Fig. 4

Effect of operating conditions on % decolourisation of RB-21 on MMCC. (a) Effect of pH (Initial concentration-100 mg L^− 1, Adsorbent doage-0.2 g, Contact time-60 min, Agitation rate-200 rpm, Volume-50 mL). (b) Influence of initial pH and final pH of point of zero charge (pH_zpc) of MMCC. (c) Effect of initial dye concentration and contact time (pH-2, Adsorbent doage-0.2 g, Contact time-60 min, Agitation rate-200 rpm, Volume-50 mL). (d) Effect of adsorbent dose (Initial concentration-100 mg L^− 1, pH-2, Contact time-60 min, Agitation rate-200 rpm, Volume-50 mL). (e) Reusability study of adsorbent (pH-2, Adsorbent dosage-0.25 g, Dye concentration-100 mg L^− 1, Contact time-50 min, Agitation rate-200 rpm, Volume-50 mL). (f) Effect of temperature (Initial concentration-100 mg L^− 1, Adsorbent doage-0.25 g, Contact time-60 min, Agitation rate-200 rpm, Volume-50 mL)