Methanotrophic physiology is strongly affected by the amount of bioavailable copper, which regulates the enzymes used by methanotrophs to oxidize methane. Methanobactin is a small peptide secreted by methanotrophic bacteria that binds copper outside of the bacterial cell. In this study, gold nanoparticles were firstly synthesized with citrate acid, followed by addition of methanobactin. Then as CuSO4was continuously added to the solution, we found a red shift in the Uv-vis absorption spectra. Meanwhile, for the mixture of methanobactin, 1,4-resorcinol and chlorauric acid, we also found an absorption at 540nm after 1h in dark. We presume that methanobactin has the bioactivity of protecting gold nanoparticles as well as delivering electron for the catalytic synthesis of gold nanoparticles. These molecules then go on to form gold nanoparticles. Gold nanoparticles can be seen with the naked eye, as they turn a gold solution from yellow/gold to a deep cranberry/red. The nanoparticles also display a characteristic absorbance of approximately 540 nm on absorption spectra.

A deep potassium-rich old brine in Hubei Province contains a large number of rubidium resource. Separation of rubidium is very difficult due to the similar physical and chemical properties of rubidium with the other coexisting alkali metals (potassium, sodium, and lithium). The process of extracting and separating Rb from the old brine with 4-tert-butyl-2-(α-methylbenzyl) phenol(t-BAMBP) as the extraction agent and sulfonated kerosene as diluents was systematically studied in this paper. The concentration of extraction agent, alkalinity of the old brine, phase ratio, the extracting time and other related factors were investigated. The optimal extraction conditions were obtained as follows: the concentration of t-BAMBP was 1.0mol/L, the concentration OH- was 0.6mol/L, the phase ratio was 3, the extraction time was 3 minutes. The percentage extraction of Rb could reach 91% for single-stage extraction, the separation coefficient of Rb and K reached up to 16.15. Sulfonated kerosene as diluent is non-toxic, high flash point, non-environmental pollution. A high extraction rate and separation factor for the development of rubidium resource of deep potassium-rich brine provided a reliable basis.