Mathematical Modelling and Optimization for Facile Synthesis of Structured Activated Carbon (ACs) from Adansonia kilima (Baobab) Wood Chips Integrating Microwave-Assisted Pyrolysis for the Elimination of Lead (II) Cations from Wastewater Effluents

Santhana Sellamuthu; Zaira Zaman Chowdhury; Khalisanni Khalid; Shahjalal Mohd Shibly; Md Mahfujur Rahman; Masud Rana; Irfan Anjum Badruddin; H M T Khaleed; Sarfaraz Kamangar; Mohd Rafie Bin Johan; Mohamed Hussein; Ajita Mitra; Abu Nasser Faisal

doi:10.3390/molecules28186640

Mathematical Modelling and Optimization for Facile Synthesis of Structured Activated Carbon (ACs) from Adansonia kilima (Baobab) Wood Chips Integrating Microwave-Assisted Pyrolysis for the Elimination of Lead (II) Cations from Wastewater Effluents

Molecules. 2023 Sep 15;28(18):6640. doi: 10.3390/molecules28186640.

Affiliations

¹ Nanotechnology and Catalysis Research Center, University of Malaya, Kuala Lumpur 50603, Malaysia.
² Malaysian Agricultural Research & Development Institute (MARDI), Serdang 43000, Malaysia.
³ Institute of Halal Management, Islamic Business School, Universiti Utara Malaysia, Kedah 06010, Malaysia.
⁴ Department of Civil Engineering, World University of Bangladesh, Dhaka 1230, Bangladesh.
⁵ Department of Mechanical Engineering, College of Engineering, King Khalid University, P.O. Box 394, Abha 61421, Saudi Arabia.
⁶ Department of Mechanical Engineering, Faculty of Engineering, Islamic University, Madinah Munawwarra 42351, Saudi Arabia.
⁷ Department of Chiemistry, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia.

Abstract

In this research, activated carbon (AC) was synthesized from ligno-cellulosic residues of Adansonia kilima (Baobab) wood chips (AKTW) using two-step semi-carbonization and subsequent pyrolysis using microwave-induced heating (MWP) in the presence of a mild activating agent of K₂CO₃. The influence of process input variables of microwave power (x₁), residence time (y₁), and amount of K₂CO₃ (z₁) were analysed to yield superior quality carbon having maximum removal efficiencies (R₁) for lead (II) cations from waste effluents, fixed carbon percentages (R₂), and carbon yield percentages (R₃). Analysis of variance (ANOVA) was used to develop relevant mathematical models, with an appropriate statistical assessment of errors. Level factorial response surface methodology (RSM) relying on the Box-Behnken design (BBD) was implemented for the experimental design. The surface area and porous texture of the samples were determined using Brunauer, Emmett, and Teller (BET) adsorption/desorption curves based on the N₂ isotherm. Surface morphological structure was observed using field emission scanning electron microscopic (FESEM) analysis. Thermogravimetric analysis (TGA) was carried out to observe the thermal stability of the sample. Change in the carbon content of the samples was determined using ultimate analysis. X-ray diffraction (XRD) analysis was performed to observe the crystalline and amorphous texture of the samples. The retention of a higher proportion of fixed carbon (80.01%) ensures that the synthesized adsorbent (AKTWAC) will have a greater adsorption capacity while avoiding unwanted catalytic activity for our synthesized final sample.

Keywords: Box–Behnken design (BBD); activated carbon (AC); conventional pyrolysis; lead (II) cations (Pb+2); ligno-cellulosic biomass; microwave-assisted pyrolysis (MWP); optimization and analysis of variance (ANOVA); response surface methodology (RSM).

Grants and funding

The authors are thankful for the funding provided by ST-077-2022 and IIRG003A-2022IISS under the University of Malaya, Kuala Lumpur 50603, Malaysia. The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for funding this work through the large group project under grant number R.G.P 2/36/44. The authors would like to acknowledge Doctors Feed Ltd., Bangladesh, and Universiti Utara Malaysia, research opportunity with grant number RI 10010030/SO 21153 for their support in this work.