The removal of Ni(II) from aqueous solution by magnetic nanoparticles prepared and impregnated onto tea waste (Fe(3)O(4)-TW) from agriculture biomass was investigated. Magnetic nanoparticles (Fe(3)O(4)) were prepared by chemical precipitation of a Fe(2+) and Fe(3+) salts from aqueous solution by ammonia solution. These magnetic nanoparticles of the adsorbent Fe(3)O(4) were characterized by surface area (BET), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Fourier Transform-Infrared Spectroscopy (FT-IR). The effects of various parameters, such as contact time, pH, concentration, adsorbent dosage and temperature were studied. The kinetics followed is first order in nature, and the value of rate constant was found to be 1.90×10(-2) min(-1) at 100 mg L(-1) and 303 K. Removal efficiency decreases from 99 to 87% by increasing the concentration of Ni(II) in solution from 50 to 100 mg L(-1). It was found that the adsorption of Ni(II) increases by increasing temperature from 303 to 323 K and the process is endothermic in nature. The adsorption isotherm data were fitted to Langmuir and Freundlich equation, and the Langmuir adsorption capacity, Q°, was found to be (38.3)mgg(-1). The results also revealed that nanoparticle impregnated onto tea waste from agriculture biomass, can be an attractive option for metal removal from industrial effluent.
We have further developed the two-brains hypothesis as a form of complementarity (or complementary relationship) of endogenously induced weak magnetic fields in the electromagnetic brain. The locally induced magnetic field between electron magnetic dipole moments of delocalized electron clouds in neuronal domains is complementary to the exogenous electromagnetic waves created by the oscillating molecular dipoles in the electro-ionic brain. In this paper, we mathematically model the operation of the electromagnetic grid, especially in regard to the functional role of atomic orbitals of dipole-bound delocalized electrons. A quantum molecular dynamic approach under quantum equilibrium conditions is taken to illustrate phase differences between quasi-free electrons tethered to an oscillating molecular core. We use a simplified version of the many-body problem to analytically solve the macro-quantum wave equation (equivalent to the Kohn-Sham equation). The resultant solution for the mechanical angular momentum can be used to approximate the molecular orbital of the dipole-bound delocalized electrons. In addition to non-adiabatic motion of the molecular core, 'guidance waves' may contribute to the delocalized macro-quantum wave functions in generating nonlocal phase correlations. The intrinsic magnetic properties of the origins of the endogenous electromagnetic field are considered to be a nested hierarchy of electromagnetic fields that may also include electromagnetic patterns in three-dimensional space. The coupling between the two-brains may involve an 'anticipatory affect' based on the conceptualization of anticipation as potentiality, arising either from the macro-quantum potential energy or from the electrostatic effects of residual charges in the quantum and classical subsystems of the two-brains that occurs through partitioning of the potential energy of the combined quantum molecular dynamic system.
Magnetic iron oxide nanoparticles (MNPs) have emerged as highly desirable nanomaterials in the context of many research works, due to their extensive industrial applications. However, they are prone to agglomerate on account of the anisotropic dipolar attraction, and therefore misled the particular properties related to single-domain magnetic nanostructures. The surface modification of MNPs is quite challenging for many applications, as it involves surfactant-coating for steric stability, or surface modifications that results in repulsive electrostatic force. Hereby, we focus on the dispersion of MNPs and colloidal stability.
A new graphene-based tetraethoxysilane-methyltrimethoxysilane sol-gel hybrid magnetic nanocomposite (Fe3O4@G-TEOS-MTMOS) was synthesised, characterized and successfully applied in magnetic solid-phase extraction (MSPE) for simultaneous analysis of polar and non-polar organophosphorus pesticides from several water samples. The Fe3O4@G-TEOS-MTMOS nanocomposite was characterized using Fourier transform-infrared spectroscopy, energy-dispersive X-ray spectroscopy, field emission scanning electron microscopy and X-ray diffraction. Separation, determination and quantification were achieved using gas chromatography coupled with micro electron capture detector. Adsorption capacity of the sorbent was calculated using Langmuir equation. MSPE was linear in the range 100-1000 pg mL(-1) for phosphamidon and dimethoate, and 10-100 pg mL(-1) for chlorpyrifos and diazinon, with limit of detection (S/N = 3) of 19.8, 23.7, 1.4 and 2.9 pg mL(-1) for phosphamidon, dimethoate, diazinon and chlorpyrifos, respectively. The LODs obtained is well below the maximum residual level (100 pg mL(-1)) as set by European Union for pesticides in drinking water. Acceptable precision (%RSD) was achieved for intra-day (1.3-8.7%, n = 3) and inter-day (7.6-17.8%, n = 15) analyses. Fe3O4@G-TEOS-MTMOS showed high adsorption capacity (54.4-76.3 mg g(-1)) for the selected OPPs. No pesticide residues were detected in the water samples analysed. Excellent extraction recoveries (83-105%) were obtained for the spiked OPPs from tap, river, lake and sea water samples. The newly synthesised Fe3O4@G-TEOS-MTMOS showed high potential as adsorbent for OPPs analysis.
Graphene (G) modified with magnetite (Fe3O4) and sol-gel hybrid tetraethoxysilane-methyltrimethoxysilane (TEOS-MTMOS) was used as a clean-up adsorbent in magnetic solid phase extraction (MSPE) for direct determination of acrylamide in various food samples prior to gas chromatography-mass spectrometry analysis. Good linearity (R2=0.9990) was achieved for all samples using matrix-matched calibration. The limit of detection (LOD=3×SD/m) obtained was 0.061-2.89µgkg-1 for the studied food samples. Native acrylamide was found to be highest in fried potato with bright-fleshed (900.81µgkg-1) and lowest in toasted bread (5.02µgkg-1). High acrylamide relative recovery (RR=82.7-105.2%) of acrylamide was obtained for spiked (5 and 50µgkg-1) food samples. The Fe3O4@G-TEOS-MTMOS is reusable up to 7 times as a clean-up adsorbent with good recovery (>85%). The presence of native acrylamide was confirmed by mass analysis at m/z=71 ([C3H5NO]+) and m/z=55 ([C3H3O]+).
New-generation adsorbent, Fe3O4@SiO2/GO, was developed by modification of graphene oxide (GO) with silica-coated (SiO2) magnetic nanoparticles (Fe3O4). The synthesized adsorbent was characterized using Fourier transform infrared spectroscopy, X-ray diffractometry, energy-dispersive X-ray spectroscopy, and field emission scanning electron microscopy. The developed adsorbent was used for the removal and simultaneous preconcentration of As(III) and As(V) from environmental waters prior to ICP-MS analysis. Fe3O4@SiO2/GO provided high adsorption capacities, i.e., 7.51 and 11.46 mg g(-1) for As(III) and As(V), respectively, at pH 4.0. Adsorption isotherm, kinetic, and thermodynamic were investigated for As(III) and As(V) adsorption. Preconcentration of As(III) and As(V) were studied using magnetic solid-phase extraction (MSPE) method at pH 9.0 as the adsorbent showed selective adsorption for As(III) only in pH range 7-10. MSPE using Fe3O4@SiO2/GO was developed with good linearities (0.05-2.0 ng mL(-1)) and high coefficient of determination (R (2) = 0.9992 and 0.9985) for As(III) and As(V), respectively. The limits of detection (LODs) (3× SD/m, n = 3) obtained were 7.9 pg mL(-1) for As(III) and 28.0 pg mL(-1) for As(V). The LOD obtained is 357-1265× lower than the WHO maximum permissible limit of 10.0 ng mL(-1). The developed MSPE method showed good relative recoveries (72.55-109.71 %) and good RSDs (0.1-4.3 %, n = 3) for spring water, lake, river, and tap water samples. The new-generation adsorbent can be used for the removal and simultaneous preconcentration of As(III) and As(V) from water samples successfully. The adsorbent removal for As(III) is better than As(V).
A series of doped and un-doped magnetic adsorbents CuCexFe2-xO4 (x=0.0-0.5) for fluoride were prepared with the micro-emulsion method. Fluoride adsorption was optimized for solution pH, temperature, contact time, and initial concentration and was monitored via normal phase ion chromatography (IC). The effect of concomitant anions was also explored to perform and simulate competitive fluoride adsorption in real water samples. Optimal adsorption was discovered by a simple quadratic model based on central composite design (CCD) and the response surface method (RSM). The adsorption, electrochemical and magnetic properties were compared between doped and un-doped ferrites. Doped ferrites (x=0.1-0.5) were found to be superior to un-doped ferrites (x=0) regarding the active sites, functional groups and fluoride adsorption. The characterization, optimization and application results of the doped ferrites indicated enhanced fluoride adsorption and easy separation with a simple magnet.
The application of magnetized graphene (G) layers synthesized on the carbon nanofibers (CNFs) (m-G/CNF) was investigated as novel adsorbent for the magnetic solid-phase extraction (MSPE) of polycyclic aromatic hydrocarbons (PAHs) in water samples followed by gas chromatography-flame ionization detector (GC-FID). Six important parameters, affecting the extraction efficiency of PAHs, including: amount of adsorbent, adsorption and desorption times, type and volume of the eluent solvent and salt content of the sample were evaluated. The optimum extraction conditions were obtained as: 5min for extraction time, 20mg for sorbent amount, dichloromethane as desorption solvent, 1mL for desorption solvent volume, 5min for desorption time and 15% (w/v) for NaCl concentration. Good performance data were obtained at the optimized conditions. The calibration curves were linear over the concentration ranges from 0.012 to 100ngmL(-1) with correlation coefficients (r) between 0.9950 and 0.9967 for all the analytes. The limits of detection (LODs, S/N=3) of the proposed method for the studied PAHs were 0.004-0.03ngmL(-1). The relative standard deviations (RSDs) for five replicates at two concentration levels (0.1 and 50ngmL(-1)) of PAHs were ranged from 3.4 to 5.7%. Appropriate relative recovery values, in the range of 95.5-99.9%, were also obtained for the real water sample analysis.
The use of the eddy current technique (ECT) for the non-destructive testing of conducting materials has become increasingly important in the past few years. The use of the non-destructive ECT plays a key role in the ensuring the safety and integrity of the large industrial structures such as oil and gas pipelines. This paper introduce a novel ECT probe design integrated with the distributed ECT inspection system (DSECT) use for crack inspection on inner ferromagnetic pipes. The system consists of an array of giant magneto-resistive (GMR) sensors, a pneumatic system, a rotating magnetic field excitation source and a host PC acting as the data analysis center. Probe design parameters, namely probe diameter, an excitation coil and the number of GMR sensors in the array sensor is optimized using numerical optimization based on the desirability approach. The main benefits of DSECT can be seen in terms of its modularity and flexibility for the use of different types of magnetic transducers/sensors, and signals of a different nature with either digital or analog outputs, making it suited for the ECT probe design using an array of GMR magnetic sensors. A real-time application of the DSECT distributed system for ECT inspection can be exploited for the inspection of 70 mm carbon steel pipe. In order to predict the axial and circumference defect detection, a mathematical model is developed based on the technique known as response surface methodology (RSM). The inspection results of a carbon steel pipe sample with artificial defects indicate that the system design is highly efficient.
Magnetic paper were prepared via the in situ synthesis method with ferrites in the presence of polyethylenimine (PEI). In this work, the thermomechanical pulp (TMP) fibers were used due to low percentage of collapse lumen and the large lumen size for optimum loading degree. Four cycles of the reaction were performed on the TMP fibers with pH values of 4-10. It was found that variation of pH value played an important role in the loading degree of pulp during synthesis process. The magnetic, morphological and structural properties of the magnetic paper obtained were reported. At the
optimum pH of 6.0, saturation magnetization was found to be 3.08 emu/g, remainance magnetization was 0.11 emu/g and coercive force was 12.64 Oe. The optimum loading degree was found to be 23.25%.
The present work highlights the facile synthesis of hydrophobic palm fatty acid functionalized Fe3O4 nanoparticles (MNP-FA) for the efficient removal of oils from the surface of water. An intense hydrophobic layer was introduced on the surface of Fe3O4 nanoparticles functionalized by the palm fatty acid obtained from the hydrolysis of palm olein. Scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), Energy dispersive X-ray spectroscopy (EDX) and water contact angle analysis (WCA) measurements were used to characterize the newly fabricated palm fatty acid adorned magnetic Fe3O4 nanoparticles (MNP-FA). The obtained results confirmed the successful synthesis of palm fatty acid-functionalized magnetic nanoparticles. Oil removal tests performed with MNP-FA revealed that this newly prepared material could selectively adsorb lubricating oil up to 3.5 times of the particles' weight while completely repelling water. The main parameters affecting the adsorption of oil i.e., sorption time, mass of sorbent and pH of water were optimized.
A palygorskite-iron oxide nanocomposite (Pal-IO) was synthesized in situ by embedding magnetite into the palygorskite structure through co-precipitation method. The physico-chemical characteristics of Pal-IO and their pristine components were examined through various spectroscopic and micro-analytical techniques. Batch adsorption experiments were conducted to evaluate the performance of Pal-IO in removing Pb(II) from aqueous solution. The surface morphology, magnetic recyclability and adsorption efficiency of regenerated Pal-IO using desorbing agents HCl (Pal-IO-HCl) and ethylenediaminetetraacetic acid disodium salt (EDTA-Na2) (Pal-IO-EDTA) were compared. The nanocomposite showed a superparamagnetic property (magnetic susceptibility: 20.2 emu g-1) with higher specific surface area (99.8 m2 g-1) than the pristine palygorskite (49.4 m2 g-1) and iron oxide (72.6 m2 g-1). Pal-IO showed a maximum Pb(II) adsorption capacity of 26.6 mg g-1 (experimental condition: 5 g L-1 adsorbent loading, 150 agitations min-1, initial Pb(II) concentration from 20 to 500 mg L-1, at 25 °C) with easy separation of the spent adsorbent. The adsorption data best fitted to the Langmuir isotherm model (R2 = 0.9995) and pseudo-second order kinetic model (R2 = 0.9945). Pb(II) desorption using EDTA as the complexing agent produced no disaggregation of Pal-IO crystal bundles, and was able to preserve the composite's magnetic recyclability. Pal-IO-EDTA exhibited almost 64% removal capacity after three cycles of regeneration and preserved the nanocomposite's structural integrity and magnetic properties (15.6 emu g-1). The nanocomposite holds advantages as a sustainable material (easily separable and recyclable) for potential application in purifying heavy metal contaminated wastewaters.
This work describes the development of a new methodology based on magnetic nanoparticles assisted dispersive liquid-liquid microextraction (DLLME-MNPs) for preconcentration and extraction of chloramphenicol (CAP) antibiotic residues in water. The approach is based on the use of decanoic acid as the extraction solvent followed by the application of MNPs to magnetically retrieve the extraction solvent containing the extracted CAP. The coated MNPs were then desorbed with methanol, and the clean extract was analysed using ultraviolet-visible spectrophotometry. Several important parameters, such as the amount of decanoic acid, extraction time, stirring rate, amount of MNPs, type of desorption solvent, salt addition and sample pH, were evaluated and optimized. Optimum parameters were as follows: amount of decanoic acid: 200 mg; extraction time: 10 min; stirring rate: 800 rpm; amount of MNPs: 60 mg; desorption solvent: methanol; salt: 10%; and sample pH, 8. Under the optimum conditions, the method demonstrated acceptable linearity (R2 = 0.9933) over a concentration range of 50-1000 µg l-1. Limit of detection and limit of quantification were 16.5 and 50.0 µg l-1, respectively. Good analyte recovery (91-92.7%) and acceptable precision with good relative standard deviations (0.45-6.29%, n = 3) were obtained. The method was successfully applied to tap water and lake water samples. The proposed method is rapid, simple, reliable and environmentally friendly for the detection of CAP.
This paper proposes a novel hybrid magnetoacoustic measurement (HMM) system aiming at breast cancer detection. HMM combines ultrasound and magnetism for the simultaneous assessment of bioelectric and acoustic profiles of breast tissue. HMM is demonstrated on breast tissue samples, which are exposed to 9.8 MHz ultrasound wave with the presence of a 0.25 Tesla static magnetic field. The interaction between the ultrasound wave and the magnetic field in the breast tissue results in Lorentz Force that produces a magnetoacoustic voltage output, proportional to breast tissue conductivity. Simultaneously, the ultrasound wave is sensed back by the ultrasound receiver for tissue acoustic evaluation. Experiments are performed on gel phantoms and real breast tissue samples harvested from laboratory mice. Ultrasound wave characterization results show that normal breast tissue experiences higher attenuation compared with cancerous tissue. The mean magnetoacoustic voltage results for normal tissue are lower than that for the cancerous tissue group. In conclusion, the combination of acoustic and bioelectric measurements is a promising approach for breast cancer diagnosis.
In this present study, magnetic nanoparticles (MNPs) nanocomposites modified with polyaniline (PANI) coated newly synthesised dicationic ionic liquid (DICAT) forming MNP-PANI-DICAT were successfully synthesised as new generation material for magnetic solid phase extraction (MSPE). MNP-PANI-DICAT was characterised by FT-IR NMR, CHN, BET, SEM, TEM, and VSM techniques and the results were compared with MNP-PANI and native MNP. This new material was applied as a magnetic adsorbent for the pre-concentration and separation of polycyclic aromatic hydrocarbons (PAHs) due to the π-π interaction between polyaniline shell and dicationic ionic liquid (DICAT) with PAHs compounds. Under the optimal conditions, the proposed method was evaluated and applied for the analysis of PAHs in environmental samples using gas chromatography-mass spectrometry (GC-MS). The validation method showed good linearity (0.005-500µgL-1) with the coefficient of determination (R2) > 0.999. The limits of detection (LOD) and quantification (LOQ) of the developed method (MNP-PANI-DICAT-MSPE) were in the range of 0.0008-0.2086µgL-1and 0.0024-0.6320µgL-1, respectively. The enrichment factor (EF) of PAHs on MNP-PANI-DICAT-MSPE were in the range of 7.546-29.632. The extraction recoveries of natural water, sludge, and soil samples were ranged from 80.2% to 111.9% with relative standard deviation (RSD) less than 5.6%. The newly synthesised MNP-PANI-DICAT possess good sensitivity, reusability, and fast extraction of PAHs under the MSPE procedure in various environmental samples.
An ethanolic solution of caffeine was added to an aqueous solution of metal salts and followed by adding ethanolic solution of adenine and an aqueous solution of potassium thiocyanate to give complexes with general formula [M(CA)2(Ad)X2] where CA is caffeine, Ad is adenine, X is thiocyanate ion and M is Co(II), Ni(II), Cu(II), Zn(II) and Cd(II). The resulting products were characterized using UV-visible and infrared spectroscopies. Elemental analyses were performed using C, H, N analysis and atomic absorption techniques. The magnetic susceptibility and the conductivity were also measured. The results suggested that the complexes have octahedral geometry.
In the present research, aluminum oxide- water (Al2O3-H2O) nanofluid free convection due to magnetic forces through a permeable cubic domain with ellipse shaped obstacle has been reported. Lattice Boltzmann approach is involved to depict the impacts of magnetic, buoyancy forces and permeability on nanoparticles migration. To predict properties of Al2O3- water nanofluid, Brownian motion impact has been involved. Outcomes revels that considering higher magnetic forces results in greater conduction mechanism. Permeability can enhance the temperature gradient.
This study was designed to determine the optimum vertical height of the retraction force on the power arm that is required for efficient anterior tooth retraction during space closure with sliding mechanics.
Low-gradient magnetic separation (LGMS) of magnetic nanoparticles (MNPs) has been proven as one of the techniques with great potential for biomedical and environmental applications. Recently, the underlying principle of particle capture by LGMS, through a process known as magnetophoresis, under the influence of hydrodynamic effect has been widely studied and illustrated. Even though the hydrodynamic effect is very substantial for batch processes, its impact on LGMS operated at continuous flow (CF) condition remained largely unknown. Hence, in this study, the dynamical behaviour of LGMS process operated under CF was being studied. First, the LGMS experiments using poly(sodium 4-styrenesulfonate)-functionalized-MNP as modelled particle system were performed through batchwise (BW) and CF modes at different operating conditions. Here BW operation was used as a comparative study to elucidate the transport mechanism of MNP under the similar environment of CF-LGMS process, and it was found out that the convection induced by magnetophoresis (timescale effective is ∼1200 s) is only significant at far-from-magnet region. Hence, it can be deduced that forced convection is more dominant on influencing the transport behaviour of CF-LGMS (with resident time ≤240 s). Moreover, we found that the separation efficiency of CF-LGMS process can be boosted by the higher number of magnets, the higher MNP concentration and the lower flowrate of MNP solution. To better illustrate the underlying dynamical behaviour of LGMS process, a mathematical model was developed to predict its kinetic profile and separation efficiency (with average error of ∼2.6% compared to the experimental results).
Co(II)-Ti(IV)-substituted magnetoplumbite-type (M-type) barium ferrite nanoparticles were synthesized via the sol-gel technique employing ethylene glycol as the gel precursor. Structural and magnetic properties were characterised via X-ray diffraction (XRD), high resolution transmission electron microscopy and superconducting quantum interference device magnetometry. The particle sizes of the M-type BaCoXTiXFe12-2XO19 (0.2 ≤ ≤ 1.0) were found to be 900 Å – 1500 Å. The XRD results confirmed that the Co(II)-Ti(IV) substituted ferrites in the range of 0.2 ≤ ≤ 1.0 substitution had the M-type ferrite as the dominant phase. The hysteresis loss per-cycle decreased with increasing Co(II)-Ti(IV) substitution in M-type ferrites which showed reduced values in coercivity and remnant magnetisation with moderate effect on the saturation magnetisation.