小麦秸秆生物炭对石油烃污染土壤的修复作用

Remediation of Wheat-Straw-Biochar on Petroleum-Polluted Soil

以小麦秸秆为原材料,在300℃下缺氧裂解3、6、8 h制备生物炭,比较了3种生物炭的产率、pH值、灰分以及C、H、N元素含量,表征了300℃、6 h生物炭的表面形态,并用其作为修复材料,对大港油田的石油污染土壤进行修复。结果表明,随裂解时间的延长,生物炭产率下降,pH值升高,灰分含量增加,H/C值下降,但产率、pH值、灰分和H/C值都是从3 h到6 h差异显著,6 h到8 h差异不显著。C元素含量先升高后下降。石油污染土壤经生物炭修复14 d和28d后,总石油烃降解率分别为45.48%和46.88%,均显著高于对照组。修复14 d后土壤中的萘、苊、苯并[a]蒽、屈、苯并[b]荧蒽、苯并[k]荧蒽、苯并[a]芘、茚并[1,2,3-cd]芘也都有不同程度的下降,其中苯并[a]芘含量下降幅度达98.18%,其他几种PAH的降解率也都高于对照组,28 d后这些PAH的含量又有上升趋势。这说明小麦秸秆裂解时间对生物炭的性质有影响;300℃、6h生物炭可以用来修复石油污染的土壤。

Biochar was made from wheat straw at 300℃for 3, 6, 8 hours respectively. The productivity, pH, ash content and C, H, N content of these biochar were compared. The surface morphology of the 300 ℃-6 h biochar was characterized, and it was used to remediate the petroleum-polluted soil of Dagang oil field. Results showed that, as the extension of pyrolisis time, the productivity of biochar decreased, pH increased, ash content increased, H/C decreased. But productivity, pH, ash content and H/C changed significantly from 3 h to 6 h, unsignifi-cantly from 6 h to 8 h. C content showed a downward trend after the first rise. After remediation of biochar for 14 and 28 days, the TPH degra-dation rate were 45.48%and 46.88%respectively, higher than control group. After 14 days remediation, content of naphthalene, acenaph-thene, Benzo [a] anthracene, chrysene, Benzo [b] fluoranthene, Benzo [k] fluoranthene, Benzo [a] pyrene, Indene and [1,2,3-CD] pyrene were decreased to various degrees, with the Benzo [a] pyrene content decreased by 98.18%, and the degradation rate of other PAH higher than con-trol group. After 28 days remediation however, content of these PAH showed a rising trend. It suggested that pyrolisis time had influence on biochar’s characteristics, and 300℃-6 h biochar could be used to remediate petroleum-polluted soil.