Described herein are methods for the continuous preparation of 1,2-di(furan-2-yl)ethane-1,2-diol from furan-2-carbaldehyde. The methods can proceed chemically or electrochemically. In certain examples, the methods further comprise the application of a static mixer. The present methods produce 1,2-di(furan-2-yl)ethane-1,2-diol in greater yield, purity, chemoselectivity, and stereoselectivity than traditional batch methods.

Chlorous acid is generated from a chlorite salt precursor, a chlorate salt precursor, or a combination of both by ion exchange. The ion exchange material facilitates the generation of chlorous acid by simultaneously removing unwanted cations from solution and adding hydrogen ion to solution. Chlorine dioxide is generated in a controlled manner from chlorous acid by catalysis. Chlorine dioxide can be generated either subsequent to the generation of chlorous acid or simultaneously with the generation of chlorous acid. For catalysis of chlorous acid to chlorine dioxide, the chlorous acid may be generated by ion exchange or in a conventional manner. Ion exchange materials are also used to purify the chlorous acid and chlorine dioxide solutions, without causing degradation of said solutions, to exchange undesirable ions in the chlorous acid and chlorine dioxide solutions with desirable ions, such as stabilizing ions, and to adjust the pH of chlorous acid and chlorine dioxide solutions.

Chlorous acid is generated from a chlorite salt precursor, a chlorate salt precursor, or a combination of both by ion exchange. The ion exchange material facilitates the generation of chlorous acid by simultaneously removing unwanted cations from solution and adding hydrogen ion to solution. Chlorine dioxide is generated in a controlled manner from chlorous acid by catalysis. Chlorine dioxide can be generated either subsequent to the generation of chlorous acid or simultaneously with the generation of chlorous acid. For catalysis of chlorous acid to chlorine dioxide, the chlorous acid may be generated by ion exchange or in a conventional manner. Ion exchange materials are also used to purify the chlorous acid and chlorine dioxide solutions, without causing degradation of said solutions, to exchange undesirable ions in the chlorous acid and chlorine dioxide solutions with desirable ions, such as stabilizing ions, and to adjust the pH of chlorous acid and chlorine dioxide solutions.

A bipolar membrane BP characterized in that particles 5 of a basic metal chloride are distributed in the interface between a cation-exchange membrane 1 and an anion-exchange membrane 3.

A bipolar membrane BP characterized in that particles 5 of a basic metal chloride are distributed in the interface between a cation-exchange membrane 1 and an anion-exchange membrane 3.

A continuous resin regeneration system includes a process by which resin in need of being recharged is continuously recharged and cleaned with a plurality of two-set filtration columns so that resin regeneration and the flow of influent is continuous and interrupted. Downstream filtration columns also undergo this cycling but at slower and related rates as the first column with the dirtiest water will naturally degrade resin faster than the downstream columns. Contaminated influent is cleaned by the continuously recharged resin in multiple column sets. The degree of cleaning of earlier filtration columns affects the resin flow rate of later filtration columns.

A continuous resin regeneration system includes a process by which resin in need of being recharged is continuously recharged and cleaned with a plurality of two-set filtration columns so that resin regeneration and the flow of influent is continuous and interrupted. Downstream filtration columns also undergo this cycling but at slower and related rates as the first column with the dirtiest water will naturally degrade resin faster than the downstream columns. Contaminated influent is cleaned by the continuously recharged resin in multiple column sets. The degree of cleaning of earlier filtration columns affects the resin flow rate of later filtration columns.

There is provided a method for obtaining a purified aqueous solution of silicic acid containing less metal impurities such as Cu and Ni using water glass as a raw material with less number of purification steps than that in conventional methods without using any unnecessary additives. The method for producing a purified aqueous solution of silicic acid, the method comprising the steps of: (a) passing an aqueous solution of alkaline silicate having a silica concentration of 0.5% by mass or more and 10% by mass or less through a column filled with a polyamine-, iminodiacetic acid-, or aminophosphoric acid-type chelating resin, and (b) passing the aqueous solution passed in the step (a) through a column filled with a hydrogen-type cation exchange resin.

There is provided a method for obtaining a purified aqueous solution of silicic acid containing less metal impurities such as Cu and Ni using water glass as a raw material with less number of purification steps than that in conventional methods without using any unnecessary additives. The method for producing a purified aqueous solution of silicic acid, the method comprising the steps of: (a) passing an aqueous solution of alkaline silicate having a silica concentration of 0.5% by mass or more and 10% by mass or less through a column filled with a polyamine-, iminodiacetic acid-, or aminophosphoric acid-type chelating resin, and (b) passing the aqueous solution passed in the step (a) through a column filled with a hydrogen-type cation exchange resin.

Disclosed herein is an ion selective separation membrane including: a metal organic framework layer formed on, in, and/or around a substrate, the metal organic framework having a crystal structure that includes a first surface and a second surface and includes ion transport channels formed between respective pore windows in the first surface and the second surface; first and second electrodes to apply a potential difference across the membrane; wherein the respective pore windows have a pore size that is less than the hydrated diameter of the ion for which the ion selective separation membrane is selective.