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Abstract Background The use of bacteria to synthesize nanoparticles as an environment-friendly method has recently been considered by researchers. Bacteria residing in different mines have shown high potential in the synthesis of metal nanoparticles due to their compatibility with the environment. The aim of this study was to evaluate the ability of Zarshouran gold mine bacteria to synthesize silver nanoparticles and their antibacterial activity. Methods After isolation of mine bacteria and several screening steps, silver ion tolerant bacteria that were able to synthesize extracellular silver nanoparticles were isolated and the most suitable isolate was selected and sequenced. The characteristics, stability, and production efficiency of silver nanoparticles were evaluated using UV–vis spectrophotometry, DLS, TEM, FTIR, and X-ray diffraction analysis. Finally, the antibacterial effect of silver nanoparticles against pathogenic bacteria was investigated. Results Among the eight silver-tolerant bacteria, isolate No. 6 had high antibacterial activity and high potential in the synthesis and stabilization of silver nanoparticles. Therefore, this isolate was selected for the next experiments. The results of 16S rDNA sequencing showed that this isolate is related to Bacillus pumilus. We registered in the NCBI Bank called ROM6 with access number MW440543. The DLS and TEM analysis showed that silver nanoparticles produced by this isolate were most spherical with a size of less than 25 nm and were stable for at least 180 days. The efficiency at concentrations less than 0.9 g/l silver nitrate was over 90% and the minimum inhibition concentration of nanoparticles was determined against S. aureus, E. coli, P. aeruginosa, and A. baumannii ranging from 1.4 to 5.6 µg/ml. Conclusion We found that the bacteria residing in the gold mine have a high capacity for the synthesis of spherical and high stable silver nanoparticles with a strong antibacterial effect.

Natural gas has wide range of acid gas concentrations such as CO2 and H2S. Alkanolamines dissolved in aqueous solutions are commonly employed to scrub CO2 and H2S from natural gas. As a result, the high level of this polutant is emitted through the waste water during cleaningIn this study a novel photocatalyst, TiO2@WO3/ZnO, has been designed and fabricated. To prepare the catalyst with the highest performance, the optimized weight fraction of WO3+Zno (with 1:4 weight ratio) has been alloyed with TiO2. The results from BET and BJH indicated that the synthesized catalyst had relatively high specific surface area (10.3 m² g-1) and mesopore structure with cavities diameter of 10.9 nm. The as-synthesized photocatalyst has been employed in the alkanolamine contaminant degradation of wastewater obtained from an industrial gas refinery plant in the presence of LED light. In this regard, the degradation of alkanolamine during time was monitored using UV-Vis and fluorescence spectroscopies. The obtained results confirmed high performance of the designed catalyst in the rapid treatment of the wastewater of gas refinery effluent at very low catalyst loading of only 0.5 wt.%, thereby making it a good candidate for the catalytic purposes. Finally, a possible mechanism for catalytic degradation of alkanolamine over TiO2@WO3/ZnO was suggested. [ABSTRACT FROM AUTHOR]