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A magnetic filtration has firstly been applied to the phosphate removal from wastewater by using schwertmannite, which is ferric oxyhydroxide sulfate with high capacity of phosphate adsorption. High efficiency of phosphate removal without using magnetic seeding was obtained at magnetic intensities of around 1 Tesla, which means no necessity to use a superconducting magnet. The kinetics data of phosphate adsorption have been found to be fitted well with a pseudo-second-order model and adsorption equilibrium data have been explained by the Langmuir isotherm. The effect of pH on the phosphate adsorption in this process was characterized by zeta potential measurement. It is proposed that ligand exchange is a dominant mechanism responsible for phosphate adsorption on schwertmannite.

Due to the development of superconducting magnets, the magnetic filtration process is now undergoing its biggest evolution since its conception. In Japan, the first industrial superconducting magnetic filter has been successfully applied for factory wastewater treatment. Much effort in both theory and practice is needed to further contribute to the new developments of this high gradient magnetic filtration process. In this substantial review, we have collected the most important theoretical and practical data about magnetic filtration, its recovery and design to establish a good framework for further development of this amazing technology.Index Terms-Electromagnetic processing of materials, high gradient magnetic field, superconducting filter, wastewater treatment.

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The fine particles of schwertmannite as an iron oxyhydroxide adsorbent has been suggested as a novel and strong Cr(VI) sorbent for treatment of Cr-contaminated industrial wastewater. The removal process was conducted in both batch and continuous trials. As a result of the batch experiments, the maximal adsorption capacity of the schwertmannite was obtained as 178 mg/g which was quite high amount in comparison with the usual applied Cr(VI) sorbents in the literatures. The continuous removal process involved a combination of a fixed bed column with a high gradient magnetic field which was firstly introduced as a novel designation of a fixed bed column to overcome the difficulties accompanied with the application of some especial fine particle adsorbents through the fixed-beds. The experimental results revealed that the magnetization force had a great function in this process to control the shape and the fitness of the bed during the sorption test as well as to simplify the experimental set-up.KEY WORDS: magnetic fixed bed column; Cr removal; high magnetic field; schwertmannite; wastewater treatment; electromagnetic processing of materials.tion, however, has some inherent limitations to be utilized as a continuous filtering system because of time-dependent plugging and saturation of its matrix.The most optimal configuration for continuous-flow sorption is the packed-bed column which gets gradually saturated from the feed to the solution exit end. High-quality fixed-bed column hardware is the subject of several US patents. In our study work, the experimental trials of the process have been conducted for many times by directly packing the column with the fine particle size of schwertmannite as the most strong Cr adsorbents. Extremely fine particles and mud like properties of the adsorbent, however, has caused a verity of problems to the system such as high pressure drop, mass transfer resistance and so on. To solve the problems dealing with the system, a magnetic fixed-bed column, as a novel designation of the fixed-bed columns, has been presented in this study. Moreover, the batch Cr(VI) adsorption data containing equilibrium models using the schwertmannite adsorbent and also the effect of pH on the adsorption to predict the sorption characteristics of the adsorbent have been given. Materials and MethodsAll chemicals used were of high purity and analytical grades. The schwertmannite powder as the chemical adsorbent of Cr(VI) in these experiments was made by homogenous hydrolysis of iron ferric salt (Fe 2 (SO 4 ) 3 · nH 2 O) according to the methods mentioned in our pervious work. 14)Stock solution of 130 mg/L of Cr(VI) for use in the fixed column experiment was prepared by dissolving of a known amount of K 2 Cr 2 O 7 in dionized water. In the batch mode adsorption trials, 50 mL of the solution with desired concentrations of Cr and the adsorbent were mixed in a bottle of 100 mL and shaken for about 5 h to reach to the equilibrium state. Then the yielded solution was filtered through a paper filter and then chromium c...

A new chemical adsorbent for fluoride and phosphate removals was produced by applying a novel nanomagnetite aggregation process through the formation procedure of an iron oxide hydroxide, i.e., schwertmannite. Although there was no evidence of magnetite related peaks in the XRD pattern of the new adsorbent, because of the very small amount of the used magnetite particles, the SEM picture reveals a surface alteration on the crystal structure of the new adsorbent comparing to the schwertmannite. The results of magnetic removal of fluoride and phosphate using the new adsorbent indicate that nanomagnetite aggregation process not only improves the magnetic property, but also provides a highly-promoted fluoride and phosphate adsorption capacities comparing to the schwertmannite.KEY WORDS: fluoride removal; phosphate removal; magnetic filter; wastewater treatment; schwertmannite; nanomagnetite; electromagnetic processing of materials.

A force and/or torque are induced in a material under the imposition of a magnetic field. Their magnitudes are different from those acting on the surrounding materials because of the difference in their physical properties. Therefore, a magnetic field is a powerful tool for controlling a second phase in a mother phase such as particles suspended in a liquid. In this paper, we focus on two processes. The first one is a novel method of magnetic filtration in which schwertmannite particles in wastewater are controlled using a magnetic field. The second one is a refining process for a metallic alloy structure during solidification in which solid particles suspended in the liquid phase are controlled using the force excited by the simultaneous imposition of a magnetic field and alternating current.