Preparation And Performance Study Of Multifunctional Alginate Calcium-carbon Aerogel

Calcium alginate is a seaweed polysaccharide possessing good biocompatibility and degradability,which is mainly used in food,biology and medicine.In addition,carbon aerogels prepared from calcium alginate were mainly used in the battery,and its researches on dye adsorption,oil-water separation and emulsion separation were relatively rare.In this thesis,the preparation and adsorption properties of calcium alginate carbon aerogels at different temperatures were investigated.Comparing the different carbon aerogels,a carbon aerogel with the best adsorption performance was selected to explore its dye adsorption,oil-water separation and emulsion separation performance.On the basis of the dye adsorption performance,oil-water separation and emulsion separation performance of acid washed calcium alginate carbon aerogel were discussed.1.Preparation and application of calcium alginate carbon aerogelGenerally,calcium alginate was obtained by cross-linking sodium alginate with 5% calcium chloride.According to the thermogravimetric analysis of calcium alginate aerogel,500℃,800℃,1000℃ were selected as carbonization temperature and calcium alginate carbon aerogel-500(CCA-500),calcium alginate carbon aerogel-800(CCA-800),calcium alginate carbon aerogel-1000(CCA-1000)were obtained.Characterization results showed that CCA-500 was mainly calcium carbonate and graphite structure,CCA-800 and CCA-1000 were mainly calcium oxide and graphite structures.In the adsorption experiment,CCA-1000 showed better adsorption performance than CA,CCA-500 and CCA-800.The adsorption experiments showed that the adsorption capacities of CCA-1000 for methylene blue,methyl orange and oil red O were 205.7 mg/g,106.7 mg/g and 67.6 mg/g,respectively.The adsorption process accorded with the Pseudo-second-order kinetic model,and the adsorption process was spontaneous;CCA-1000 also had good adsorption properties for other dyes.The adsorption amounts of malachite green,crystal violet,acid fuchsin and Congo red were 7059 mg/g,2390 mg/g,6964 mg/g and 1476 mg/g,respectively.In Oilwater separation experiment,CCA-1000 completely adsorbed the oil on the water and the oil under the water with 15 s and 18 s,respectively.At the same time,The CCA-1000 taken 6 min and 8 min to separate 3 mL of carbon tetrachloride and 3mL aqueous solution.CCA-1000 separated 5 mL water-in-oil type and 5 mL oil-in-water type emulsion with 25 min and 50 min during the emulsion separation process.2.Preparation and application of carbon aerogelThe carbon aerogel(ACCA)was prepared by treating CCA-1000 with a 2 mol/L hydrochloric acid solution to remove calcium oxide in CCA-1000.Characterization results showed that carbon aerogel mainly contained carbon and oxygen and no calcium oxide.The adsorption capacities of ACCA for methylene blue,methyl orange and oil red were 196.38 mg/g,187.44 mg/g and 182.6 mg/g,respectively,indicating that ACCA had good adsorption for adsorption of different types of dyes.The adsorption of three dyes by ACCA accords with Pseudo-second-order kinetic model and Langmuir model,indicating that the adsorption process was Chemical adsorption and molecular layer adsorption.ACCA completely adsorbed the oil on water and the oil under water with 40 s and 2 s,respectively.At the same time,ACCA taken 15 min and 35 min to separate 3 mL of carbon tetrachloride and 3 mL aqueous solution.ACCA separated 5 mL water-in-oil type and 5 mL oil-in-water type emulsion with 2.5 h and 3.5 h during the emulsion separation process.