Speaker
Description
Single step semi-carbonization was carried out in a fixed bed reactor at different temperature under nitrogen (N2) gas flow using rambutan leaves (RL) as starting precursors. The semi-carbonized char (RLWC) was impregnated using KOH at different ratio using Plackett-Burman Design (PBD). RLWC was activated by changing the conditions of activation temperature, ramping of temperature, time, gas flow rate followed by ball milling process to ensure reduced particle sizes of carbon for better removal efficiencies. As synthesized RLAC was used to remove Malachite Green (MG) in presence of lead (II) cationic solution where the ionic strength of the solution was varied using NaCl. The final RLAC was characterised to observe its removal efficiency for MG in a single and multicomponent system. PBD design will exclude the insignificant factors. The significant factors suggested by PBD design was used to optimize the removal percentages of MG in single and multi-solute system. In a single solute system, the process kinetics and isotherm parameters were evaluated. The results revealed that, the optimum conditions to obtain highest removal percentages were associated with BET surface area and pore size distribution which were dependent on the physio-chemical properties of the starting materials under analysis. The results showed significant improvement in the surface area and pore size distribution characteristics of the semi-carbonized char after activation process. Adsorption data were fitted with Langmuir, Freundlich and Temkin isotherm models for MG dye in single solute system. Thermodynamics characterization was carried out to determine the magnitude of Gibb’s Free Energy, enthalpy and entropy of adsorptive removal process. Competitive sorption process between MG and Pb(II) was evaluated in terms of Langmuir monolayer adsorption capacity.
Keywords: Malachite Green (MG), Lead (Pb-II), Response surface methodology (RSM), Kinetics, Isotherm
