Various embodiments relate to an acidic ferrate composition and methods of making ferrate. A method of forming ferrate includes treating an iron source with an oxidizer in an aqueous solution having a pH of less than 7 under conditions sufficient to form ferrate.

Novel devices for synthesizing ferrate and uses thereof are described. One aspect of the invention relates to devices and systems for synthesizing ferrate at a site proximal to the site of use.

A paste for manufacturing a photocatalyst is provided. The paste for manufacturing the photocatalyst includes an alcohol paste and a photocatalyst precursor. The photocatalyst precursor is dispersed in the alcohol paste, and the photocatalyst precursor includes a first metal precursor and a second metal precursor, wherein the first metal in the first metal precursor includes Zn, Sn, Cu, Fe, Mn, Ni, Co or Ag, and the second metal in the second metal precursor includes Fe.

A method for efficiently preparing ferrate based on nascent state interfacial activity. The method is as follows: (a) preparing nascent iron solution; (b) adding an oxidizing agent to the iron solution of step (a); (c) adding alkali solution or alkali particles to the mixed solution of step (b), mixing by stirring, and carrying out solid-liquid separation; (d) adding a stabilizing agent to the liquid separated out in step (c), and thus obtaining ferrate solution. The yield is 78-98%. The prepared ferrate solution is stable and can be stored for 3-15 days.

A method of processing a workpiece having a first surface and a second surface opposite the first surface includes: generating a first beam of laser pulses having a pulse duration less than 200 ps at a pulse repetition rate greater than 500 kHz, directing the first beam of laser pulses along a beam axis intersecting the workpiece, and scanning the beam axis along a processing trajectory. The beam axis is scanned such that consecutively-directed laser pulses impinge upon the workpiece at a non-zero bite size to form a feature at the first surface of the workpiece. One or more parameters such as bite size, pulse duration, pulse repetition rate, laser pulse spot size and laser pulse energy is selected to ensure that the feature has a processed workpiece surface with a mean surface roughness (Ra) of less than or equal to 1.0 μm.

A method for preparing high-valence iron salt; the present invention relates to a method for preparing a ferrate compound, for solving the technical problems of the complex operating process, the low yield, and the low purity of ferrate products after purification in existing methods for preparing potassium ferrate. The preparation method comprises: 1. weighing solid potassium hydroxide; 2. adding the solid potassium hydroxide to a sodium hypochlorite solution to obtain a hypochlorite solution; 3. adding iron salt to the hypochlorite solution to obtain a potassium ferrate solution; 4. adding the potassium ferrate solution to a cooled potassium hydroxide solution to obtain a solid-liquid mixture; 5. filtering the solid-liquid mixture of step 4; and 6. rinsing the solid-phase substance. The present invention has safe operation, is simple, quick, energy-saving, and easy to control, is suitable for immediate use, and the obtained product can be stored stably; the ferrate yield of the present method is 60-95% and the purity of the produced potassium ferrate solid is over 95%.

Generating ferrate ex situ by activating persulfate with BOF steel slag fines and/or ferric iron. A persulfate solution flows therethrough or thereover the BOF steel slag within, for example, a filter, fluidized bed or continuously stirred tank reactor. The ex situ generation will produce a leachate that contains multiple reactive oxidant species (ROS) such as hydrogen peroxide (H.sub.2O.sub.2), superoxide (O2.), sulfate radicals, hydroxyl radicals (OH.) and uniquely ferrate species including Fe IV, V and VI. These ROS will destroy organic compounds, sterilize, and can oxidize inorganics and a wide range of targeted contaminants in distressed water (e.g., drinking water, process water, wastewater, industrial process streams/waters, municipal process streams/waters, landfill leachate, sewage/septic systems, bilge waters, drilling fluids, mine effluents). The use of BOF steel slag avoids the need for additional pH buffers and ferrate stabilizers and is an industrial byproduct comprised of recycled materials instead of a specialized reagent.

Various embodiments relate to an acidic ferrate composition and methods of making ferrate. A method of forming ferrate includes treating an iron source with an oxidizer in an aqueous solution having a pH of less than 7 under conditions sufficient to form ferrate.

Generating ferrate ex situ by activating persulfate with BOF steel slag fines and/or ferric iron. A persulfate solution flows therethrough or thereover the BOF steel slag within, for example, a filter, fluidized bed or continuously stirred tank reactor. The ex situ generation will produce a leachate that contains multiple reactive oxidant species (ROS) such as hydrogen peroxide (H.sub.2O.sub.2), superoxide (O2.), sulfate radicals, hydroxyl radicals (OH.) and uniquely ferrate species including Fe IV, V and VI. These ROS will destroy organic compounds, sterilize, and can oxidize inorganics and a wide range of targeted contaminants in distressed water (e.g., drinking water, process water, wastewater, industrial process streams/waters, municipal process streams/waters, landfill leachate, sewage/septic systems, bilge waters, drilling fluids, mine effluents). The use of BOF steel slag avoids the need for additional pH buffers and ferrate stabilizers and is an industrial byproduct comprised of recycled materials instead of a specialized reagent.

A method for efficiently preparing ferrate based on nascent state interfacial activity. The method is as follows: (a) preparing nascent iron solution; (b) adding an oxidizing agent to the iron solution of step (a); (c) adding alkali solution or alkali particles to the mixed solution of step (b), mixing by stirring, and carrying out solid-liquid separation; (d) adding a stabilizing agent to the liquid separated out in step (c), and thus obtaining ferrate solution. The yield is 78-98%. The prepared ferrate solution is stable and can be stored for 3-15 days.