Nickel recovery from spent nickel catalyst.

A process for nickel recovery from a spent catalyst of definite composition has been developed using the hydro-metallurgical route. The processing steps includes direct sulphuric acid leaching followed by separation of iron as well as silica and other impurities. For a 152 microm particle size catalyst, extraction of about 98% nickel was achieved at 363 K in 2 h using a sulphuric acid concentration (v/v) of 8% and a pulp density of 10%. The dissolution of nickel followed diffusion-controlled leaching kinetics. Increase in temperature and sulphuric acid concentration resulted in increase in the nickel recovery. The activation energy for nickel dissolution was calculated to be 62.8 kJ mol(-1). Finally, nickel was recovered as value-added products such as sulphide and oxalate with overall recovery of 90 and 88% of nickel, respectively.     

Microbial decolorization and bioremediation of melanoidin containing molasses spent wash

Molasses spent wash from cane-molasses based distilleries contains a brown coloured recalcitrantpolymer melanoidin, which if disposed untreated poses a great threat to environment. Microbial decolorization and chemical oxygen demand (COD) reduction was found to be dependent on specific carbon and nitrogen source. Under optimal condition of pH, carbon and nitrogen concentration for each treatment, it was found that Bacillus sp isolated from soil was capable of removing COD (85. 35%) and colour (81.10%) from distillery waste to the maximum extent after 9 days atpH 7 in the medium containing 0.5% peptone, 2% glucose and 10% (v/v), followed by Phanerochaete chrysosporium and lowest reduction was obtained by using native microbial consortium.     

Impact of cadmium and lead on Catharanthus roseus--a phytoremediation study

The Madagascar Periwinkle, Catharanthus roseus (L.) G. Don (a valued medicinal plant) was exposed to different concentrations ofheavymetals like, CdCl, and PbCl, with a view to observe their bioaccumulation efficiency. Germination was inhibited by both the heavy metals in the seeds previously imbibed in GA, and KNO, for 24 hr. EC50 (the effective concentration which inhibits root length by 50%) was recorded as 180 microM for CdCl2, and 50 microM for PbCl2. Both alpha-amylase and protease activity were reduced substantially on treatment of seeds with increasing concentrations of CdCl2, and PbCl2. Malondialdehyde (MDA) a product of lipoxigenase (LOX) activity also increased due to the treatment of both CdCl, and PbCl2. When two-months-old plants grown in normal soil were transferred to soils containing increasing amounts of these two heavy metals, senescence of lower leaves and extensive chlorosis were noticed after four days of transfer However, plants gradually acclimatized and after 20 days the chlorophyll content was almost comparable to normal. Plants receiving CdCl2 treatment (250 microg g(-1) and less) became acclimatized after two weeks and started normal growth. But PbCl2 of 432 microg g(-1) and less could not affect the plant growth throughout, after a preliminary shock was erased. In case of CdCl2 treatment, a stunted growth with reduced leaf area, reduced biomass and sterility were recorded after six months, while plants show normal growth and flowering in case of PbCl2 treatment. Total alkaloid was also found to be decreased in the roots of CdCl2 treated plants. No change was observed in case of PbCl2. GA3 treatments to the CdCl2 treated plants show internode elongation and increase in leaf area with relatively elongated leaves and thinning of stem diameter AAS analyses of leaves of treated plants exhibited 5-10% accumulation of cadmium, but there was no accumulation of lead at all.     

Modelling fertility: an application of count regression models

Often the lifecycle data occur as count of the vital events and are recorded as integers. The purpose of this article is to model the fertility behavior based on religious, educational, economic, and occupational characteristics. The responses of classified groups according to these determinants are examined for significant influence on fertility using Poisson regression model (PRM) based on the National Family Health Survey -3 dataset. The observed and predicted probabilities under PRM indicate modal value of two children for the Poisson distribution modeled data. Presence of dominance of two child in the data motivates the authors to adopt multinomial regression model (MRM) in order to link fertility with various socioeconomic indicators responsible for fertility variation. Choice of the explanatory factors is limited to the availability of data. Trends and patterns of preference for birth counts suggest that religion, caste, wealth, female education, and occupation are the dominant factors shaping the observed birth process. Empirical analysis suggests that both the models used in the study perform similarly on the sample data. However, fitting of MRM by taking birth count of two as comparison category shows improved Akaike information criterion and consistent Akaike information criterion values. Current work contributes to the existing literature as it attempts to provide more insight into the determinants of Indian fertility using Poisson and MRM.     

Effect of nickel-stresses on uptake, pigments and antioxidative responses of water lettuce, Pistia stratiotes L

Water lettuce plants were exposed to various concentrations (0, 0.01,0.1, 1.0 and 10.0 ppm) of nickel as nickel sulphate in nutrient medium. The effect of graded nickel (Ni +2) concentrations on visible symptoms of toxicity, pigments (chlorophyll a, b and total) and antioxidative attributes were evaluated. Plants exposed to high nickel (1.0 and 10.0 ppm) showed visible toxicity symptoms, such as wilting, chlorosis in young leaves, browning of root tips and broken off roots, observed at 6 days after treatment. Nickel was accumulated more in root (863.3 microg g-1 dry weight) than leaves (116.2 microg g-1 dry weight) at 6 days of treatment. Nickel exposure decreased chlorophyll a, b and total chlorophyll contents. Relative water content decreased at high nickel (1.0 and 10.0 ppm).Antioxidants, such as proline content and peroxidase activity increased with increase in nickel concentrations, whereas, other carotenoids and protein contents at 1.0 ppm and activity of catalase at 10 ppm of nickel were decreased. The low level of nickel stimulates photosynthetic pigments and antioxidative attributes. The study may be helpful in phytoremedial strategies and biological indication of nickel toxicity in aquatic plants.     

Characteristics of chlorofluorocarbons (CFCs) emitted from a municipal waste treatment facility

The emission concentrations of several chlorofluorocarbons (CFCs) were measured from a municipal waste treatment facility (located in Seoul, Republic of Korea) to investigate the emission characteristics of CFCs in the urban environment. To this end, a total of five CFCs (CFC-10, CFC-11, CFC-20, CFC-30, and CFC-113) were analyzed by the thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) method. The results of this study indicate that the formation of CFC-11 (8.21 ± 1.68 ppb in spring) and CFC-20 (3.92 ± 3.93 ppb in spring) proceeded very actively within the facility. Moreover, CFC-113 was also found in relatively high concentrations (3.34 ± 1.31 ppb in spring) in the treatment facility. Unlike other CFCs, CFC-10 was observed mainly at ambient (and reference) locations and one point inside the treatment facility. In conclusion, emissions of some important CFCs are a prominent process, as they were measured either frequently or abundantly both in winter and spring. It is further indicated that certain CFCs (like CFC-11 and CFC-30) are subject to highly significant seasonal variations.     

Management of root knot nematode on tomato through application of fungal antagonists, Acremonium strictum and Trichoderma harzianum

Management of root knot nematode disease infecting tomato, by the use of fungal bioagents Acremonium strictum and Trichoderma harzianum isolated from egg masses of M. incognita infecting tomato has been carried out. The rhizosphere and rhizoplane of root knot nematode infested tomato revealed consistent association of Acremonium strictum. In the present study A. strictum and other fungal bioagents viz. Aspergillus niger, Paecilomyces lilacinus, Rhizoctonia solani and Trichoderma harzianum isolated earlier from egg-masses of M. incognita, identified and maintained have been investigated through in-vitro and in-vivo trials for their potentiality against M. incognita. Out of the above, isolated mycoflora A. niger was identified to be toxic against M. incognita while A. strictum and T. harzianum was found to possess both egg parasitic or opportunistic and toxic properties. A field trial with all the above fungal bioagents both alone and together showed significant promising performance by the dual treatment of A. strictum and T. harzianum in improving the health of the tomato plant with a remarkable reduction in M. incognita population.     

Discussion of “Mahmodinia,S., & Javan,M. (2021). Vortical structures,entrainment and mixing process in the lateral discharge of the gravity current. Environmental Fluid Mechanics, 21(5), 1035–1067”

Environmental Fluid Mechanics - The authors of the discussed paper presented an interesting study of the lateral gravity currents for the different flow conditions. The authors showed the...     

Management of disease complex caused by root knot nematode and root wilt fungus on pigeonpea through soil organically enriched with Vesicular Arbuscular Mycorrhiza, karanj (Pongamia pinnata) oilseed cake and farmyard manure

This investigation was undertaken to compare the percentage response of colonization and development of VA-Mycorrhiza (Glomus fasciculatum) on a number of pulse crops viz. cowpea, chickpea, soybean, pigeonpea and lentil under glasshouse conditions. Among the above-mentioned crops, pigeonpea exhibited the best performance and was selected for further studies. In this host the development and colonization percentage of G. fasciculatum was investigated under two separate substrates i. e. soil amended with FYM and karanj oilseed cake keeping a control treatment of field soil. A third treatment amended with karanj oilseed cake and farm yard manure (FYM) was also kept which responded best in terms of colonization percentage. This treatment showing improved plant health as well as integration with G. fasciculatum was selected as an ideal treatment for the management of disease complex caused by root knot nematode, Meloidogyne incognita and root wilt fungus, Fusarium udum on pigeonpea. Thus the treatment constituting FYM, karanj oilseed cake and VA-Mycorrhiza reduced the disease incidence caused by both maladies to a great extent with the most promising improvement in plant growth parameters as compared to all others. The present investigation, in addition to proposing an ideal eco-friendly treatment for the management of this disease complex also proposed an excellent medium for the proliferation of the obligate bio-protectant, G. fasciculatum.     

Microbial biomass, P-nutrition, and enzymatic activities of wheat soil in response to phosphorus enriched organic and inorganic manures

Compost was prepared from wheat straw enriched with Rajasthan rock phosphate and Aspergillus awamori. The resulting phospho-compost along with phosphorus enriched FYM, mineral fertilizer (rock phosphate) and super phosphate were evaluated for their individual contribution in improving organic matter status, P availability, and enzymatic activities of soil under wheat crop grown in a micro plot. The results showed that total organic carbon, nitrogen, microbial biomass, and humus content (an index of organic matter status of soil) of soil was highest when farm yard manure (FYM) after its enrichment with 12.5% rock phosphate was applied. Microbial enriched phospho-compost was the product yielding highest soil available phosphorus, phosphorus uptake, urease, and cellulase activities. However, FYM amended with 25% rock phosphate resulted in the greatest enhancement of beta- glucosidase. Measured parameters indicated a sure improvement of chemical and biological activities of soil after the application of phosphorus enriched organic amendments compared to the commercial fertilizer commonly used by the Indian farmers.