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Item type:Publication, Removal of heavy metals using a wetland batch system with Carrizo (Phragmites Australis)(Research Square, 2020-11-09)Abstract One of the greatest environmental issues related to the development of the mining activity is the generation of Acid Mine Drainage (AMD). This effluent generated by active and abandoned mines in Peru produces multiple discussions about the role of the industry for a sustainable development. Many methods have been developed for AMD treatment, being wetlands a good option for heavy metal removal. In this sense, removal of heavy metal by using laboratory constructed wetlands with Phragmites Australis was studied. During a 9-day period the variation of different physicochemical parameters and heavy metals concentrations was recorded. The pH decreased to a constant value of 8.24 after the sixth day. The electrical conductivity presented a slight variation from 1 to 1.33 µS cm-1 on the ninth day. Moreover, fluctuating values of Dissolved Oxygen and Turbidity were observed. A reduction between 69% and 93% of ammonia nitrogen (NH3-N) was registered. Cu concentration was reduced in 68% and 87%; Zn concentrations dropped in 53% and 95%; and Pb was reduced in 20% and 55%. It was concluded that Phragmites Australis can be an alternative in the treatment of the contaminants produced by AMD. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Removal of heavy metals using a wetland batch system with carrizo (Phragmites australis (Cav.) Trin. ex Steud.): a laboratory assessment(Elsevier, 2021-08-16)One of the greatest environmental issues related to the development of the mining activity is the generation of Acid Mine Drainage (AMD). This effluent generated by active and abandoned mines in Peru produces multiple discussions about the role of the industry for a sustainable development. Many methods have been developed for AMD treatment, being wetlands a good option for heavy metal removal. In this sense, removal of heavy metal by using laboratory constructed wetlands with phragmites australis (cav.) trin. ex steud. was studied. During a 9-day period the variation of different physicochemical parameters and heavy metals concentrations was recorded. The pH decreased to a constant value of 8.24 after the sixth day. The electrical conductivity presented a slight variation from 1 to 1.33 μS cm−1 on the ninth day. Moreover, fluctuating values of Dissolved Oxygen and Turbidity were observed. A reduction between 69% and 93% of ammonia nitrogen (NH3-N) was registered. Cu concentration was reduced in 68% and 87%; Zn concentrations dropped in 53% and 95%; and Pb was reduced in 20% and 55%. It was concluded that phragmites australis (cav.) trin. ex steud. can be an alternative in the treatment of the contaminants produced by AMD. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Effect of the concentration and the type of dispersant on the synthesis of copper oxide nanoparticles and their potential antimicrobial applications(American Chemical Society, 2021-07-27)High Resolution Image Download MS PowerPoint Slide The bactericidal properties of copper oxide nanoparticles have growing interest due to potential application in the medical area. The present research investigates the influence of sodium dodecyl sulfate (SDS) and poly(vinylpyrrolidone) (PVP) on the production of copper oxide nanoparticles prepared from copper sulfate (CuSO 4 ) and sodium borohydride (NaBH 4 ) solutions. Different analytical techniques were used to determine the crystal nature, mean size diameter, and surface morphology of the copper oxide nanoparticles. The X-ray diffraction (XRD) patterns showed formation of nanoparticles of cuprite (Cu 2 O) and tenorite (CuO) when PVP and SDS were added at the beginning of the reaction. In fact, when the Cu/PVP ratio was 1.62, Cu 2 O nanoparticles were obtained. In addition, nanoparticles of CuO were synthesized when the Cu/PVP ratios were 0.54 and 0.81. On the other hand, a mixture of copper oxides (CuO and Cu 2 O) and cuprite (Cu 2 O) was obtained when PVP (Cu/PVP = 0.81 and 1.62) and SDS (Cu/SDS = 0.90) were added 30 min after the beginning of the reaction. Transmission electron microscopy (TEM) images show agglomerated nanoparticles with a size distribution ranging from 2 to 60 nm, while individual particles have sizes between 4.1 ± 1.9 and 41.6 ± 12.8 nm. The Kirby–Bauer method for the determination of antibacterial activity shows that small CuO (4.1 ± 1.9 nm) and Cu 2 O (8.5 ± 5.3 nm) nanoparticles inhibit the growth of Escherichia coli, Staphylococcus aureus MRSA, S. aureus and Pseudomonas aeruginosa bacteria. The antibacterial test of cotton fabric impregnated with nanoparticles shows positive results. The determination of the optimal ratio of copper oxide nanoparticles per cm 2 of fabric that are able to exhibit a good antibacterial activity is ongoing.1 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Effect of pH and ammonia concentration on the shape and size of fluorapatite nanoparticles obtained by chemical reaction(Elsevier, 2021-11-15)Nanoparticles of fluorapatite (FAp Nps) were prepared by one step chemical reaction in aqueous solutions. The pH of the system was kept constant at 6 and 8. The FAp Nps were characterized with Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDAX), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). The Ca/P calculated from EDAX analysis was 1.69. The results of XRD analysis and FTIR showed the presence of FAp phases. The DRX results confirm the formation of FAp with a hexagonal structure. TEM images show semispherical and elongated nanoparticles with mean diameter of 3.78 nm, 8.63 nm and 10.46 nm, when the pH and ammonia concentrations is varied. Ammonia concentration and pH influence the morphology and size of the FAp Nps. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Copper oxide nanoparticles doped with lanthanum, magnesium and manganese: Optical and structural characterization(Royal Society Publishing, 2022-11-16)Copper oxide (Cu 2 O) is a promising semiconductor for photovoltaic and photocatalytic applications since this material has a high optical absorption coefficient and lower band gap (2.17 eV). Doped lanthanum (La), magnesium (Mg) and manganese (Mn) Cu 2 O nanoparticles (Cu 2 O Nps) were prepared by a displacement reaction. The doped and undoped Cu 2 O Nps were characterized with scanning electron microscopy-energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), transmission electron microscopy (TEM) and ultraviolet-visible spectroscopy. The EDS results confirm the presence of La, Mg and Mn in the Cu 2 O Nps. The XRD results confirm the formation a single cubic phase of Cu 2 O with a cuprite structure. TEM images confirm the formation of Nps with mean diameters between 12.0 ± 6.1 and 30.8 ± 11.0 nm. Doped and undoped Nps present a narrow band gap (2.40 eV), blue shifted with respect to bulk Cu 2 O. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Schoenoplectus californicus as potential remover of metal elements from mine effluents: A laboratory assessment(Wiley, 2022-11-30)Acid mine drainage (AMD) is one of the most significant environmental challenges facing the mining industry worldwide. For this reason, many methods for AMD treatment are developed, being wetlands a good option for metal elements removal from these mining effluents. The efficiency of Peruvian native plants such as Schoenoplectus californicus ( S. californicus ) to remove metal elements in effluents through artificial wetlands is studied. Batch removal tests are carried out with different effluents containing copper, zinc, lead, and iron. For iron‐metal binary effluents, copper, zinc, and lead are removed by 82%, 75%, and 88%; while in the effluent containing all metals, the removal rate is 90% and 92% for copper and lead, respectively. According to the preliminary results, it is concluded that iron interferes more in the removal of zinc and lead than in copper from binary effluents. The use of S. californicus turns out to be an efficient, attractive, and economical alternative for the treatment of effluents contaminated with copper, zinc, lead, and iron. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Assessment of Natural Radioactivity and Radon Exhalation in Peruvian Gold Mine Tailings to Produce a Geopolymer Cement(MDPI, 2023-03-01)Mining generates significant amounts of waste that can represent a source of contamination for areas close to the extraction area, generating a negative impact both on the environment and the health of people. This study aims to evaluate the radiological risk derived from exposure to natural radionuclides contained in tailings from Peruvian gold mines and to establish whether the tailings can be used as raw materials in building materials. The mine tailings come from a mining project in the northern highlands of Peru. Radon exhalation was measured using Rad7 in a closed chamber and activity concentration of 226Ra, 232Th, and 40K radioisotopes by gamma spectrometry using NaI 3” × 3” detector. Maximum activity concentrations measured for 226Ra and 232Th were 15.38 Bq kg−1 and 11.9 Bq kg−1, respectively; meanwhile, activity concentration for 40K ranged from 182.7 Bq kg−1 to 770.8 Bq kg−1. All activity concentrations were below the worldwide average except for 40K. The radon exhalation rate varied from 2.8 to 7.2 mBq kg−1 h−1. The gamma index (Iγ), and radiological parameters, including the Radium equivalent activity (Raeq), and the external hazard index (Hex), being below the recommended levels by UNSCEAR, ensure the safe use of these mines tailing to produce a geopolymer cement.