Impact of density of coating agent on antibacterial activity of silver nanoparticle impregnated plasma treated activated carbon

To use stabilized nanoparticles(NPs) in water as disinfectants over a very long period, the amount of coating agent(for NP stabilization) needs to be optimized. To this end, silver nanoparticles(Ag-NPs) with two different coating densities of tri-sodium citrate(12.05 and46.17 molecules/nm~2, respectively), yet of very similar particle size(29 and 27 nm, respectively)were synthesized. Both sets of citrate capped NPs were then separately impregnated on plasma treated activated carbon(AC), with similar Ag loading of 0.8 and 0.82 wt.%, respectively. On passing contaminated water(containing 10~4 CFU Escherichia coli/m L of water) through a continuous flow-column packed with Ag/AC, zero cell concentration was achieved in 22 and 39 min, with Ag-NPs(impregnated on AC, named as Ag/AC) having lower and higher coating density, respectively. Therefore, even on ensuring similar Ag-NP size and loading, there is a significant difference in antibacterial performance based on citrate coating density in Ag/AC.This is observed in lower coating density case, due to both:(i) higher Ag~+ ion release from Ag-NP and(ii) stronger binding of individual Ag-NPs on AC. The latter ensures that, Ag-NP does not detach from the AC surface for a long duration. TGA-DSC shows that Ag-NPs with a low coating density bind to AC with 4.55 times higher adsorption energy, compared to Ag/AC with a high coating density, implying stronger binding. Therefore, coating density is an important parameter for achieving higher antibacterial efficacy, translating into a faster decontamination rate in experiments, over a long period of flow-column operation.     

The energy-environment nexus: aerosol science and technology enabling solutions

Energy issues are important and consumption is slated to increase across the globe in the future. The energy-environment nexus is very important as strategies to meet future energy demand are developed. To ensure sustainable growth and development, it is essential that energy production is environmentally benign. There are two temporal issues—one that is immediate, and needs to address the environmental compliance of energy generation from fossil fuel sources; and second that is the need to develop newer alternate and more sustainable approaches in the future. Aerosol science and technology is an enabling discipline that addresses the energy issue over both these time scales. The paper is a review of aspects of aerosol science and engineering that helps address carbon neutrality of fossil fuels. Advanced materials to meet these challenges are discussed. Future approaches to effective harvesting of sunlight that are enabled by aerosol studies are discussed.     

Monitoring of soil biochemical quality parameters under greenhouse spinach cultivation through animal waste recycling

Under the intensive agricultural system, direct application of animal slurries to soils can provide a sustainable disposal of these wastes by inducing positive changes in soil quality and fertility. However, how animal wastes quantitatively affect the key nutrients (C, N, P and S) transforming soil enzymes is not clearly known. A greenhouse spinach cultivation study demonstrated that pig slurry, either in raw (RS) or processed (aerobically aged) (PS) form, significantly (p?β-glucosidase (23–39%), urease (59–103%), nitrate reductase (73–103%) and dehydrogenase (27–72%)) and microbial growth in soil as compared to the unamended control. However, it did not significantly (p?>?.05) alter the aryl sulphatase enzyme activity. Slurry applications also significantly improved the macro (N, P and K) and micronutrients (Cu, Mn, Zn and Fe) uptake by spinach plant and hence the yield (2.9–3.38 times higher than control). Similarly, compared to chemical fertilisers the application of pig slurries improved soil biological and biochemical parameters as well as plant nutrients uptake. This study demonstrated the closing of global energy and nutrient cycles through land application of animal wastes without compromising the crop yield.     

Prioritising development planning in the Indian semi-arid Deccan using sustainable livelihood security index approach

This paper presents the status of sustainable livelihood security index (SLSI) of Karnataka, the most drought prone state in the Southern part of India. Computation of ecological security index, economic efficiency index and social equity index, and finally SLSI were carried out at the district level for the entire state, using empirical data. The selected indicators were first normalised, and then using estimated weights, indices were computed. The results indicate that the state has a very low SLSI with only 27.6% of total geographical area (TGA) and 21.7% of population being placed in the ‘sustainable’ and ‘highly sustainable’ categories (covering 10 districts) while only 34% of the TGA covering six districts falls in the ‘moderately sustainable’ category. The remaining area, confined mostly to the northern parts of the state, comprising 14 districts (51.8% of the state’s TGA) is categorised as ‘less sustainable’ and ‘very less sustainable’ exposing 44.4% (27.14 million) of state’s population to the perils of uncertain rainfall, high soil erosion rates, high social inequality and poor resource use efficiency. There is an urgent need to reorient development programmes and prioritise development investments in these vulnerable districts so that they are provided resources and opportunities to improve their ecological (more forest cover and less soil erosion), economic (higher agricultural productivity) and social (improved health and education facilities and rural infrastructure) status and achieve sustainable levels of livelihood.     

An experimental study of soil conservation using herbaceous plants in Majuli Island, Assam, India

A model experiment on soil conservation utilising the plantation of certain herbaceous plants in a selected stretch of Majuli, the largest riverine island in the world, was carried out. The plantation followed work to establish the proper inclination for the river bank. The soil erosion in the experimental site was reduced to only about 2% compared with about 15–20% in the previous years. All the four species selected for the present study had excellent soil binding capacity and were thus helpful in stabilizing the highly vulnerable soil in the flood plain areas of the region.     

Clays and modified clays in remediating environmental pollutants

Environmental Science and Pollution Research -     

Problems of livestock development in the Himalayan region

Summary This paper outlines the complexities and problems of animal husbandry in the Himalayas of India. In particular, the climatic influences of temperature, rainfall and humidity are emphasised. A wide range of possible improvements to decrease livestock malnutrition and mortality are proposed.Dr J.C. Biswas, BSc, MVSc, works in the Animal Genetics and Breeding Laboratory; Dr R. Somvanshi, MVSc, FRCVS (Sweden) is Veterinary Pathologist in charge of the Clinical Pathology and Medicine Section in Livestock Production Research and Lt.Col. Dr G.S.C. Ranga Rao, MVSc, is Veterinary Parasitologist and Joint Director. All three work at the Indian Veterinary Research Institute.     

Municipal landfill leachate treatment for metal removal using water hyacinth in a floating aquatic system.

Experiments were carried out to investigate the ability of water hyacinth (Eichhornia crassipes) to remove five heavy metals (cadmium, chromium, copper, nickel, and lead) commonly found in leachate. All experiments were conducted in batch reactors in a greenhouse. It was found that living biomass of water hyacinth was a good accumulator for copper, chromium, and cadmium. The plants accumulated copper, chromium, and cadmium up to 0.96, 0.83, and 0.50%, respectively, of their dry root mass. However, lead and nickel were poorly accumulated in water hyacinth. Also, nonliving biomass of water hyacinth dry roots showed ability to accumulate all metals, except Cr(VI), which was added in anionic form. The highest total metal sorption by nonliving dry water hyacinth roots was found to take place at pH 6.4. The current research demonstrates the potential of using water hyacinth for the treatment of landfill leachate containing heavy metals.     

Social perceptions of the impacts of Colombo water supply projects

The complexity of development activities, in which the interactions between various forces often mean that outcomes are unpredictable and unanticipated, highlights the importance of objective and comprehensive evaluations. In the specific case of the evaluation of towns east and south of Colombo water supply projects, the findings have major implications for the implementation of the Millennium Development Goals, if the water-related objectives are to be fulfilled. The study found that 30% of the households of these towns that are receiving clean, piped water are not using it for drinking. Instead, they are continuing to drink contaminated well water. Whereas it is considered that the main beneficiaries of water supply projects have been women and people who are sick, elderly, or disabled, the general perception is that the health conditions of the families have not improved with the provision of clean water (in fact, many claim that their health conditions have deteriorated). In spite of the higher cost of the supplied water, people are willing to pay for it as long as the supply is reliable.