Cross-linked polyvinyl polymers comprising charged groups and methods of making are disclosed. The polymers are effective and durable adsorbent of dyes from aqueous solutions. Also, a method of removal of dyes from contaminated water is disclosed.

A pure water production method for producing pure water by decarboxylating water to be treated under acidic conditions and then deionizing the result by using a reverse osmosis membrane separation device, the pH of inflow water flowing into the reverse osmosis membrane separation device and the water quality of permeated water of the reverse osmosis membrane separation device being measured, and the pH of the inflow water being adjusted on the basis of the measured pH and water quality so that the water quality of the permeated water is within a prescribed range, wherein the pH of the inflow water is changed by a predetermined width, and an operation condition adjusting step is performed for adjusting the pH of the inflow water by comparing the(average value before the water quality change average value after the water quality change.

A new and innovative power and treated water co-generation system is provided that includes a modified Kalina cycle and a forward osmosis (FO) membrane. The Kalina cycle of the provided system is used for power production, whereas the system's FO process is used for water production. The provided system modifies a typical Kalina cycle to include a more efficient and relatively low-temperature heat source, while still utilizing the same working fluid, which is ammonia-water. The draw solution for the provided system's FO process is also ammonia-water, which is known and efficient for desalination and wastewater treatment. In some aspects, the working fluid of the system may be a specific ammonia-water composition including between 30-95% ammonia. The presently disclosed system combines the Kalina process and the FO process into an improved and innovative heat integration system to minimize energy requirements and enable operation at both small and large scales.

The present invention relates to a composite semipermeable membrane including: a support membrane including a base and a porous support layer; and a separation functional layer disposed on the porous support layer and including a crosslinked aromatic polyamide, in which the separation functional layer contains sulfo groups in an amount of 7.0×10.sup.−5 to 5.0×10.sup.−2 g/m.sup.2 and includes a structure represented by the formula 1.

Provided is a high permeance nanofiltration membrane with nanoring-like structure and preparation method thereof. The membrane includes a base film and a polyamide layer having nanoring-like structure morphology on its surface. The method includes: (1) formulating a piperazine nanoemulsion containing a surfactant, vegetable oil, piperazine and water; and (2) infiltrating a base film with the piperazine nanoemulsion, and removing excess droplets from the surface of the base film to obtain a treated base film; covering the surface of the treated base film with a solution of trimesoyl chloride in n-hexane to perform interfacial polymerization; and drying the resulting membrane. Introduction of nano-oil droplets into aqueous phase as templates to construct nanoring-like structure morphology on the surface of the polyamide layer significantly increases the specific surface area and free volume of the polyamide layer without losing the salt rejection rate of the membrane, thereby greatly improving its water permeance.

A system and method for treating reverse-osmosis (RO) concentrated water with high temporary hardness. The system includes a crystallization unit, a precipitation unit, a dewatering unit, and a programmable logic controller (PLC) system. The crystallization unit, precipitation unit and dewatering unit are connected in series, and the PLC system is configured to control pumps, valves, and displays in the crystallization unit, precipitation unit and dewatering unit. The crystallization unit includes a storage tank and a crystallization reactor communicated therewith. The crystallization reactor is provided with a pH meter, a liquid-level gauge, and a stirrer. A connection pipe between the crystallization reactor and the RO concentrated water is provided with an inlet pump and a inlet valve. A connection pipe between the crystallization reactor and the storage tank is provided with a feeding pump and a feeding valve.

This document describes systems and methods for treating and recovering water from feed solutions using a multilayer module with an expansion chamber. The multilayer module comprises a feed spacer layer, a permeate spacer layer and a membrane layer, wherein water vapor evaporated from the feed solution in the feed spacer passes through the membrane layer into the permeate spacer layer. The expansion chamber receives the water vapor from the permeate spacer layer and the feed solution from the feed spacer layer.

A water desalination system includes a first set of ultrafiltration membranes, a second set of ultrafiltration membranes, a first backwashing system configured to treat at least one of the first set of ultrafiltration membranes or the second set of ultrafiltration membranes with brine generated by a reverse osmosis process, and a second backwashing system configured to treat at least one of the first set of ultrafiltration membranes or the second set of ultrafiltration membranes with one or more chemicals and reverse osmosis permeate water.

A hollow fiber membrane module includes a pressure vessel, a plurality of hollow fiber membrane elements arranged in series inside the pressure vessel, and a connector that connects the hollow fiber membrane elements to each other. Each of the hollow fiber membrane elements includes a plurality of hollow fiber membranes, and a double-core tube extending in a longitudinal direction of the plurality of hollow fiber membrane elements. The connector includes a first channel and a second channel that do not communicate with each other. Between the hollow fiber membrane elements, the outer channels of the hollow fiber membrane elements are connected to each other through the first channel, the inner channels of the hollow fiber membrane elements are connected to each other through the second channel, and hollow portions of the hollow fiber membranes communicate with the inner channels through the second channel.

The water treatment apparatus of the present invention comprises a flocculation part into which water to be treated is introduced, at least two flocculant adding devices installed so that different flocculants can be added to the flocculation part, one or two or more water quality measurement devices for measuring the quality of the water to be treated, and a controlling part for issuing, on the basis of the measurement result from the water quality measurement device(s), a command relating to whether addition of the flocculants to the corresponding flocculant adding device is required or not and to the added amounts of the flocculants, wherein at least one of the flocculant adding devices is an auxiliary flocculant adding device.