Study On Adsorption Properties Of Siraitia Grosvenorii Residue To Dyes

In recent years,the rapid development of domestic textile industry has been led to the serious problem in dye wastewater.The wastewater treatment method has been continuously improved,and it has begun to pay attention to green environmental protection treatment method.In this experiment,siraitia grosvenorii residue,an agricultural waste from siraitia grosvenorii processed by Guilin Jifusi Siraitia Grosvenori Co.,Ltd.,was selected as raw material.In this experiment,the siraitia grosvenorii residue was chemically modified to prepare siraitia grosvenorii residue.A systematic study and compare the adsorption effects of different kinds of siraitia grosvenorii residue on anionic dyes(methyl orange,reactive blue 19,amaranth and sunset yellow)and cationic dyes(methylene blue,methyl violet,rhodamine B and neutral red).Scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR)and X-ray diffraction(XRD)were used to compare the structural characteristics of different kinds of siraitia grosvenorii residues before and after dye adsorption.The results showed that the crystal structure of pretreated and modified siraitia grosvenorii residues belonged to cellulose I.The surface of modified siraitia grosvenorii residues were appeared many holes,and the voids were looser.After interacting with dyes,the dyes filled the voids of siraitia grosvenorii residue.The specific content of this experiment is as follows:1.To investigate the effect of pretreated siraitia grosvenorii residue on the adsorption properties of neutral red solution,methyl violet solution and Rhodamine B solution.The influencing factors such as adsorbent dosage,adsorbing time,adsorbing temperature and p H were explored.Based on the previous single factor experiment results,the orthogonal experiment of adsorbing neutral red by pretreated siraitia grosvenorii residue was designed,the optimal experimental conditions were as follows: the concentration of 20 mg/L neutral red solution,the dosage of the adsorbent was 0.4 g,the adsorption time was 30 min,the adsorption temperature was 35 °C and p H 8,decolorization rate 94.88%;the orthogonal experiment of adsorbing methyl violet by pretreated siraitia grosvenorii residue,the optimal experimental conditions were as follows: the concentration of 20 mg/L methyl violet solution,the dosage of the adsorbent was 1.0 g,the adsorption time was 30 min,the adsorption temperature was 35 °C and p H 10,decolorization rate 92.77%;the orthogonal experiment of adsorbing Rhodamine B by pretreated siraitia grosvenorii residue,the optimal experimental conditions were as follows: the concentration of 20 mg/L Rhodamine B solution,the dosage of the adsorbent was 1.0 g,the adsorption time was 10 min,the adsorption temperature was 15 °C and p H 4,decolorization rate 53.74%.It could be seen that the pretreated siraitia grosvenorii residue has the best effect on adsorbing neutral red solution.The neutral red solution belongs to the cationic dye,and the molecular formula is C15H17 Cl N4,which forms a cation after solution water.2.To investigate the effect of alkaline modified siraitia grosvenorii residue on the adsorption properties of methylene blue.The influencing factors such as adsorbent dosage,adsorbing time,adsorbing temperature and p H were studied.Based on the previous single factor experiment results,the orthogonal experiment of adsorbing methylene blue by alkaline modified siraitia grosvenorii residue was designed,the optimal experimental conditions were as follows: the concentration of 20 mg/L methylene blue,the dosage of the adsorbent was 0.8 g,the adsorption time was 30 min,p H 8 and the adsorption temperature was 25 °C,decolorization rate 98.54%.It could be seen that the alkalized modified siraitia grosvenorii residue has a good adsorption effect on the methylene blue solution.The methylene blue dye belongs to the cationic dye,and the molecular formula is C16H18 Cl N3S,which forms a cation after solution water.3.Study on the adsorption mechanism of pretreated siraitia grosvenorii residue.The cationic dye neutral red was used as the research object,and the static adsorption was used for investigation.The experimental results were based on the method of fitting analysis.It was concluded that the adsorption research model fitted the simulation of quasi-second-order kinetic equation;the adsorption process accorded with the Freundlich isotherm equation model.4.Study on desorption of pretreated siraitia grosvenorii residue.The adsorption of cationic dye neutral red by pretreated siraitia grosvenorii residue was used as the research object,used acid elution for desorption experiments.The results showed that the adsorption of dyes by pretreated siraitia grosvenorii residue could be recycled.After four desorptions,the decolorization rate of pretreated siraitia grosvenorii residue to neutral red was still above 90%.5.Study on dynamic adsorption experiment of pretreated siraitia grosvenorii residue.The adsorption of cationic dye neutral red by pretreated siraitia grosvenorii residue was used as the research object,used column adsorption experiment.In each experiment,4 m L effluent was collected for detection.When the effluent was 144 m L,the absorbance appeared,the adsorption capacity at the penetration point was 8.338 mg/g;when the effluent was 148 m L,the adsorption capacity began to decrease;when the effluent was 160 m L,the adsorption saturation point appeared,and the adsorption capacity was 7.625 mg/g.The results showed that the pretreated Siraitia grosvenorii residue could handle the treatment of 160 column volume effluent,that was,0.3 g of pretreated siraitia grosvenorii residues could handle 126.4 m L of dyes.