Dalian University of Technology

Xie Quan

Shuo Chen

Hongtao Yu

Yaobin Zhang

Gaoliang Wei

Yiwen Liu

Yanjun Mao

Tao Liu

Qi Zhang

Chengyu Yuan

Xusheng Meng

Wuzhe Quan

Zhiqiang Zhao

Huimin Zhao

Yang Yang Li

Yanping Shi

Haiguang Zhang

The present disclosure provides a rigid self-supporting MXene separation membrane and a preparation method and use thereof, belonging to the technical field of membranes. In the present disclosure, a MXene material is mixed with an aluminum salt powder to conduct one-step membrane formation by hot-pressing. The pressure forms the powder into a membrane and imparts rigidity, enabling a self-supporting structure; the heating breaks an ionic bond of an inorganic metal salt to reach a molten ionic state, and free metal cations react with active oxygen-containing functional groups on the surface of the MXene to form new chemical bonds (such as an Al—O bond); such a chemical bond has higher energy, achieving a desirable anti-swelling effect to improve the membrane stability. The separation membrane further has excellent conductivity and hydrophilicity.

Rigid self-supporting MXene separation membrane and preparation method and use thereof

The invention, belonging to the field of membrane technology, presents a method for the direct growth of ultrathin porous graphene separation membranes. Etching agent, organic solvent and polymer are coated on metal foil, and then they are calcined at high temperature in absence of oxygen; after removal of metal substrate and reaction products, single-layered or multi-layered porous graphene membranes are obtained. Alternatively, the dispersion or solution of etching agent is coated on metal foil, on which a polymer film is then overlaid. The obtained sample is subsequently calcined at high temperature in absence of oxygen; after removal of metal substrate and reaction products, single-layered or multi-layered porous graphene membranes are obtained. The method involved in this invention is simple and highly efficient, and allows direct growth of ultrathin porous graphene separation membranes, without needing expensive apparatuses, chemicals and graphene raw material. Additionally, the graphene membranes prepared with this method have controlled pore size, ultrahigh water flux and strong resistance to irreversible fouling.

Method for directly growing ultrathin porous graphene separation membrane

A method for preparation of conductive polymer/carbon nanotube (CNT) composite nanofiltration (NF) membrane and the use thereof. This conductive polymer/CNT composite NF membrane is obtained by polymerizing conductive polymer into a CNT membrane and then in-situ cross-linking with glutaraldehyde under acidic condition. The synthetic method for the conductive polymer/CNT composite NF membrane is simple and has no need of expensive equipment. The prepared membrane has controllable membrane structure and possesses superior electrical conductivity and electrochemical stability. The membrane can couple with electrochemistry for electrically assisted filtration. With the electrical assistance, the membrane can achieve improved ion rejection performance while retaining high permeability by enhancement of membrane surface charge density, which alleviates the permeability-selectivity trade-off. Furthermore, the electrically assisted NF membrane filtration can also enhance the removal for small molecular organic pollutants.

Method of preparation of conductive polymer/carbon nanotube composite nanofiltration membrane and the use thereof

A method for preparing an electron donor biofilm carrier includes proportioning organic polymer basic raw material and functional modifiers in a range of set-point, mixing the materials, feeding the mixtures into a screw extruder, processing them into a bar-type material, and then cut the bar-type material into granules with the cutting machine, and feeding the granules into the screw extruder, processing them into pipes of various shapes according to the selected screw extruder heads, and then cutting the pipes according to the required size. The electron donor biofilm carrier is mainly used in anaerobic or anoxic suspended carrier biofilm technologies. Electron donors with a standard electrode potential below 100 Mv are used as the functional material for preparation of electron donor biofilm carrier.

Method for preparing electron donor biofilm carrier

The invention, belonging to the field of biological treatment of pollutants and functional materials, presents a method for the preparation of biofilm carrier with biochar fixed by thermoplastic resin. Extrusion grade polyethylene/polypropylene particles are used as the basic material. One or some combination of plant biochar, straw biochar, rice husk biochar, shell biochar, excess sludge and animal waste biochar are used as the functional material. The biofilm carrier with biochar fixed by thermoplastic resin is prepared by the screw extrusion process, which is a simple, flexible and controllable method, and possesses strong adaptability. The reactor with these biofilm carriers has high removal efficiency of refractory organic pollutants.

Method for the preparation of biofilm carrier with biochar fixed by thermoplastic resin

The invention, belonging to the field of biological treatment of pollutants and functional materials, presents a non-dissolved redox mediator biofilm carrier and its preparation method. The graphene oxide and/or carbonylation modified graphene oxide are used as the non-dissolved redox mediator, which is called as the functional material, and the extrusion grade polyethylene/polypropylene particles are used as the basic material. The non-dissolved redox mediator biofilm carrier is prepared by the screw extrusion process, which is a simple, flexible and controllable method, and possesses strong adaptability. The reactor with these biofilm carriers has high removal efficiency of refractory organic pollutants.

Non-dissolved redox mediator biofilm carrier and its preparation method

The invention, belonging to the field of membrane technology, presents a method for the high-throughput preparation of carbon nanotube hollow fiber membranes. This method contains three major steps. Firstly, the pristine carbon nanotubes (CNTs) are added into a mixture of concentrated nitric acid and sulfuric acid, which is then heated at 40&#x2dc;80&#xb0; C. for 0.5&#x2dc;6 hours. Secondly, the surface-functionalized CNTs and polyvinyl butyral (PVB) are dispersed and dissolved, respectively, in organic solvents at a mass ratio of 1:0.2&#x2dc;1:4&#x2dc;8 to form homogeneous spinning solution, which is squeezed into water as shell liquid with water as core liquid at a flow rate ratios of 0.5&#x2dc;5:1 through a spinneret to form CNT/PVB hollow fibers. Finally, the dry fibers are calcinated at 600&#x2dc;1000 &#xb0; C. for 1&#x2dc;4 hours in absence of oxygen to produce free-standing CNT hollow fiber membranes. The method involved in this invention is simple and highly efficient without needing any templates, expensive apparatuses and chemicals. Additionally, the obtained electrically conductive CNT hollow fiber membranes feature a high porosity, high water flux and strong acid/alkali resistance.

Method for the high-throughput preparation of carbon nanotube hollow fiber membranes

The invention discloses a wastewater processing method of hydrolysis-acidification enhanced by addition of zero-valent iron (ZVI), including the following steps: 3&#x2dc;6 ZVI-filling layers are settled in the middle of an anaerobic hydrolysis-acidification reactor. Excess sludge taken from sewage treatment plant using as seed sludge is added into this anaerobic hydrolysis-acidification reactor for startup and domestication. In the present invention, ZVI are added into this anaerobic hydrolysis-acidification reactor to accelerate organic matters degradation and produce more acetic acids, accompanied with higher COD removal obtained. ZVI can be protected from rust in this anaerobic biological environment due to the air isolation. Also, ZVI can enhance anaerobic hydrolysis of wastewater through reducing refractory pollutants involved in wastewaters. This novel method made the effluent from the hydrolysis-acidification reactor present less COD concentration and simpler substrate form, benefiting for the following anaerobic methanogenesis or aerobic treatment.

Wastewater processing method of hydrolysis-acidification enhanced by addition of zero-valent iron (ZVI)

The invention, belongs to the field of wastewater treatment technology, is a two-phase anaerobic reactor enhanced by addition of zero valent iron (ZVI). In the reactor, 2&#x2dc;4 ZVI-filling layers are settled in the middle of the anaerobic hydrolysis-acidification tank, the effluent of which is fed into the rear anaerobic methanogenic tank. The degradation of organics is effectively enhanced in the anaerobic hydrolysis-acidification tank with dosing of ZVI, which may produce more acetic acid that is a desired substrate for the subsequent methanogenesis. Meanwhile, the acidic environment of the hydrolysis-acidification tank is helpful for the dissolution of ZVI to maintain its activity. The reactor is reasonably designed with high performance and strong shock resistance in anaerobic treatment of various wastewaters. Tests in lab-scale showed that hydrolysis-acidification and methanogenesis in this combined system were significantly improved compared with a reference reactor without addition of ZVI.

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Liaoning, China

Xie Quan