层状双氢氧化物(LDHs)协助固定重金属是一种高效的有发展前景的重金属污染土壤修复策略.LDHs强化修复重金属污染土壤过程中,土壤微生物群落和酶活性的响应已有充分研究,然而,LDH 原位修复过程中细菌的迁移响应尚不清楚.本文以铜绿假单胞菌作为土壤细菌代表,研究了其在 Mg3 AlCO3-LDH 阻控修复Cd中的迁移响应.研究发现,LDH 显著限制了铜绿假单胞菌在石英砂中的迁移,其程度与LDH的用量正相关.如不添加 LDH 时,细菌的总洗脱率为(50.76±0.88)%;而 LDH 含量为 0.77%时,细菌洗脱率为(29.19±0.52)%.共存 Cd 会进一步导致抑制细菌的迁移,洗脱率降至(19.49±0.83)%.LDH 对 Cd 有很强的亲和力,可有效地将 Cd 的迁移率从 93.6%降低到 68.9%;细菌的共存会进一步限制Cd的迁移,增加额外 14.1%的保留.
Effects of LDHs and co-existing Cd on bacterial transport in saturated porous medium
Layered double hydroxide(LDH)-assisted immobilization is a promising and efficient strategy for the remediation of heavy metal-contaminated soil.The effects of LDH itself and sequestered heavy metals on the soil microbial community and enzymatic activity have been well studied.However,the mobility and transport of bacteria during in-situ LDH-aided remediation is poorly understood.In this study,the transport of Pseudomonas aeruginosa,a typical soil bacterium,in a quartz sand-packed column with Mg3 AlCO3-LDH and cadmium(Cd)was carried out.LDH mixed within quartz sand significantly restricted the transport of Pseudomonas aeruginosa.For example,0.77%LDH addition led to(29.19±0.52)%bacterial elution,compared with(50.76±0.88)%without LDH addition.The copresence of Cd resulted in further retention of bacteria within the column with only(19.49±0.83)%elution.LDH could retain Cd efficiently from 93.6%to 68.9%due to high affinity for Cd.The coexistence of bacteria further limited Cd transport,and an extra 14.1%was observed compared with LDH only.
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