Abstract: The present disclosure provides oxide nanotubes formed by anodizing and oxidatively-annealing a titanium or titanium allow substrate with or without ultrasonication. If desired, carbon nanotubes may be grown in the oxide nanotubes. The substrates show improved specific capacity and charge-discharge rates for use as an electrode in lithium-ion batteries.

Abstract: A method for removing a selected heavy metal ion from an aqueous solution is provided herein. Said method comprises contacting the solution with collophane at a pH effective for capture of the selected heavy metal ion by the collophane. Heavy metal ions include Sb.sup.2+, As.sup.3+, Cd.sup.2+, Cr.sup.3+, Co.sup.2+, Cu.sup.2+, Fe.sup.3+, Pb.sup.2+, Mn.sup.2+, Hg.sup.2 +, UO.sub.2.sup.2+ or Zn.sup.2+, preferably Fe.sup.3+, Pb.sup.2+, and Hg.sup.2+, As.sup.3+ and UO.sub.2.sup.2+. The process is pH-sensitive and selective removal of desired heavy metal ions may be achieved by varying pH and other conditions to favor removal of the desired ions and leave other heavy metal ions whose removal is inhibited under such conditions in solution.