硅藻泥包埋纳米零价铁处理含铬废水的研究

Treatment of chromium-containing wastewater by diatom mud immobilized nanoscale zero valent iron

采用环境友好型矿物材料硅藻泥(Diatom Mud)包埋纳米零价铁(nZVI)得到复合材料(D-nZVI),分别用XRD、SEM和TEM对样品分析表征.同时,通过考察D-nZVI中硅藻泥的用量、投加量、含Cr(VI)废水浓度、p H值、处理时间等对Cr(VI)去除率的影响,进一步研究了反应动力学等.结果表明,在25℃的条件下,D-nZVI中硅藻泥的用量为20%时,D-nZVI对Cr(VI)的去除效率要高于nZVI.p H值较低时D-nZVI的处理效果更好,并且含Cr(VI)废水的浓度越高,去除率越低,投加量增多和反应时间越长,Cr(VI)的去除率越高.当D-nZVI的用量为16 g·L-1,Cr(VI)废水浓度为10 mg·L-1,p H=3时,Cr(VI)的去除率达99%.从SEM和TEM样品分析结果可以看出,硅藻泥表面有很多小而均匀的小孔,较好地包埋或附着在纳米零价铁的表面上,起到了很好的抗氧化作用,为D-nZVI吸附、还原和共沉淀降解Cr(VI)提供了有力依据.

Environmental friendly material diatom mud was used to embed nanoscale zero valent iron（nZVI） to obtain a composite material（D-nZVI）.The sample was characterized by XRD,SEM and TEM.The effect of diatom mud dosage,pH value,and reaction time on Cr（VI） removal was investigated,and reaction kinetics were further explored.The results show that under the conditions of 25 ℃,diatom mud dosage of 20%,removal efficiency of Cr（VI）is higher by D-nZVI than by nZVI.At lower pH,D-nZVI shows better performance,and higher Cr（VI） concentrations result in lower removal efficiency.The removal efficiency increases with sample dosage and reaction time.When the D-nZVI dosage is 16 g·L^-1,the concentration of Cr（VI） is 10 mg·L^-1,Ph is 3,Cr（VI） removal rate reaches 99%.SEM and TEM results show that there exist many small uniform pores on the diatom mud surface,which were preferably embedded or attached to the surface of the Nzvi.This provides a strong basis for the D-Nzvi adsorption,co-precipitation and reduction degradation of Cr（VI）.