Graphene based adsorbents for remediation of noxious pollutants from wastewater.

The contamination of water resources with noxious pollutants is a serious issue. Many aquatic systems are contaminated with different toxic inorganic and organic species; coming to wastewater from various anthropogenic sources such as industries, agriculture, mining, and domestic households. Keeping in view of this, wastewater treatment appears to the main environmental challenge. Adsorption is one of the most efficient techniques for removing all most all types of pollutants i.e. inorganics and organics. Nowadays, graphene and its composite materials are gaining importance as nano adsorbents. Graphene; a two-dimensional nanomaterial having single-atom graphite layer; has attracted a great interest in many application areas (including wastewater treatment) due to its unique physico-chemical properties. The present paper is focused on the remediation of noxious wastes from wastewater using graphene based materials as adsorbents, and it contains all the details on materials - i.e., from their synthesis to application in the field of wastewater treatment (removal of hazardous contaminants of different chemical nature - heavy and rare-earth metal ions, and organic compounds - from wastewater effluents. The efficiency of the adsorption and desorption of these substances is considered. Certainly, this article will be useful for nano environmentalist to design future experiments for water treatment.

Stereoselective uptake and degradation of (±)-o,p-DDD pesticide stereomers in water-sediment system.

The environmental stereoselective uptake and degradation of (±)-o,p-DDD pesticide stereomers in water-sediment system are described. The results were analyzed by artificial neural network model. The optimized experimental parameters were concentration of o,p-DDD streamers (7.0 µg L-1 ), experimental time (60 min), pH (6), dose (5.0 g L-1 ), and temperature (25°C). The maximum uptake and degradation were 87% and 85% and 33.0% and 30.5% for (-)- and (+)-stereomers of o,p-DDD in 15-day time. Both uptake and degraded phenomenon showed first-order rate reaction. Thermodynamic variables indicated exothermic nature of uptake and degradation processes. The uptake and degradation were slightly higher for (-)-stereomer than (+)-stereomer of o,p-DDD. It was assumed that both uptake and degradation processes are accountable for the removal of the streomers of o,p-DDD from earth's ecosystem, but the uptake is responsible for major contribution. The magnitudes of relative errors obtained by artificial neural network model were in the range of ±0.2 to 3.5, indicating good applicability of the experimental data. The results are very useful to control the environmental contamination due to the chiral o,p-DDD pesticide as its two enantiomers have different ecological toxicities.

Chemical chiral pollution: Impact on the society and science and need of the regulations in the 21st century.

The chiral pollution is a serious issue for our health and environment due to the enantio-selective biodegradation of the chiral pollutants. It has adverse impact on our society and science. There is a big loss of our economy due to the use of racemic agrochemicals. The most notorious chiral pollutants are pesticides, polychloro biphenyls, polyaromatic hydrocarbons, brominated flame retardants, drugs, and pharmaceuticals. More than 1500 chiral pollutants are present in the environment. Unfortunately, there is no regulation and control of the chiral pollutants. Therefore, it is an urgent need of the present 21st century to develop a data bank on the chiral pollutants, guidelines for controlling the production, sale and use of the racemic agrochemicals and the other industrial products. The Governments of the different countries should come forward to initiate the regulations. US, FDA, US EPA, and WHO are the most important regulatory authorities and should think about the chiral pollutants. The present article highlights the impact of the chiral pollution on the society and science. Besides, the efforts have also been made to emphasize the need of the regulations to control the chiral pollution.