Adsorption of phenol and nitrophenols by carbon nanospheres: Effect of pH and ionic strength - Lazo-Cannata, Jose C; Nieto-Marquez, Antonio; Jacoby, Andres; Paredes-Doig, Ana L; Romero, Amaya; Sun-Kou, Maria R; Luis Valverde, Jose (Separation And Purification Technology, 2011)