柠檬酸杆菌吸附重金属镉的研究

STUDY ON BIOSORPTION OF HEAVY METAL ION-CADMIUM BY CITROBACTER FREUDII

采用柠檬酸杆菌生物吸附剂,吸附重金属镉。考察了柠檬酸杆菌吸附Cd2+过程中的影响因素,包括pH、菌浓度和金属离子浓度。结果表明,柠檬酸杆菌对Cd2+的吸附随pH的增大而增大,当pH为7时吸附率达到最大值;当菌体浓度为4.0g·L-1时,吸附率达89.45%;当溶液中Cd2+起始浓度为20mg·L-1时,菌体对Cd2+的吸附率最大,达到93.12%;其吸附等温线符合Langmuir和Freundlich模型,但Langmuir模型拟合效果更好。

Citrobacter freudii was used as the biosorbent to adsorb heavy metal ion-cadmium. The factors which affect the adsorption of Cd^2＋ by Citrobacter freudii were investigated, including pH, the strain dosage and the initial concentrate of Cd^2＋. The results showed that the adsorption efficiency increased with the increase ofpH and reached its maximum at pH 7; when the strain dosage and the initial concentrate of Cd^2＋ were 4.0g·L^-1 and 20mg·L^-1, respectively, the adsorption efficiency reached 89.45% and 93.12%, respectively. The adsorption pattern of Cd^2＋ on Citrobacter freudii was in accordance with Langmuir and Freundlich isotherm, but the Langrnuir isotherm is better.