A new technology is under development to selectively recover regulated metal ions from electroplating rinse waters. The electroplating metal ions are recovered in a concentrated form with the appropriate counter ions ready for return to the original electroplating bath. The technology is based on the use of specially designed water-soluble polymers that selectively bind with the metal ions in the rinse bath. The polymers have such a large molecular weight that they can be physically separated using available ultrafiltration technology. The advantages of this technology are high metal selectivity with no sludge formation, rapid processing, low energy, low capital costs, and small size. We have tested and demonstrated the recovery of zinc and nickel (using a new alloy electroplating bath designed to replace cadmium) from rinse waters. The metal-ion concentrate was returned to the original electroplating bath. Impurity metals such as iron and copper were removed from the zinc/nickel concentrate and were not returned to the electroplating bath. Test panels were electroplated as a baseline and compared with new test panels electroplated after the addition of the recovered zinc and nickel. No adverse effects on the bath integrity were observed. The rinse water was depleted of the electroplating metals to less than 0.1 ppm zinc and nickel, and the water was satisfactory for discharge to the sewer system.

Polyethylenimine (PEI) was modified with ligands containing sulfur donors to give soluble polymers for binding toxic metal ions. Reaction of purified PEI with mercaptosuccinic anhydride, ethylene sulfide, or methylthiocyanate gave PEI-MSA (25% functionalization), PEI-ET (100% functionalization), and PEI-TU (25% functionalization), respectively. Purification of the polymers was accomplished by diafiltration. The capacities for toxic metal ions (Hg, Cd, and Pb) and transition metal ions (Cu and Ni) were measured for each of the polymers. PEI-ET and PEI-TU showed high affinity for the softer metal ions, Hg and Cd, with loading capacities substantially higher than those for the base polymer PEI. Both polymers had high capacities for Cu. Release of the metal ions from the polymers was accomplished by lowering pH; however, small amounts of metal remained bound to the polymers at pH 1. Competition studies showed that PEI-TU and PEI-ET bound Hg and Cu more strongly than Cd and Pb.

Three water-soluble polymers incorporating increasing levels of 2,3-dihydroxy propyl attached to polyethylenimine (PEI) backbone were synthesized, characterized by NMR, and investigated for their ability to bind boric acid (BA). B-11 NMR spectroscopy showed that BA interacted with the polymeric 2,3-dihydroxy propyls by forming borate monoester and borate diesters in the boron concentration range of 100-1000 ppm and at 0.0775M polymer. Borate monoester species predominated for low functionalization levels (33% of the PEI amines functionalized), whereas borate diester species dominated for the higher functionalized polymers (66-100% of the PEI amines functionalized). All three polymers showed that 100% of the BA was bound as a mixture of borate mono- and diesters at 100-ppm boron. The overall best performer based on total borate ester formation was the 2/3-PEI, with a binding K-d of 631 at 200 ppm boron. Borate ion concentration was measured from the B-11 NMR chemical shift of the BA/borate peak and it decreased as 1/3-PEI > 2/3-PEI > 3/3-PEI. Variable temperature B-11 NMR showed drastic reduction of borate ester species at 65 degrees C. Thus, PEI polymers, as the ones investigated in this work, are reasonable candidates for the selective recovery and recycle of BA. (c) 2006 Wiley Periodicals, Inc.

Multiwall carbon nanotubes (MWNTs) were synthesized using chemical evaporation deposition (CVD). The morphology and microstructure of MWNTs were observed via HRTEM. The multiwall carbon nanotubes are entangled to bundles with a diameter of several tens of nanometers. Electrochemical properties of MWNTs were examined via a variety of electrochemical testing techniques. The MWNTs electrode demonstrated a reversible lithium storage capacity of 340 mAh/g with good cyclability at moderate current density. The kinetic properties of lithium insertion in MWNTs electrodes were characterized via ac impedance measurements. It was found that the lithium diffusion coefficient DLi decreases with an increase of Li-ion concentration in MWNTs electrodes.

A 13-year-old boy developed widespread osteoblastic bone metastases, with dissemination throughout the neuraxis, 1 year following treatment of a differentiated (Kernohan and Sayre grade II) astrocytoma of the left parietal cortex. This unusual clinical picture and the possible route of tumour dissemination are discussed.

We have developed a process for dissolving and removing elemental and ionic forms of mercury from solid surfaces. The process uses water-soluble chelating polymers (WSCP) that have been designed for mercury-ion selectivity and performance in the presence of dilute acid and mild oxidant. After a solution of the polymer is used to selectively leach the solids (e.g., mixed waste debris) and assist in the oxidation of elemental mercury, Hg(0), to ionic mercury, Hg(II), the resulting aqueous wash and rinse phases are treated by ultrafiltration with commercially available membranes to concentrate the mercury-polymer complex. The metal ion concentrate is released from the WSCP by adjusting the chemistry of the system, and the polymer and the original permeate waters are recycled for further debris-leaching, greatly reducing secondary wastes. The mercury concentrate is precipitated as the stable sulfide (HgS) for solid waste management.