In this review the phenomenon of proton conductivity in materials and the elements of proton conduction mechanismsproton transfer, structural reorganization and diffusional motion of extended moietiesare discussed with special emphasis on proton chemistry. This is characterized by a strong proton localization within the valence electron density of electronegative species (e.g., oxygen, nitrogen) and self-localization effects due to solvent interactions which allows for significant proton diffusivities only when assisted by the dynamics of the proton environment in Grotthuss and vehicle type mechanisms. In systems with high proton density, proton/proton interactions lead to proton ordering below first-order phase transition rather than to coherent proton transfers along extended hydrogen-bond chains as is frequently suggested in textbooks of physical chemistry. There is no indication for significant proton tunneling in fast proton conduction phenomena for which almost barrierless proton transfer is suggest...

Proton Conductivity: Materials and Applications

Effective removal of Cu (II) ions from aqueous solution by amino-functionalized magnetic nanoparticles.

Study on the adsorption of Cu(II) by EDTA functionalized Fe3O4 magnetic nano-particles

Biosorption of copper(II) by immobilizing Saccharomyces cerevisiae on the surface of chitosan-coated magnetic nanoparticles from aqueous solution.

Fresh water accounts for 3% of water resources on the Earth. Human and industrial activities produce and discharge wastes containing heavy metals into the water resources making them unavailable and threatening human health and the ecosystem. Conventional methods for the removal of metal ions such as chemical precipitation and membrane filtration are extremely expensive when treating large amounts of water, inefficient at low concentrations of metal (incomplete metal removal) and generate large quantities of sludge and other toxic products that require careful disposal. Biosorption and bioaccumulation are ecofriendly alternatives. These alternative methods have advantages over conventional methods. Abundant natural materials like microbial biomass, agro-wastes, and industrial byproducts have been suggested as potential biosorbents for heavy metal removal due to the presence of metal-binding functional groups. Biosorption is influenced by various process parameters such as pH, temperature, initial concentration of the metal ions, biosorbent dose, and speed of agitation. Also, the biomass can be modified by physical and chemical treatment before use. The process can be made economical by regenerating and reusing the biosorbent after removing the heavy metals. Various bioreactors can be used in biosorption for the removal of metal ions from large volumes of water or effluents. The recent developments and the future scope for biosorption as a wastewater treatment option are discussed.

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Application of Biosorption for Removal of Heavy Metals from Wastewater

Efficacy of the soil amendments cereal straw (CS) and fresh cow dung (FCD) in reducing fipronil residues in soil, groundwater and rice crop under the sub-tropical field conditions is reported. The fipronil 0.3 G was applied at the rate of 25g a.i.ha−1 and its residues were analysed using HPLC. Although both the amendments were helpful in reducing leaching of fipronil to groundwater as compared to the control, FCD was more effective with lesser leaching of the pesticide. The residues of the pesticide were detected in soil, water and straw but were within the recommended limits (MRL: 0.01 to 0.2 μg g−1 in different commodities). In rice grains, the level of fipronil residues was below detection limit (<0.002 μg g−1).

Potential of Soil Amendments in Reducing Fipronil Residues in Soil, Ground Water and Rice Crop under Sub-tropical Field Conditions

Diluted magnetic semiconductors (DMSs), having interesting magnetic/transport properties, are currently being explored in photocatalytic application as well. This report presents photocatalytic and low temperature magnetic/transport study of chemically synthesized 3-5 nm sized cubic Zn1-xCuxS (0 ≤ x ≤ 0.04) DMS nanoparticles. Both studies have their own importance, former relates to dye degradation, while later attempts to understand origin of magnetic behavior in DMSs (which is still debatable). As a photocatalyst, Cu doped ZnS NPs showed enhanced degradation-efficiency for methylene blue dye. Magnetization study showed enhanced magnetic moment in Cu doped samples, which in the low temperature regime got further enhanced and was understood due to defect induced ferromagnetism. Low temperature transport study showed the decrease in resistivity of the Cu doped samples and was understood in terms of defects states created due to doping of the Cu ions and governed by conduction mechanism, namely thermal activation and variable range hopping.

Enhanced Photocatalytic Activity and Low Temperature Magnetic/Transport Study of Cu-Doped ZnS-Based Diluted Magnetic Semiconductor Nanoparticles

Environmental contamination by heavy metals is a serious problem throughout the world. Heavy metals are non-biodegradable and persistent and can be differentially toxic to microbes, plants, animals, and humans. Remediation techniques for heavy metal-contaminated soils are based on the extraction or an in-situ stabilization of contaminants. The extraction is generally carried out either ex situ or in situ by using some plants. Phytoextraction of metals can be enhanced by using some amendments. The “in situ” stabilization techniques are less expensive and achieved by using some organic or inorganic amendments. Soils can naturally reduce mobility and bioavailability of heavy metals, as they are retained in soil through sorption, precipitation, and complexation reactions. This natural attenuation process (natural remediation) can be accelerated by the addition of amendments. It is important to apply suitable remedial technologies to reduce the risk of metal contamination in polluted soil. This chapter focuses on the various amendments for heavy metal remediation either through mobilization or immobilization metals in polluted soil. A short overview of the sources of metal contaminations in soil and effect of metal contamination are also presented herein. Post remediation effects of amendments on soil properties have been also discussed in this chapter.

Amendments for Heavy Metal Remediation in Contaminated Soil

Radiation Effects and Defects in Solids: Incorporating Plasma Science and Plasma Technology

GaAs/AlGaAs heterostructure based pHEMT material and fabricated pHEMT devices characteristics were studied with Ni ions irradiation at different fluences. The structural, electrical and optical characteristics were compared before and after irradiation. The structural property of the material was found unchanged while optical and electrical deterioration was observed for used fluences.

P. C. Srivastava

Papers

Potential of Soil Amendments in Reducing Fipronil Residues in Soil, Ground Water and Rice Crop under Sub-tropical Field Conditions

Enhanced Photocatalytic Activity and Low Temperature Magnetic/Transport Study of Cu-Doped ZnS-Based Diluted Magnetic Semiconductor Nanoparticles

Amendments for Heavy Metal Remediation in Contaminated Soil

Radiation Effects and Defects in Solids: Incorporating Plasma Science and Plasma Technology

Effect of Ni Ions Irradiation on GaAs pHEMT Materials and Devices