Colocasia esculenta stem as novel biosorbent for potentially toxic metals removal from aqueous system

Environmental Science and Pollution Research - Biosorption is an ingenious technique that uses biological materials to acquire trace metal ions from wastewater. In the present study, the ability of...     

Nanotechnology in cosmetics: a boon or bane?

Recent advances in the field of nanotechnology enabled the manufacturing of elaborated nanometer-sized particles for various biomedical applications. The cosmetic industry is one of the most enthusiastic early adopters of nanotechnology which routinely uses nano-scale ingredients. However, in the absence of mandatory product labeling, it is difficult to estimate the number of cosmetics, sunscreens and personal care products containing nanoparticles that are now commercially available. The increased capacity of nanoparticles to penetrate skin and gain access to human cells is a double-edged sword as it may be useful for medical purposes, but might also result in far greater uptake of substances that exert adverse health effects. Since nanomaterials represent a large group of structurally, physically, and chemically variable substances, specific toxicological studies are required for each product prior to commercialization. This review aims to delineate the most investigated applications, risk and safety considerations, and regulation of nanotechnology in the field of cosmetics.     

The environmental impact of a chloro-alkali factory in a river basin in Eastern India

Summary It has been established that the electrodes of the dialyser in a chloro-alkali plant in Eastern India release mercury beyond the permissible limits into the River Koel. Mercury in elemental form, as well as certain organo-mercury compounds, including methyl mercury, have been detected at a distance of 25 km from the discharge point. Even at a distance of 5–10 km, the mercury content of the sediment may be as high as 0.6–3.2 mg kg^–1 above the value of sediment upstream of the plant. This sediment itself is contaminated, probably by battery and paint factories, etc., still further upstream. Thus, the chloro-alkali factory has contributed 60–320 times above the permissible limit (0.01 mg kg^–1) of mercury release, at a distance of 5–10 km from the point of release. Furthermore, various phytoplankton and zooplankton have been contaminated, leading to very high mercury contents in certain fish. This food chain, therefore, threatens man himself.Dr Sajalendu Nanda is currently a Research Associate at Bangur Institute of Neurology in Calcutta. He possesses an MSc in Environmental Biology and a PhD in Ecology. His address for correspondence is c/o Dr P.K. Tapaswi, Professor-in-Charge at the Biological Sciences Division of the Indian Statistical Institute.     

Biodegradable Soy-Based Plastics: Opportunities and Challenges

Today's plastics are designed with little consideration for their ultimate disposability or the effect of the resources (feedstocks) used in making them. This has resulted in mounting worldwide concerns over the environmental consequences of such materials when they enter the mainstream after their intended uses. This led to the concept of designing and engineering new biodegradable materials–materials that have the performance characteristics of today's materials but that undergo biodegradation along with other organic waste to soil humic materials. Hence, the production of biodegradable materials from annually renewable agricultural feedstocks has attracted attention in recent years. Agricultural materials such as starches and proteins are biodegradable and environmentally friendly. Soybean is a good candidate for manufacturing a large number of chemicals, including biodegradable plastics, as it is abundantly available and cheap. Soy protein concentrate, isolate, or flakes could be compounded with synthetic biodegradable plastics such as polycaprolactone or poly (lactic acid) to make molded products or edible films or shopping bags and make the environment cleaner and greener.     

Investigation of some basic water quality parameters of the north Bengal Terai river Kaljani--a tributary of river Torsa, and comparison thereof with the mainstream

Some physico-chemical parameters of Kaljani River were studied in and around Alipurduar municipality. The principal characteristics of Kaljani River are high TSS, Mg-hardness, COD, and Phosphate 'P' Comparison of water quality parameters of the two rivers demonstrated higher range of alkalinity, ammonia 'N' content and chloride content in Torsa than Kaljani. River Kaljani showed higher COD range than Torsa. Mean BOD value of both these rivers ranged between 0.93-1.65 mg/l. Overall TDS content of Kaljani was found to be lower than Torsa. Maximum phosphate 'P' content was observed at the downstream of both the rivers.     

Conversion of biomass into hydrogen by supercritical water gasification: a review

Environmental Chemistry Letters - The rising issues of global warming due to the rapid use of fossil fuels are calling for sustainable energies such as dihydrogen, thereafter named...     

Densification of waste biomass for manufacturing solid biofuel pellets: a review

Environmental Chemistry Letters - The demand for bioenergy is increasing due to the diminishing popularity of fossil fuels and rising greenhouse gas emissions. However, according to recent reports,...     

A convenient and eco-friendly way to synthesize Pt(II) and Pd(II) porphyrins in ionic liquids by microwave activation

Due to the slow rate of incorporation of inert-metal ions into free-base porphyrins compared to other transition metals, several methods have been proposed to accelerate the rate of metalation. However, these methods have disadvantages such as low yields, difficulties of purification of final products, and environmental effects. To avoid those disadvantages, we reacted Pt(II) and Pd(II) salts with H₂(TPP), H₂(TMPyP)⁴⁺, and their β-pyrrole derivatives, H₂(Br₈TPP) and H₂(Br₈TMPyP)⁴⁺, in 1-butyl-3-methylimidazolium bromide ([bmim]⁺Br⁻) under microwave irradiation. The combination of microwave heating and ionic liquids provides efficient thermal energy transfer among the porphyrins and metal salts. In addition, ionic liquids stabilize charged species as well as their intermediates, due to their high dipole moment and high boiling point. This not only shortens the reaction time but also gives high yields of products at relatively low temperatures, of about 100°C compared to conventional synthesis methods: 150°C for DMF, 190°C for DMSO. Here, we demonstrate that Pt(II)/Pt(II) metalloporphyrins are synthesized at high rates, e.g. 6–30 min for 100% metalation, with high yields of 79–93% in [bmim]⁺Br⁻ by microwave activation.     

Studies on the primary production in a river basin in eastern India

Measurement of the primary production has been estimated over a study area of approximately 25 km² of the North Koel River, in the Palamau District, in Bihar, India. A caustic chemical factory which is discharging effluent into the river is situated at Rehala, Palamau, on the bank of the North Koel. Huge amounts of mercury are released into the river. The physical and chemical characters of the caustic chemicals in the effluent have a significant influence on the primary production on the North Koel river. The gross production is compared with other fresh water habitats (riverine and other) in India. It is observed that the gross production value is the lowest (at 1.14 gc/m²/day) of any recorded riverine ecosystem in India.