Adsorption of Fe2+ and Zn2+ ions from landfill leachate by natural bentonite from Kriva Palanka (B-KP), Republic of Macedonia - B. Bliznakovska, K. Atkovska, G. Ruseska, S. Bogoevski, B. Boskovski, P. Makreski, A. Grozdanov (My University, 2014)