Remediation Of Lead Polluted Soil With Honeycomb Briquette Combustion Residue

Lead （Pb） is the most common soil polluting element. Soil pollution with lead hasnegative effect on food quality, plant growth, health of human and animals.Thus, remediationof Pb polluted soil is of critical importance. Compared with cadmium and arsenic, Pb is noteasily absorbed by plants. Therefore, reducing the phytoavailability of Pb in polluted soil isthe primary method in remediation of Pb polluted soil. The purpose of this study was toexplore stabilizing effect of honeycomb briquette combustion residue （HBCR） on Pb in Pbpolluted soil. The basic properties, immobilization effect of HBCR on Pb in polluted soil,effect of modification on the basic properties of HBCR, effect of modified HBCR on theavailability of Pb in soil were investigated. The main results were as follows:i) Ranges of pH and EC,<0.05mm particle contents, Pb and Zn contents of five areasHBCR samples were6.62^-13.04,0.564-3.407mS·cm^-1,11.39%-34.42%,20.61-99.57and23.68-92.50mg·kg^-1, respectively. The average values were11.41,1.279mS·cm^-1,22.46%,55.08and48.41mg·kg^-1, respectively.ii) Contents of DTPA-Pb in Pb-spiked soil with low phosphorus availability(Olsen-P=2.50mg·kg^-1) decreased10.72mg·kg^-1after the HBCR amendment. Olsen-Pcontents increased2.71mg·kg^-1after the HBCR amendment. Soil pH increased0.1after theHBCR amendment.iii) Contents of Ca₂-P increased0.42and0.95mg·kg^-1for the unspiked soil and thePb-spiked soil without phosphorus amendment after the HBCR amendment, respectively. Forthe Pb-spiked soil with phosphorus amendment, HBCR amendment decreased26.25mg·kg^-1.Contents of Ca₈-P increased4.67,0.25and4.90mg·kg^-1after the HBCR amendment,respectively, for the unspiked soil, Pb-spiked soil without phosphorus amendment andPb-spiked soil with phosphorus amendment.iv) For Pb-spiked soil with phosphorus amendment, amendment with unmodified HBCR,water-washed HBCR and acid-washed HBCR decreased contents of DTPA-Pb67.2,195.1and116.8mg·kg^-1, respectively, while for Pb-spiked soil with phosphorus amendment,contents of DTPA-Pb decreased102.0,91.84and86.84mg·kg^-1, respectively. Amendmentwith HBCR increased the ratio of carbonate phase Pb and decreased the ratio of manganesephase Pb. HBCR washed with water or acid reduced the capacity of increasing soil pH and EC, while its ability of increasing the content of available phosphorus was not substantiallyaffected.v) The effect of acid-washed HBCR amendment on Pb polluted soil with differentphosphorus availability was also investigated. The results indicated that, for F soil with higherphosphorus availability and S soil with lower phosphorus availability, acid-washed HBCRamendment resulted in higher contents of Olsen-P. Contents of DTPA-Pb of F and S soildecreased101.8and49.85mg·kg^-1after the acid-washed HBCR amendment, respectively.The results indicated that, HBCR is a kind of alkaline, coarse solid waste with highcontents of electrolyte. Lower availability of Pb in Pb polluted soil can be realized withHBCR amendment. Immobilization effect of Pb with water and acid washed HBCR was notnegatively affected or was improved by the modification, while its negative effect on pH andEC was decreased.