Adsorption of heavy metal ions in ternary systems onto Fe(OH)3

The adsorption behavior of amorphous Fe(OH)₃ has been studied in multicomponent metal system. The metal ions uptake in the ternary system is lower than in the single system, suggesting that certain sites on the surface of the solid are blocked due to competition. The selectivity trend in the ternary system is observed to be Ni²⁺>Zn²⁺>Cd²⁺ which is, however, lost with increase in the temperature of the aqueous solution. Further, the observed selectivity trend is neither related to electronegativity of the metal ions nor to the pH of the hydrolysis, but has been found dependent on charge to radius ratio. The metal ions adsorption is found to increase with pH, while the converse is true with the rise in temperature. The uptake of metal ions data has been interpreted in terms of stoichiometry, binding constants and adsorption capacities. The negative values of ΔG show that uptake of metal ions is favored at lower temperatures, indicating that the adsorption mechanism essentially remains ion exchange in nature.     

An investigation on the influence of filler loading and compatibilizer on the properties of polypropylene/marble sludge composites

In this article, polypropylene reinforced marble sludge (PP/MS) was prepared, and the effects of MS loading and polypropylene-g-maliec anhydride (PP-g-MAH) as compatibilizer on density, melt flow index (MFI), and mechanical properties of PP/MS composite were investigated. Our studies show that tensile strength, flexural strength and tensile modulus increased with increasing the MS loading but tensile strength increased till 30 pph of MS further addition of MS in PP composites decreased the strength. The % elongation at break and Izod Impact Strength decreased with increasing of MS loading. Studies revealed that PP/MS composites containing PP-g-MAH enhance the properties compared to without compatibilizer.     

HALL EFFECTS ON UNSTEADY FLOW DUE TO NON-COAXIALLY ROTATING DISK AND A FLUID AT INFINITY

An investigation is made on the unsteady magnetohydrodynamic (MHD) flow caused by the non-coaxial rotation of a disk and a fluid at infinity being permeated by a transverse magnetic field. The disk is porous and nonconducting and executes oscillations in its own plane. The Laplace transform method is used to obtain the exact solution of the velocity field. The structure of the steady and unsteady flow fields is investigated. It is shown that the ultimate steady-state blowing solution is established in the presence of Hall current also for resonant frequency, which was not possible in the hydrodynamic case. The combined effects of Hall current, rotation, and suction or blowing are examined. The physical significance of mathematical results is given with various limiting cases.     

Efficient elimination of environmental pollutants through sorption-reduction and photocatalytic degradation using nanomaterials

With the rapid development of industrial, large amounts of different inorganic and organic pollutants are released into the natural environments. The efficient elimination of environmental pollutants, i.e., photocatalytic degradation of persistent organic pollutants into nontoxic organic/inorganic chemicals, in-situ solidification or sorption-reduction of heavy metal ions, is crucial to protect the environment. Nanomaterials with large surface area, active sites and abundant functional groups could form strong surface complexes with different kinds of pollutants and thereby could efficiently eliminate the pollutants from the aqueous solutions. In this review, we mainly focused on the recent works about the synthesis of nanomaterials and their applications in the efficient elimination of different organic and inorganic pollutants from wastewater and discussed the interaction mechanism from batch experimental results, the advanced spectroscopy techniques and theoretical calculations. The adsorption and the photocatalytic reduction of organic pollutants and the sorption/reduction of heavy metal ions are generally considered as the main methods to decrease the concentration of pollutants in the natural environment. This review highlights a new way for the real applications of novel nanomaterials in environmental pollution management, especially for the undergraduate students to understand the recent works in the elimination of different kinds of inorganic and organic chemicals in the natural environmental pollution management.     

Functional expression in insect cells, one-step purification and characterization of a recombinant phospholipase D from cowpea (Vigna unguiculata L. Walp)

Phospholipase D (PLD) is an important enzyme involved in signaltransduction, vesicle trafficking and membrane metabolism. Inthis study, large amounts of a recombinant plant PLD were secretedinto the culture medium of baculovirus-infected insect cellsand purified to homogeneity in the form of a fully active enzyme.The transient production of recombinant PLD yielded a protein(rPLDa, 88 kDa) together with a shorter form (rPLDb, 87 kDa),which accumulated in the medium. N-Terminal amino acid sequencingof the rPLDa and rPLDb showed that rPLDb resulted from proteolyticcleavage at Gly8–Ile9. Immunoblotting showed that bothrPLDa and rPLDb are recognized by a polyclonal antibody previouslyraised against native soybean PLD. One-step calcium-dependentoctyl-Sepharose chromatography was used to obtain the two highlypurified forms of rPLD, as attested by gel electrophoresis,N-terminal amino acid sequence and mass spectrometry. The N-terminalregion of PLD is homologous with the C2 domains which are presentin a number of enzymes known to be involved in signal transductionand/or phospholipid metabolism. The truncated rPLDb lacks thefirst acidic amino acid in its N-terminus, which is probablyinvolved in the calcium binding site. The rPLDb was thus easilyeluted from the octyl-Sepharose column by decreasing the calciumconcentration of the buffer from 50 to 30 mM, whereas, the rPLDawas eluted after chelating calcium ions with EDTA. The purifiedrPLD yield reached a level of 10 mg per liter of serum-freeculture medium. The availability of baculovirus-derived rPLDconstitutes a valuable source of enzyme for future crystallographicstudies to determine its three-dimensional structure.