NL2028569B1

NL2028569B1 - PREPARATION METHOD OF MgO/GQD/CHITOSAN OLIGOSACCHARIDE/PVA COMPOSITE ADSORPTIVE MEMBRANE

Info

Publication number: NL2028569B1
Application number: NL2028569A
Authority: NL
Inventors: An Xiaochi; Gong Zhijin; Yang Ge; Che Chengchuan; Liu Jinfeng
Original assignee: Univ Qufu Normal
Priority date: 2021-06-29
Filing date: 2021-06-29
Publication date: 2023-01-09

Abstract

The present disclosure belongs to the field of sewage treatment, and.specifically relates to a preparation.method.of an.MgO/GQD/chitosan oligosaccharide/PVA.composite adsorptive membraneandaniapplicationthereof.Inthispreparationnethod, a magnesium. chloride solution. is dropwise added into a dispersion of graphene oxide quantum dots and stirred to get a mixed solution of the magnesium chloride solution and the dispersion.of graphene oxide quantum.dots, into which is added a surfactant and reacted, then calcined. to get MgO/GQD nanocomposites; chitosan oligosaccharide is dissolved in an acetic acid solution, into which are added the MgO/GQD nanocompositesandaacrosslinker,stirred,adjustedtheEflL and stirred.magnetically for 0.8—1.5 h; then washed.to neutral and lyophilized to get MgO/GQD/chitosan oligosaccharide nanocomposite powder; the composite powder is dissolved in water together with PVA, the resulting mixed solution is spun toformthecompositeadsorptivemembrane.TheMgO/GQD/chitosan oligosaccharide/PVA.composite adsorptive membrane prepared.in the present disclosure has the advantages of large adsorption capacity, good mechanical strength, recoverability and excellent biological properties.

Description

PREPARATION METHOD OF MgO/GQD/CHITOSAN OLIGOSACCHARIDE/PVA

COMPOSITE ADSORPTIVE MEMBRANE

TECHNICAL FIELD The present disclosure belongs to the field of sewage treatment, and specifically relates to a preparation method of an MgO/GQD/chitosan oligosaccharide/PVA composite adsorptive membrane and an application thereof.

BACKGROUND ART In recent years, under the dual influence of natural factors and human factors, surface water pollution is becoming more and more serious in China. Adsorption method is considered as an economical and effective method for the sewage treatment. However, traditional adsorbents have the defects of low adsorption capacity and inconvenience of separation, so absorbent materials with stronger adsorptive properties are required. For applications in actual sewage treatment, sewage treatment materials should be environmental-friendly, recoverable or degradable, and recyclable. Polyvinyl alcohol gel has attracted much attention because of nontoxic, inexpensive, microbial decomposition resistance, highmechanical strength and other characteristics. Metal ions are generally applied in the anionic adsorption of sewage because of its ability to interact with anions. Adsorbents of carbon nanomaterials have become a research hotspot because of their features such as high specific surface area, availability, simple synthetic steps, and stable physicochemical structures. Graphene has some degree of cytotoxicity, but it has been found in studies that the cytotoxicity of graphene decreases with the decrease of the lamellar size. As a special nanomaterial, quantum dots (QDs) are attracting the general attention of researchers because of their excellent physicochemical properties. At the same time, the application of guantum dots in the biological field also faces the barrier of nano toxicity and side effects.

Therefore, it is of significant economic and social benefits to develop an adsorptive membrane with large adsorption capacity, good mechanical strength, recoverability and excellent biological properties.

SUMMARY The present disclosure provides a preparation method of an MgO/GQD/chitosan oligosaccharide/PVA composite adsorptive membrane with large adsorption capacity, good mechanical strength, recoverability and excellent biological properties.

To realize the above objective, the present disclosure employs the following technical schemes: A preparation method of an MgO/GQD/ chitosan oligosaccharide/PVA composite adsorptive membrane, including the following steps: 1) Preparation of MgO/GQD nanocomposites: a magnesium chloride solution is dropwise added into a dispersion of graphene oxide quantum dots and stirred uniformly to get a mixed solution of the magnesium chloride solution and the dispersion of graphene oxide quantum dots, into which is added a surfactant and reacted while adjusting pH to 8-10; at the end of the reaction, they are cooled, filtered and rinsed repeatedly until there is no Cl-, and dried; then calcined to get Mgo/GQD nanocomposites; 2) Preparation of MgO0/GQD/chitosan oligosaccharide nanocomposites: chitosan oligosaccharide is dissolved in an acetic acid solution, into which are added the Mgo/GQD nanocomposites prepared in step 1) and a crosslinker, stirred magnetically at 18-23°C for 60-90 min while adjusting pH to 9-12, and continually stirred magnetically at 60-80°C for

0.8-1.5 h; finally the resulting mixture is washed repeatedly to neutral and lyophilized to get MgQ/GQD/chitosan oligosaccharide nanocomposite powder; 3) Preparation of MgO/GQD/chitosan oligosaccharide/PVA composite adsorptive membrane: the lyophilized MgO/GQD/ chitosan oligosaccharide nanocomposite powder obtained from step 2) is dissolved in water together with PVA,

and the mixed solution is spun to form the composite adsorptive membrane.

Preferably, the dispersion of graphene oxide quantum dots in step 1) is prepared as below: graphene oxide quantum dots areweighed and dispersed in deionized water by ultrasonication for 20-50 min, in which the mass to volume ratio of graphene oxide quantum dots to deionized water is 0.1-0.5 g:10 mL.

Preferably, in step 1), the concentration of the magnesium chloride solution is 0.2-0.6 mol/L; the volume ratio of the magnesiumchloride solution to the dispersion of graphene oxide quantum dots is 1:1; the surfactant used in step 1) is sodium dodecyl benzene sulfonate, and the mass to volume ratio of sodium dodecyl benzene sulfonate to the mixed solution of the magnesium chloride solution and the dispersion of graphene oxide quantum dots is 0.02-0.06 g:50 mL; and the reaction time after adding the surfactant is 20-50 min.

Preferably, in step 1), the reaction temperature after adjusting the pH is 70°C, and the reaction time is 2-4 h; at the end of the reaction, they are cooled to 18-23°C, the drying temperature is 40-60°C; and the calcination is carried out in a muffle furnace at 350°C.

Preferably, in step 2), the concentration of the acetic acid solution is 4%, and the mass to volume ratio of the chitosan oligosaccharide to the acetic acid solution is 0.5-2.0 g:100 mL.

Preferably, in step 3), the water is deionized water; and the mass to volume ratio of the MgQ/GQD/chitosan oligosaccharide nanocomposite powder, PVA, and deionized water is 1-5 g:8-12 g:100 mL.

Preferably, the preparation method specifically includes: 1) Preparation of MgQ/GQOD nanocomposites: a magnesium chloride solution is firstly formulated; secondly, graphene oxide quantum dots are weighed and dispersed in deionized water by ultrasonication for 20-50 min, the above magnesium chloride solution is dropwise added into the dispersion of graphene oxide quantum dots and stirred uniformly, a surfactant is then added into the mixture to react for 20-50 min; diluted aqueous ammonia is then added to adjust pH to 8-10 and react at 70°C for 2-4 h; at the end of the reaction, they are cooled to 18-23°C, separated by filtration and rinsed with deionized water repeatedly until there is no Cl, and then dried in an oven at 40-60°C for 12-16 h; finally, the dried substances are calcined in a muffle furnace for 3-5 h to get MgO/GQD nanocomposites; 2) Preparation of MgO/GQD/chitosan oligosaccharide nanocomposites: firstly, chitosan oligosaccharide is dissolved in an acetic acid solution at a concentration of 4% and dispersed by ultrasonication for 20-50 min; MgO/GQD nanocomposites and a crosslinker are added into the acetic acid solution of chitosan oligosaccharide and stirred magnetically at 18-23°C for 60-90 min, pH is adjusted, then continually stirred magnetically at 60-80°C for 0.8-1.5 h; finally, the resulting mixture is washed with deionized water firstly and then washed with absolute ethyl alcohol repeatedly to neutral, and then lyophilized into powder; 3) Preparation of MgO/GQD/chitosan oligosaccharide/PVA composite adsorptive membrane: the lyophilized MgQ/GQOD/ chitosan oligosaccharide nanocomposite powder from step 2) is dissolved in deionized water together with PVA, and the mixed solution is wet spun horizontally to form the composite adsorptive membrane.

An MgQ/GQD/ chitosan oligosaccharide/PVA composite adsorptive membrane prepared by the above preparation method.

An application of the above composite adsorptive membrane, in which the composite adsorptive membrane is applied in wastewater treatment.

Preferably, for the dispensing of the composite adsorptive membrane in wastewater, the ratio of the membrane width to the base area of the wastewater treatment equipment is 0.1-0.3 m:1 m?, and the membrane height is the same as the water level of wastewater in the wastewater treatment equipment.

In the present disclosure, the composite adsorptive membrane is prepared by means of horizontal wet spinning, with MgQ/GQOD/ chitosan oligosaccharide as the adsorbent and with PVA as the support.

Chitosan, the product of deacetylation of chitin, was degraded to get low molecular polymer—chitosan oligosaccharide, the segmental molecule of which is attached 5 with a lot of active groups including amino groups and hydroxyl groups, thus having the advantages of high solubility, strong adsorption capacity and good biocompatibility.

Beneficial effects (1) The composite adsorptive membrane prepared in the present disclosure has the advantages of large adsorption capacity, good mechanical strength, recoverability, and good biocompatibility.

(2) With MgO/GQD/chitosan oligosaccharide as the adsorbent, its superficial metal ions help to improve the adsorption capacity of the composite adsorptive membrane to anions such as phosphate ions significantly.

(3) With MgO/GQD/chitosan oligosaccharide as the adsorbent, GOD is modified with chitosan oligosaccharide so that the biccompatibility of GOD is improved and the adsorption capacity to heavy metals and organic dyes are improved at the same time.

DETAILED DESCRIPTION OF THE EMBODIMENTS The present disclosure will be further illustrated in combination with the following specific embodiments. It should be understood that these embodiments are only used to illustrate the present disclosure, rather than restricting the scope of the present disclosure. Moreover, it should be understood that various changes or modifications can be made to the present disclosure by those skilled in the art after reading the description of the specification, and all these equivalent forms also fall within the scope defined in the attached claims of the application.

Graphene oxide quantum dots used in the following embodiments were purchased from XFNANO, Model NO. XF074.

Embodiment 1 A preparation method of an MgO/GQD/chitosan oligosaccharide/PVA composite adsorptive membrane, including the following steps: 1) Preparation of MgO/GQD nanocomposites: a magnesium chloride solution of 0.2mol/Lwas firstly formulated; secondly, graphene oxide quantum dots were weighed and dispersed in deionized water by ultrasonication for 30 min, where the dosage ratio of graphene oxide quantum dots to deionized water was

0.1 g:10 mL; the above magnesium chloride solution was dropwise added into the dispersion of graphene oxide quantum dots, where the volume ratio of the magnesium chloride solution to the dispersion of graphene oxide quantum dots was 1:1; they were stirreduniformly and sodium dodecyl benzene sulfonate was then added into the mixture to react for 30 min; diluted aqueous ammonia was then added to adjust pH to 8 and react at 70°C for 3 h; at the end of the reaction, they were cooled to 18°C, separated by filtration and rinsed with deionized water repeatedly until there was no Cl, and then dried in an oven at 50°C for 12 h; finally, the dried substances were calcined in a muffle furnace at 350°C for 4 h to get MgO/GQD nanocomposites; where the dosage ratio of sodium dodecyl benzene sulfonate to the mixed solution of the magnesium chloride solution and the dispersion of graphene oxide quantum dots was 0.04 g:50 mL.

2) Preparation of Mg0O/GQD/chitosan oligosaccharide nanocomposites: firstly, chitosan oligosaccharide was dissolved in an acetic acid solution at a concentration of 4% and dispersed by ultrasonication for 30 min, where the dosage ratio of chitosan oligosaccharide to the acetic acid solution was 0.5 g:100 mL; MgO/GQD nanocomposites and a crosslinker were added into the acetic acid solution of chitosan oligosaccharide and stirred magnetically at 18°C for 60 min, pH was adjusted to 10, then continually stirred magnetically at 60°C for 1 h; finally, the resulting mixture was washed with deionized water and absolute ethyl alcohol repeatedly to neutral, and then lyophilized into powder; 3) Preparation of MgQ/GQD/chitosan oligosaccharide/PVA composite adsorptive membrane: the lyophilized MgQ/GQOD/ chitosan oligosaccharide nanocomposite powder from

: step 2) was dissolved in deionized water together with PVA, where the dosage ratio of the MgO/GQD/chitosan oligosaccharide nanocomposite powder, PVA, and deionized water is 1 g:12 g:100 mL; and the mixed solution was wet spun horizontally to form the composite adsorptive membrane.

An application of the above composite adsorptive membrane in the wastewater treatment, where for the dispensing of the composite adsorptive membrane in wastewater, the ratio of the membrane width to the base area of the wastewater treatment equipment was 0.1 m:1 m?, and the membrane height was the same as the water level of wastewater in the wastewater treatment equipment.

Embodiment 2 A preparation method of an MgOC/GQD/chitosan oligosaccharide/PVA composite adsorptive membrane, including the following steps: 1) Preparation of MgQ/GQD nanocomposites: a magnesium chloride solutionof 0.4 mol/Lwas firstly formulated; secondly, graphene oxide quantum dots were weighed and dispersed in deionized water by ultrasonication for 20 min, where the dosage ratio of graphene oxide quantum dots to deionized water was

0.2 g:10mL; the above magnesium chloride solution was dropwise added into the dispersion of graphene oxide quantum dots, where the volume ratio of the magnesium chloride solution to the dispersion of graphene oxide quantum dots was 1:1; they were stirreduniformly and sodium dodecyl benzene sulfonate was then added into the mixture to react for 20 min; where the dosage ratio of sodium dodecyl benzene sulfonate to the mixed solution of the magnesium chloride solution and the dispersion of graphene oxide quantum dots was 0.02 g:50 mL; diluted aqueous ammonia was then added to adjust pH to 9 and react at 70°C for 2 h; at the end of the reaction, they were cooled to 23°C, separated by filtration and rinsed with deionized water repeatedly until there was no Cl, and then dried in an oven at 50°C for 12 h; finally, the dried substances were calcined in a muffle furnace at 350°C for 4 h to get Mg0/GQD nanocomposites.

2) Preparation of Mg0/GQD/chitosan oligosaccharide nanocomposites: firstly, chitosan oligosaccharide was dissolved in an acetic acid solution at a concentration of 4% and dispersed by ultrasonication for 30 min, where the dosage ratio of chitosan oligosaccharide to the acetic acid solution was 2.0 g:100 mL; MgO/GQOD nanocomposites and a crosslinker were added into the acetic acid solution of chitosan oligosaccharide and stirred magnetically at 23°C for 90 min, pH was adjusted to 9, then continually stirred magnetically at 80°C for 0.8 h; finally, the resulting mixture was washed with deionized water and absolute ethyl alcohol repeatedly to neutral, and then lyophilized into powder.

3} Preparation of MgO/GQD/chitosan oligosaccharide /PVA composite adsorptive membrane: the lyophilized MgO/GQD/chitosan oligosaccharide nanocomposite powder from step 2) was dissolved in deionized water together with PVA, where the dosage ratio of the MgO/GQOD/ chitosan oligosaccharide nanocomposite powder, PVA, and deionized water was 2 g:8 g:100 mL; and the mixed solution was wet spun horizontally to form the composite adsorptive membrane.

An application of the above composite adsorptive membrane in the wastewater treatment, where for the dispensing of the composite adsorptive membrane in wastewater, the ratio of the membrane width to the base area of the wastewater treatment equipment was 0.3 m:1 m?, and the membrane height was the same as the water level of wastewater in the wastewater treatment equipment.

Fmbodiment 3 A preparation method of an MgO/GQD/ chitosan oligosaccharide/PVA composite adsorptive membrane, including the following steps: 1) Preparation of MgO/GQD nanocomposites: a magnesium chloride solution of 0.6mol/Lwas firstly formulated; secondly, graphene oxide guantum dots were weighed and dispersed in deionized water by ultrasonication for 50 min, where the dosage ratio of graphene oxide quantum dots to deionized water was

0.5 9:10 mL; the above magnesium chloride solution was dropwise added into the dispersion of graphene oxide quantum dots, where the volume ratio of the magnesium chloride solution to the dispersion of graphene oxide quantum dots was 1:1; They were stirred uniformly and sodium dodecyl benzene sulfonate was then added into the mixture to react for 50 min; where the dosage ratio of sodium dodecyl benzene sulfonate to the mixed solution of the magnesium chloride solution and the dispersion of graphene oxide quantum dots was 0.06 g:50 mL; diluted aqueous ammonia was then added to adjust pH to 10 and react at 70°C for 4 h; at the end of the reaction, they were cooled to 20°C, separated by filtration and rinsed with deionized water repeatedly until there was no Cl, and then dried in an oven at 60°C for 14 h; finally, the dried substances were calcined in amuffle furnace at 350°C for 4 h to get MgQ/GQD nanocomposites.

2) Preparation of MgO/GQD/chitosan oligosaccharide nanocomposites: firstly, chitosan oligosaccharide was dissolved in an acetic acid solution at a concentration of 4% and dispersed by ultrasonication for 30 min, where the dosage ratio of chitosan oligosaccharide to the acetic acid solution was 1 g:100 mL; MgO/GQD nanocomposites and a crosslinker were added into the acetic acid solution of chitosan oligosaccharide and stirred magnetically at 20°C for 75 min, pH was adjusted to 12, then continually stirred magnetically at 70°C for 1.1 h; finally, the resulting mixture was washed with deionized water and absolute ethyl alcohol repeatedly to neutral, and then lyophilized into powder.

3) Preparation of Mg0/GQD/chitosan oligosaccharide/PVA composite adsorptive membrane: the lyophilized MgO/GQD/chitosan oligosaccharide nanocomposite powder from step 2) was dissolved in deionized water together with PVA, where the dosage ratio of the Mg0/GQD/chitosan oligosaccharide nanocomposite powder, PVA, and deionized water was 1.5 g:10 g:100 mL; and the mixed solution was wet spun horizontally to form the composite adsorptive membrane.

In the step 13, the concentration of the magnesiumchloride solution was 0.2 mol/L.

In the step 1), the used surfactant was sodium dodecyl benzene sulfonate, and the dosage ratio of sodium dodecyl benzene sulfonate to the mixed solution of the magnesium chloride solution and the dispersion of graphene oxide quantum dots was 0.03 g:50 mL.

An application of the above composite adsorptive membrane in the wastewater treatment, where for the dispensing of the composite adsorptive membrane in wastewater, the ratio of the membrane width to the base area of the wastewater treatment equipment was 0.2 m:1 m?, and the membrane height was the same as the water level of wastewater in the wastewater treatment equipment.

Application embodiment 1 The composite adsorptive membranes of Embodiments 1-3 were applied in the treatment of phosphorus-containing wastewater at the conditions as below: phosphorus-containing wastewater with an initial phosphorus concentration of 10 mg/L was fed into shake flasks at 150 mL for each flask; the composite adsorptive membranes were fixed on the inner bottom of the shake flasks, and then the shake flasks were cultured on a shaking table at a rotating speed of 150 r/min at 30°C for 5 d, samples were taken every other day to determine the phosphorus content and calculate the adsorption rate, with the results as shown in Table 2.

The initial phosphorus concentration was 10 mg/L, and the composition of wastewater was: potassium dihydrogen phosphate

0.0439 g, sodium chloride 0.05 g, with deionized water added to 1 L.

Table 1 Adsorption efficiency of the composite adsorptive membrane Groups Initial Concentration | Adsorption phosphorus after 5 days efficiency (%) concentration | ( mg/L) ( mg/L)

72.36

2.598 74.02

The basic principles, major features and advantages of the present disclosure have been shown and described above.

It should be understood by those skilled in the art that, the present disclosure is not limited to the above embodiments, and the above embodiments and the specification only describe the principle of the present disclosure.

Without deviating from the spirit and scope of the present disclosure, various changes and improvements can be made to the present disclosure, which all fall within the protection scope of the present disclosure.

The protection scope of the present disclosure is defined by the attached claims and the equivalents thereof.

Claims

CONCLUSIONS

A preparation method for a MgQ/GQD/chitosanoligosaccharide/PVA composite absorption membrane, comprising the following steps: 1) preparing MgO/GQD nanocomposites: a magnesium chloride solution is added dropwise to a dispersion of graphene oxide quantum dots added and stirred uniformly to obtain a mixed solution of the magnesium chloride solution and the graphene oxide quantum dots dispersion, to which a surfactant is added and reacted while adjusting the pH to 8-10; at the end of the reaction, they are cooled, filtered, rinsed several times until there is no Cl, and dried; then calcined to get MgO/GQD nanocomposites; 2) preparation of MgO/GQD/chitosan oligosaccharide nanocomposites: chitosan oligosaccharide is dissolved in an acetic acid solution, to which the MgO/GQD nanocomposites prepared in step 1} and a cross-linking agent are added, at 18-23°C magnetically stirred for 60-90 min while adjusting pH to 9-12, and magnetically stirred continuously at 60-80°C for 0.8-1.5 h; finally, the resulting mixture is washed several times until neutral and freeze-dried to obtain MgO/GQD/chitosan oligosaccharide nanocomposite powder GQD/chitosan oligosaccharide nanocomposite powder obtained from step 2) is dissolved in water together with PVA, and the mixed solution is spun to form the composite adsorption membrane.

The preparation method according to claim 1, wherein the dispersion of graphene oxide quantum dots in step 1) is prepared as follows: graphene oxide quantum dots are weighed and dispersed in deionized water by ultrasonication for 20-50 minutes, the mass-to- volume ratio of graphene oxide quantum dots to deionized water is 0.1-0.5 g: 10 mL.

The preparation method according to claim 1, wherein in step 1) the concentration of the magnesium chloride solution is 0.2-0.6 mol/L, the volume ratio of the magnesium chloride solution to the dispersion of graphene oxide quantum dots is 1 :1, the surfactant in step 1) is sodium dodecylbenzene sulfonate, and the mass-to-volume ratio of sodium dodecylbenzene sulfonate to the mixed solution of the magnesium chloride solution and the dispersion of graphene oxide quantum dots is 0.02-0.06 g: is 50 mL, and the reaction time after addition of the surfactant is 20-50 min.

The preparation method according to claim 1, wherein in step 1) the reaction temperature after adjusting the pH is 70°C, and the reaction time is 2-4 hours, at the end of the reaction they are cooled to 18-23°C wherein the drying temperature is 40-60°C, and the calcination is carried out in a muffle furnace at 350°C.

The preparation method according to claim 1, wherein in step 2) the concentration of the acetic acid solution is 4%, and the mass-to-volume ratio of the chitosan oligosaccharide to the acetic acid solution is 0.5-2.0 g:100 mL .

The preparation method according to claim 1, wherein in step 3) the water is deionized water, and the mass to volume ratio of the MgO/GQD/chitosan oligosaccharide nanocomposite powder, PVA, and deionized water 1-5 g: 8 -12 g: 100 mL is.

The preparation method according to claim 1, specifically comprising:

1) preparing Mg0/GQD nanocomposites: first a magnesium chloride solution is formulated,

second, graphene oxide quantum dots are weighed and dispersed in deionized water by ultrasonic treatment for 20-50 min, the above magnesium chloride solution is added dropwise into the dispersion of graphene oxide quantum dots, and stirred uniformly, a surfactant is then added to the mixture added to react for 20-50 min; dilute aqueous ammonia is then added to adjust the pH to 8-10 and allowed to react at 70°C for 2-4 h; at the end of the reaction they are cooled to 18-23 °C, separated by filtration and rinsed several times with deionized water until there is no Cl: and then dried in an oven at 40-60 °C for 12-16 h ; finally, the dried substances are calcined in a muffle furnace for 3-5 h to obtain MgO/GOQD nanocomposites;

2) preparing MgO/GOQD/chitosan oligosaccharide nanocomposites: first, chitosan oligosaccharide is dissolved in an acetic acid solution at a concentration of 4% and dispersed by ultrasonic treatment for 20-50 min; MgO/GQD nanocomposites and a crosslinking agent are added into the acetic acid solution of chitosan oligosaccharide and magnetically stirred at 18-23°C for 60-90min, the pH is adjusted, then continuously at 60-80°C for 0.8 to 1, 5 h magnetically stirred; finally, the resulting mixture is washed first with deionized water and then with absolute ethyl alcohol several times until neutral, and then freeze-dried to powder;

3) preparing MgO/GQD/chitosan oligosaccharide/PVA composite absorption membrane: the lyophilized MgO/GQD/chitosan oligosaccharide nanocomposite powder from step 2) is dissolved in deionized water together with PVA, and the mixed solution is horizontally wet spun to form the composite absorption membrane.

A composite absorption membrane of MgO/GQD/chitosanoligosaccharide/PVA prepared according to the preparation method according to any one of claims 1-7.

Use of the composite adsorption membrane according to claim 8, wherein the composite absorption membrane is used in wastewater treatment.

The use according to claim 9, wherein, before delivery of the composite adsorption membrane into waste water, the ratio of the membrane width to the base area of the waste water treatment plant is 0.1-0.3 m : 1 mf, and the membrane height is the same as the water level of waste water in the waste water treatment plant. -0-0-0-