Susceptibility Meter Research Articles

Compressive Strength Analysis of Mortar Made from Volcanic Sand in Nagari Aia Angek Based on Magnetic Mineral Content

Mortar is a binder or adhesive with a standard viscosity of ingredients (water, cement, and sand). Mortar made has strength, mortar strength is measured using Cement Compression testing machine. Sand in mortar making contains magnetic minerals such as magnetite (Fe3O4) or Fe2+3Fe+2O4-2, hematite mineral (α-Fe2O3) which will be measured for magnetic susceptibility value using Bartington Magnetic Susceptibility Meter Sensor Type B (MS2B). To determine the concentration of magnetic minerals and their relationship with mortar compressive strength, the rock magnetism method was used. Measurement of sand samples of Kamumuan River, Sungai Limau District using Bartington Magnetic Susceptibility Meter Sensor Type B (MS2B) by categorizing sand into 3 treatment, namely Addition of magnetic minerals (PTM) with χLF value 3863.3 x 10-8m3/kg and χFD (%) 0.72, reduction of magnetic minerals (PKM) with χLF value 1920 x 10-8m3/kg and χFD (%) 0.79, normal magnetic minerals (PM) with χLF value 2334.7 x 10-8m3/kg and χFD (%) 0.62. The sample has a grain type that is almost no superparamagnetic grain and has antiferromagnetic properties. Samples grouped by treatment were made into mortar and tested using a cement compression testing machine with the results of mortar compressive strength, namely ATM of 49.4 Kg/cm², AKM of 46.6 Kg/cm², and AM 52.3 Kg/cm². Based on the analysis conducted, the magnetic minerals contained in the sand affect the results of the compressive strength of the mortar, the higher the susceptibility value in the sand, the stronger the compressive strength of the mortar

Compressive Strength Analysis of Mortar Made from Volcanic Sand in Nagari Aia Angek Based on Magnetic Mineral Content

Compressive strength testing is carried out on mortar made from a mixture of sand, cement and water. Mortar is one of the construction materials in building structures that has the main function as a material for construction parts. The compressive strength test is useful for measuring and knowing the strength of objects against compressive forces. The method used in this research is rock magnetism to determine the abundance of magnetic minerals and compressive strength testing to determine the relationship of compressive strength results to the magnetic minera content of Nagari Aia Angek volcanic sand. Volcanic sand is measured using a Bartington Susceptibility Meter Type MS2B with 3 forms of mineral separation treatment, namely Magnetic Mineral Reduction (PMM) with a value of χlf 505,99 x10 m-83 /kg, χfd (%) 2.72%, Additional Magnetic Minerals (TMM) with a value of χlf 1026.72 x10 m-83 /kg, χfd (%) 2.14%, and No Treatment (TP) with a value of χlf 853.98 x10 m-83 /kg, χlf (%) 2.16. The results of testing the compressive strength of mortar using Compression Testing Mechine on 3 volcanic sand treatments were obtained (PMM) with a value of 169.14 kg/cm2, (TMM) with a value of 147.11 kg/cm2, and (TP) with a value of 141.81 kg/cm2. The magnetic properties of volcanic sand samples are antiferrimagnetic and have superparamagnetic mixed grains and coarse grains. There is a relationship between the compressive strength value of mortar and the concentration of magnetic minerals, the higher the compressive strength value, the higher the χfd (%) value obtained

Effect of gas content on cavitation nuclei

Cavitation inception originates from nuclei in a liquid. This paper proposes a Gibbs free energy approach that provides a smooth transition from homogeneous to heterogeneous nucleation when gas is present. The impact of gas content on nucleation is explored. It is found that the gas content stabilises nuclei, a phenomenon not present in pure liquid–vapour systems. This reduces the energy barrier over that required to nucleate a vapour bubble. Different gas saturation levels are studied. Gas content can significantly reduce the energy barrier required for nucleation, and under certain circumstances eliminate it. An analytic solution for the critical radius and activation energy is obtained that accounts for gas content. The classical Blake radius is recovered as a limiting case. The hysteresis between incipience and desinence is explained using the asymmetry observed in the critical radii. The solution is used to obtain the initial bubble radius, given a critical pressure condition in cavitation susceptibility meter experiments. The relationship between initial bubble diameter and critical pressure is described by an analytic solution that accounts for gas content. A model for the derivative of the cumulative nuclei histogram with respect to bubble diameter is proposed. An analytic expression is obtained that shows good agreement with decades worth of experimental data compiled by Khoo et al. (Exp. Fluids, vol. 61, issue 2, 2020, pp. 1–20) from ocean to water tunnels. The expression recovers the $-4$ power law that is observed experimentally.

Verification of Geophysical Surveys by New Archaeological Excavations on the Grounds of the Middle La Tène Site of Němčice in 2021–2022

The Němčice site located in a strategic area of an agricultural plateau represents one of the most important archaeological sites in Moravia. Non-destructive archaeological surveys including a largescale magnetometer survey, field artefact collections, and metal detector surveys have been carried out there repeatedly over the past two decades. New archaeological excavations during a new project were focused on selected areas and situations identified during magnetometer prospection. The results of an archaeological investigation of the site using test pits confirmed settlement, glass-making and ritual activity under magnetic anomalies at the site. The new possibility of comparing uncovered sunken features and distributions of magnetic anomalies provided new feedback for a more precise interpretation of similar anomalies from magnetograms. An additional detailed apparent magnetic susceptibility measurement in situ showed another possibility for the application of the geophysical method during archaeological excavations. We were able to obtain additional information about the fills or possible post-depositional processes of various sunken features in the case of vertical profiles monitored by magnetic susceptibility meter measurements. The use and combination of various geophysical data has been beneficial in the case of an archaeological site as important as Němčice, and will continue to be so in future archaeological research of the site.

Identifikasi Pola Redistribusi Tanah Yang Tidak dan Telah Mengalami Longsor Berdasarkan Nilai Suseptibilitas Magnetik di Daerah Batu Busuk Kota Padang

The research has been carried out to identify patterns of soil redistribution based on magnetic susceptibility values in the Batu Busuk area, Lambung Bukit Village, Pauh District, Padang City. The sample was carried out at three locations, namely Location A (experienced landslides), Location B (not experienced landslides), and Location C (not experienced landslides), with a track length of 40 meters for each location, which has 5 points with variations in depth of 10, 20, 30, 40 and 50 cm. The magnetic susceptibility of the sample was measured using a Bartington Magnetic Susceptibility Meter with a low frequency of 0.465 kHz and a high frequency of 47 kHz. The results showed that most of the samples from Location A and Location C had χfd (%) value of less than 4.0%, while for Location B, it was the opposite. The sample Location B has a pattern where the value of χfd increases with increasing χlf value, not so for the samples for Locations A and C. The susceptibility values for the samples for Location B and Location C decrease with increasing sampling depth, while the sample for Location A fluctuates. The pattern of soil redistribution based on the distribution of sample magnetic susceptibility values for Location B and Location C is relatively more even. On the contrary, Location A. Location A and Location C have experienced erosion, where the erosion rate in Location A is higher than in Location C. In contrast, the soil conditions in Location B are relatively stable.

The Content of Magnetic Material in Black Sand of Yeh Gangga Beach

Yeh Gangga Beach is one of the black sand beaches in the Tabanan district. The abundant black sand on this beach stretches along the shoreline with varying grain sizes. This black sand characterizes the specific surface composition as iron sand deposits with high magnetic mineral content. The very high need and use of magnetic minerals in various fields prompt a study of the magnetic mineral content in the black sand of Yeh Gangga beach.The magnetic material content was determined by the extraction method which was expressed in terms of mass fraction. The grain size distribution was determined by the sieve method using a sieve shaker consisting of six mesh numbers, namely 30, 100, 170, 200, 270, and 325.The density of magnetic materials was determined by the principle of mass and volume ratio. The magnetic susceptibility was tested by using a Bartington MS2B susceptibility meter. Meanwhile, the characterization of the elements and their oxides used non-magnetic methods, namely the X-Ray Fluorescence test.The research results show that the magnetic material fraction of Yeh Gangga black sand reach 84.84% with 58.39% of the grains having sizes in the range 150r ≥90 μm. The magnetic susceptibility value is 28.26 10-6 m3/kg with an Fe element content of 85.15% w. The hematite (Fe2O3) content reaches 81.69%. This magnetic material has a density of 1914.43 kg/m3.

Identifikasi Mineral Magnetik Pada Tanah Permukaan Dari Daerah Tercemar Abu Terbang dan Abu Dasar

ABSTRACT. Magnetic susceptibility measurements have been carried out at three points (A1, A2 and A3) on the surface soil around the Asam-asam power plant. This study aims to determine the magnetic minerals that may be present in these soil samples. Magnetic susceptibility measurements were carried out using the Bartington Susceptibility Meter MS2B. Based on the range of susceptibility values in soil samples, it shows the content of magnetic minerals such as ilmenite, pyrrhotites and titanomagnetite which are thought to come from fly ash and bottom ash from combustion at the PLTU.KEYWORDS: magnetic minerals, soil, flying ash, bottom ash

The Variations of Clinker Superparamagnetic Value from PT. Semen Padang by Using a Bartington Magnetic Susceptibility Meter Sensor Type B

Clinker is a significant material in the cement manufacturing process. Before clinker formation, the raw material is burned in a Rotary Kiln with a temperature of up to 1450℃. After that, it is cooled in a Greet Cooler to a temperature of 100℃ and produces clinker. During the clinker manufacturing process, always being test on samples, but there has been no test based on magnetic susceptibility. The purpose of this research is to know the variation of the superparamagnetic clinker value based on the magnetic susceptibility value. The method used is the rock magnetism method using a Bartington Magnetic Susceptibility Meter MS2B Type. A sampling of clinker is taken hourly every day from PT. Padang Cement. From the value of magnetic susceptibility based on low-field magnetic susceptibility , it was obtained that the values ​​varied from 3.2 × 10-8m3/kg to 22.6 ×10-8m3/kg. The frequency of dependents is also diverse, ranging from 0.0% to 7.4%. Based on the obtained, the type of grain produced also varies. 136 samples of clinker containing less than 10% superparamagnetic grains, and 32 samples belonging to Medium have a percentage of 2%-10% where the sample comprises superparamagnetic grains. Between 10% and 75% is a mixture of fine and coarse superparamagnetic grains.

The “Meteorite meter”: A handheld instrument for the combined measurement of magnetic susceptibility and electrical conductivity, with application to meteorite identification and classification

AbstractWe developed a simple, handheld, and user‐friendly magnetic susceptibility meter specialized for the identification of meteorites. The measurement is based on an LC resonance circuit. When provided with a rough estimate of the sample mass, the instrument displays directly the mass‐normalized magnetic susceptibility expressed in logχm (with χm in 10−9 m3 kg−1), a parameter that is widely used in the classification of meteorites. Moreover, the measurement of the impedance of the LC resonator provides a proxy of the electrical conductivity (C‐index) that can be helpful to distinguish metal‐bearing samples from magnetite‐bearing samples. This C‐index offers an additional diagnostic for the identification of meteorites. Our tests demonstrate that the precision and the accuracy of this instrument called “Meteorite meter” (MetMet) are sufficient to allow distinguishing most meteorites from most terrestrial rocks, for a minimum recommended sample mass of 5 g. The distinction of some meteorite groups is also possible, in particular the separation of the three ordinary chondrite groups. Meteorite hunters, collectors, and curators and non‐specialists, including children, can use this instrument as a guidance in the identification and classification of meteorites. This kind of instrument has an immense advantage over the widely used testing of meteorites with magnets, as it does not affect the paleomagnetic records of meteorites that are highly valuable for scientists.

Determination of Magnetic susceptibility of hydrocarbon contaminated soils in Port Harcourt and Bonny Island, Rivers State, Nigeria

In this study, determination of magnetic susceptibility were carried out on 366 soil samples using MS2B magnetic susceptibility meter connected to a computer system using MULTISUS2 software. The soil samples were selected from six sites namely: Shell environment, Nigeria Liquefied Natural Gas environment, Port Harcourt Refining Company James Hart, New Jerusalem and Port Harcourt respectively. Three of the six sites; Shell, NLNG and Port-Harcourt Refining Company environments have their soils contaminated with hydrocarbon. One hundred and ninety two (192) soil samples were collected from these hydrocarbon contaminated sites and 174 from non-hydrocarbon contaminated soil (control samples). The magnetic susceptibility values obtained from Shell environment and for hydrocarbon samples showed higher (enhanced) magnetic susceptibility with average values of 117.54x10-8 m3kg-1 and 2016.39x10-8 m3kg-1 and a moderate magnetic susceptibility for with an average value of 20.83x10-8 m3kg-1 in comparison to magnetic susceptibility values obtained from the control samples whose average values were 2.39x10-8 m3kg-1, 12.42x10-8 m3kg-1 and 3.31x10-8 m3kg-1 for James Hart, New Jerusalem and Port Harcourt respectively. This means that the hydrocarbon sites are highly magnetic which could be indication of pollution. The results of the percentage frequency dependent susceptibility (χFD%) obtained in the hydrocarbon samples showed about 16% of the samples had percentage frequency dependent susceptibility (χFD%) values between 0-2%, 53% had values of χFD% between 2-10% and 31% had χFD% between 10-12% and above while about 21% of the control samples had χFD% values between 0-2%, 58% between 2-10% and 21% between 10-12% and above. The high magnetic susceptibility value in the hydrocarbon soil samples is an indication of pollution due to hydrocarbon deposit. The Government is therefore advised to monitor the location and activities of the oil companies and initiate quick mop up strategies should be put in place in the eventuality of oil spillage.

Magnetic Mineral Consistency Analysis the main ingredients of cement and Rowmix materials with Magnetic Susceptibility Method using Bartington Magnetic Susceptibility Type B (MS2B)

Cement has hydraulic properties (mixed with water) will form a bond and harden. Cement-making materials consist of the main ingredients (Limestone, Iron Sand, Silica, and Clay) which are the ingredients in the manufacture of Rowmix in the Rowmill. In the main ingredient there is a magnetic mineral content for the manufacture of Component Compoun. To see changes in magnetic minerals from the cement manufacturing process, it is necessary to analyze the consistency of the material until the initial manufacture. The purpose of this study was to determine the consistency of the magnetic mineral as the main ingredient of cement in the Rowmix manufacturing process. The research method used is rock magnetism using a Bartington Susceptibility Meter Type B (MS2B) which can measure based on mass and volume with 2 different frequencies, namely Low Frequency and High Frequency. This measurement uses 6 different samples, namely the main ingredients of cement (Limestone, Irond Sand, Silica, Clay) and Rowmix materials (Rowmix 1 (RX1) and Rowmix 2 (RX2). From these measurements, the susceptibility values obtained from the main ingredients including Limestone approx. 23.7 x 10−8 m3/kg - 46.6 x 10−8 m3/kg, Irond Sand ranged from 470 x 10−8 m3/kg - 1791.1 x 10−8 m3/kg, Clay ranged from 852.7 x 10−8 m3/kg - 986.4 x 10−8 m3/kg, Silica ranges from 148.2 x 10−8 m3/kg - 166.9 x 10−8 m3/kg, while in Rowmill I process (Rx1) around 133, 4 x 10−8 m3/kg - 180.3 x 10−8 m3/kg, Rowmill 2 (Rx2) 133.4 x 10−8 m3/kg - 244.2 x 10−8 m3/kg, Magnetic susceptibility values in the main material range from 1532 x 10−8 m3/kg up to 2838,6 x 10−8 m3/kg, while the value of Rowmix 1 (RX1) and Rowmill 2 (Rx2) is lower than the magnetic susceptibility value of the main ingredient.

Radiometric and magnetic susceptibility characterization of soil profiles: Geophysical data and their relationship with Antarctic periglacial processes, pedogenesis, and lithology

Maritime Antarctica is still pedologically unexplored by proximal geophysical sensors. In-depth soil geophysical characterizations in depth can provide comprehensive information regarding how weathering, pedogenesis, and periglacial processes operate in periglacial environments, with advantages like non-invasive methodology, fast and precise data acquisition, practical equipment operation, and cost-effectiveness. This research aimed to carry out the first proximal gamma-spectrometric and magnetic geophysical characterization of soil profiles in maritime Antarctica and to relate the geophysical variables analyzed with periglacial processes, weathering, pedogenesis, geology, and landscape dynamics. The study was carried out in the Keller Peninsula (King George Island, Maritime Antarctica) with the pedological characterization of soil profiles, using two proximal geophysical sensors (gamma spectrometer and susceptibility meter) that quantify, respectively, soil radionuclides uranium, thorium and potassium as well as soil magnetic susceptibility. For that, twenty soil profiles were described and characterized, and soil samples were collected for physico-chemical analysis. In addition, readings were carried out with the two geophysical sensors in each soil profile, through soil horizons up to the lithic contact and/or permafrost top. We performed exploratory statistical analyses in R software as follows: visualizing the geophysical variables in soil depth for each profile and soil class, obtaining descriptive statistics among soil classes, analyzing geophysical variables by geology and soil classes, performing Spearman correlation between geophysical variables and soil physico-chemical attributes, and applying principal component analysis to pedological classes, geophysical variables, and soil physico-chemical attributes. The results showed that radionuclide contents increased with soil profile depth in all profiles and soil classes analyzed, except for Cryosols where permafrost is present, and cryoturbation was more pronounced. The potassium content was high in all soil profiles, evidencing the low degree of chemical weathering and leaching. The soil magnetic susceptibility values tended to decrease in depth, mainly where permafrost was present. The gravel content contributed more to the levels of radionuclide content. The clay content in some soil classes present contributed secondarily to uranium and thorium contents. Soil profiles located on marine terraces were influenced by periglacial reworking and deposition of different materials, showing increases in magnetic susceptibility values with soil depth by the absolute accumulation of ferrimagnetic minerals. Principal component analyses efficiently separated Regosols from other soil classes by soil κ related to lithology, whereas Cambisols and other soil classes were separated by radionuclide contents related to incipient pedogenesis. These findings may give new insights into understand this inhospitable continent.

Magnetic Susceptibility of Pumice at Mount Singgalang, West Sumatera

Volcanic activity produces eruptions that release pyroclastic material at the time of the explosion. Mount Singgalang is a volcano that has experienced an eruption after 1600. Several types of volcanic rocks around the Mount Singgalang area are Basalt, Andesite, Tuff Breccia, Lava Breccia, and Pumice Tuff. Pumice is formed when saturated liquid magma gas bursts like a carbonated beverage and soon cools, causing the froth that results to solidify into a glass full of gas bubbles. Some minerals contained in pumice are obsidian, cristobalite, feldspar, and tridymite. Pumice contains magnetic minerals, namely ilmenite (FeTiO3), and magnetite (Fe3O4). The purpose of this study is to quantify the magnetic susceptibility and quantity of pumice on Mount Singgalang in West Sumatera. When utilizing the Bartington Magnetic Susceptibility Meter to analyze a sample, magnetic susceptibility parameters are utilized to pinpoint the features of a magnetic rock mineral. The value of the magnetic susceptibility of pumice on Mount Singgalang, in West Sumatera has a value that varies between 2763.3 x 10-8m3/kg - 2192.1 x 10-8m3/kg. The results showed that the tested samples had antiferromagnetic magnetic mineral properties with frequency-dependent susceptibility values (χfd), indicating that all of the measured samples contained almost no superparamagnetic (SP) grains and were generally dominated by multi-domain (MD) grains.

Environmental effects of potentially toxic elements and the magnetic susceptibility distribution in the surface bottom sediments in the Vistula estuary (Gulf of Gdańsk, Poland)

PurposeThis study is aimed at analyzing the spatial distribution of magnetic susceptibility and the content of potentially toxic elements (PTEs) in the surface layer of bottom sediments in the Vistula estuary (Gulf of Gdańsk, Poland) in relation to local sedimentary conditions. We also assessed the usefulness of magnetic susceptibility measurements to identify changes in sediment properties caused by anthropogenic factors.Materials and methodsBottom sediments were collected along three transects using the Van Veen grab sampler. The following properties were determined: granulometric composition, organic matter and carbonate content, pH, electrical conductivity, and heavy metal content (Cd, Cr, Cu, Fe, Ni, Pb, and Zn). Specific (mass) magnetic susceptibility (χ) was measured using the MS2 Bartington® laboratory magnetic susceptibility meter. To characterize the conditions of the sedimentary environment in the study area, statistical analysis was performed on selected parameters of grain size distribution, such as mean grain diameter (Mz) and sorting (σ1) indices.Results and discussionThe research showed significant differences in the sedimentary environment (erosion vs. deposition processes) along the studied transects which were controlled by the wave regime, sea currents, and river water inflow. Open-water sediments were richer in organic matter and more saline than deltaic sediments, which in turn were characterized by higher pH and higher carbonate content. The highest mean total content of Pb, Cu, Ni, and Zn and the highest magnetic susceptibility (χ) were determined in open-water sediments, while the highest Fe and Cr values were obtained for deltaic sediments. Statistically significant differences between these sediments were found only for organic matter (LoI), Pb, Cu, and Cd content. Magnetic susceptibility showed a moderate correlation with Pb, Cu, Cd, and Zn (rs 0.4–0.6).ConclusionPTE content and magnetic susceptibility of sediments showed a very high heterogeneity within the study area, depending mainly on the location (delta vs. open waters), grain size composition, and organic matter content. Our results demonstrated that magnetic susceptibility analysis is an easy method that can be used to complement the identification of technogenic changes in the marine environment.

Hand Magnets and the Destruction of Ancient Meteorite Magnetism

AbstractMeteorites provide invaluable records of planetary formation and evolution. Studies of their paleomagnetism have constrained accretion in the protoplanetary disk, the thermal evolution and differentiation of planetesimals, and the history of planetary dynamos. Yet, the potential of these magnetic records in advancing the field of planetary science is severely hindered by a widely used technique: application of hand magnets to assist in meteorite classification. Touching a meteorite with a magnet results in near‐instantaneous destruction of its magnetic record. Here, we showcase the destructive effects of exposing meteorites to magnets through numerical modeling, a controlled remagnetization experiment on a terrestrial basalt, and a paleomagnetic study of the oldest known Martian meteorite, the Northwest Africa (NWA) 7034 pairing group. NWA 7034 is a polymict regolith breccia containing zircon crystals with crystallization ages older than 4.4 billion years. As such it contains materials that are sufficiently old to have formed during the time Mars is most likely to have had a core dynamo. Unfortunately, we found that all nine paired stones of NWA 7034 that we investigated were remagnetized by hand magnets, as has been observed for many other hot desert meteorites. We recommend that magnets not be applied to meteorites during collection and curation. Instead, a low‐field susceptibility meter is a far more sensitive and completely nondestructive tool for meteorite classification.

Using Magnetic Susceptibility to Assess Soil Pollution in the Tiruvannamalai District, Tamil Nadu with Statistical Approach

Objective: This study used magnetic susceptibility measurements and statistical methods to investigate soil pollution. Method: Using the grid approach, soil samples were collected in and around Tiruvannamalai district, Tamil Nādu. Standard procedures were used to determine the physicochemical parameters of soil samples such as the percentages of sand, silt and clay, EC and pH. A dual frequency susceptibility meter was used to assess the magnetic susceptibility of the soil samples collected at low-frequency (clf) and high-frequency (chf). Multivariate statistical analysis such as factor analysis (FA), Pearson correlation (PC), and cluster analysis (CA) were conducted to determine the influence of Physicochemical parameters on magnetic susceptibilities and to detect soil contamination from anthropogenic or natural sources. Findings: Significant magnetic enhancement values may be concentrated in the soil, indicating ferrimagnetic minerals in the study area in some locations. Novelty: Contamination sources of pollution using magnetic susceptibility with statistical approach. Keywords: Soil; Physicochemical properties; magnetic susceptibility; Statistical Methods; Pollution

Analysis of Magnetic Material Abundance in Black Sand

The analysis of the magnetic material abundance on the black sand of Nyanyi beach revealed magnetic material content, grain size, density, magnetic mineral content, and magnetic susceptibility value.The results of this study can be used for black sand development inTabanan district. The black sand magnetic material was determined by the extraction method. Mineral content was tested by using XRF equipment, and the magnetic properties of black sand were determined by using a Bartingtons MS2 Magnetic Susceptibility Meter and a Vibrating Sample Magnetometer. The data were analyzed descriptively quantitatively. The results show thatNyanyi beach sand physically has a characteristic dark gray color, tends to be black, and shiny with a weight fraction of magnetic material reaching 95.52%.The density of the magnetic material is 2072.6 with varying grain sizes of 53 600 .The average value of magnetic susceptibility is 27.212x 10-with Fe2O3magnetic mineral content of 86.68% and the element of Fe is 89.41%.The values of saturation magnetization, remanance magnetization, and coervicity reach37.74; 4.64; 103.93 Oe.

Graphene-magnetite functionalized diatomite for efficient removal of organochlorine pesticides from aquatic environment

A unique composite based on graphene oxide, magnetite, and diatomite was synthetized by eco-friendly dry coating technique for the removal of four toxic organochlorine pesticides from agricultural drainage. The prepared composite was fully characterized using X-ray fluorescence (XRF), X-ray diffraction (XRD), particle size analyzer, Vibrating-sample magnetometer (VSM), magnetic susceptibility meter, zeta potential, scanning electron microscopy-energy dispersive X-ray spectrometer (SEM-EDS), and Brunauer–Emmett–Teller analysis (BET) techniques. The characterization results confirmed the fabrication of a discrete core/shell structured composite possess both adsorptive and magnetic nature. The surface area, pore volume and pore diameter were 23.4 m2/g, 0.0026 cm3/g, and 4.5 nm, respectively. The amenability to use the fabricated composite as an adsorbent for some organochlorine pesticides was investigated under different conditions of concentration, time, pH, and temperature. Batch adsorption experiment showed that 97% removal efficiency was observed for all the studied pesticides with adsorption capacities of 7.78 mg/g after 2 h contact time and at any pH region. The adsorption was exothermic (ΔH < 0), spontaneous (ΔG° < 0), followed pseudo 2nd order kinetics (R2 > 0.998), and fitted well to Langmuir's isotherm pattern for all pesticides (R2 > 0.98). It is assumed that organochlorine pesticides were initially physisorbed by the graphene nanoplatelets via hydrophobic and π-π interactions along with chemisorption for forming monolayer. Moreover, the pesticides molecules could diffuse in the DMG composite micropores and be trapped in the structural defects. The regeneration of the composite exhibited over 90% removal efficiency even after seven cycles. The fabricated composite was examined to remove organochlorine from a real water sample, the obtained results suggest the possibility to use this composite as an economical, effective and sustainable adsorbent for the treatment of pesticides contaminating water.

Feasibility study on the use of magnetic susceptibility for recovery of vanadium component in magnetite

ABSTRACT Vanadium in the vanadium-bearing titanomagnetite (VTM) exist by replacing iron in the magnetite crystal, and magnetite should be recovered separately from titanium components in the vanadium-bearing titanomagnetite. In the present study, a sensing system was proposed by measuring magnetic susceptibility of magnetite because the magnetic susceptibility can be easily and quickly measured. The effects of mixing ratio of magnetite and ilmenite with silica and the distance between the magnetic susceptibility meter and the sample bed on the magnetic susceptibility were investigated. The magnetic susceptibility of the mixture of magnetite and ilmenite with 0.1 g or 0.2 g of silica decreased with increasing the ratio of ilmenite in the mixture, but the effect of silica addition was not significant. When the distance between the magnetic susceptibility meter and the sample bed increased, the magnetic susceptibility of magnetite decreased, but the magnetic susceptibility decreased with increasing the thickness of magnetite sample bed of magnetite. Because the magnetic susceptibility depended strongly on the content of magnetite, the sensing system using the magnetic susceptibility measurement could be successfully applied to detect magnetite.

Irregular Magnetic Susceptibility Pattern of Iron Sand from Pasia Jambak Beach, Pasia Nan Tigo, Padang, Indonesia

West Sumatra has the potential of abundant natural resources in the form of iron sand, one of which is located in the Pasia Jambak Beach area, Pasia Nan Tigo, Padang. Basically iron sands have magnetite (Fe3O 4), hematite (α-Fe2O 3), and maghemite (γ-Fe2O 3) which can be used as a mineral of high economic value. However, the iron sand of Pasia Jambak Beach, Pasia Nan Tigo, has no known magnetic mineral. This study aims to investigate the magnetic mineral content of the iron sand of Pasia Jambak Beach, Pasia Nan Tigo, Padang based on its magnetic susceptibility. The variation of the investigated susceptibility value is based on depth. Magnetic susceptibility measurements were carried out using a Bartington Magnetic Susceptibility Meter with a MS2B sensor dual frequency. The results showed that the magnetic susceptibility value of the iron sand of Pasia Jambak Beach, Pasia Nan Tigo, Padang varied based on the depth from 291.1 x 10−8 m3/kg to 12445.5 x 10−8 m3/kg with an average value of 2016.35 x 10−8 m3/kg. Variations in the susceptibility value of iron sand obtained at each depth have changes or variations in the susceptibility value that are irregular or do not have a certain pattern.