Role of aerosols in deciding pH of rainwater

Nature of precipitation – alkaline or acidic – depends upon the concentration of major water soluble inorganic gaseous and soil derived particulates dissolved in it. If concentration of cations is higher than that of anions, the precipitation becomes alkaline and vise-a-versa. pH is the main parameter indicating the nature of precipitation. If pH of the solution is < 5.65, it is acidic and > 5.65, alkaline, in the pH scale ranging between 0 & 14. Difference in the chemical composition of rainwater having pH in the alkaline range and acidic range has been studied in this paper. For this purpose, precipitation chemistry data of Allahabad, Jodhpur, Mohanbari and Nagpur for the period 1988-97 have been considered. APWM & S.D. have been worked out. Precipitation chemistry data considering APWM values in acidic range and in alkaline range have been separated and compared. Coefficients of correlation have been calculated in possible cation-anion combinations. It is seen that the lowest pH values (monthly mean) have been recorded during 1997 – MHB (3.77), NGP (4.12), both in acidic range. % Frequency of occurrences of pH values in acidic range was the highest at Mohanbari (66%) in the study period. Jodhpur recorded all pH values in alkaline range indicating influence of soil derived alkaline particulates. Among cations Ca+² has shown its dominance over all cations. Jodhpur has recorded the highest APWM value of Ca+² (9.27mg/lit) in 1997. Data have also been compared with WMO Laboratory simulated acid rain sample analysis data and other non-departmental data. Results are discussed in the paper.

Purified proteases of two Antarctic bacteria: from screening to characterization

Proteases are widely used in industrial processes, and the discovery of new, more kinetically efficient proteases can have a positive impact on industry. Enzymes from Antarctic microorganisms exhibit cold-adaptive properties, making them useful in biotechnology. The cold and harsh environment of Antarctica makes it a valuable source for new biotechnologically related enzymes. In this study, we characterized two cold-adapted proteases purified from Pseudoalteromonas issachenkonii P14M1-4 and Flavobacterium frigidimaris ANT34-7, isolated from King George Island, Antarctica, and compared these with proteases from the non-cold-adapted bacteria Bacillus licheniformis and Geobacillus stearothermophilus. The best temperature growing conditions were used for protease purification and characterization. The protease from P. issachenkonii P14M1-4 was identified as a 40–43 kDa metal-dependent subtilisin-like serine protease and the protease from F. frigidimaris ANT34-7 was identified as a 28 kDa metalloprotease. The enzymes showed an optimum temperature of between 35°C and 40°C and an optimum pH in the neutral to alkaline range. Their activation energies, catalytic constants and growth capacities at different temperatures categorize them as cold-adapted enzymes. We conclude that the characteristics exhibited by these proteases make them useful for biotechnological purposes requiring high activity at low temperatures. Moreover, to the best of our knowledge, this is the first characterization of a cold-adapted protease from F. frigidimaris.

Рathogenetic methods of therapy using medicinal-table mineral water

The pathogenetic rationale for the use of «Prolom Voda» produced in the Republic of Serbia is presented. Research conducted at the accredited testing center of natural healing resources of the Federal State Budgetary Institution «Russian Scientific Center for Restorative Medicine and Balneology» of the Ministry of Health of Russia 9 accreditation certificate No. pH in the alkaline range.

Extraction of Protein Isolates From Grouper (Epinephelus Diacanthus) Filleting Waste Using pH Shift Method; Influence of Process Variables on Recoveries

Recovery of proteins from grouper (Epinephelus diacanthus) filleting waste was done using isoelectric solubilization method. During the isolation, influence of process variables such as; temperature, ratio of solvent and homogenate, pH, time of centrifugation and speed of centrifugation on protein yields was studied. It was observed that the homogenate to solvent ratio, centrifugation speed protein recoveries. For isolating the proteins from grouper waste using pH shift process the optimum conditions found were; pH-11.0 in alkaline range, pH 3.0 in acidic range, 120 min extraction time, homogenate to solvent ratio of 1:6 and centrifugation speed of 10000 rpm. During the pH shift processing of grouper proteins myoglobin, total pigments and lipid content of proteins were reduced by 90.77, 70.79 and 82.69%, and 93.91, 79.59 and 82.04%, in alkaline and acidic extraction process, respectively. A significant increase in the lightness and whiteness values of the isolates was observed as compared to the raw material. Protein isolates obtained using acidic solubilisation process were found to be whiter than alkali-aided protein isolate.

Effect of pH in the Hydrothermal Preparation of Bi2WO6 Nanostructures

In this study, Bi2WO6 was prepared by the hydrothermal method. The effects of reaction temperature (150/170/200 °C) and reaction time (6/12/24 h) were investigated. The role of strongly acidic pH (1 >) and the full range between 0.3 and 13.5 were studied first. Every sample was studied by XRD and SEM; furthermore, the Bi2WO6 samples prepared at different temperatures were examined in detail by EDX and TEM, as well as FT-IR, Raman and UV-vis spectroscopies. It was found that changing the temperature and time slightly influenced the crystallinity and morphology of the products. The most crystallized product formed at 200 °C, 24 h. The pure, sheet-like Bi2WO6, prepared at 200 °C, 24 h, and 0.3 pH, gradually transformed into a mixture of Bi2WO6 and Bi3.84W0.16O6.24 with increasing pH. The nanosheets turned into a morphology of mixed shapes in the acidic range (fibers, sheets, irregular forms), and became homogenous cube- and octahedral-like shapes in the alkaline range. Their band gaps were calculated and were found to vary between 2.66 and 2.59 eV as the temperature increased. The specific surface area measurements revealed that reducing the temperature favors the formation of a larger surface area (35.8/26/21.6 m2/g belonging to 150/170/200 °C, respectively).

Near-infrared fluorescent aza-BODIPY dyes for sensing and imaging of pH from the neutral to highly alkaline range

New aza-BODIPY pH indicators with spectral properties modulated solely by photoinduced electron transfer (PET) are presented.

Detection of Ammonia Based on Stimuli-Responsive Hydrogels

This article describes an ammonia-responsive hydrogel based on acrylic acid (AAc) and 2-(dimethylamino)ethyl methacrylate (DMAEMA). The influence of the hydrogel composition on swelling behavior in the alkaline range was shown. Furthermore, the hydrogel swelling in ammonia solutions was tested and a detection limit in the range of 1 mmol/L ammonia in dependence of the buffer solution was determined.

Sorption of rare-earth erbium from aqueous solution onto sol-gel-derived zirconia

Zirconia powder was synthesized via sol gel method and used for erbium sorption. The adsorption is strongly dependent on pH of the medium where the removal efficiency increases as the pH turns to alkaline range. The process was very fast initially and maximum adsorption was attained within 60 min of contact. Pseudo-second-order model and homogeneous particle diffusion model (HPDM) was found to be the best to correlate the diffusion of erbium into zirconia particles. Adsorption thermodynamic parameters were calculated. Erbium adsorption is an endothermic (?H > 0) and good affinity of erbium ions towards the zirconia (?S > 0).