nanomaterials Article Efficient Copper Removal from an Aqueous Anvironment using a Novel and Hybrid Nanoadsorbent Based on Derived-Polyethyleneimine Linked to Silica Magnetic Nanocomposites Olivija Plohl 1,*, Matjaž Finšgar 2, Sašo Gyergyek 2,3, Urban Ajdnik 1, Irena Ban 2 and Lidija ...