Fig. 7From: Nanoscale zero-valent iron-impregnated agricultural waste as an effective biosorbent for the removal of heavy metal ions from wastewaterEffect of contact time for the removal of Ni(II) ions by NZVI-CNS. Nickel ions concentration = 25–150 mg/L, solution pH = 5.0, adsorbent dose = 2 g/L, volume of sample = 100 mL, contact time = 5–60 min, temperature 30 °CBack to article page