磁性壳聚糖改善污泥脱水性能的研究
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摘要
采用天然壳聚糖为原料,戊二醛为交联剂,Fe3O4为磁核制备磁性壳聚糖,以改善污泥脱水性能.考察了磁性壳聚糖投加量、污泥pH值、调理时间对磁性壳聚糖改善污泥脱水性能的影响,探讨了磁性壳聚糖的作用机理,并通过响应面法研究了磁性壳聚糖和CPAM复配处理污泥对污泥脱水性能的影响.结果表明,保持污泥pH值为6.8时,经20mg/L的磁性壳聚糖调理30min后,污泥比阻(SRF)和含水率(MC)分别由原污泥的13.8×1012m/kg和98.7%降低至4.8×1012m/kg和75.5%,说明磁性壳聚糖明显改善了污泥脱水性能.响应面实验所拟合的响应值为污泥SRF的二次模型P(Prob>F)<0.05、R2=0.98>0.90,响应值为污泥MC的二次模型P(Prob>F)<0.05、R2=0.95>0.90,表明模型显著,且实验设定变量之间的相关性较好.根据响应值的分布情况,确定污泥脱水的最佳条件为磁性壳聚糖18mg/L、CPAM26mg/L、调理时间27min,相应SRF和MC分别为3.3×1012m/kg和59.5%,污泥脱水效果较单独采用磁性壳聚糖或CPAM时得到了明显的提高.
Natural chitosan was used as raw material to prepare magnetic chitosan by cross linking with glutaraldehyde and Fe3 O4 for enhancement of the sludge dewatering. The effects of magnetic chitosan dosage, sludge p H and conditioning time on the performance of magnetic chitosan for sludge dewatering were investigated, and the enhancement mechanism was discussed. Subsequently, response surface methodology(RSM) was employed to optimize the process of sludge dewatering by the complex of CPAM and magnetic chitosan. When sludge pH value was 6.8, after conditioned by 20 mg/L of magnetic chitosan for 30 min, SRF and MC were decreased from 13.8×1012 m/kg and 98.7% of the original sludge to 4.8×1012 m/kg and 75.5%, respectively, indicated that the sludge dewatering was significantly enhanced. SRF and MC were settled as the target responses in the experiments designed by RSM, as the determination coefficients(R2) of 0.98 and 0.95, the two quadratic models could agree with experimental data well. The optimal conditions for sludge dewatering were magnetic chitosan dosage of 18 mg/L, CPAM dosage of 26 mg/L, and conditioning time of 27 min, under this optimal condition, SRF and MC appeared as 3.3×1012 m/kg and 59.5%, respectively, better than the individual using of the magnetic chitosan or CPAM in sludge dewatering.
Natural chitosan was used as raw material to prepare magnetic chitosan by cross linking with glutaraldehyde and Fe3 O4 for enhancement of the sludge dewatering. The effects of magnetic chitosan dosage, sludge p H and conditioning time on the performance of magnetic chitosan for sludge dewatering were investigated, and the enhancement mechanism was discussed. Subsequently, response surface methodology(RSM) was employed to optimize the process of sludge dewatering by the complex of CPAM and magnetic chitosan. When sludge pH value was 6.8, after conditioned by 20 mg/L of magnetic chitosan for 30 min, SRF and MC were decreased from 13.8×1012 m/kg and 98.7% of the original sludge to 4.8×1012 m/kg and 75.5%, respectively, indicated that the sludge dewatering was significantly enhanced. SRF and MC were settled as the target responses in the experiments designed by RSM, as the determination coefficients(R2) of 0.98 and 0.95, the two quadratic models could agree with experimental data well. The optimal conditions for sludge dewatering were magnetic chitosan dosage of 18 mg/L, CPAM dosage of 26 mg/L, and conditioning time of 27 min, under this optimal condition, SRF and MC appeared as 3.3×1012 m/kg and 59.5%, respectively, better than the individual using of the magnetic chitosan or CPAM in sludge dewatering.
引文
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[21]Shen C,Chen H,Wu S,et al.Highly efficient detoxification of Cr(VI)by chitosan-Fe(III)complex:Process and mechanism studies[J].Journal of hazardous materials,2013,244:689-697.
[22]Guo J Y,Jiang S L,Pang Y J.Feasibility and mechanism of combined conditioning with coagulant and flocculant to enhance sludge dewatering[J].Science of Total Environment,2018,6:10758-10765.
[23]Ganjidoust H.Effect of synthetic and natural coagulant on lignin removal from pulp and paper wastewater[J].Water Science and Technology,1997,35:291-296.
[24]Liu X,Li X M,Yang Q,et al.Landfill leachate pretreatment by coagulation-flocculation process using iron-based coagulants:Optimization by response surface methodology[J].Chemical Engineering Journal,2012,200:39-51.
[25]Guo J Y,Yu J,Xin X,et al.Characterization and flocculation mechanism of a bioflocculant from hydrolyzate of rice stover[J].Bioresource Technology,2015,177:393-397.
[2]Chen Z,Zhang W J,Wang D S,et al.Enhancement of activated sludge dewatering performance by combined composite enzymatic lysis and chemical re-flocculation with inorganic coagulants:Kinetics of enzymatic reaction and re-flocculation morphology[J].Water Research,2015,83:367-376.
[3]Skinner S J,Studer L J,Dixon D R,et al.Quantification of wastewater sludge dewatering[J].Water Research,2015,82:2-13.
[4]Zhai L F,Sun M,Song W,et al.An integrated approach to optimize the conditioning chemicals for enhanced sludge conditioning in a pilot-scale sludge dewatering process[J].Bioresource Technology,2012,121:161-168.
[5]Guo J Y,Chen C.Sludge conditioning using the composite of a bioflocculant and PAC for enhancement in dewaterability[J].Chemosphere,2017,185,277-283.
[6]申亮.壳聚糖和溶酶菌联用强化污泥脱水性能研究[D].长沙:湖南大学,2015.Shen L.Study on enhancing sludge dewaterability by combining chitosan with lysozyme[D].Changsha:Hunan University,2015.
[7]李晶.壳聚糖絮凝剂对污泥脱水性能影响的研究[D].济南:山东大学,2008.Li J.Effects of chitosan on sludge dewaterability[D].Jinan:Shandong University,2008.
[8]高明.壳聚糖接枝共聚污泥脱水剂的制备及污泥脱水性能[D].哈尔滨:哈尔滨工业大学,2010.Gao M.Sludge dewatering reagent preparation by grafted copolymer of chitosan and the sludge dewatering ability[D].Harbin:Harbin Institute of Technology,2010.
[9]罗曦,雷中方,张振亚,等.好氧/厌氧污泥的胞外多聚物(EPS)提取方法的研究[J].环境科学学报,2005,25(12):1624-1629.Luo X,Lei Z F,Zhang Z Y,et al.Study on the extraction of extracellular polymeric substance(EPS)from aerobic/anaerobic sludge[J].Acta Sciences Circumstantiae,2005,25(12):1624-1629.
[10]薛秀玲,樊国峰,李吉安.活性污泥中EPS的2中测定方法及其对膜通量的影响[J].环境工程学报,2013,7(9):3466-3470.Xue X L,Fan G F,Li J.Two methods for determination of extracellular polymeric substances in active sludge and its effects on membrane fouling[J].Chinese Journal of Environmental Engineering,2013,7(9):3466-3470.
[11]Chaplin M F,Kennedy J F.Carbohydrate Analysis,2nd ed.,Oxford University Press:New York,1994.
[12]Bradford M M.A rapid and sensitive method for the quantization of microgram quantities of protein utilizing the principle of protein-dye binding[J].Analytical Biochemistry,1976,72:248-254.
[13]潘媛媛.磁性壳聚糖的改性及其对模拟废水的处理研究[D].太原:中北大学,2013.Pan Y Y.The modification of magnetic chitosan and the research on simulated wastewater[D].Taiyuan:North University of China,2013.
[14]吕龙.三价铁交联壳聚糖去除水体中高氯酸盐的研究[D].成都:成都理工大学,2014.Lv L.Removal of per-chlorate from aqueous solution by cross-linked Fe(III)-chitosan complex[D].Chengdu:Chengdu University of Technology,2014.
[15]Guo J Y,Chen C,Jiang S L,et al.Feasibility and mechanism of combined conditioning with coagulant and flocculant to enhance sludge dewatering[J].ACS Sustainable Chemistry Engineering,2018,6:10758-10765.
[16]吴海忠.城市消化污泥脱水性能及资源化研究[D].北京:北京建筑大学,2013.Wu H Z.Research on dewaterability and reclamation of urban digested sludge[D].Beijing:Beijing University of Civil Engineering and Architecture,2013.
[17]林霞亮.壳聚糖复合调理剂改善污泥脱水性能的试验研究[D].广州:华南理工大学,2015.Lin X L.Experimental study on effect of complex chitosan conditioners on sewage sludge dewatering[D].Guangzhou:South China University of Technology,2015.
[18]Li L Z,Mao L Y,Wang X L,et al.Synthesis and flocculation property of chitosan-acrylamide graft copolymer[J].Chemical Research in Chinese Universities,2004,20:221-224.
[19]周健,罗勇,龙腾锐,等.胞外聚合物、Ca2+及pH值对生物絮凝作用的影响[J].中国环境科学,2004,24(4):437-441.Zhou J,Luo Y,Long T R,et al.Effects of extracellular polymeric substances,Ca2+and pH on bioflocculation[J].China Environmental Science,2004,24(4):437-441.
[20]Klepka M T,Nedelko N,Greneche J M,et al.Local atomic structure and magnetic ordering of iron in Fe-chitosan complexes[J].Biomacromolecules,2008,9:1586-1594.
[21]Shen C,Chen H,Wu S,et al.Highly efficient detoxification of Cr(VI)by chitosan-Fe(III)complex:Process and mechanism studies[J].Journal of hazardous materials,2013,244:689-697.
[22]Guo J Y,Jiang S L,Pang Y J.Feasibility and mechanism of combined conditioning with coagulant and flocculant to enhance sludge dewatering[J].Science of Total Environment,2018,6:10758-10765.
[23]Ganjidoust H.Effect of synthetic and natural coagulant on lignin removal from pulp and paper wastewater[J].Water Science and Technology,1997,35:291-296.
[24]Liu X,Li X M,Yang Q,et al.Landfill leachate pretreatment by coagulation-flocculation process using iron-based coagulants:Optimization by response surface methodology[J].Chemical Engineering Journal,2012,200:39-51.
[25]Guo J Y,Yu J,Xin X,et al.Characterization and flocculation mechanism of a bioflocculant from hydrolyzate of rice stover[J].Bioresource Technology,2015,177:393-397.