Towards efficient dye degradation and bactericidal behavior of Mo-doped La2O3 nanostructures

In this study, different concentrations (0, 0.02, 0.04 and 0.06 wt. %) of Mo doped onto La2O3 nanostructures were synthesized using one-pot co-precipitation process. The aim was to study the...

Optimization of the extraction and precipitation process of a leaf protein concentrate from Moringa oleifera Lam.

This study aimed to determine the best extraction and precipitation conditions of Moringa oleifera Lam. leaf protein. The influence of pH (10, 11, 12) and the concentration of NaCl (0, 0.25, 0.5) for the protein extraction process were studied through a Completely Randomized Design (CRD) with factorial arrange 32. The combination of pH 11 and 12 with 0 M NaCl had the best yield (P<0.05). The treatment of pH 11 without NaCl followed a precipitation stage for its purification, and the effect of different levels of pH (4, 4.5, 5) and temperature (40, 60, 80 °C) were evaluated using a CRD with factorial arrange 22 and 6 central points. The temperature did not affect the yield of the process in a significant way and the amount of precipitate was maximized at pH 4 and 4.5. From 100 g of the dry leaf, 7.26±0.19 g of protein was isolated with a recovery of 26.93±0.22 g 100 g-1 from the total protein. Due to their astringency and bitterness, consuming large amounts of Moringa oleifera Lam leaves is not a solution; therefore, obtaining a leaf proteinconcentrate could be useful for diverse applications in nutritional supplements, and as raw material for functional products development.

Development of a Methodology and Software Package for Predicting the Formation of Organic Deposits Based on the Results of Laboratory Studies

One of the main problems in the oil industry is the fallout of asphaltene–resin–paraffin deposits (ARPDs) during oil production and transportation. The formation of organic deposits leads to reduced equipment life and reduced production. Currently, there is no single methodology for the numerical simulation of the ARPD dropout process. The aim of our work was to obtain a correlation dependence characterizing the rate of wax growth over time for oils in the Perm Krai, depending on temperature, pressure, and speed conditions. Experimental data for 20 oil samples were obtained using a Wax Flow Loop installation that simulates fluid movement in tubing. The developed correlation was tested in 154 wells. The results of numerical modeling of the paraffin precipitation process made it possible to correct the inter-treatment period of scraping for 109 wells (71%), indicating the high accuracy of the developed approach.

Optimizing Solvent Selection and Processing Conditions to Generate High Bulk-Density, Co-Precipitated Amorphous Dispersions of Posaconazole

Co-precipitation is an emerging method to generate amorphous solid dispersions (ASDs), notable for its ability to enable the production of ASDs containing pharmaceuticals with thermal instability and limited solubility. As is true for spray drying and other unit operations to generate amorphous materials, changes in processing conditions during co-precipitation, such as solvent selection, can have a significant impact on the molecular and bulk powder properties of co-precipitated amorphous dispersions (cPAD). Using posaconazole as a model API, this work investigates how solvent selection can be leveraged to mitigate crystallization and maximize bulk density for precipitated amorphous dispersions. A precipitation process is developed to generate high-bulk-density amorphous dispersions. Insights from this system provide a mechanistic rationale to control the solid-state and bulk powder properties of amorphous dispersions.

Separation and Stabilization of Arsenic from Lead Slime by the Combination of Acid Leaching and Forming Scorodite

In this paper, a scheme is proposed for the treatment of arsenic-containing lead slime by the combination of acid pressure oxidation leaching and forming scorodite. On the basis of thermodynamic calculations, the effects of six factors including acid concentration, oxygen partial pressure (pO2), liquid to solid ratio (L/S), agitating speed, leaching time and temperature for the removal of arsenic were studied in an acid pressure oxidation leaching process, then the optimum leaching conditions were established: L/S of 10 mL/g, leaching time of 2.5 h, pO2 of 2.0 MPa, leaching temperature of 170 °C, acid concentration of 100 g/L and stirring speed of 300 r/min. Under the optimal conditions, the leaching rate of arsenic from lead slime reached 99.10% and the arsenic content of the leaching residue was about 0.80%. After a decontamination procedure, the total arsenic concentration in the acid solution obtained from leaching experiments was 37.18 g/L, and the initial pH was 0.50. Finally, as high as 98.5% of arsenic extracted from the lead slime was stabilized in the form of scorodite (FeAsO4·2H2O) by the precipitation process under the following conditions: initial pH value of 1.0, Fe(II)/As molar ratio of 1.3, pO2 of 2.5 MPa, temperature of 160 °C and precipitation time of 2.0 h.

Microbial Diversity of Bacteria Involved in Biomineralization Processes in Mine-Impacted Freshwaters

In order to increase the knowledge about geo-bio interactions in extreme metal-polluted mine waters, we combined microbiological, mineralogical, and geochemical analyses to study the indigenous sulfate-reducing bacteria (SRB) involved in the heavy metal (HM) biomineralization processes occurring in Iglesiente and Arburese districts (SW Sardinia, Italy). Anaerobic cultures from sediments of two different mining-affected streams of this regional framework were enriched and analyzed by 16S rRNA next-generation sequencing (NGS) technique, showing sequences closely related to SRB classified in taxa typical of environments with high concentrations of metals (Desulfovibrionaceae, Desulfosporosinus). Nevertheless, the most abundant genera found in our samples did not belong to the traditional SRB groups (i.e., Rahnella, Acinetobacter). The bio-precipitation process mediated by these selected cultures was assessed by anaerobic batch tests performed with polluted river water showing a dramatic (more than 97%) Zn decrease. Scanning electron microscopy (SEM) analysis revealed the occurrence of Zn sulfide with tubular morphology, suggesting a bacteria-mediated bio-precipitation. The inocula represent two distinct communities of microorganisms, each adapted to peculiar environmental conditions. However, both the communities were able to use pollutants in their metabolism and tolerating HMs by detoxification mechanisms. The Zn precipitation mediated by the different enriched cultures suggests that SRB inocula selected in this study have great potentialities for the development of biotechnological techniques to reduce contaminant dispersion and for metal recovery.

Geobiology of Andean Microbial Ecosystems Discovered in Salar de Atacama, Chile

The Salar de Atacama in the Chilean Central Andes harbors unique microbial ecosystems due to extreme environmental conditions, such as high altitude, low oxygen pressure, high solar radiation, and high salinity. Combining X-ray diffraction analyses, scanning electron microscopy and molecular diversity studies, we have characterized twenty previously unexplored Andean microbial ecosystems in eight different lakes and wetlands from the middle-east and south-east regions of this salt flat. The mats and microbialites studied are mainly formed by calcium carbonate (aragonite and calcite) and halite, whereas the endoevaporites are composed predominantly of gypsum and halite. The carbonate-rich mats and microbialites are dominated by Bacteroidetes and Proteobacteria phyla. Within the phylum Proteobacteria, the most abundant classes are Alphaproteobacteria, Gammaproteobacteria and Deltaproteobacteria. While in the phylum Bacteroidetes, the most abundant classes are Bacteroidia and Rhodothermia. Cyanobacteria, Chloroflexi, Planctomycetes, and Verrucomicrobia phyla are also well-represented in the majority of these systems. Gypsum endoevaporites, on the contrary, are dominated by Proteobacteria, Bacteroidetes, and Euryarchaeota phyla. The Cyanobacteria phylum is also abundant in these systems, but it is less represented in comparison to mats and microbialites. Regarding the eukaryotic taxa, diatoms are key structural components in most of the microbial ecosystems studied. The genera of diatoms identified were Achnanthes, Fallacia, Halamphora, Mastogloia, Navicula, Nitzschia, and Surirella. Normally, in the mats and microbialites, diatoms form nano-globular carbonate aggregates with filamentous cyanobacteria and other prokaryotic cells, suggesting their participation in the mineral precipitation process. This work expands our knowledge of the microbial ecosystems inhabiting the extreme environments from the Central Andes region, which is important to ensure their protection and conservation.