  
Paloma Herbello-Hermelo ◽  
María Carmen Barciela-Alonso ◽  
Pilar Bermejo-Barrera ◽  
Antonio Moreda-Piñeiro
Keyword(s):  
Hexavalent Chromium ◽  
Inductively Coupled Plasma ◽  
Metallic Nanoparticles ◽  
Raw Materials ◽  
Arsenic Content ◽  
European Regulation ◽  
Chromium Vi ◽  
Icp Ms ◽  
Relative Standard ◽  
Textile Products

Metals, metallic compounds, and, recently, metallic nanoparticles appear in textiles due to impurities from raw materials, contamination during the manufacturing process, and/or their deliberate addition. However, the presence of lead, cadmium, chromium (VI), arsenic, mercury, and dioctyltin in textile products is regulated in Europe (Regulation 1907/2006). Metal determination in fabrics was performed by inductively coupled plasma-mass spectrometry (ICP-MS) after microwave-assisted acid digestion. The ICP-MS procedure has been successfully validated; relative standard deviations were up to 3% and analytical recoveries were within the 90–107% range. The developed method was applied to several commercial textiles, and special attention has been focused on textiles with nanofinishing (fabrics prepared with metallic nanoparticles for providing certain functionalities). Arsenic content (in textile T4) and lead content (in subsamples T1-1, T1-2, and T3-3) were found to exceed the maximum limits established by the European Regulation 1907/2006. Although impregnation of yarns with mercury compounds is not allowed, mercury was quantified in fabrics T1-2, T5, and T6. Further speciation studies for determining hexavalent chromium species in sample T9 are necessary (hexavalent chromium is the only species of chromium regulated). Some textile products commercialised in Europe included in this study do not comply with European regulation 1907/2006.

scholarly journals Electrocoagulation as an Alternative for the Removal of Chromium (VI) in Solution

Tecnura ◽  
2021 ◽  
Vol 25 (68) ◽  
pp. 28-42
Author(s):  
Candelaria nahir Tejada tovar ◽  
Angel Villabona Ortíz ◽  
Rafael Contreras Amaya
Keyword(s):  
Residence Time ◽  
Cost Effective ◽  
Joint Effect ◽  
Steel Plates ◽  
Aqueous Environment ◽  
Chromium Vi ◽  
Effective Removal ◽  
Removal Of Heavy Metals ◽  
Toxic Pollutant ◽  
The Cost

Context: The contamination of water sources by the discharge of effluents contaminated with chromium (VI) is a current environmental problem because it is a toxic pollutant for humans, animals, plants, and microorganisms; it can be carcinogenic and has a high solubility in an aqueous environment. This research aims to study the electrochemical removal of hexavalent chromium by electrocoagulation using iron and aluminum electrodes with monopolar configuration, evaluating the effect of residence time, voltage, and the number of electrodes on the removal efficiency. Methodology: The experiments were conducted in a 3L batch electrocoagulation cell, using 10 and 6 aluminum and stainless steel plates as electrodes, connected at a distance of 1.5 cm in a monopolar configuration in parallel to the power source. Contaminated solution with Cr (VI) was treated at a concentration of 50 mg/L, evaluating two levels of residence time (20 and 30 min), voltage (20 and 30 V), and the number of electrodes (6 and 10 electrodes). Results: After the electrocoagulation removal tests, it was obtained removal percentages between 60.15 and 92.9%. The most significant positive variable in the process was the increase in the residence time. It can be inferred that electrocoagulation performs better at lower voltages and longer residence times and that the joint effect of the increase of the number of electrodes and the contact time would increase the performance of the process, achieving greater removal. Conclusions: The process of reduction of chromium (VI) by electrocoagulation has the potential to be used for the cost-effective removal of heavy metals from water

2D Color-Intensity Representation of Ultrasonic Thickness Gauge Measurements

2020 ◽  
pp. 1192-1198
Author(s):  
M.S. Mohammad ◽  
Tibebe Tesfaye ◽  
Kim Ki-Seong
Keyword(s):  
Cost Effective ◽  
The Other ◽  
Thickness Gauge ◽  
Color Intensity ◽  
Digital Readout ◽  
Flat Surfaces ◽  
Video Cameras ◽  
Wide Range ◽  
Cost Effective Alternative ◽  
Ultrasonic Thickness

Ultrasonic thickness gauges are easy to operate and reliable, and can be used to measure a wide range of thicknesses and inspect all engineering materials. Supplementing the simple ultrasonic thickness gauges that present results in either a digital readout or as an A-scan with systems that enable correlating the measured values to their positions on the inspected surface to produce a two-dimensional (2D) thickness representation can extend their benefits and provide a cost-effective alternative to expensive advanced C-scan machines. In previous work, the authors introduced a system for the positioning and mapping of the values measured by the ultrasonic thickness gauges and flaw detectors (Tesfaye et al. 2019). The system is an alternative to the systems that use mechanical scanners, encoders, and sophisticated UT machines. It used a camera to record the probe’s movement and a projected laser grid obtained by a laser pattern generator to locate the probe on the inspected surface. In this paper, a novel system is proposed to be applied to flat surfaces, in addition to overcoming the other limitations posed due to the use of the laser projection. The proposed system uses two video cameras, one to monitor the probe’s movement on the inspected surface and the other to capture the corresponding digital readout of the thickness gauge. The acquired images of the probe’s position and thickness gauge readout are processed to plot the measured data in a 2D color-coded map. The system is meant to be simpler and more effective than the previous development.

Breakthrough analysis for hexavalent chromium removal from drinking water in a fixed bed column

2009 ◽  
Vol 9 (6) ◽  
pp. 661-670 ◽  
Author(s):  
S. P. Dubey ◽  
K. Gopal
Keyword(s):  
Aqueous Solution ◽  
Hexavalent Chromium ◽  
Fixed Bed ◽  
Entropy Change ◽  
Spectroscopic Technique ◽  
Fixed Bed Column ◽  
Chromium Vi ◽  
Fixed Bed Adsorption ◽  
Optimal Column ◽  
Eucalyptus Bark

The activated carbon of Eucalyptus globulus was tested for their effectiveness in removing hexavalent chromium from aqueous solution using column experiments. Result revealed that adsorption of chromium(VI) on eucalyptus bark carbon was endothermic in nature. Thermodynamic parameters such as the entropy change, enthalpy change and Gibbs free energy change were found to be 1.39 kJ mol−1 K−1, 1.08 kJ mol−1 and −3.85 kJ mol−1, respectively. Different chromium concentrations were used for the fixed bed adsorption studies. The pre- and post-treated adsorbents were characterized using a FTIR spectroscopic technique. It was concluded that Eucalyptus bark carbon column could be used effectively for removal of hexavalent chromium from aqueous solution at optimal column conditions. This study showed that this biological material is potential adsorbent of Cr(VI) from water.

Advances in sample digestion using microwave-ultraviolet radiations: phosphorus and sulfur determination in animal feed

2020 ◽  
Vol 16 ◽  
Author(s):  
Diogo L. R. Novo ◽  
Priscila T. Scaglioni ◽  
Rodrigo M. Pereira ◽  
Filipe S. Rondan ◽  
Gilberto S. Coelho Junior ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Animal Feed ◽  
Optical Emission ◽  
Emission Spectrometry ◽  
Official Method ◽  
Dissolved Carbon ◽  
Inductively Coupled ◽  
Relative Standard ◽  
Wide Range ◽  
Sulfur Determination

Background: Conventional analytical methods for phosphorus and sulfur determination in several matrices present normally analytical challenges regarding inaccuracy, detectability and waste generation. Objective: The main objective is proposing a green and feasible analytical method for phosphorus and sulfur determination in animal feed. Methods: Synergic effect between microwave and ultraviolet radiations during sample preparation was evaluated for the first time for the animal feed digestion associated with further phosphorus and sulfur determination by ion chromatography with conductivity detection. Dissolved carbon and residual acidity in final digests were used for the proposed method assessment. Phosphorus and sulfur values were compared with those obtained using conventional microwave-assisted wet digestion in closed vessels associated with inductively coupled plasma optical emission spectrometry and with those obtained using Association of Official Analytical Chemists International official method. Recovery tests and certified reference material analysis were performed. Animal feeds were analyzed using the proposed method. Results: Sample masses of 500 mg were efficiently digested using only 2 mol L -1 HNO3. The results obtained by the proposed method was not differing significantly (p > 0.05) from those obtained by the conventional and official methods. Suitable recoveries (from 94 to 99%), agreement with certified values (101 and 104%) and relative standard deviations (< 8%) were achieved. Phosphorus and sulfur content in commercial products varied in a wide range (P: 5,873 to 28,387 mg kg-1 and S: 2,165 to 4,501 mg kg-1 ). Conclusion: The proposed method is a green, safe, accurate, precise and sensitive alternative for animal feed quality control.

The Future of Plasma-Based Surface Engineering Techniques in Tribology (Keynote)

2005 ◽  
Author(s):  
Allan Matthews ◽  
Adrian Leyland
Keyword(s):  
Surface Engineering ◽  
Performance Enhancement ◽  
Bulk Material ◽  
Cost Savings ◽  
Cost Effective ◽  
Ceramic Coatings ◽  
Performance Improvements ◽  
Treatment Techniques ◽  
Wide Range ◽  
Macro Scale

Over the past twenty years or so, there have been major steps forward both in the understanding of tribological mechanisms and in the development of new coating and treatment techniques to better “engineer” surfaces to achieve reductions in wear and friction. Particularly in the coatings tribology field, improved techniques and theories which enable us to study and understand the mechanisms occurring at the “nano”, “micro” and “macro” scale have allowed considerable progress to be made in (for example) understanding contact mechanisms and the influence of “third bodies” [1–5]. Over the same period, we have seen the emergence of the discipline which we now call “Surface Engineering”, by which, ideally, a bulk material (the ‘substrate’) and a coating are combined in a way that provides a cost-effective performance enhancement of which neither would be capable without the presence of the other. It is probably fair to say that the emergence and recognition of Surface Engineering as a field in its own right has been driven largely by the availability of “plasma”-based coating and treatment processes, which can provide surface properties which were previously unachievable. In particular, plasma-assisted (PA) physical vapour deposition (PVD) techniques, allowing wear-resistant ceramic thin films such as titanium nitride (TiN) to be deposited on a wide range of industrial tooling, gave a step-change in industrial productivity and manufactured product quality, and caught the attention of engineers due to the remarkable cost savings and performance improvements obtained. Subsequently, so-called 2nd- and 3rd-generation ceramic coatings (with multilayered or nanocomposite structures) have recently been developed [6–9], to further extend tool performance — the objective typically being to increase coating hardness further, or extend hardness capabilities to higher temperatures.

scholarly journals Gamma models for estimating the odds ratio for a skewed biomarker measured in pools and subject to errors

Biostatistics ◽  
2019 ◽  
Author(s):  
Dane R Van Domelen ◽  
Emily M Mitchell ◽  
Neil J Perkins ◽  
Enrique F Schisterman ◽  
Amita K Manatunga ◽  
...  
Keyword(s):  
Odds Ratio ◽  
Adjusted Odds Ratio ◽  
Lower Cost ◽  
Cost Effective ◽  
Ratio Estimation ◽  
Statistical Efficiency ◽  
Function Model ◽  
Processing Error ◽  
Wide Range ◽  
Pooled Samples

SUMMARYMeasuring a biomarker in pooled samples from multiple cases or controls can lead to cost-effective estimation of a covariate-adjusted odds ratio, particularly for expensive assays. But pooled measurements may be affected by assay-related measurement error (ME) and/or pooling-related processing error (PE), which can induce bias if ignored. Building on recently developed methods for a normal biomarker subject to additive errors, we present two related estimators for a right-skewed biomarker subject to multiplicative errors: one based on logistic regression and the other based on a Gamma discriminant function model. Applied to a reproductive health dataset with a right-skewed cytokine measured in pools of size 1 and 2, both methods suggest no association with spontaneous abortion. The fitted models indicate little ME but fairly severe PE, the latter of which is much too large to ignore. Simulations mimicking these data with a non-unity odds ratio confirm validity of the estimators and illustrate how PE can detract from pooling-related gains in statistical efficiency. These methods address a key issue associated with the homogeneous pools study design and should facilitate valid odds ratio estimation at a lower cost in a wide range of scenarios.

scholarly journals Major and trace-element geochemistry of Late Cretaceous clastic rocks in the Jitai Basin, southeast China

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kai Yan ◽  
Chun-lian Wang ◽  
Steffen Mischke ◽  
Jiu-yi Wang ◽  
Li-jian Shen ◽  
...  
Keyword(s):  
Late Cretaceous ◽  
Brackish Water ◽  
Inductively Coupled Plasma ◽  
Salt Water ◽  
Trace Element Geochemistry ◽  
Element Geochemistry ◽  
Humid Climate ◽  
Southeast China ◽  
Clastic Rocks ◽  
Wide Range

AbstractMajor, trace and rare earth element (REE) geochemistry of the late Cretaceous lower Zhoutian Formation from the Jitai Basin of Southeast China were measured by inductively coupled plasma mass spectrometry (ICP-MS) analysis to infer the provenance of the sediments and to reconstruct the palaeoenvironment and palaeoclimate. The wide range of Sr/Cu ratios point to a fluctuating palaeoclimate, and the negative correlation between the FeO/MnO and Al2O3/MgO ratios and the Sr/Cu ratio indicates that the late Cretaceous climate during the lower Zhoutian Formation in the Jitai Basin can be divided into two parts. The lower part experienced two cooling periods, whilst the upper part was dominated by warm-humid climate. Mostly corresponding trends of the B/Ga, Sr/Ba and Sr/Cu ratios show that the salinity changed consistently with the late Cretaceous climate during the lower Zhoutian Formation in the Jitai Basin. During the lower part, the salinity changed from salt water to fresh/brackish water. In the upper part, water was mainly fresh/brackish, and there were many changes from fresh/brackish water to salt water. The relatively stable Ni/Co, V/Cr, V/(V + Ni) and Ce/Ce* data indicate a long period of oxic conditions. The La-Th-Sc, Th-Sc-Zr/10 and La/Th-Hf data of the silt- and sandstones of the lower Zhoutian Formation show that its provenance was mainly a mixture of felsic upper crust sediments and older sedimentary rocks.

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