Strong enhancement of methylene blue removal from binary wastewater by in-situ ferrite process

Dye wastewater containing heavy metal ions is a common industrial effluent with complex physicochemical properties. The treatment of metal-dye binary wastewater is difficult. In this work, a novel in-situ ferrite process （IFP） was applied to treat Methylene Blue （MB）-Cu（II） binary wastewater, and the operational parameters were optimized for MB removal. Results showed that the optimum operating conditions were OH/M of 1.72, Cu2＋/Fe2＋ ratio of 1/2.5, reaction time of 90 min, aeration intensity of 320 mL/min, and reaction temperature of 40℃. Moreover, the presence of Ca2＋ and Mg2＋ moderately influenced the MB removal. Physical characterization results indicated that the precipitates yielded in IFP presented high surface area {232.50 m2/g） and a multi-porous structure. Based on the Langmuir model, the maximum adsorption capacity toward MB was 347.82 mg/g for the precipitates produced in IFP, which outperformed most other adsorbents. Furthermore, IFP rapidly sequestered MB with removal efficiency 5 to 10 times greater than that by general ferrite adsorption, which suggested a strong enhancement of MB removal by IFP. The MB removal process by IFP showed two different high removal stages, each with a corresponding removal mechanism. In the first brief stage （〈5 min）, the initial high MB removal （～95%） was achieved by predominantly electrostatic interactions. Then the sweep effect and encapsulation were dominant in the second longer stage.

Cost-effective integrated strategy for the fabrication of hard-magnet barium hexaferrite powders from low-grade barite ore

Ultrafine barium hexaferrite（BaFe12O19） powders were synthesized from the metallurgical extracts of low-grade Egyptian barite ore via a co-precipitation route. Hydrometallurgical treatment of barite ore was systematically studied to achieve the maximum dissolution efficiency of Fe（～99.7%） under the optimum conditions. The hexaferrite precursors were obtained by the co-precipitation of BaS produced by the reduction of barite ore with carbon at 1273 K and then dissolved in diluted HCl and FeCl3 solution at pH 10 using NaOH as a base; the product was then annealed at 1273 K in an open atmosphere. The effect of Fe^3＋/Ba^2＋ molar ratio and the addition of hydrogen peroxide（H2O2） on the phase structure, crystallite size, morphology, and magnetic properties were investigated by X-ray diffraction, scanning electron microscopy, and vibrating sample magnetometry. Single-phase BaFe（12）O（19） powder was obtained at an Fe^3＋/Ba^2＋ molar ratio of 8.00. The formed powders exhibited a hexagonal platelet-like structure. Good maximum magnetization（48.3 A×m^2×kg^–1） was achieved in the material prepared at an Fe^3＋/Ba^2＋ molar ratio of 8.0 in the presence of 5% H2O2 as an oxidizer and at 1273 K because of the formation of a uniform, hexagonal-shaped structure.

Evolution of Through-Thickness Texture in Ultra Purified 17%Cr Ferritic Stainless Steels

Texture inhomogeneity usually takes place in ferritic stainless steels due to the lack of phase transformation and recrystallization during hot strip rolling,which can deteriorate the formability of final sheets.In order to work out the way of weakening texture inhomogeneity,conventional hot rolling and warm rolling processes have been carried out with an ultra purified ferritic stainless steel.The results showed that the evolution of through-thickness texture is closely dependent on rolling process,especially for the texture in the center layer.For both conventional and warm rolling processes,shear texture components were formed in the surface layers after hot rolling and annealing;sharp α-fiber and weakγ-fiber with the major component at{111}〈110〉 were developed in both cold rolled sheet surfaces,leading to the formation of inhomogeneousγ-fiber dominated by{111}〈112〉after recrystallization annealing.In the center layer of conventional rolled and annealed bands,strongα-fiber and weakγ-fiber textures were formed;the cold rolled textures were comprised of sharpα-fiber and weakγ-fiber with the major component at{111}〈110〉,and inhomogeneousγ-fiber dominated by{111}〈112〉 was formed after recrystallization annealing.By contrast,in the centre layer of warm rolled bands,the texture was comprised of weakα-fiber and sharpγ-fiber,andγ-fiber became the only component after annealing.The cold rolled texture displayed a sharpγ-fiber with the major component at{111}〈112〉and the intensity ofγ-fiber close to that ofα-fiber,resulting in the formation of a nearly homogeneousγ-fiber recrystallization texture in the center layer of the final sheet.