Preparation Of Two-dimensional Laminar Nano-GO,MoS₂ Membranes And Its Application In Depthtreatment Of Papermaking Wastewater

With the increasingly wastewater diacharge standards and the limitation for water consumption in papermaking production,it is of great significance to research the depthtreatment reuse technology of papermaking effluent.In the normal treating process of papermaking process,the technological processes of primary physicochemical treatment,secondary biochemical treatment and advanced oxidation treatment is usually used,but the effluent quality often have high conductivity and contain much organism,so it is difficult to reach the requirement of reuse,and limit the efficient reuse of papermaking effluent.Membrane separation technology is a kind of advanced technology in wastewater treatment,but the application researching in papermaking effluent is fewer.In this paper,the membrane separation technology is applied in reusing papermaking effluent.Two kinds of layer membrane separation of low-cost graphene oxide?GO?and molybdenum disulfide?MoS₂?are produced by a kind of simple and easy impregnation method,then the separation performance of the two membranes is researched,and they are used in Fenton oxidized effluent treatment,try to find a more economical and environmental protection method in the advanced treatment and reuse of papermaking effluent.Firstly,the actual papermaking Fenton oxidized effluent quality is analyzed.The origanism composition of effluent is analyzed by infrared spectroscopy?FT-IR?and gas chromatography-mass spectrometry?GC-MS?,and detects the ion content of effluent by ion chromatography and atomic absorption spectroscopy.The experimental results shows that the effluent has low organic content,it is mainly made up of short-chain alkane compounds.Also the effluent contains a large number of zwitterion and has high conductivity.Secondly,the graohene oxide is used as membrane material,and the graphene oxide membrane was fabricated on the modified ceramics tube through dip-coating method.The graphene oxide and graphene oxide membrane is characterized by X-ray diffraction?XRD?,atomic force microscopy?AFM?and scanning electron microscope?SEM?,and use them in simulating wastewater desalting and actual papermaking effluent advanced treatment.The characterization results shows that graohene oxide is two-dimensional sheet material,has good film forming characteristerics,the surface of membrane is continuous and uniform,and no obvious defects exist.When the prepared film is applied in the simulation system,the membrane flux can reach 4.27kg/m2 h and the desalination rate is over 80%.When it was used in the actual papermaking effluent,the interception rates of Mg²⁺?Ca²⁺and SO₄^2-can respectively reach 71%,70% and 54%.Good separation performance and stability are still maintained even treating papermaking wastewater for more than 20 h.Furthermore,MoS₂ is used as membrane material,MoS₂ atom-thick 2D sheets with 1nm thickness and 200 nm transverse length are prepared by exfoliation of bulk MoS₂ via Li intercalation.MoS₂ nanosheets have good film-forming property on the surface of ceramic substrates,forming continuous,uniform and non-obvious defect film.The flux can reach 7?78kgm^-2h^-1Mpa^-1 and the desalination rate is over 90% when treating the wastewater under operating condition of room temperature and 0.8MPa.The retention rate of Mg²⁺,Ca²⁺,Na⁺ and SO₄^2-can reach 90.4%,92.3%,67.9% and 82.8% respectively,when it used to treat Fenton oxidized effluent.In the long continuous operation,MoS₂ membrane maintains better stability,good fouling resistance and has great prospects for the wastewater treatment in actual production.