Stable Incorporation of Co2+ into Ferrite Structure at Ambient Temperature: Effect of Operational Parameters

Abstract

Removal of heavy metals (HM) from industrial wastewater is of primary environmental importance. The seeded ambient temperature ferrite process, in which heavy metals are removed from solution by their incorporation into a magnetite structure, is an attractive alternative for both complete metals separation and generation of stable magnetic sludge. Despite its potential, the effects of various operational parameters on the composition and stability of the final product are not fully understood to-date. The current paper addresses the combined effect of selected operational parameters on Co 2+ incorporation efficiency. Co 2+ , which is used in many industries (e.g., plating, alloys manufacturing, catalytic converters, and paint pigments) and hence may pose a significant environment risk, was shown previously to be incorporated successfully into ferrite structures. Co 2+ -bearing ferrites were synthesized from Fe(II) solutions at ambient temperature (20 and 30°C), applying slow oxidation, pH 10.5, 20 g (as Fe) l −1 ferrite seed, and different Fe 2+ to Co 2+ influent ratios. Pure magnetite was used as an initial seed, which was gradually exchanged, as the reaction proceeded, by the Co 2+ -bearing ferrite generated within the reactor (until full exchange at steady state). Under all conditions investigated >99% of the Co 2+ was removed from solution (yielding Co 2+ levels below 20 μg/l in the effluent) while the generated precipitates were composed predominately of magnetite/ferrite (based on XRD analysis). Favorable results in terms of Co 2+ incorporation efficiency and sludge stability were obtained when the following operational conditions were applied: 1:10 Co 2+

Research of the treatment of depleted nickel­plating electrolytes by the ferritization method

“…In recent years, numerous studies on the treatment of wastewater and technological solutions by ferritization were carried out. The process of extraction of cobalt ions from concentrated solutions was explored in paper [4]. Inclusion of Со +2 ions into the ferrite structure and chemical stability of sediments was indicated.…”

“…Given a decrease in the oil stocks in the world, mankind has begun to look for alternative sources in order to obtain fuel whose production volumes grow every year. Conversion of synthesis-gas to liquid hydrocarbons using the Fischer-Tropsch process (FT-synthesis) [1][2][3][4] is an alternative technique for obtaining the motor fuel.…”

“…The Fischer-Tropsch synthesis is an important technology, aimed at converting coal, natural gas, or biomass, into valuable products, such as motor fuels or raw materials for petrochemicals [1,3]. The process is named after Franz Fischer and Hans Tropsch [3,4], who showed the possibility of this reaction in 1923, by converting a mixture of carbon monoxide and hydrogen into hydrocarbons using an iron catalyst.…”

Energy-saving integrated ferritisation treatment of nickel-containing wastewater

“…In recent years, numerous studies have been conducted on wastewater treatment by ferritization (Chaiyaraksa & Klaikeow 2006;Pritosiwi 2012). The authors (Morgan et al 2001;Petrick et al 2008) demonstrated incorporation of HM ions into ferrite structure. In papers (Kochetov et al 2010;Heuss-Aßbichler et al 2016) the ferritisation process was used for treatment of rinsing and concentrated coppercontaining water, respectively.…”

Magnetic Removal of Cobalt from Waste Water by Ferrite Co-precipitation

“…The the bigger the grain size and magnetization level, the higher the removal efficiency of the magnetic filter. The characteristics of the final product will depend on the formation conditions (Petrick et al, 2008). By controlling these parameters it is possible to obtain an increase on grain size and magnetization levels (Ayyappan et al, 2009).…”