The present invention relates to the process of purification of boric acid by ion exchange method. Boric acid is dissolved in hot demineralized water. The hot solution is pressure-filtered. The hot saturated solution, which is purified from water-insoluble, is passed through a column containing strong cation exchange resin, followed by a column containing weak anion exchange resin at the same temperature and cooled afterwards. The crystals settling by cooling are separated from the mother liquor, the amount of aqueous solution within them is reduced and then dried. The waste solution formed during crystallization and filtrate formed after separation of crystals from aqueous solution are mixed and used in boric acid dissolving process. The developed method enables the reduction of sodium, sulfate, chloride and iron impurities of technical grade boric acid to less than 1 ppm and is more economic and environmental friendly than current methods.

An etching solution recycling system for a wafer etching apparatus is provided. The etching solution recycling system includes a settling tank, a seed provider, and a fluid control unit. The settling tank is connected to an etching tank of the wafer etching apparatus and configured to receive an etching solution from the etching tank. The seed provider is configured to provide at least one seed crystal into the settling tank to reduce the silicate concentration in the etching solution in the settling tank. The fluid control unit is configured to deliver the etching solution in the settling tank back into the etching tank.

Provided is a technique for continuously performing poor solvent crystallization or reactive crystallization. A porous membrane in which multiple pores through which a liquid passes are formed internally partitions the treatment container into a first flow space and a second flow space. A raw material liquid supply unit continuously supplies a raw material liquid to the first flow space. A treatment liquid supply unit continuously supplies a treatment liquid to the second flow space at a pressure at which the treatment liquid passes through the porous membrane and enters the first flow space. An extraction unit continuously extracts a mixed liquid of the raw material liquid and the treatment liquid from the first flow space. An aging unit precipitates and grows crystals of a target substance from a mixed liquid.

A method for the purification of a bisphenol A dianhydride composition includes contacting the bisphenol A dianhydride composition with a halogenated solvent to form a solution, and one or more of filtering the solution to remove ionic species; washing the solution with aqueous media to remove ionic species; crystallizing bisphenol A dianhydride from the solution to remove ionic species; and contacting the solution with an adsorbent to remove ionic species. A purified bisphenol A dianhydride composition is also described. The bisphenol A dianhydride composition can be used in the preparation of a poly(etherimide), and poly (etherimides) made from the bisphenol A dianhydride composition can be useful for forming a variety of articles.

A device and method for increasing solid holdup in a reaction crystallizer are disclosed. The device includes a discharge pipe, a clear liquid pipe, a clear liquid tank and a gas collecting pipe. A lower end of the discharge pipe is inserted into the crystallizer below the liquid level, while that of the clear liquid pipe is inserted into the clear liquid tank below the liquid level. By using the gas collecting pipe, the reaction crystallizer and the clear liquid tank are communicated all the time. When feeding, a liquid-solid mixture in the crystallizer automatically enters the discharge pipe and flows upward slowly therein, during which solid particles gradually settle down and automatically fall back into the crystallizer while the clear liquid keeps on flowing upward, enters the clear liquid pipe and thereby flows into the clear liquid tank. The clear liquid tank maintains a constant liquid level via overflowing.

A process and apparatus for enhanced boron removal from water. The process includes the steps of reacting potassium carbonate or ammonium carbonate with calcium borate in a stream of feed water to form a stream having calcium carbonate and potassium borate salt or ammonium borate salt. The stream having calcium carbonate and potassium borate or ammonium borate is introduced to an ion exchange vessel containing resin having methylglucamine in salt form with potassium carbonate or sodium carbonate to form borate and potassium sulfate or sodium sulfate. The resin in the ion exchange vessel is periodically regenerated.

This disclosure provides systems and methods that utilize integrated mechanical vapor or thermal vapor compression to upgrade process vapors and condense them to recover the heat of condensation across multiple processes, wherein the total process energy is reduced. Existing processes that are unable to recover the heat of condensation in vapors are integrated with mechanical or thermal compressors that raise vapor pressures and temperatures sufficient to permit reuse. Integrating multiple processes permits vapor upgrading that can selectively optimize energy efficiency, environmental sustainability, process economics, or a prioritized blend of such goals. Mechanical or thermal vapor compression also alters the type of energy required in industrial processes, favoring electro-mechanical energy which can be supplied from low-carbon, renewable sources rather than combustion of carbonaceous fuels.

Controlling aerosol production during absorption in ammonia-based desulfurization. The absorption reaction temperature, the oxygen content and water content of the process gas may be controlled, and an absorption circulating liquid containing ammonium sulfite may be used for removing sulfur dioxide in flue gas, so as to control aerosol production during absorption in the ammonia-based desulfurization.

The invention is directed to a method for recovering lactose from an aqueous lactose solution comprising a concentration step, wherein water is removed from the aqueous lactose solution by freezing out water at a temperature below the eutectic temperature of the aqueous lactose solution and at a lactose concentration higher than the eutectic concentration of the aqueous lactose solution, thereby obtaining a concentrated lactose solution; and a crystallization step, wherein at least part of the concentrated lactose solution is subjected to crystallization at a temperature above the eutectic temperature of the concentrated lactose solution, thereby obtaining lactose crystals.

The invention provides a novel microfluidic platform for use in electro-crystallization and electro-crystallography experiments. The manufacturing and use of graphene as X-ray compatible electrodes allows the application of electric fields on-chip, during X-ray analysis. The presence of such electric fields can be used to modulate the structure of protein (or other) molecules in crystalline (for X-ray diffraction) or solution form (for X-ray scattering). Additionally, the presence of an electric field can be used to extend the lifetime of fragile samples by expediting the removal of reactive secondary radiation damage species.