Preparation And Properties Of Sewage Sludge Modified Hydrogel

In this study,sewage sludge ash is obtained by incinerating sludge after air-drying.The superabsorbent hydrogel was prepared by free radical polymerization,using sewage sludge ash as inorganic filler,grafting acrylic acid(AA)and acrylamide(AAm)on sodium alginate(NaAlg).The effect of the addition ratio of sewage sludge ash,incineration temperature and grinding number on the performance of hydrogel was studies and the optimal parameters were determined as a result.The structure of the sewage sludge ash and hydrogels were investigated by varies physical chemistry methods and modern instruments analysis.The sewage sludge ash modified hydrogel and ordinary hydrogel were applied to the swelling behavior and adsorption of dye methylene blue(MB).The main research results are as follows:(1)The results showed that the optimum addition conditions of sewage sludge ash were as follows: 10wt% sewage sludge ash(with respect to NaAlg),incineration temperature was 700 ?,grinding mesh was 100-200 mesh.The sewage sludge ash modified hydrogel(SSAG10)prepared under these conditions had better swelling performance.At the same time,XRD,FTIR,TGA and SEM analysis showed that sewage sludge ash modified hydrogel(SSAG10)contained more carboxylic acid groups(COO-),and it has porous structure and certain thermal stability.(2)By studying the kinetics of under different preparation conditions and ordinary hydrogel(SSAG0)that without sewage sludge ash,it is clear that sewage sludge ash modified hydrogel has better swelling ability and reusability than ordinary hydrogel(SSAG0).The swelling value of SSAG10 hydrogel prepared under the optimum conditions swelling value is 799g/g,while SSAG0 is only 637 g/g.The swelling properties of hydrogels are influenced by the pH,temperature and the type and concentration of ions.Hydrogels have the greatest swelling properties when the temperature is 25 C and the pH is 7.Divalent ions have the greatest influence on the swelling behavior of hydrogels.After repeated cycles of regeneration,the sewage sludge ash modified hydrogels still has good swelling properties.(3)The adsorption properties of sewage sludge ash modified hydrogel(SSAG10)and ordinary hydrogel(SSAG0)prepared under optimal conditions for MB in solution were studied.The results showed that the hydrogel had better adsorption effect on MB when the pH was more than 7.The results show that the adsorption behavior of SSAG0 and SSAG10 hydrogels accords with quasi-second-order equation,and the adsorption rate of SSAG0 is higher than that of SSAG0.Meanwhile,there is diffusion between particles in the whole adsorption process.The adsorption data were fitted by isothermal model.The results showed that the adsorption behavior of SSAG0 and SSAG10 hydrogels accorded with Langmuir model.The maximum adsorption capacity was 460.13 mg/g and 468.95 mg/g,respectively.Compared with SSAG0 hydrogel,SSAG10 has better stability and reusability after 5 times recycling.