Study On The Adsorption Properties Of Physalis Alkekengi Colloid And Composite Gel Silk Material

The artificial large-scale use of organic dyes and antibiotics in industrialization has brought negative effects on our surroundings.Organic dyes are not considered biodegradable.Dyes are mainly used in papermaking,hair colorants,pharmaceutical and food industries.Most dyes are toxic,and some of them can cause cancer and harm human cells,affecting the human body and other organisms.Organic dyes and antibiotics are considered to be one of the main sources of water pollution.The discharge of untreated and moderately used effluent from industrial waste liquids into natural ecosystems poses many difficulties.Organic dyes may also affect aquatic organisms and the food chain of many organisms,leading to inequality in our surrounding environment.When concentrations are low,adverse effects can lead to human health problems such as irritation,allergies and cancer.Many methods are used to remove these dyes.Commonly used are coagulation,oxidation degradation,photocatalytic degradation,nanofiltration,reverse osmosis,electrodialysis,adsorption in addition to physics,biodegradation,adsorption and so on.Compared with other methods,adsorption method is considered to be a more suitable water reuse method than other methods,because of its low cost,simple design,easy operation and toxic substances inhibition.Nicandra physaloides（L.）Gaertn seed gum（NPG）is a kind of pure polysaccharide secreted by Nicandra physaloides（L.）Gaertn seed（NP）after contacting with water.Because NPG is odorless,non-toxic,colorless and edible,it has been widely used in cosmetics,medicine,food and other fields.In addition,NPG crosslinked with divalent metal ions(Ca²⁺,Cu²⁺,Ni²⁺)to form a gel with a spatial network structure.And NPG has good flexibility,can be synthesized into aerogel,film,fiber and other different shapes,to adapt to different application environment.Based on the above background,the main work of this paper is as follows:（1）When GO is used for water treatment alone,due to its good hydrophilicity,it is difficult to remove from the treated water.In this paper,vacuum freeze-drying method and the principle that NPG can be formed in Ca²⁺is adopted to prepare pseudoacid slurry seed gum/graphene oxide（NPG/GO）composite material for adsorption of methylene blue（MB）in the water environment.The structure,morphology and thermal stability of the prepared adsorbents were characterized by thermogravimetric analyzer（TGA）,Brunauer-Emmett-Teller（BET）,scanning electron microscope（SEM）,and other techniques.The effects of adsorbent dosage,mass ratio of GO to NPG,initial dye concentration,pH value,Ca²⁺concentration,contact time and temperature on the adsorption properties of NPG/GO composites were analyzed in detail.When Ca²⁺concentration is 5 wt%and the mass ratio of GO to NPG is 1:1.25,the adsorption effect of NPG/GO composite is the best.The average pore size and specific surface area of NPG/GO are smaller than those of GO,which are 4.8 nm and 2.70 m²/g,respectively.Thermodynamic analysis and adsorption kinetics study show that the adsorption process of methylene blue on NPG/GO is spontaneous and endothermic,and the adsorption process conforms to the pseudo-second-order kinetic model and Langmuir isotherm.（2）In this study,based on the principle that NPG can be formed in Cu²⁺,the pseudo-acid slurry seed gum/carboxymethyl chitosan（NPG/CMC）was prepared by freeze-drying method to remove tetracycline（TC）from water.The structure,thermal stability and morphology of NPG/CMC aerogel were characterized by thermogravimetric analysis（TGA）,Brunauer-Emmett-Teller（BET）,X-ray diffraction（XRD）,scanning electron microscopy（SEM）and Fourier transform infrared spectroscopy（FTIR）.The average pore sizes of NPG and NPG/CMC were 3.04 nm and 1.2 nm,and the specific surface areas were 2.67 and 0.73 m²/g,respectively.Thermodynamic and kinetic studies show that the adsorption process of NPG/CMC on TC is a spontaneous exothermic process,and the adsorption process conforms to the pseudo-second-order kinetic model and Langmuir isotherm.When the concentration of Cu²⁺is 5 wt%and the mass ratio of CMC to NPG is 1:1,the maximum adsorption capacity of NPG/CMC aerogel on TC is332.23 mg/g,calculated by linear fitting of Langmuir isotherm.