Bacillus sp. SL合成硒纳米颗粒吸附染料动力学研究

Research on kinetics of dye adsorption using SeNPs synthesized by Bacillus sp. SL

考察了由Bacillus sp. SL合成的硒纳米颗粒(SeNPs)吸附染料特性.菌株SL合成的SeNPs以球形为主,粒径为100~200 nm.选用阴离子染料刚果红和阳离子染料亚甲基蓝作为底物.亚甲基蓝在碱性条件下更易被吸附,酸性条件更适合刚果红的吸附.准二级动力学模型能更好地描述SeNPs对两种染料的吸附过程(R2>0.99).吸附等温线更符合Langmuir模型.318 K时,刚果红和亚甲基蓝的最大吸附量分别为1 158.30 mg/g和1 721.10 mg/g.该吸附过程自由能变化(ΔG)小于零,焓变(ΔH)及熵变(ΔS)均大于零.CaCl2处理后的SeNPs在5次循环后,对刚果红的吸附率保持在80%以上,对亚甲基蓝的吸附率下降到38%.综上,菌株SL合成的SeNPs对刚果红和亚甲基蓝表现出良好的吸附性能和重复利用性能,是有潜力的微生物合成的染料吸附剂.

The adsorption properties of selenium nanoparticles(SeNPs) synthesized by Bacillus sp. SL on anionic dye Congo Red and cationic dye Methylene Blue are investigated. The SeNPs synthesized by strain SL are mainly spherical, with particle size of 100-200 nm. Methylene Blue is more easily adsorbed under alkaline conditions, and acidic conditions are more suitable for the adsorption of Congo Red. The two adsorption processes could be better described by pseudo-second-order kinetic model(R~2>0.99). The adsorption isotherm is more consistent with Langmuir model. At 318 K, the maximum adsorption capacity of Congo Red and Methylene Blue is 1 158.30 mg/g and 1 721.10 mg/g, respectively. The free energy change(ΔG) is less than zero, while enthalpy change(ΔH) and entropy change(ΔS) are both greater than zero. The adsorption rate of Congo Red remains 80% using SeNPs treated with CaCl2after 5 cycles, and the adsorption rate of Methylene Blue decreases to 38%. In conclusion, SeNPs synthesized by strain SL exhibit good adsorption and reuse ability for Congo Red and Methylene Blue, which are potential dye adsorbents synthesized by microorganisms.