Comparing the removal of heavy metals cadmium and nickel by bacteria isolated from the wastewater of steel industry factories and investigating the effective parameters in their removal and studying the RSM response surface methodology

Document Type : Research Article


1 department of microbiology, University of Mzanadran

2 department sea physices, university of mazandaran

3 nantes


Today, the environmental pollution by heavy metals has increased and the accumulation of these pollutants in water ecosystems has brought severe risks to the health of humans, animals, plants, and the environment. Cadmium and nickel are known as toxic and carcinogenic metals. In this research, the isolation of bacteria from the steel industry factory in Sari, the effluent of the sausage and sausage factory of Golestan province, Lavij hot spring in Mazandaran, which has the ability uptake cadmium and nickel, has been investigated. In the following, the optimization process of biological absorption (the effect of parameters such as: temperature, concentration of metals, dosage of bacteria, pH...) was investigated. Based on the above results, the best isolate is used to remove these metals. Biochemical, morphological, and molecular results have shown the closeness of the selected isolate to the genus Bacillus. According to the minimum inhibitory concentration test of selected Bacillus bacteria, it has shown resistance up to 1500 ppm of cadmium and 2200 ppm of nickel. The optimal pH for the removal of cadmium and nickel metals by the isolated bacteria is 6.5 and 5.5, respectively, and the biosorption efficiency of cadmium and nickel metals is 0.72 and 0.63 mmol/g, respectively. The temperature for the removal of cadmium and nickel by Bacillus bacteria is 45 degrees Celsius. The absorption isotherm for both metals is similar to the Langmuir isotherm, which shows that the surface absorption process is single-layer, and its kinetics is according to the second-order kinetic model, and the optimal dosage of Bacillus bacteria biomass is about 1.5 g/liter. The selected isolate has suitable characteristics for use in real and industrial scale containing the mentioned metals.


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