Abstract: The present invention refers to the method for synthesis an absorbent material consisting of a phase of tetravalent manganese feroxyhyte (?-Fe(1-x)MnxOOH) with a negatively charged grain surface in which a percentage of iron has been isomorphically substituted by manganese atoms at 0.05-25%. Its' production is carried out in two continuous flow stirred-tank reactors arranged in serial configuration, where mild acidic conditions (pH 5-6) prevail in the first reactor and mild alkaline conditions (pH 9-10) together with high redox potential (600-700 mV) in the second reactor. The material can be used to uptake mercury, as well as other heavy metals from both water and hot gas streams. Specifically, the adsorption capacity is determined by the magnitude of the negative surface charge and the isoelectric point that can be both adjusted by the synthesis process parameters.

Abstract: The present invention refers to the method for synthesis an absorbent material consisting of a phase of tetravalent manganese feroxyhyte (?-Fe(1?1)MnxOOH) with a negatively charged grain surface in which a percentage of iron has been isomorphically substituted by manganese atoms at 0.05-25%. Its' production is carried out in two continuous flow stirred-tank reactors arranged in serial configuration, where mild acidic conditions (pH 5-6) prevail in the first reactor and mild alkaline conditions (pH 9-10) together with high redox potential (600-700 mV) in the second reactor. The material can be used to uptake mercury, as well as other heavy metals from both water and hot gas streams. Specifically, the adsorption capacity is determined by the magnitude of the negative surface charge and the isoelectric point that can be both adjusted by the synthesis process parameters.

Abstract: The present invention refers to a method for the synthesis of an adsorbing material consisting of a single-phase tetravalent manganese feroxyhite (?-Fe(1-x)MnxOOH), in which a percentage of 0.05 to 25% of iron atoms has been isomorphically substituted by Mn(IV) atoms. Its production takes place in a continuous two-stage flow reactor at weakly acidic conditions (pH 4-7) and high redox (300-800 mV). The material can be used for the removal of both pentavalent and trivalent arsenic as well as other heavy metals form water. More specifically, its adsorption capacity and selectivity depending on the trivalent and pentavalent arsenic water content, are determined by the manganese percentage and the compact or hollow morphology of its structural unit which can be both controlled by the parameters of the synthesis procedure.

Abstract: The present invention refers to a method for the synthesis of an adsorbing material consisting of a single-phase tetravalent manganese feroxyhite (?-Fe(1-x)MnxOOH), in which a percentage of 0.05 to 25% of iron atoms has been isomorphically substituted by Mn(IV) atoms. Its production takes place in a continuous two-stage flow reactor at weakly acidic conditions (pH 4-7) and high redox (300-800 mV). The material can be used for the removal of both pentavalent and trivalent arsenic as well as other heavy metals form water. More specifically, its adsorption capacity and selectivity depending on the trivalent and pentavalent arsenic water content, are determined by the manganese percentage and the compact or hollow morphology of its structural unit which can be both controlled by the parameters of the synthesis procedure.