耐铅链霉菌诱导碳酸钙沉淀对水中Pb2+的去除研究

微生物诱导碳酸钙沉淀(MICP)可将水中游离的Pb_²⁺转化为稳定的沉淀物。本文筛选出一株耐Pb_²⁺的脲酶阳性SHT17菌株,16S rRNA 鉴定为Streptomyces mutabilis(登录号为OL677072)。探究该链霉菌诱导碳酸钙沉淀对水中Pb_²⁺的去除能力。通过电感耦合等离子体发射光谱仪(ICP-OES)对水中Pb_²⁺浓度进行检测,利用扫描电子显微镜(SEM)、X-射线能谱(EDS)、X-射线衍射(XRD)和傅里叶红外光谱(FTIR)对菌株诱导的沉淀物进行分析。结果表明,链霉菌能有效地去除水中Pb_²⁺。当Pb_²⁺浓度为200 mg/L时,水中Pb_²⁺去除率达到99.66%,并且去除的Pb_²⁺以碳酸盐的形式被固定在链霉菌诱导生成的沉淀物中。此外,随着初始Pb_²⁺浓度升高,该菌对Pb_²⁺去除率均在65%以上,且大致呈下降趋势。不同钙源影响着链霉菌诱导形成的沉淀物的形貌。

Removal of Pb2+ from water by Pb-tolerant Streptomyces-induced precipitation of calcium carbonate

Microbially induced calcium carbonate precipitation (MICP) can transform free lead ions into stable precipitation. In this study, a lead-tolerant and urease-positive SHT17 strain was screened, and which was identified as Streptomyces mutabilis (Accession No. OL677072) by 16S rRNA sequences. The removal ability of Pb_²⁺ from water was researched by Streptomyces-induced precipitation of calcium carbonate. The Pb_²⁺ concentration was measured by inductively coupled plasma optical emission spectrometry (ICP-OES). The microbial-induced precipitation was analyzed by scanning electron microscopy (SEM), X-ray energy distribution (EDS), X-ray diffraction (XRD) and fourier transform infrared spectroscopy (FTIR). The results showed that Streptomyces mutabilis possessed the highest Pb_²⁺ removal ability. The Pb_²⁺ removal rate reached 99.66% (with initial Pb_²⁺ concentration 200 mg/L), and removed Pb_²⁺ was fixed in the Streptomyces-induced carbonate precipitation. Furthermore, with the increase of the initial Pb_²⁺ concentration, the removal rate of Pb_²⁺ was above 65%, and showed a general downward trend. Different calcium sources affect the morphology of the Streptomyces-induced precipitations.