浒苔生物炭促进土壤Pb固定并缓解植物Pb毒性

Enteromorpha prolifera biochar promoted the immobilization of Pb in soil and reduced the phytotoxicity of Pb to Vetiveriazizanioides(L.)Nash.

本文利用浒苔在不同温度下制备的生物炭(400℃和600℃,记为BC400与BC600),以30g/kg生物炭添加量对1200mg/kg的Pb污染土壤进行香根草盆栽实验,研究浒苔生物炭对土壤中Pb固定和植物中Pb毒性的影响.结果表明,浒苔生物炭与香根草能协同促进土壤中Pb固定,较生物炭组提高了16.89%和14.82%,比植物组提高17.40%和15.02%.生物炭理化性质影响Pb固定,BC400的pH值(8.97)低于BC600(10.59),但BC400固定Pb的效果优于BC600,因为羟基(—OH)、羰基(C═O)等基团较BC600丰富,且微孔结构完整.浒苔生物炭可抑制香根草对Pb的吸收,促进香根草生长,其中BC400有助于植物地上部分及根部Pb浓度降低(分别降低23.50%和22.92%),同时降低富集系数,提高香根草的生物量、叶绿素含量及根系活力,提高抗氧化酶SOD、CAT和POD活性,丙二醛含量可降低13.40%.总之,浒苔生物炭通过高pH值和微孔结构吸附Pb,并通过官能团增加与金属的结合位点固定Pb,以降低Pb的毒性,提高香根草生存能力.鉴于滨海地区浒苔生物质资源丰富,生物炭与植物联合作用可作为Pb污染土壤修复的技术措施之一.

In this paper,Enteromorpha prolifera biochar prepared at 400℃(BC400)and 600℃(BC600)was added to the soil containing 1200mg/kg of Pb at a concentration of 30g/kg.A pot experiment of Vetiveria zizanioides(L.)Nash was conducted to study the effects of Enteromorpha prolifera biocharon Pb immobilization in the soil and phytotoxicity of Pb in plants.The results showed that the plants and biochar showed significant synergistic effects on Pb immobilization.Such effects increased Pb immobilization rates by 16.89%and 14.82%comparing with the biochar group alone,and increased Pb immobilization rates by 17.40%and 15.02%comparing with the plant alone.The physical and chemical properties of biochar affected the immobilization of Pb.The pH value of BC400 was lower than BC600,whereas BC400 had a better immobilization effect than BC600.This was because the hydroxyl(—OH)and carbonyl(C═O)groups of BC400 were more abundant than the BC600,and the microporous structure was more intact than BC600.Enteromorpha prolifera biochar inhibited the absorption of Pb by Vetiveria zizanioides(L.)Nash and promoted the growth of Vetiveria zizanioides(L.)Nash.BC400 reduced the enrichment factor and the concentration of Pb in the aboveground and root parts of Vetiveria zizanioides(L.)Nash(by 23.50%and 22.92%,respectively).BC400 increased the biomass,chlorophyll content,and root vitality of Vetiveria zizanioides(L.)Nash.It also increased SOD,CAT,and POD activities,and reduced malondialdehyde content by 13.40%.In summary,Enteromorpha prolifera biochar adsorbed Pb better through providing a higher pH value,its microporous structure,and fixed more Pb in soil by increasing the binding sites with metals through functional groups,so as to reduced phytotoxicity,and improved the viability of Vetiveria zizanioides(L.)Nash.In view of the abundance of biomass resources of Enteromorpha prolifera in the coastal area,the combined action of biochar and plants can be used as one of the technical measures for remediation of Pb contaminated soil.