An apparatus providing for metal ion/nitrate entrapment comprises a chemically activated, microfiltration, composite polymer and silica-based membrane including a polyamino acid attached thereto through reaction of a terminal amine group of the polyamino acid with the membrane. A method for preparing...http://www.google.com.au/patents/US6306301?utm_source=gb-gplus-sharePatent US6306301 - Silica-based membrane sorbent for heavy metal sequestration
