The Optimal Conditions For Removing Methylene Blue By Bacillus C412 And Its Mechanism

Even though China's total water resources are abundance,the huge population and uneven geographical distribution of fresh water resources is making China become one of the serious water shortage countries.Nowadays in China,the shortage of water resources and the water crisis caused by pollution had become a major problem.Among them,the pollution of dyes to water body is particularly serious,hence finding suitable methods to control the pollution of dyes to water has attracted more and more attention.Methylene blue(MB)is a soluble cationic dye and a serious pollutant that is widely used in textile industry.In this work,Bacillus methylotrophicus C412 was used as a microorganism to treat methylene blue wastewater.The main research contents are shown as follows:1.The optimum methylene blue removal condition was found by single factor and optimization experiment,under the condition that the concentration of methylene blue 25 mg/L,the OD600 of the initial cell inoculation dosage 0.18,pH 7.63 and fermentation time 12 h.Under this condition,methylene blue removal rate can reach 92.14%.2.Using polyvinyl alcohol mixed sodium alginate-embedded Fe3O4 and activated carbon to make sustained-release material.The sustained-release material has good adsorption and desorption ability for methylene blue.The adsorption kinetic model accords with the quasi-second-order kinetic model.Using the material to adsorb methylene blue to extract the ratio of the sustained-release materials according to different methylene blue concentrations.Namely,when the methylene blue solution of 250 mg/L is adsorbed,the sustained-release materials used are made from 50 g/L polyvinyl alcohol,5 g/L sodium alginate,0.055 g Fe3O4 and 0.01 g activated carbon,the total volume was 10 mL.While the methylene blue solution of 500 mg/L is adsorbed,the use of the sustained-release material by the 50 g/L of polyvinyl alcohol,5 g/L Sodium alginate is embedded 0.055 g Fe3O4 and 0.02 g activated carbon the total volume was 10 mL,too.3.The use of molasses waste liquid as the main source of carbon source to find a suitable low-cost medium allocation method,namely:molasses waste liquid content 5%,2.5 g/L molasses,1 g/L beef paste,3 g/L(NH4)2SO4,1 g/L NaCl,0.05 g/L MgS04 · 7H20,5 g/L K2HP04,2 g/L KH2PO4(pH = 7),the medium can be cultured C412 efficiently.Moreover,the cultured somatic cells also have good methylene blue removal ability,and the high concentration of bacteria cells can shorten the time of methylene blue removal.The methylene blue in the high concentration methylene blue wastewater was transferred to the culture medium by using sustained-release materials.The C412 was used to removal methylene blue,and the methylene blue in the medium was removed with a continuous 13 cycles to 90%of the total methylene blue removal rate.4.The mechanism of methylene blue removal was obtained by high performance liquid chromatography and real-time fluorescence quantitative PCR.First,the methylene blue in solution is adsorbed to the inside of the cells through the adsorption of the somatic cells.Then,the synergistic action of the superoxide dismutase,the heme peroxidase,the catalase,the acireductone dioxygenase and the laccase was finally achieved by methylene blue.