复配材料固化/稳定化重金属污染底泥研究

SOLIDIFICATION/STABILIZATION OF HEAVY METAL CONTAMINATED SEDIMENT BY COMPOUD MATERIALS

利用高效重金属稳定化材料与硅酸盐水泥配制复配材料(FP),用于固化/稳定化重金属污染底泥。设置3个FP掺量梯度:10%、20%、30%;3个固化体养护时间:7,28,42 d;以硅酸盐水泥为对照(CK)。以抗压强度与颗粒固化体浸出浓度为指标,考察FP的固化与稳定化效果。结果表明:相比于原底泥浸出,10%FP掺量下,As的浸出浓度在7 d时已降低93%以上;28 d时,不同FP掺量下Pb的浸出浓度可降低82.5%~97.68%;Cu、Zn的浸出浓度在FP掺量为30%、养护42 d时达最低值,分别下降了60.97%和89.07%。FP组Cu、As的浸出浓度在掺量为10%、养护7 d时已显著低于CK,而其Zn的浸出浓度在FP掺量达30%、养护42 d时显著低于CK(P<0.01)。增加FP掺量、延长养护时间均能显著提高FP组固化体的抗压强度(P<0.05),在养护42 d时,FP组抗压强度显著高于CK(P<0.05),当掺量为30%时,FP组抗压强度可达2.1MPa以上。

A compound materials(FP)with a combination of Portland cement and efficient heavy metal stabilization material was used to solidify and stabilize river sediment containing heavy metals.In this paper,we set three FP dosages of 10%,20%,30%,three curing times of 7,28,42 d,and selected Portland cement as the control(CK).The compressive strength and leaching concentration were selected as indicators to test the solidifying and stabilizing effect of FP.The results showed that compared to the direct leaching of sediment,the leaching concentration of As in the sediment was reduced by more than 93%,that of Pb was reduced by 82.5%~97.68%under different FP dosages after 28 days.The leaching concentration of Cu and Zn reached the lowest value when the FP dosage was 30%and curing time was 42 days,which were 60.97%and 89.07%lower than the direct leaching of the sediment,respectively.Under different treatments,the leaching concentration of Cu and As in FP group was all significantly lower than that in CK(P<0.01);that of Zn in FP group was significantly lower than in CK after 42 days under 30%FP dosage(P<0.05).With the dosage of FP or the curing time increased,compressive strength of the solidified products was also significantly enhanced(P<0.05).Compressive strength of the solidified products of FP was significantly higher than that of CK(P<0.05)after 42 days,and when the dosage of FP increased to 30%,the compressive strength reached 2.1 MPa.