Provided herein are in situ methods for fabricating a mixed-matrix membrane or a mixed-matrix hollow fiber membrane for increasing formation of zeolitic imidazolate framework nanoparticles inside the mixed-matrix membrane. Generally, in the method a polyimide polymer coated onto at least one support is hydrolzed with a base and the poly(amic acid)-salt film formed thereby undergoes ion exchange with a metal ion, treatment of the formed poly(amic acid)-metal salt film with an organic linker to produce metal-organic framework nanoparticles in situ, and imidization of the treated poly(amic acid)-metal salt film produces a polyimide/metal-organic framework mixed-matrix membrane or a mixed-matrix hollow fiber membrane module. Also provided is the mixed-matrix membrane and the polymer mixed-matrix hollow fiber membrane module fabricated by the methods and methods for separating a binary gas mixture via the fabricated mixed-matrix membrane.

Vacuumed gap membrane distillation (VAGMED) modules, and multi-stage VAGMED systems and processes using the modules are provided. In an embodiment, the membrane distillation modules can comprise: a) a condenser including a condensation surface; b) a first passageway having an inlet for receiving a first feed stream and an outlet through which the first stream can pass out of the first passageway, the first passageway configured to bring the first feed stream into thermal communication with the condensation surface; c) an evaporator including a permeable evaporation surface allowing condensable gas to pass there through; d) a second passageway having an inlet for receiving a second feed stream and an outlet through which the second feed stream can pass out of the second passageway, the second passageway configured to bring the second feed stream into communication with the permeable evaporation surface; and e) an enclosure providing a vacuum compartment within which the condenser, the evaporator and the first and second passageways of the module are contained.

Vacuumed gap membrane distillation (VAGMED) modules, and multi-stage VAGMED systems and processes using the modules are provided. In an embodiment, the membrane distillation modules can comprise: a) a condenser including a condensation surface; b) a first passageway having an inlet for receiving a first feed stream and an outlet through which the first stream can pass out of the first passageway, the first passageway configured to bring the first feed stream into thermal communication with the condensation surface; c) an evaporator including a permeable evaporation surface allowing condensable gas to pass there through; d) a second passageway having an inlet for receiving a second feed stream and an outlet through which the second feed stream can pass out of the second passageway, the second passageway configured to bring the second feed stream into communication with the permeable evaporation surface; and e) an enclosure providing a vacuum compartment within which the condenser, the evaporator and the first and second passageways of the module are contained.

A filter for a liquid purifier may include a filter housing having an inlet and an outlet; and a filter module provided in the filter housing, and configured to purify liquid introduced through the inlet, and to supply the purified liquid to the outlet. The filter module may include an electrostatic adsorption nonwoven fabric having a hollow portion. The filter module may be configured to receive the liquid introduced through the inlet is to pass through the electrostatic adsorption nonwoven fabric and then is to discharge out of the outlet of the filter housing.

A filter for a liquid purifier may include a filter housing having an inlet and an outlet; and a filter module provided in the filter housing, and configured to purify liquid introduced through the inlet, and to supply the purified liquid to the outlet. The filter module may include an electrostatic adsorption nonwoven fabric having a hollow portion. The filter module may be configured to receive the liquid introduced through the inlet is to pass through the electrostatic adsorption nonwoven fabric and then is to discharge out of the outlet of the filter housing.

A method of treating a switchable polarity material comprises introducing a first feed stream comprising a solvent and a non-polar form of the switchable polarity material to a first side of a gas diffusion membrane. A second feed stream comprising an acid gas is introduced to a second side of the gas diffusion membrane opposing the first side of the gas diffusion membrane. Molecules of the acid gas of the second feed stream are diffused across the gas diffusion membrane and into the first feed stream to form a product stream comprising a polar form of the switchable polarity material. A treatment system for a switchable polarity material, and a method of liquid treatment are also described.

A membrane module includes a housing. The housing includes a housing, comprising: a first plurality of porous hollow fiber membranes, and a second plurality of porous hollow fiber membranes different from the first plurality of porous hollow fiber membranes. The first plurality of porous hollow fiber membranes has a first length, and the second plurality of porous hollow fiber membranes has a second length that is at least 1.1 times greater than the first length. The membrane module can be used in separation methods, such as membrane distillation methods.

A membrane module includes a housing. The housing includes a housing, comprising: a first plurality of porous hollow fiber membranes, and a second plurality of porous hollow fiber membranes different from the first plurality of porous hollow fiber membranes. The first plurality of porous hollow fiber membranes has a first length, and the second plurality of porous hollow fiber membranes has a second length that is at least 1.1 times greater than the first length. The membrane module can be used in separation methods, such as membrane distillation methods.

A membrane distillation system includes a hollow fiber aerator configured to provide gas bubbles to a relatively cool permeate stream so that the relatively cool permeate stream contains gas bubbles when it contacts a porous and hydrophobic membrane in a direct contact membrane distillation process. The system can further include an additional hollow fiber aerator configured to provide gas bubbles to a relatively hot feed stream so that the relatively hot feed stream contains gas bubbles when it contacts a porous and hydrophobic membrane in a direct contact membrane distillation process.

A water treatment device using a hollow fiber membrane module is provided, including: a water container filled with raw water; a hollow fiber membrane module installed in the water container and provided with hollow fiber membranes therein to perform water treatment by a water pressure difference; and a raw water supplying part positioned on the water container, and configured to supply the raw water into the water container through the hollow fiber membrane module, in which the hollow fiber membrane module causes the raw water supplied from the raw water supplying part collide with the hollow fiber membrane to move the hollow fiber membrane, so that it is possible to minimize contamination of the hollow fiber membrane, minimize use of energy using electricity, and wash the hollow fiber membrane by a physical method.