Removal of Pb(II) from aqueous solution by a zeolite–nanoscale zero-valent iron composite

The effectiveness of nanoscale zero-valent iron (nZVI) to remove heavy metals from water is reduced by its low durability, poor mechanical strength, and tendency to form aggregates. A composite of zeolite and nanoscale zero-valent iron (Z–nZVI) overcomes these problems and shows good potential to remove Pb from water. FTIR spectra support nZVI loading onto the zeolite and reduced Fe0 oxidation in the Z–nZVI composite. Scanning electron micrographs show aggregation was eliminated and transmission electron micrographs show well-dispersed nZVI in chain-like structures within the zeolite matrix. The mean surface area of the composite was 80.37 m2/g, much greater than zeolite (1.03 m2/g) or nZVI (12.25 m2/g) alone, as determined by BET-N2 measurement. More than 96% of the Pb(II) was removed from 100 mL of solution containing 100 mg Pb(II)/L within 140 min of mixing with 0.1 g Z–nZVI. Tests with solution containing 1000 mg Pb(II)/L suggested that the capacity of the Z–nZVI is about 806 mg Pb(II)/g. Energy-dispersive X-ray spectroscopy showed the presence of Fe in the composite; X-ray diffraction confirmed formation and immobilization of Fe0 and subsequent sorption and reduction of some of the Pb(II) to Pb0. The low quantity of Pb(II) recovered in water-soluble and Ca(NO3)2-extractable fractions indicate low bioavailability of the Pb(II) removed by the composite. Results support the potential use of the Z–nZVI composite in permeable reactive barriers

Removal of Pb(II) from aqueous solution by a zeolite–nanoscale zero-valent iron composite

The effectiveness of nanoscale zero-valent iron (nZVI) to remove heavy metals from water is reduced by its low durability, poor mechanical strength, and tendency to form aggregates. A composite of zeolite and nanoscale zero-valent iron (Z–nZVI) overcomes these problems and shows good potential to remove Pb from water. FTIR spectra support nZVI loading onto the zeolite and reduced Fe0 oxidation in the Z–nZVI composite. Scanning electron micrographs show aggregation was eliminated and transmission electron micrographs show well-dispersed nZVI in chain-like structures within the zeolite matrix. The mean surface area of the composite was 80.37 m2/g, much greater than zeolite (1.03 m2/g) or nZVI (12.25 m2/g) alone, as determined by BET-N2 measurement. More than 96% of the Pb(II) was removed from 100 mL of solution containing 100 mg Pb(II)/L within 140 min of mixing with 0.1 g Z–nZVI. Tests with solution containing 1000 mg Pb(II)/L suggested that the capacity of the Z–nZVI is about 806 mg Pb(II)/g. Energy-dispersive X-ray spectroscopy showed the presence of Fe in the composite; X-ray diffraction confirmed formation and immobilization of Fe0 and subsequent sorption and reduction of some of the Pb(II) to Pb0. The low quantity of Pb(II) recovered in water-soluble and Ca(NO3)2-extractable fractions indicate low bioavailability of the Pb(II) removed by the composite. Results support the potential use of the Z–nZVI composite in permeable reactive barriers

Cottonseed Oilcake Extract Mediated Green Synthesis of Silver Nanoparticles and Its Antibacterial and Cytotoxic Activity

Agroindustrial byproduct mediated green synthesis of silver nanoparticles was carried out using cottonseed oilcake (CSOC) extract. The aqueous silver nitrate formed stable silver nanoparticles with CSOC extract as a reducing agent for Ag+ to Ag0. The synthesized nanoparticles were characterized using energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) techniques. The synthesized silver nanoparticles (AgNPs) (4 mM) significantly inhibited the growth of phytopathogens, Pseudomonas syringae pv. actinidiae and Ralstonia solanacearum. Further, cytotoxicity of AgNPs was evaluated using rat splenocyte cells. The splenocyte viability was decreased according to the increasing concentration of AgNPs and 90% of cell death was observed at 100 μg/mL

Characterization of a mercury-reducing Bacillus cereus strain isolated from the Pulicat lake sediments, south east coast of India

Pulicat Lake sediments are often severely polluted with the toxic heavy metal mercury. Several mercury-resistant strains of Bacillus species were isolated from the sediments and all the isolates exhibited broad spectrum resistance (resistance to both organic and inorganic mercuric compounds). Plasmid curing assay showed that all the isolated Bacillus strains carry chromosomally borne mercury resistance. Polymerase chain reaction and southern hybridization analyses using merA and merB3 gene primers/probes showed that five of the isolated Bacillus strains carry sequences similar to known merA and merB3 genes. Results of multiple sequence alignment revealed 99% similarity with merA and merB3 of TnMERI1 (class II transposons). Other mercury resistant Bacillus species lacking homology to these genes were not able to volatilize mercuric chloride, indicating the presence of other modes of resistance to mercuric compounds

A comparative study on bioactive constituents between wild and in vitro propagated Centella asiatica

Centella asiatica (Umbelliferae) has been used for centuries in Indian ayurvedic medicine for the treatment of a wide number of health disorders. The aim of this study was to estimate and compare the concentration of bioactive compounds between wild and in vitro propagated C. asiatica plants. A marked decrease in the total phenolic compounds, flavonoids, and ascorbic acid was observed between in vitro propagated and wild type plants collected from wet land habitat. The radical scavenging activity of the wild type plant extracts also varied with the habitats. This study clearly indicates that environmental factors play a crucial role in the plant metabolic activity and medicinal activity

Anticancer effects of pH- sensitive carvacrol zinc oxide quantum dots on DMBA induced mammary carcinoma in female sprague dawley rats

Objectives: The current research explores the anticancer effects of pH sensitive CVC-ZnO QDs (Carvacrol-loaded Zinc Oxide Quantum Dots) on DMBA induced mammary carcinoma in rats. Methods: Female SD rats were used, and mammary cancer was induced by chemical carcinogen via subcutaneous injection near the mammary gland. Different concentrations of CVC-ZnO QDs were orally supplemented to evaluate the optimum dose. We assessed the growth rate, body weight changes, tumor volume, tumor incidence and tumor burden in both the inducer and treatment groups. We also evaluated the biochemical parameters (antioxidant status, lipid peroxidation, detoxification enzymes, and lipid profile) and histopathological changes in the kidney and mammary tissues. Results: Our findings indicate that CVC-ZnO QDs treated rats significantly decreased the tumor weight, incidence, burden, lipid peroxidation levels, phase I detoxification enzyme activities and increased the body weight, phase II detoxification enzyme activities, and antioxidant status compared to the DMBA alone treated rats. CVC-ZnO QDs treatment also altered the lipid profile of plasma and mammary tissue. Furthermore, histopathological results confirmed that the CVC-ZnO QDs protect against DMBA-mediated damage to the mammary and kidney. Conclusion: The findings indicate that the CVC-ZnO QDs administered at 4 mg/kg b.w exhibited a significant anticancer effect against DMBA-induced mammary cancer

\u3ci\u3eMonascus\u3c/i\u3e pigment production by solid-state fermentation with corn cob substrate

Natural pigments are an important alternative to potentially harmful synthetic dyes. We investigated the feasibility of corn cob powder as a substrate for production of pigments by Monascus purpureus KACC 42430 in solid-state fermentation. A pigment yield of 25.42 OD Units/gram of dry fermented substrate was achieved with corn cob powder and optimized process parameters, including 60% (w/w) initial moisture content, incubation at 30°C, inoculation with 4 mL of spores/gram of dry substrate, and an incubation period of 7 days. Pigment yield using corn cobs greatly exceeded those of most other agricultural waste substrates. The pigments were stable at acidic pH, high temperatures, and in salt solutions; all important considerations for industrial applications. Our results indicate the viability of corn cob substrate in combination with M. purpureus for industrial applications